NOAATRNMFSCIRC-388

A UNITED STATES DEPARTMENT OF COMMERCE PUBLICATION NOAA Technical Report NMFS CIRC-388

/.v \ S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Marine Fisheries Service

Proceedings of the First U.S.-Japan Meeting on Aquaculture at Tokyo, Japan October 18-19, 1971

Under fhe Aquaculture Panel, U.S.-Japan Cooperafive Program in Natural Resources (UJNR)

Panel Chairmen:

WILLIAM N. SHAW - United States

ATSUCHI FURUKAWA - Japan

SEATTLE. WA February 1974 J NOAA TECHNICAL REPORTS

National Marine Fisheries Service, Circulars

The ma^r rMponsibilities of the National Manne Fisheries Service iNMFS) are to monitor and assess the abundance and K^oKraphic distribution of fisherv resources, to

understand and predict fluctuations in the quantity and distribution of these resources, and to establish levels for optimum use of the resources. NMFS is also charged with the development and implementation of policies for manaRing national Tishing K^ounda. development and enforcement of domestic ftshenes regulations, surveillance of foreign fishing off United States coastal waters, and the development and enforcement of international fishery agreements and policies- NMFS also assists the fishing industr>' through marketing service and economic analysis programs, and mortgage insurance and vessel construction subsidies. It collects, analyzes, and publishes statistics on various phases of the indu8tr>'

The NOAA Technical Report NMFS CIRC senes continues a series that has been in existence since 1941, The Circulars are technical publications of general mteresi in- tended to aid conservation and management. Publications that review in considerable detail and at a high technical level certain broad areas of research appear in this aeries. Technical papers originating in economics studies and from management investigations appear in the Circular series. NOAA Technical Reports NMFS CIRC are available free in limited numbers to governmental agencies, both Federal and State. They are also available in exchange for other scientific and technical publications in the marine sciences. Individual copies may be obtained (unless otherwise noted) from D83. Technical Information Division. Environ- mental Science Information Center. NOAA. Washington. D.C. 20235. Recent Circulars are:

315. Synopsis of biological data on the chum salmon, Oncorhynchus keta (Walbaum) 347. Synopsis of biological data on Pacific perch, Setxutodes alutus By Richard

1792. By Richard G. Bakkala March 1970. iii + 89 pp.. 15 figs., 51 tables. L. Major and Herbert H Shippen December 1970. iii -f 38 pp., 31 figs., 11 tables.

319. Bureau of Commercial Fisheries Great Lakes Fishery Laboratory, Ann Arbor. 349. Use of abstracts and summaries as communication devices in technical articles. By

Michigan. By Bureau of Commercial Fisheries. March 1970, 8 pp., 7 figs. F. Bruce Sanford. February 1971, iii + 11 pp., 1 fig.

330. EASTROPAC Atlas: Vols. 1-7. CaUlog No. I 49.4:330/(vol.> 11 vols. Available from 350. Research in fiscal year 1969 at the Bureau of Commercial Fisheries Bioloincal

the Superintendent of Documents. U.S. Government Printing Office, Washington, D.C. Laborator.-. Beaufort, N.C. By the Laborator>- staff November 1970. ii + 49 pp.. 21 figs.. 20402. 17 tables.

331. Guidelines for the processing of hot-smoked chub. By H. L. Seagran. J. T. 351. Bureau of Commercial Fisheries Exploratory Fishing and Gear Research Base. Graikoski. and J. A. Emerson. January 1970, iv + 23 pp., 8 figs., 2 tables. Pascagoula. Mississippi. July 1, 1967 to June 30, 1969. By Harvey R. Bullis. Jr.. and John R. Thompson, November 1970. iv + 29 pp.. 29 figs.. 1 ubie

332. Pacific hake. (12 articles by 20 authors.) March 1970. iii + 152 pp.. 72 figs.. 47 ubies. 352. Upstream passage of anadromous fish through navigation locks and use of the stream for spawning and nurser>- habitat. Cape Fear River. N.C. 1962-66. By Paul R. Nichols and Darrell E. Louder. October 1970. iv + 12 9 figs.. 4 tables. 333, Recommended practices for vessel sanitation and fish handling. By Edgar W. Bow- pp.. man and Alfred Larsen. March 1970. iv + 27 pp., 6 figs. 356. Floating laboratory for study of aquatic organisms and their environment. By

George R. Snyder, Theodore H. Robert J. McConnell. May 1971, iii -t- 16 335. Progress report of the Bureau of Commercial Fisheries Center for Estuarine and Blahm. and pp.. 11 figs. Menhaden Research, Pesticide Field Station. Gulf Breeze. Fla.. fiscal year 1969, By the Laboratory staff. August 1970. iii + 33 pp.. 29 figs., 12 tables. 361. Regional and other related aspects of consumption — some preliminary findings from the 1969 Consumer Panel Survey. By Morton M. Miller and Darrel A. Nash. 336. The northern fur seal. By Ralph C. Baker. Ford Wilke. and C Howard Baltzo. April June 1971, iv -f 18 pp., 19 figs., 3 UbIes. 10 apps. 1970. iii + 19 pp.. 13 figs.

362. Research vessels of the National Marine Fisheries Ser%ice By Robert S. Wolf 337, Program of Division of Economic Research. Bureau of Commercial Fisheries, fiscal August 1971. iii + 46 pp., 25 figs.. 3 tables. For sale by the Superintendent of Documents. year 1969 By Division of Economic Research. April 1970. iii + 29 pp,. 12 figs.. 7 tables. U.S. Government Printing Office, Washington, DC. 20402.

338, Bureau of Commercial Fisheries Biological Laboratory, Auke Bay, Alaska. By 364. History and development of surf harvesting gear. By Phillip S. Parker. Oc- Bureau of Commercial Fisheries. June 1970. 8 pp., 6 figs. tober 1971. iv + 15 pp.. 16 figs, Ffor sale by the Superintendent of Documents. U.S. Government Printing Office, Washington. DC, 20402. 339, Salmon research at Ice Harbor Dam. By Wesley J. Ebel. April 1970. 6 pp.. 4 figs.

365. Processing EASTROPAC STD data and the construction of vertical temperature 340, Bureau of Commercial Fisheries Technological Laboratory, Gloucester, and salinity .actions by computer. By Forrest R. Miller and Kenneth A. Bliss. February Massachusetts. By Bureau of Commercial Fisheries. June 1970, 8 pp., 8 figs. 1972. iv + 17 pp.. 8 figs.. 3 appendix figs For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. DC. 20402. 341, Report of the Bureau of Commercial Fisheries Biological Laboratory. Beaufort, N.C. for the fiscal year ending June 30. 1968. By the Laboratory staff. August 1970, iii + 366. Key to field identification of anadromous juvenile salmonids in the Pacific 24 pp.. 11 figs,. 16 tables, Northwest. By Robert J. McConnell and George R. Snyder. January 1972, iv + 6 pp., 4 figs. For sale by the Superintendent of Documents, U.S. Government Printing OfTice. 342, Report of the Bureau of Commercial Fisheries Biological Laborabory, St. Washington. DC. 20402 Petersburg Beach. Florida, fiscal year 1969. By the Laboratory staff. August 1970, iii + 22 20 figs., 8 tables. pp.. 367. Engineering economic model for fish protein concentration processes. By K, K. Almenas. L. C Durilla. R.C Ernst. J W Gentry. M. B. Hale, and J M Marchello. Oc- Superintendent of Documents, 343, Report of the Bureau of Commercial Fisheries Biological Laboratory. Galveston, tober 1972, iii + 175 pp.. 6 figs.. 6 ubIes. For sale by the US. Government Printing Office. Washington, DC. 20402, Texas, fiscal year 1969. By the Laboratory sUff. August 1970, iii + 39 pp., 28 figs., 9 tables. 368. Cooperative Gulf of Mexico estuarine inventory and study. Florida: Phase 1. area description. By J Kneeland McNulty. William N, Lindall. Jr.. and James E. Sykes. 344- Bureau of Commercial Fisheries Tropical Atlantic Biological Laboratory progress in November 1972. vii + 126 pp., 46 figs., 62 tables. For sale by the Superintendent of research 1965-69, Miami. Florida By Ann Weeks October 1970. iv + 65 pp., 53 figs. Documents, US. Government Printing Office, Washington. DC, 20402.

346. Sportsman's guide to handling, smoking, and preserving Great Lakes coho salmon. 369. Field guide to the anglefishes (Pomacanthidae) in the western Atlantic, By Henry

By Shearon Dudley, J. T. Graikoski, H. L. Seagran. and Paul M. Earl, September 1970. iii A. Feddem. November 1972, iii + 10 pp., 17 figs. For sale by the Superintendent of 4- 28 pp., 15 figs. Documents. U.S. Government Printing Office, Washington, D.C. 20402.

Continued on inside back cover. —

^O ftTMOSp^, U.S. DEPARTMENT OF COMMERCE

Frederick B. Dent, Secretary

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION

Robert M. White, Administrator

NATIONAL MARINE FISHERIES SERVICE ''Mew of Robert W. Schoning, Directot— —

Laijti^cttiD i mm Bioiotiual LIBRARY j JUL 29 197^

NOAA Technical Report NMFS CIRC-388

Proceedings of the First U.S.-Japan Meeting on Aquaculture at Tokyo, Japan, October 18-19, 1971

WILLIAM N. SHAW (Editor)

Under fhe U.S.-Japan Cooperative Program

in Natural Resources (UJNR)

•OV-^TIO/^

SEATTLE, WA February 1974

Kor sHle h\ ihe Superintendent of Documents. VS. Government Printini! Oftice ''6-1 Wiishinnton. DC 10W2 PREFACE

The United States and Japanese counterpart panels on aquaculture were formed in 1969 under the

United States-Japan Cooperative Program in Natural Resources (UJNR). The panels currently in- clude specialists drawn from the federal departments most concerned with aquaculture. Charged with exploring and developing bilateral cooperation, the panels have focused their efforts on exchanging information related to aquaculture w hich could be of benefit to both countries. The UJNR was started by a proposal made during the Third Cabinet-Level Meeting of the Joint

United States-Japan Committee on Trade and Economic Affairs in January 1964. In addition to aquaculture, current subjects included in the program are desalination of seawater, toxic microor- ganism, air pollution, water pollution, energy, forage crops, national park management, mycoplas- mosis, wind and seismic effects, protein resources, forestry, and several joint panels and committees in marine resources research, development, and utilization. Accomplishments include: Increased communications and cooperation among technical specialists: exchanges of information, data, and research findings: some 30 missions involving over 300 scientists and engineers; seven meetings of the Conference, a policy coordinative body: administration staff meetings: exchanges of equipment, materials, and samples; several major technical conferences: and beneficial effects on international relations. Because of the importance of natural resources in this cooperation, the Secretary of State asked the Secretary of the Interior to serve as U.S, Coordinator of the UJNR,

William N, Shavs - United States

Atsushi Furukawa - Japan CONTENTS

Page

Opening remarks

HIATT. ROBERT W. Remarks at first meeting, UJNR panel on aquaculture. 18-19 I October 1971

Papers presented by Japanese panel members HASEGAWA. YOSHIO, and YUKIMASA KUWATANl. Present status of major marine cultivation and propagation in Hokkaido and some problems of the research activities 3

SUTO, SHUNZO. Mariculture of seaweeds and its problems in Japan 7 KAWATSU. HIROSHI. Some technical problems in freshwater fish culture in Japan 17 KAN-NO. HiSASHl, and TOMOO HAYASHl. The present status of shellfish culture in Japan 23 FUJIYA, MASARU. Fish farming and the constraints in Japan 27

Papers presented by U.S. panel members MOCK. CORNELIUS R. Larval culture of penaeid shrimp at the Galveston Biological Laboratory 33 WILDMAN. ROBERT D. Aquaculture in the National Sea Grant Program 41 SHAW. WILLIAM N. Aquaculture of molluscs along the United States Atlantic and Gulf coasts 57 WILLOUGHBY. HARVEY. Freshwater fish culture in the United States 67 LONGWELL. A. CROSBY. Genetics of the American , virginica Gmelin 75 GLUDE. JOHN B. Recent developments in shellfish culture on the U.S. Pacific coast ... 89

Overview papers based on U.S. panel members" tleld trips WILDM.'\N. ROBERT D. Seaweed culture in Japan 97 WILLOUGHBY. HARVEY. Freshwater fish culture in Japan 103 SHAW. WILLIAM N. Shellfish culture in Japan 107 MOCK. CORNELIUS R. Crustacean culture Ill GLUDE. JOHN B. Marine fish culture in Japan 115 LONGWELL. A. CROSBY. Some impressions regarding genetics and the fisheries

of Japan 1 23 The National Marine Fisheries Service (NMFS) does not approve, rec- ommend or endorse any proprietary product or proprietary material mentioned in this publication. No reference shall be made to NMFS, or to this publication furnished by NMFS, in any advertising or sales pro- motion which would indicate or imply that NMFS approves, recommends or endorses any proprietary product or proprietary material mentioned herein, or which has as its purpose an intent to cause directly or indirectly the advertised product to be used or purchased because of this NMFS publication. REMARKS AT FIRST MEETING UJNR PANEL ON AQUACULTURE, 18-19 OCTOBER 1971

ROBERT W. HIATT'

Japan's objective has The initial meeting of the UJNR (United States- mass production systems, variety and to sustain a large group Japan Natural Resources) Aquaculture Panel is a been to produce activity. significant event in the most comprehensive bilateral of seashore residents in gainful economic production of export- cooperative program between our two countries. In the last few decades the mass not This meeting brings together technical representa- able products such as oyster spat has sustained a of Japan's mariculturists but those of the tives of an ancient but still far from scientifically only host western United States and other areas of the world mature endeavor m any country, and it is especial- item indicated that 15 ly significant that this initial meeting takes place in as well. Recently, a news the country acknowledged to be in the vanguard of planeloads of seed from Sendai will be the "'art" of aquaculture. shipped to Bordeaux, , via New York to re- farms there. My personal interest in this field is great, as my plenish the declining oyster breeding professional background in marine ecology has in- Each plane will carry approximately 243 million seed volved studies of Hawaiian fish ponds as well as oysters. attempts at rearing zoeal stages of crabs. My feeling Mariculture, like most other industries, makes for the field thus enables me to sympathize with major surges when breakthroughs in technology those who have labored long and hard at aquacul- occur. Most of these breakthroughs have occurred tural problems, and my interest has led me to visit in Japan, indicating that the world renowned many of the aquacultural activities of Japan during "green thumb" of the Japanese is based on substan- my brief period of residence in this country. tial scientific observation, experimentation, and de- Japanese panel members have spent much time duction. and effort on the conference program which should Everyone is well aware of the great strides in not only give each delegation a summary review of mariculture being made in Japan, both with plant and aquacultural activities in each country, but will sift . Special mention should be made of through the problems of the field and thus establish very promising success in marine cultivation of rain- principal points for the agenda of the next panel bow trout, which ultimately may replace our di- meeting to be held in the United States. Field trip minishing salmon supply on the world's tables. One organization has been both elaborate and detailed so need only to let his mind wander a bit to realize what that special interests of the U.S. participants can be potential lies in the selection of rainbow trout for

fulfilled. rapid growth, a la Lauren R. Donaldson of the Uni-

Aquaculture in the Western world most likely versity of Washington, combined with the greatly dates from the early Roman period when oysters accelerated growth rate of trout reared in seawa- were brought under cultivation. Whether or not ter. .-Xsian aquacultural activities antedate those of the During the field trips the impact of Japan's indus-

West I do not know, but there is little doubt that trialization and urbanization on mariculture will be

Japan's mariculture is the most varied and success- most apparent. Many of these problems are also

ful in any country today. Unlike aquaculture in being experienced in the United States. 1 hope that Southeastern Asia which deals with few species in during the course of these and future joint panel meetings an assessment can be made of this threaten- Scientific Attache. U.S. Embassy. Tokyo. Japan. ing environmental circumstance so that agencies in each country, recently established for environmen- ically these are viable concepts and should receive tal affairs, can bring proper action to bear on preserv- attention very soon. outstanding series of ing the basic environment for aquaculture. We all We all look forward to an

trips. I should like to take this realize that pollution ofinshore waters may not be all meetings and field behalf of the Government, to bad. We have not really attempted to utilize con- opportunity, on U.S. panelists for an outstanding job trolled eutrophication or warmed water from power thank the Japanese organization. plants to increase maricultural production. Theoret- of PRESENT STATUS OF MAJOR MARINE CULTIVATION AND PROPAGATION IN HOKKAIDO AND SOME PROBLEMS OF THE RESEARCH ACTIVITIES

YOSHIO HASEGAWA and YUKIMASA KUWATANI'

GENERAL FEATURES OF THE is very difficult to establish and maintain artificial WATERS AROUND HOKKAIDO equipment (rafts, longlines, etc.) for marine cultiva- tion.

Hokkaido is the northernmost island of Japanese archipelago. It has a long shoreline extending about Pacific Region 2.700 km, which corresponds to about 10% of the

Japanese coastline. The island is surrounded by The Pacific coast can also be divided into two three different seas—the Japan Sea, the Pacific regions by Cape Erimo. In the eastern region, there Ocean, and the Okhotsk Sea. The coastline of Hok- are many small bays or inlets in the Akkeshi area, kaido is influenced by two warm currents, the but the largest embayment, Uchiura Bay, is found in Tsushima and the Kuroshio, and one cold current, the Oyashio (Fig. 1). The seasonal fluctuations of these warm and cold currents considerably influence the oceanographic conditions in each local region. Therefore, Hokkaido has many specific ecological features as a result of these oceanographic, as well as topographic, conditions.

Japan Sea Region

The Japan Sea coast of Hokkaido can be divided into two regions by the Shakotan Peninsula: The northern region is characterized by simple sandy beaches, while the southern region, including the

Shakotan Peninsula, is characterized by a rough, rocky shoreline. Along this coast, the warm Tsushima Current Hows northward. In addition, some upweliing of cold water-masses from the lower layers of the Japan Sea occurs both in the offshore waters and the inshore area of the Tsushima Cur- rent. This intermingling of warm and cold water- masses complicates the oceanographic conditions of the area. Moreover, strong northwest winds bring stormy weather conditions to this region during the winter. Therefore, because of the oceanographic conditions, stormy winters, and open topography, it

. ' Hokkaido Regional Fisheries Research Laboratory. Yoichi. Figure I —Sea currents and isothermal lines in Japanese waters Hokkaido. Japan. during .August. the western region. The whole coastline of the between Hokkaido and Kunashiri Island is called

Pacific region, except in the area of Tsugaru Strait, the Nemuro Strait. This region is characterized by where wide, rocky shores are found, is made up of many large and small brackish lakes along the coast. simple, sandy beaches. The fundamental water sys- The warm Soya Current (a branch of the Tsushima tem of this region consists of two warm currents, the Current) flows southward along the Okhotsk Sea Kuroshio and the Tsugaru, and one cold current, the coast and a cold East Sakhalin Current runs along Oyashio. In the western region, the warm Tsugaru the outside and parallel with the Soya Current. Con- Current and the cold Oyashio Current interchange siderable freezing of seawater, especially in lakes alternatively by seasons; therefore, the oceano- and inlets, and drifting ice occur from December to graphic conditions of this region are quite variable. April in this region. Because of these icy conditions, On the other hand, in the eastern region, the coastal fishing activities as well as maintaining artificial area is affected entirely by the cold Oyashio Current equipment for marine cultivation are greatly re- throughout the entire year. Dense sea fogs often stricted during this period. occur during the summer (June to August), espe- cially in the eastern part. There are. on the average, PRESENT STATUS OF THE PRODUCTIVITY 58 foggy days per year. OF IMPORTANT MARINE ORGANISMS

Okhotsk Sea Region The major species which are artificially cultivated and propagated in Hokkaido are restricted in num- The Okhotsk Sea coast can be divided into two bers because of environmental conditions of this regions by the Shiretoko Peninsula: The northern region. Almost all are northern forms which have region is characterized by a flat sandy beach; in the their major distributional range in Hokkaido (Table southern region, a big embayment is formed between 1). Recently, the cultivation of fishes and other the Shiretoko Peninsula and the Nemuro Peninsula. marine organisms has become of major interest in

In addition, some of the Kurile Islands are located in Hokkaido, and it has become necessary to establish the entrance of this embayment. The channel lying seed production systems for some of the most impor-

Table 1. —Catch statistics for main fishing species as the subject of the cultivation and propagation in

Hokkaido in 1969, and show it related percent to the total Japanese landings. —

tant northern forms. The species listed in this article Accordingly, Hokkaido has played an important are presently being cultivated in Hokkaido. role as a source of seed for southern Japan. The present status of some important inverte- Growth rates vary considerably along the Hokkaido brates and seaweeds is as follows: coast and successful transplants have been made from poor growing grounds to good growing grounds. (Patinopecten yesoenssis)

Sea are distributed along the whole coast Sea urchin (Strongylocentrotus intermedius and of Hokkaido. However, in recent years, the major S. nudus) areas of production have been limited to the Okhotsk Sea region, especially in the southern half of the Hokkaido's species of the sea urchins differ from northern region and the Nemuro Strait area in the those of the southern part of Japan. They are of southern region. Scallop production in Hokkaido commercial importance in Hokkaido and are found reached its peak in 1934, when 78,674 tons were along all coasts. Recently, effective management of harvested. Since then, production has been declin- sea urchin populations has been carried out and. as a ing, with accompanying wide annual fluctuations. A result, the annual catch has shown a rising tendency. low of 3,843 tons was recorded in 1968. However, in In managing the populations, severe regulations 1969, production rose to 8,618 tons. This increase have been established on the fishing grounds, desig- may be due to the gradual development of the artifi- nated fishing seasons, and minimum carapace size. cial cultivation and the use of underwater off-bottom Also, young individuals (those with immature techniques in Lake Saloma and Uchiura Bay, and ovaries) have been transplanted to productive the stocking of seed scallops along the Okhotsk Sea grounds rich in seaweeds. coast. It is not clear whether the remarkable reduc- tion in production was caused by overfishing or by a decrease in the amount of scallop setting as a result Kelp (Laminaria spp.) of some adverse oceanographic conditions. Laminaria growing along the coast of Hokkaido Japanese surf clam (Mactra sachaHensis) are classified into several species, namely L. japonica, L. religiosa, L. ochotensis, L. diaboUca, This clam is found along the entire Hokkaido L. angustata, andL. angustata var. longissima. The coast. Major areas of production are the Pacific classification is based on their morphological coast region and the Nemuro Strait. In Hokkaido, characters. However, from the taxonomical as well is the annual production of surf nearly 5.000 as distributional viewpoints, it is appropriate to di- tons. Commercial-sized clams range in age composi- vide the above-mentioned Luminaiia into two major tion from 4 to 10 yr old, and it is doubtful that the groups Laminaria japonica group (including L. resource would recover if overfished. At present, japonica. L. ochotensis, and L. diaboUca) and the clam resource is being carefully managed by Laminaria angustata group (including L. angustata regulating the size of the catch, fishing seasons, fish- andL. angustata var. longissinui)- The former group ing grounds, and minimum shell size. Transplanting is found in Uchiura Bay, the Tsugaru Strait, the ofjuvenile clams has been attempted for the purpose Japan Sea, the northern part of Okhotsk Sea region, of preserving this resource. and along the coast of Shiretoko Peninsula. The latter group grows along the coast of the Pacific Ocean. Since 1955, the annual production of Abalone (Haliotis discus) Laminaria in Hokkaido has fluctuated between Abaione are limited to the Japan Sea coast, the 100,000 and 150,000 tons in fresh weight. The most

Tsugaru Strait, and Uchiura Bay: it has never been abundant harvests were recorded, based on a 5-yr found in other areas. This restriction in its geo- cycle, in 1957, 1962, and 1967. Since the 19th cen- graphical range may be attributed mainly to the low tury, various attempts have been made to increase seawater temperatures during the winter season. Laminaria production. These include the planting of

The number of abalone per unit of area is considera- stones and rocks and the blasting of rocky reefs. In ble in Hokkaido. Because of cold waters, the growth the recent years, cultivation of Laminaria, rate is slower than in the southern part of Japan. especially forced cultivation, by a longline type or rope-curtain type, was popularized, as in Uiuhiria in seed to be stocked and places where stocking \\ ill be southern Hokkaido. done. 4) Explanation of an annexing effect to the natural

Brown algae (Undaria pinnatifida) stocks as an important problem in the future.

The distributional range of Undaria in Hokkaido Scallop is generally the same as that of abalone. In recent times, the annual production of Undaria in Hok- 1) Clarification of the major factors causing the kaido has been constant at about 10.000 tons in fresh decline in populations on both the Japan Sea coast weight. and the northern part of the Okhotsk Sea coast. 2) Establishment of a large-scale, dependable sys- Red algae (Porphyra spp., mainly Porphyra yezoensis) tem for the mass production of seed (target is 800 million individuals).

Hokkaido is still an underdeveloped area for the cultivation of Porphyra because there are many ob- Japanese surf clam stacles hindering its growth, such as heavy wind- storms along the Japan Sea coast, freezing of sea Establishment of a large-scale, dependable system waters, and floating drift ice in the inlets along the for producing seed both naturally and artificially. eastern part of the Pacific coast and the Okhotsk coast. However, since 1953. the cultivation oi Por- Abalone and sea urchin phyra has increased gradually in Uchiura Bay, Ak- keshi Bay. and the northern part of the Japan Sea Establishment of a technique for artificially plant- coast. In the former two places, the algae are not ing seaweeds and clarification on the ability of damaged by the above obstacles, while in the latter abalone and sea urchin to propagate following plant- place, they are protected by special breakwater ing. fences. Laminaria

IMPORTANT PROBLEMS 1) Investigation of methods of growing high qual- OF THE RESEARCH ACTIVITIES ity Laminaria {2-yr old plants). 2) Improvement of methods forthe forced cultiva- As in many agencies, organization, staff, budgets, tion of Laminaria (1-yrold plants). and facilities are problems affecting research ac- 3) Study how to protect the cultured Laminaria tivities. However, these are omitted from this dis- from the noxious bryozoan. Memhranipora ser- cussion for want of space. The problems to be solved rilamella. in future studies are as follows: Porphyra

All species being artificially propagated 1) Identification of the new local species and the

1) Identification of food organisms and develop- breeding of Porphyra. ing best methods for their mass production. 2) Study the adaptation of each local species to its 2) Determination of an adaptive environmental environmental conditions. condition for each species. 3) Establishment of a suitable culture technique 3) Determination of the size and the quality of for each local condition. MARICULTURE OF SEAWEEDS AND ITS PROBLEMS IN JAPAN

SHUNZO SUTO'

D>4TRODUCTION or by removing useless weeds which will otherwise occupy the substrate of the species being cultivated.

The change in annual production of seaweeds in Another problem is found in the natural produc- Japan is shown by species in Tatile 1, where the tion. Sometimes, a local decay of seaweeds, often production from cultivation and harvest of wild lasting more than several years, causes not only the populations are mentioned separately. decrease in the algal production, but also the de- Japanese and people in East Asia consume most of crease in the abalone catch, which feed on seaweeds, the seaweed harvested for human food, and its use in and also affect the catch of coastal fish, owing to the industrial materials is comparatively less. The situa- lack of production of juvenile fishes that grow tion differs clearly from that in the other areas of the around the seaweed beds. The reasons why the world. Japanese taste for "norV (Undaria. decay of seaweeds occur and why seaweeds cannot Lam'maria. Monostroma, etc.) is quite developed, recover soon are being studied at the present. and the shortage of its supply and resulting rise of its price have encouraged efforts to increase its produc- NORI (PORPHYRA) tion from the natural beds and also the development Cultivation of Nori of its cultivation on the surface of the sea.

Of course, the progress of cultivation depends on Historical Reviews social economic factors and the techniques to make The cultivation of nori started about 300 yr ago it profitable. Nori cultivation, it is said, started about around the coast of Tokyo Bay and developed 300 yr ago and harvested quantities are increasing gradually in many localities on the bays facing the every year. The cultivation of [//z^/ana (a member of Pacific coast of Japan, where this culture can find Laminariaceae) has recently grown to an industry and protection from strong surf and an adequate tidal the one for Laininaria has just begun. Monostroma range necessary for growth. has been cultivated for 30 yr, and in the past 10 yr, Nori grounds were limited in those days to the the amount of its harvest has kept a constant level, shallow waters around the mouth of rivers, on the satisfying the consumers" demands. basin of which cities and rice farms developed, sup- The amounts of Laminaria, Undaria, Gelidium, plying rich nutrients to nori grounds. etc. harvested from their natural beds have not in- Bundles of twigs of trees such as oaks, cherry, etc. creased much from year to year. Little increase in were set in rows on the ground in the fall as the Undaria production seems to come from overhar- collectors, to which nori spores attach themselves vesting. Many efforts have been made to increase its and grow. In the winter, grown nori plants are har- production, but so far none has proved to be effec- vested, made into dried products similar to sheets of tive on the whole: though in some local grounds paper, and are sold to consumers, mostly city successful attempts have been reported setting —by dwellers. stones to enlarge seaweed bed substrate, by blowing The cultivators were mainly farmers in the coastal up shallow beds with dynamite to lower their level. regions. Gradually product dealers controlled and exploited the cultivators, whose income was very

' Mariculture Division. Tokai Regional Fisheries Research low, which in turn held back the industry from rapid Laboratory. .-Vrasaki. Nagai. ^okosuka. Kanagawa-ken, Japan. progress. Table 1. —Change in annual amount of seaweed production. [Wet basis: 1,000 tons.]

Seaweed Harvested Consumed from 1936-40 1941-45 1946-50 1951-55 1956-60 l%l-65 1966-70 in

Nori Cultivation 27 33 36 18 45 61 169 Food tPorphyra) Natural bed 7 7 Food

Wakame Cultivation 4 66 Food

(Undaria) Natural bed 37 31 48 51 57 57 Food

Monostroma Cultivation 12 14 15 Food

Laminuria Natural bed 305 132 139 148 142 144 167 Food.

A part,

alginate

material

Gelidiiim Natural bed 12 17 15 13 18 Agar material

Gracilaria Natural bed 12 12 Agar

material

Iridaea and

Chondnis Natural bed Mostly-

plastering

Cloiopellis Natural bed 5 Starch

for silk

clothes

Ecklonia and

Eisenia Natural bed 118 A part,

alginate

material

The nori harvest increased only gradually, doubled in 1945, became four times in 1955, and is amounting to 1 billion sheets—a sheet is a paperlike now six times that of the prewar level. product of nori, of about 20 x 20 cm in size and about Social economic reasons for this abrupt rise are: 3 g in weight —just before World War 11. 1) Increase in the demand by consumers. The Advances in the culture techniques were also food rationing system during and after World War poor. Old collectors (twigs from trees of oak, cherry, 11 supplied nori to all of the people in Japan, mak- etc.) were replaced by bamboo twigs, promising ing many new consumers. The increase of con- more harvest than the old ones. Modern net collec- sumers and the halt of the import of nori from tors were found more effective to increase the har- Korea brought about a severe shortage of nori and vest, but they were adopted only in limited localities the rise of market price. because of the higher cost than the old collectors.

It should he mentioned here, that the nori cultiva- 2) Innovation of fisheries systems after the War. tion in Korea had a rapid growth 10 years prior to Nori cultivators organized themselves in cooper- World War it by introducing new techniques which ative unions, which shut out the capital control of produced about the same amount of nori as in dealers and established a cooperative selling sys- Japan. tem that raised the rate of net income from about After World War 11, nori cultivation in Japan 30% in the prewar times to an income of 60-70%. made rapid progress. The amount of the harvest Rise of the market price of nori and increase of the net income made the nori cultivation the in Japan, being followed by the artificial control of most profitable fishery. This was followed also by nori spores. In 19.S.*i-60, nori producers cultured a the rapid expansion of the industry throughout necessary amount of Conchocelis for themselves Japan, making strong demands on the advances of through the summer and produced nori spores to culture techniques. start its culture. The technique removed the short- of natural spores which had limited the 3) Expansion of the nori grounds. Increase of age population, fertilization of rice fields, and the growth of the cultivation especially in the western progress of industry made the coastal waters Japan. richer in nutrients, making cultivation possible to spread away from areas adjacent to river mouths It can be said, that the replacement of old collec- where nori often suffers from declining salinity tors by net doubled the production of pre- World War during rainy weather. II time, also doubling the seed control.

It should be mentioned that a change of species in Under these circumstances, the following culture nori occurred with the change of culture techniques. techniques were pushed forward at a rapid advance: P. yezoensis became dominate in place of P. tenerci, the former seems to adapt more readily to higher

1) Techniques to find new grounds suitable for salinities and to easier cultivation of spores. The nori culture. Conditions required are a) sufficient change increased the harvest but produced a low- exchange of water by currents and waves, b) suffi- grade product with decreased odor and hardening cient supply of nutrients, and c) protection from when tasted. freshwater inflows and strong surf. General View of Actual Nori Cultivation 2) Improvement of collectors. Old collectors

were replaced by a net made of palm fiber string At present, nori is cultivated in most bays and and then of synthetic fiber string of 2-3 mm in inland seas along the Pacific coast of Japan. Nori diameter. The strings are netted in a mesh of about grounds are about 60,000 hectares in area, produc- 20 cm, and the standard size of a net is 18.2 x 1.3 ing about 5-6 billion sheets of nori a year worth 70-80 m-. The nets are set stretched horizontally into the billion yen. Fishermen's cooperative unions obtain sea and are tied to bamboo poles set in two rows on prefectural government sanction to set nori grounds the shallow sea. The net collector has many ad- and manage them. About 60,000 fishermen set their vantages over the old ones in rearing nori. It is far own collectors, harvest grown nori on them, and easierto deal with, surf resistant and more produc- produce dried paperlike products. The products are tive. The replacement made possible a wider cul- sold through the cooperative unions to the dealers. ture, spreading from the limited waters near the Coastal waters of 0-5 m in depth are available for mouth of rivers to deeper waters of rougher wave nori grounds of classic net systems, setting the nets action, as the waters became more nutritious. by spreading them between two rows of bamboo The net collector made possible the poles. By the actual development of the new floating cultivator's control on the growth of nori. Elevat- net system, cultivators have been able to turn waters ing the net a little from its standard level slows the 20-m deep into profitable grounds. growth of nori but controls the growth of weeds, Usually a net, in a cultivating set, has a spread of such as Enteroinorpha and diatoms which may 18.2 m X 1.3 m. Now 5 million sets are prepared for overcome the nori and decrease the harvest. Low- all the grounds. About 10 million nets are used per

ering the net accelerates the nori growth, but the year, i.e., in a set two nets are spread one after nori often becomes weak by disease; Enter- another during a harvesting season, from November oinorpha and diatoms grow vigorously on to next March or April.

the net, displacing the cultured nori, if the weather Every fisherman has equipment for harvesting

in winter is calm and not too cold. Nori cultivators nori plants and also for manufacturing them into can then control the net level height as well as the paperlike products. Generally the cooperative un- nori growth, protecting against diseases and in- ions prepare cold storage for preserving nets with jurious ueeds. young buds in living condition. These unions some- 3) Seed control. Soon after the findings of K. M. times have equipment for culturing Conchocelis and Drew on the "Conchocelis phase" in the life his- also for manufacturing nori products.

tory of Porphyra. its whole history was made clear Paperlike products are gathered by unions and )

sold to the dealers, who preserve the products and Reiirini; of nori pUiiils iiiiil their luirvesl. -.\boul sell them to consumers. Each Japanese eats an aver- 50 days after budding, nori plants grow to 15-20 cm in age of 50-60 sheets of nori per year. Nori is rich in length and then are harvested. After the first harvest vitamins, and two sheets of nori can supply one many buds remain on the nets, promising another daily dose of them. harvest in 15-20 days. In this way harvesting can be repeated several times from a net throughout the nori

Processing in Actual Nori Cultivation season. But generally the crop decreases in repeat- ing harvests; sometimes the crop may die from the Seed. — Present cultivation depends completely on diseases of nori or by some accident. Then, the cul- the spores from cultured Conchocelis. The culture is tivators replace these nets with the refrigerated ones done by each fisherman or by his cooperative union. that can replace the crop in 15-30 days.

The culture begins at the end of the last season. Harvesting is done by using machines which make Many cleaned oyster shells are spread on the bottom the labor at sea more comfortable and etTicii-nt. of shallow tanks filled with seawater. Cut pieces of Manufactitrinii paperlike dried prodiicls from mature nori plants are put on the water, so that the nori plants are cleaned by carpospores released from the plant will attach cropped nori. —Cropped with seawater. Then they are chopped and themselves to the shells and develop to the Con- washing chocelis phase on them. Shells with Conchocelis are spread on screens made of fine twigs of bamboo orot fine plastic rods and finally dried in a dryer with an hung down in other tanks 0.5- 1 .0 m in depth, where done quickly at low they are kept throughout the summer. The water in old burner. Drying has to be temperatures, commonly in 2-3 hrwith the tempera- the tanks is changed if it becomes dirty. Light in the ture lower than 50°C. In these conditions nori is kept tanks is controlled so that Conchocelis grows well alive until the end of the drying procedure. This without getting ill. At the end of summer, the Con- chocelis matures and produces many spores which makes the product glossy, tasty, and sweet smelling, retains all vitamins. develop into nori buds. and

In the fall, when the seawater temperature goes dow n below 24°C, fishermen prepare the cultivation. Recent Advances in Culture Techniques Twenty to forty nets are set in a layer in the sea. Shells with fertile Conchocelis are put into many Recent yearly changes of nori production is shown vinyl bags, and these are hung just under the nets in in Figure I, with changes of numbers of cultivating order to have the spore find the collector as they sets, of nets used, and of nets stored in refrigerators. come out of the bag. Sometimes the net layer is put The overall nori production has increased year by into a large polyethylene bag with Conchocelis and year but show sharp fluctuations. In these days

left floating on the surface of the sea. This method progress in culture techniques has tended towards I prevents the cultivator from wasting spores and can new methods on how to expand the nori grounds. 2) also be done in deeper waters. After several days, how to prevent sharp declines in the yearly produc- when the spores have fixed themselves to the nets, tion, and 3) how to reduce labor in culti\ation and to these nets are taken out from the bag and are tied to make laborers more comfortable. the poles for spore development. Techniques to prevent sharp declines in the yearly

Biiiii;inii up ofyoiiiii; hints. -A set of 20-40 layered production. -O^ course, nori growth is affected by

nets is separated into sets of 5-6 layered nets, which certain conditions, especially by the climate in the are then separated into single nets, as the buds grow. growing season. But the sharp drops in production In the process of separation, when the buds are 5-50 were caused by severe outbreaks of diseases which mm in length, the necessary amount of nets with occur successively in important grounds. It was buds are taken out of the water, dried and stored in found that the disease occurs in connection with refrigerators set at -20°C. Here the buds are kept overpopulation of the plants on the grounds —setting alive, preparing for the recovery of crops when the of too many nets for greater harvest. This finding led planted nori suffers from a prevailing disease or a to the development of the techniques to get a far heavy storm. Fishermen always control the level of more stable cropb\ controlling the amount of nets to nets as the climate and the tide changes, so that the be set on a ground. buds do not suffer from severe drying out in low tide The technique to store live nori buds in cold stor-

and alsi) from mowth of weeds and diatoms. age was first applied in 196.^, making it possible for

10 crops to recover when the planted nori become se- grounds in the new areas after the old grounds were verely damaged by disease or by some accident. destroyed by polluted waters and so on until 1965: Nets with young buds are dried until the water con- after that the development and loss came into bal- nori grounds are still showing an tent of the nori comes down to about 20-309f , are ance. However, packed in polyethylene bags, and are stored in re- overall increase by using a new rearing system, i.e.. frigerators at about -20°C, in which buds can be a floating-net system, which can make profitable kept alive for more than 6 mo and capable of recover- grounds out of waters of about 20 m deep and with ing normal growth whenever they are returned to strong wave action. sea. Even wet buds can endure the cold storage for a Generally a square frame of synthetic rope is set short period, while many of the weeds and diatoms floating on the surface of the sea with the help of are killed. Also a parasitic fungus, which often buoys and anchors, and 20 nets with small buoys can causes disease on nori. loses its ability to reproduce be set in it. Waters with currents faster than 30 by this treatment. cm/sec or with somewhat strong wave action are The number of nets with young buds stored in convenient for rearing nori by this system. The refrigerators has increased in the past 5 yr. as shown frame systems can resist the impact of a wave 4 m in in Figure 1. This brought about new difficulties in height without any damage to nori. bud rearing, because cultivators have to rear the Mechanization of processes in nori culti- buds with doubled amount of nets. In 1966-70, when vation. — Labor shortages and culture enlarge- too many nets are set during bud rearing, these nets ment demanded the mechanization of each process often caused severe damage to the buds, resulting in of production. It turns culture labor into a comfort- a sharp decline in harvest. This problem is now able and profitable one. keeping the young labor force solved by reducing the nets to a reasonable and from tlowing out into land industries. This is an manageable amount on each ground. exception to the labor shortage situation for all Techniques to expand nori grounds. -By using the fisheries. For instance, oyster culture appears more net collectors, nori culture has developed the profitable in some localities than nori cultivation, but

labor in oyster culture is far more severe and dirty, causing an outflow of young labor from the culture

industry. This loss of labor is making the culture fall behind the nori cultivation. 10 NETS USED Introducing engineering principles to nuike or to c 9 improve nori grounds. -From about 1965 engineering >- 2 in nori cultivation. o = principles have been introduced 8 For example, concrete or iron piles were set to de- crease wave action in order to have nori culture 7 possible behind them. On the grounds in shallow c Z waters, water ways were dug to better the exchange O Q 6 = 2 of water and to increase the harvest, and now in iQ < "" digging are planned. Here tn 5 TOTAL SET several old grounds works Z I- LlI — the connection between the biological and engineer- O ^ PRODUCTION FLOATING F 4 SYSTEM ing techniques have to collaborate closely to make O u. the effort effective for production increment. -I 3 C3/f^ 1 Problems in Nori Cultivation 2 NETS — CLASSIC REFRIGERATED SYSTEM The demand for nori by consumers, which is sup- posed to increase year by year, was estimated at about 5-6 billion sheets a year in 1970. The import of

I960 1965 1970 nori from Korea is now politicallv limited to 200

million sheets a year, but it may increase to I billion Figure I. —Change inannualamount of "nori" production and in in the future. Cultivation in Japan produced 6 the amount of cultivating sets and nets used. Generally a net is sheets

spread in a set. billion sheets in 1970. satisfying the amount of con-

11 )

sumers" demand, and Japan is capable of increasing 3) How to improve the qualities of the products? fertilizing technique its supply with the increase of the consumers" de- Development of an effective mand, ifthe following technical problems are solved: will be expected. and 2) how to improve 4) Breeding of nori and introducing foreign 1 ) How to prevent a bad crop, the quality of the products. Porpliyrci will be helpful for items 1-3 —nori with nori of higher produc- There is another problem which has arisen, the more resistance to diseases, spreading of industrial pollution. Coastal waters be- tivity, perhaps of not maturing under winter's came polluted and nori products became contami- short-day conditions, and nori of higher quality, nated with cadmium, mercury, etc. We are afraid we making the product more glossy, w ith more odor is highly may need hygienic control in the future if pollution and better taste. A variety off. teneni increases. productive and resistant to diseases but of lower quality. The most important problem in nori culture is 5) Techniques for mass manufacturing of crop found in its administration, income of the cultivators products. increased more quickly than that of city laborers, but increase came from in recent years this is not so. The WAKAME (UNDARIA) the rise in nori prices and also from the increase in the harvests. In the future the rise in the prices can Biology be expected, but the increase in the harvest will "Wakame" is a seaweed peculiar to Japan and cause oversupply. The mechanization of the culture Korea, and 60.000 tons of this raw seaweed are processes is raising the cost of nori. especially in the landed annually. 10.000 tons in dry weight. Cur- case of small-scale operations. rently cultivation extends the seaweed industry to The technique to store live nori buds in cold stor- the northern areas, now including many districts all age is also used for cropped nori plants. This will over Japan. The output from cultivation was over inevitably stimulate the development of factories 60,000 tons in 1970. which store cropped nori and make it into products The seaweed grows from beginning of winter to far more efficiently than each fisherman can. Until spring, then dies out after liberating zoospores. now, the income of a cultivator was the sum of Within 20-40 days several hundred million spores harvest plus manufacturing, and if the latter is re- come out from one plant. The spores germinate im- moved, he must recover his loss by production in- mediately to a microscopic filamentous alga, which crease. lies dormant during the summer, in the fall, when the In the near future nori cultivators will be divided water temperature goes below 20°C. egg and sper- into two groups, the majority going into mass pro- matium are produced, germinate, and grow into the duction using the floating system and the minority wakame plant. This seaweed grows to several mil- going into small-scale operations producing nori of limeters long in 1 mo. 10 cm in 2 mo. and 1-2 m long in special quality. 3-4 mo. The temperature at the northern limit of The number of cultivators has been kept at a level distribution is 2°C in the winter and at the southern of 60.000 in the past 20 yr. but this level will decrease limit. 14°C. with the scale-up of each operation. Substitution of cultivators will occur, and cultivators who combine Cultivation farming will decrease and ones who combine fishery Historical Reviews will increase. Under these changes of circumstances, the tech- in 193.*^ Kanda found that the life history of nical problems will be: wakame was almost the same as that o\' hiiiiiiuirin. its cultivation started in the 1940"s along the coast of crop? 1 How to prevent cultivation from a bad southern Manchuria, together uith that of outbreaks of A bad crop is generally caused by luiiiiliuiriii, where their natural growth is almost diseases, and techniques to forecast and prevent zero. the outbreak of diseases are expected. .•\fter World War ii. the industry was introduced

2) How to simplify each culture process? The into China w hich produced 30,000 tons of raw prod- present processes were developed for small-scale uct a year, most of which isLaminaria. Meanwhile operations. They have to be modified to fit the in Japan, the cultivation did not develop because of need of a large-scale operation. sufficient supply of natural products.

12 However, with increase in population, shortages In waters which are too rough or with many float- in the supply of wiki wakame occurred in the 1960's, ing 5«/\i,'flii///?( plants, the rope is set at a depth of 1 stimulating the development of its cultivation. A m, where the buds can escape being damaged by new product, salted wakame, was developed and wave action or by rubbing off by Sciif^a^siiiu. welcomed by consumers for convenience in cook- Wakame grows quickly in winter. The optimum ing, and this product did a great deal for increasing temperature for its growth may be about IO°C. The consumption. longer the period of lower than 15°C, the greater the Under these circumstances wakame cultivation harvest. However, temperatures lower than 5°C had an abrupt growth mainly in northern districts of may injure the plant and may decrease the crop. Fast Japan. The annual production was almost zero in current and strong wave action are favorable for 1963 and was over 60,000 tons in 1970, which ex- growth of the alga, if they do not damage the cultiva- ceeds the harvest from natural beds. tion set. Harvest is done by cutting the weed which has Processes in Cultivation grown to about 1 m in length. Most of it is dried under At the end of the season, wakame becomes mature the sun or in a drier. Some of it is sold raw to meet

1 of cultivating and develops zoospores, at the time fishermen start local demands. The yield from m is in in the to prepare the "seed strings"" for the next season. rope in a season about 10 kg wet weight For collecting spores, strings of 2-3 mm in diame- northern areas and about 5 kg in warmer districts. ter made of synthetic fiber are used. The 100-m long The amount of labor work in wakame cultivation strings are reeled over a frame made of vinyl plastic is far less than that in nori cultivation. The set of the tube of 2-3 cm in diameter. A tank is filled with fresh former is more resistant against rough waves than seawater. Mature sporophylls of wakame are put that of the latter. For these conditions the former is into the tank after half drying. Enormous numbers of more profitable in northern open coast than the lat- spores are released into waters, when the vinyl ter. However, the amount of consumption is now frames with strings are set in the tank so as to catch limiting progress of the industry. the spores. Several sporophylls are necessary for With the spreading of the cultivation, new prob- seeding a 100-m string. After 1-2 hr the frames are lems are occurring, i.e. , damages caused by bacterial diseases and by the eating of young buds by isopods taken out and are put into culture tanks of about 1 m deep, where they are kept through the summer under and gastropods. controlled light intensity. It is desirable to keep the Harvest of Wild Wakame water temperature lower than 25°C. Favorable light intensity over them is 500 lux at 25°C and 1 ,000 lux at The amount of production changes every year 20°C. primarily because of the variations in water tempera- Germlings of wakame develop in the fall when the ture. The low temperature in the growing season, water temperature goes below 20°C. When young winter to spring, brings about a good crop except at buds grow to about 1 mm in length, the frames with the north limit. strings are put into the sea hanging from a raft, so as Elimination of harmful seaweeds in wakame beds to accelerate their growth. is found to be effective in increasing production dur- fouling In northern waters, where invasion of ing the season. The bed is likely to be taken over by seaweeds and is less, the seeded strings are other perennial weeds, Phyllospadix in the north and often cultured in the sea. Sargassiim and Ecklonia in the south. The best time

Management and Harvesting to control the weeds may be during the germinating season of wakame buds. The cultivation starts when the seawater tempera- We have never produced a favorite culture area by ture becomes 15°C and fouling organisms become throwing stones into the sea. which is effective in the scarce. A synthetic rope of 100 m long and of 8-10 case of Laminaria and Gelidium. Limiting the mm in diameter is floated into the sea with the help of amount of the harvest and transplanting mature buoys and anchors. Often many branch ropes are plants were found ineffective for producing a better hung from the rope. Seed strings with young buds of crop the following year.

wakame are rolled up to the rope. Sometimes seed Wakame is an annual plant and there is an enorm- strings are attached to the ropes at 10-cm intervals ous mortality in the microscopic phase in the sum- after being cut into pieces of about 10 cm long. mer. These conditions may cause the ineffectiveness

13 of the foregoing techniques. However, after germi- used should not be one in which the bottom is altered nation the plant grows to maturity with a little mor- by the movement of sands. Use of a short cylinder of tality. If some devices are used to plant young hiids concrete which was thrown into the sea was prac- in large quantities, the efficiency will he quite reli- ticed on a large-scale basis at Nemuro, Hokkaido. able. Trials of this method are now underway. The expense is supposed to be recovered in 7-8 yr. The reefs which are too high to drain the even surface are dynamited so that Laminaria plants are LA\fI\ARIA able to grow. To eliminate harmful weeds such as Phyllospadix from the bed bottom explosives are Biology also useful. An explosive equivalent to 150-31)0 g of Important species are Laminaria japonica and L. dynamite has an effective area of about 4 m-. ani;iisuita. L.japonicd is the best quality though not much is produced. HalfofallZ.£(/;;//;^//7« harvested is Cultivation L. angus tata var. longissima. China is said to produce .30,000 tons oi Laminaria Laminaria mature in the fall. Some hundred mil- lion zoospores, each having two cilia, come out from annually due to the recent progress in cultivation to a frond. A germling is a microscopic filiment. When produce a dietary balance. the water temperature goes to 10°C or below in In Japan the emphasis has been on increasing the winter, the germling gives rise to spermatia and eggs. production of Laminaria plants which grow nat- A fertilized egg germinates and grows into a urally in the sea, because it supplied sufficient Laminaria plant. The filaments do not fruit at water amounts for the demand of consumers. With in- temperature over 10°C and for this reason Laminaria crease of consumption and rise of market price, grows only in northern Japan. cultivation has been attempted. Young plants are seen in early spring, then grow There are some obstacles preventing a break- rapidly, but start to decay from the top of the frond in through in Laminaria cultivation, especially the fact the autumn. In the second year, a growth at the top that the plant takes 2 yr to grow into a desirable of the stipe develops and becomes a second year's market product for Japanese consumers, i.e., 2 yr blade. The growth in the spring is good at 5°-I5°C, plants. Research is now going on to reduce this but never takes place at over 20°C in the summer. period. The second year's blades are the main parts of the plant harvested because the firsi year's blades are of GELIDIUM (AND OTHER AGAR WEEDS) unsuitable quality for consumption in Japan. Introduction Harvesting The production of raw seaweeds for agar-agar in

The harvesting season is from July to August. A recent years has been 6,500 tons dry weight and drying process after harvesting is important to get an 5,500 tons are imported. The latter, sold at a cheap excellent product. Hokkaido is subjected to foggy price though not of good quality, replaced the ones days frequently: therefore, the drying by a drier is raised in Japan. Agar output was 5,500 pounds in useful for increasing production and for improving 1963. Korea which exported raw materials in prewar quality. days is now producing more agar-agar every year and soon is going to exceed Japan's production. Culture Techniques Biology Shinran-shonin. an old famous Buddhist priest, is said to have been the first to propagate Laminaria in Raw seaweeds for producing agar belong to the 1718. At present a large amount of the national ex- families of Gelidiaceae and Gracilariaceae. Of penditure is invested in Hokkaido. these. Geliclium amansii is the most important

Throwing stones into the sea for propagation im- species. It grows between low tide level and 20- to provement has been practiced for many years with 30-m depth. They are found in areas which are influ- good results. The yield rate in the area where stones enced by warm currents. More than 609?^ of the total are thrown is roughly the same as the one in natural production comes from Izu Peninsula and Izu Is- growing districts. The area in which this technique is lands, where the rock of the andesite, clear water.

14 and warm current are located and where the trans- cost of the large labor force, which is needed for parency of the water is high which enables G. ainan- setting seed plants on the rope, leaves little for profit. sii to grow. In the Izu Islands, plants do not appear In order to expand the growing area, stones should in around the in large amounts in the region directly washed by be placed on the sandy bottom and the warm current, but grow in good amounts in the growing areas. Stones weighing 20-100 kg are used waters with an upweiling of bottom water. They al- since they are not moved by wave action and do not so do not grow in muddy water, or on rocks covered embed into the sand. Soon after calcareous algae with fouling organisms, but grow well on rocks on such as Lithotluimnion appear on the stones and sandy bottom. spores of Gelidium grow on them. It does not make much difference if the stones are G. (iiminsii reach 10 cm high in 1 yrand 20 cm in 2 yr. The span of the lifetime of a plant seems to be 2 set at the best time so far as production is concerned, yr. but a holdfast remains several years and pro- but does make a big difference whether it is a suitable duces new plants. The crop largely depends upon the place or not. Production on new substrate provided plants that developed from these holdfasts. along the Izu Peninsula is almost the same as that of natural populations, i.e., 1-2 kg/m-. The expendi- The plants are able to grow in densities up to 1 kg/m- at Izu Peninsula, the most favorable bed. At tures for setting stones is recovered in 4 yr. In re- harvesting, plants up to 0.2 kg/m^ are usually left to gions where production is less than 0.3-0.4 kg/m^ it is not recommended that stones be added because grow because these plants grow back to 1 kg/m-

within 2 mo after harvesting. Harvesting is done the costs cannot be recovered. three times in a season, the yield per square meter is Introduction of a gradually dissolving lump of fer- well over 2 kg. tilizer into the bed is said to be effective in restoring Sometimes in vast areas most algae except both color and growth during the summer. It has not Surgassum disappear and calcareous algae take been clear whether it is profitable or not. over. The cause of this phenomenon, "Isoyake" in

Japanese, is still obscure. All trials, such as adding stones and transferring plants, to bring about recov- CONCLUSION AND PROBLEMS ery of the vegetation have been unsuccessful. There are two different ways to increase seaweed Harvest production: 1) to increase harvest from its natural ground and 2) to cultivate in or near the surface

its rocky natural Harvest is done under the control of a being completely independent from Fishermen's Cooperative Association that manages ground. the ground. A rest period is required during the

harvesting season to save labor and increase yield in Problems in Propagation Protection the fruitful years. Plants remaining at the end of the fishing season do not thrive the next year. There- Many attempts to increase natural crops by in- fore, the plants should be cropped as many times as creasing the size of the seaweed bed by setting possible. stones or concrete blocks on sandy bottoms around the seaweed ground have proved to be quite effec- Culture Techniques tive. Annual growth on these stones was the same as the ones grown nearby on natural substrate.

Gcliiliiini is a perennial with a slow rate of growth. Expenditures for setting stones is recovered

The most reliable technique for propagation is to within 4-5 yr with Gelidiiim and in 5-8 yr with produce more places in favorable areas by throwing Liiniinaria on the most favorable grounds. Regions stones into the sea. The elimination of harmful of low production cannot be recommended for set- weeds, such as Eckloiiki and Eisenia that grou in ting stones in the sea. Fov IriJaea andClionclnis. the

Gi'liJinni beds, is effective for 1 or 2 yr. period of cost recovery would be 20 yr: therefore,

Cultivation is not an efficient way for increasing this attempt for habitat improvement is not a profita- production because the spores take 2 yr to grow and ble one. reach harvesting size. Branchesof plants attached to In Porphyra. a concrete cover on rugged rocks

a rope, which is hung into the sea. grow well. How- increased their harvest. This investment is recov- ever, the costs of plants for seed are high, and the ered in 3-4 yr on profitable beds.

15 )

However, even in a good ground, a project of niques make the cultivation of a seaweed to be setting stones or a concrete cover could not be an profitable or not. object of investment from a private enterprise. In 2) How many water areas can be made into Japan, the privilege to harvest seaweeds is reserved profitable grounds. for Fishermen's Cooperative Association, who in return is responsible to manage and protect this When these terms are met, the amount of production resource by means of propagating seaweeds and can increase enormously, as it has in the cultivation enlarging their substrate. This association has of Porpliyra. Monostroma, and UnJtirici. and that of worked on substrate enlargement by stone setting Luiniinaiia will follow them in the near future. This is v\ith government aid of 100 million yen per year, an in contrast to the difficulties in increasing production amount too small to improve their total production. from natural beds, being limited by bottom condi- Other attempts to improve the production from tions. natural beds are found to be not so effective. Elimi- However, the cultivation ofGelitliiiin. Gnu iliirici. nation of injurious weeds may sometimes improve Irichu'd. and Chondnis has yet not developed, be- production in 1 to 2 yr. Also, trials to recover from cause it is not profitable. This stems from the fact decreased production in "Isoyake"" waters by stone that these crops are too small or that their cultivation setting proved to be ineffective. requires too much labor. Here an epochal improve- On the seaweed grounds, the fauna and tlora have ment in techniques is expected in making their culti- interrelations with each other depending on en- vation practical. vironmental conditions. Due to the difficulties in In the already industrialized cultivation of changing the environment with a limited budget, the Forpliyni and so on, the problems are: way to increase production or recover from produc- tion declines is to change the succession 1 How to save labor in its cultivation and make mechanisms of flora and fauna. it more comfortable. Mechanization of the work is For instance, in waters where seaweed population being done. However, it will result in a reorganiza- has decreased by some accident, starved , tion of the management, from fishermen's private top shells, and other gastropods eat up and may ones to their cooperative operation. consume the young seaweed buds, decreasing the 2) to change water areas of rough waves flora recovery. Therefore, to protect these buds, it is How necessary to put a large amount of transplanted sea- into profitable grounds: that is to say, how to weeds sufficient enough to feed gastropods and improve the culture apparatus to make it more other grazers, preventing the ingestion of buds resistant to waves and how to reduce wave action needed for the vegetation to recover. by some engineering techniques.

3) How to protect cultivated plants from dis-

Problems in Seaweed Cultivation eases, which cause large fluctuations in yearly production. In cultivation, seaweeds grow on a net, a rope, era 4) Hou to improve the quality of products, raft set or floating at or near the surface of the sea. especially in Porpliyra. to meet better the con- This means the cultivation is done free from the sumers' demands. An effective fertilizing tech- bottom conditions, on which natural growth of sea- nique is expected to develop. weeds largely depends. The cultivation can be done anywhere on any species, if techniques and water 5) Breeding is expected to be useful to answer conditions make it profitable. The problems are: some of these problems. Looking for more favor-

able species abroad will be of consequence in the

I ) Whether demand of consumers and tech- breeding.

16 SOME TECHNICAL PROBLEMS IN FRESHWATER FISH CULTURE IN JAPAN

HIROSHI KAWATSU'

INTRODUCTION increase of 236. This can be compared to an increase of only 26% for wild fish from inland waters in this During the past 10 yr. considerable attention has same period (Table !). been paid to fish culture in various countries, espe- Government statistics on fish culture in Japan cially in the United States and Japan. Inour country, classify the culture methods into four categories, freshwater fish culture has a long history, but the namely, 1) standing-water pond, 2) running-water recent remarkable improvement of culture tech- pond, 3) irrigation pond, and 4) net culture in lakes. niques has brought on a great change in production Running-water ponds give the highest production methods. per unit area for all species; net culture is second. Harvest from irrigation ponds is slightly higher than larger water PRESENT STATUS OF FRESHWATER FISH from standing-water ponds, because the PRODUCTION area of the former is more favorable to the growth of fish. Four major species of freshwater fishes are cul- In 1968, the number of ponds utilized in various culture in number and 8,500 tured in Japan: 1( rainbow trout, Salmo gairdneri. types offish was 35,239 in total of 18 of these ponds were 2) common carp, Cyprinus carpio, 3) eel, Anguilla hectares area. A 7,5 used to produce food fish. The number offish farms japonica, and ayu. Plecoglossus altivelis . From 1959 to 1969, production of cultured fish for food in- classified by water area are listed in Table 2. Almost creased from 15,000 to 52,000 tons, for a percent all the rainbow trout and ayu are cultured in running-water ponds, and eel in standing-water ponds. In the case of carp, both standing- and running-water ponds are used. Number and area of ' Freshwater Fisheries Research Laboratory. Hino-shi. Tokyo. Japan. ponds per fish farm are shown in Table 3. These

Table I. —Annual catch and crop in inland waters, 1959-69. Table 2. —Number of management units by size of water area in freshwater fish culture. 1%8. Rainbow Trout

Figure I. — Di'^lribution offish farms.

19 coast. Rainbow trout farms are distributed in all In the latter, the water is filtered and recirculated parts of the country. However, fish farms which back to the culture ponds. In the process of circula- produce fish for export are centered in Shizuoi

Carp: I- Improvement of breed. are being developed.

Eel: 1. Stabilization of elver supply. Establishment of spawning techniques is an ex-

2. Prevention of epidemic diseases. tremely difficult problem because the physiology Rainbow trout: and spawning behavior of adults and the life history

1. Prevention of epidemic diseases. of hatchery fry are not well understood. Several

2. Improvement of breed. public institutions are wrestling with this problem,

Ayu: 1. Mass production of fry. under the guidance of T. Hibiya, Professor of Fa- 2. Prevention of epidemic diseases. culty of Agriculture, University of Tokyo. Other fish species: The prevention of epidemic disease is another im-

1. Culture of native trout fingerlings for portant problem in eel culture. It is difficult to keep stocking in natural waters. accurate records of mortalities in eel culture, be- 2. Transplantation of foreign species cause turbidity of the pond water inhibits finding or suitable to the tastes of Japanese. seeing dead fish. Attempts at estimating losses in Shizuoka Prefecture have revealed a seasonal pat-

tern. That is, the mortality begins to increase in Carp March and reaches its peak in April or May. Figure 2

No urgent problems are found in carp culture at shows these seasonal changes of mortality in present, but in the future, improvement of the breed Shizuoka Prefecture in 1968. In that year, most of will be desirable. The selective breeding of strains the loss in the spring was due to fungus disease, considered to have desirable characteristics has while in summer bacterial gill disease caused the been started by several institutions. most mortalities. In 1970, eel production suffered heavy losses.

During the first half of the year, crop mortality to- Eel taled 2,600 tons in Shizuoka Prefecture (Table 5). In eel culture, elvers are collected along the This was due to a new epidemic disease, bran- Pacific coast from December to April. Eel culturists chionephritis, named by S. Egusa. Professor of Fa- are often troubled with scarcity of young eels be- culty of Agriculture, University of Tokyo. Fortu- cause of fluctuations in abundance from year to year. The demand for elvers has rapidly increased in re- Tahle .^. —Loss of eel in Shizuoka Prefecture. cent years proportionally with the increase of culture ponds. Three counterplans have been adopted to Year Amount of loss

solve the problem: I) improvement of survival Ions rate of elvers, 2) imporlation of elvers from foreign 1964 492 countries, and 3) establishment of spawning tech- 1965 200 niques. 1966 522 Heating apparatus to increase winter tempera- 1967 199

tures in ponds is proving to be effective for improv- l%8 449 1%9 20.'> ing the survival of eels. This apparatus includes two 1970 1,639 main systems, heating and a circulating filter system.

20 Ayu « Marketable eel Ayu is familiar to the taste of Japanese and is also the most impoilant game fish in inland waters. Most O O Fingerling fingerlings for culture are caught in Lake Biwa and along the seashore. Fingerlings from Lake Biwa are of good quality: however, the supply is limited by the natural standing crop. The catch from the seashore is also limited for the same reason. .Attempts at artifi- cial production of ayu fry have been started in sev- eral prefectures. At present, two systems of fry pro- duction are used, one type uses salt water and the other fresh water. At present, saltwater culture gives better results. In both types of culture, Rotifem are used as the starting feed. Bnicliioniis plicatilis is used for seawater culture and B. calyciflorns for freshwater culture. Vibrio and Gliii>ea infections are the principal dis- eases of ayu culture. Vibrio infections annually Apr May Jun Jul Aug. Sep.Oct. Nov. Dec. Jan. Feb. Mar occur in Shiga and Tokushima Prefectures. This dis- Month ease also is observed in wild populations in Shiga 2. change of loss in eel culture ponds [n Figure —Seasonal Prefecture. Disinfection of fingerlings is widely Shizuoka Prefecture, in 1968. practiced in many culture farms. PRODUCTION OF this epidemic did not return last winter nately, NATIVE TROUT FINGERLINGS FOR (1971). STOCKING IN NATURAL WATERS

fishing, it been Rainbow trout With the development of game has requested to propagate the populations ofcold-water fishes in natural streams. Rainbow trout are Prevention of epidemic disease is also the most game for this purpose, because these fish do important problem in trout production. Infectious not suitable native trouts on pancreatic necrosis (IPN). Vibrio infection, bacter- not remain in the stocking area. The the other hand appear to be very suitable for this ial gill disease, and Hexainita infection are the prin- this information, many pre- cipal diseases in Japan. Among them. IPN is most purpose. Prompted by carried out the ex- harmful. Fortunately, viral hemonhagic septicemia fectural trout hatcheries have perimental production of native trout fingerlings. ( VHS) and whirling disease, Myxosomci cerehralis. realized in various have not yet been discovered in Japan. However, Large-scale production will be preventive systems against these two epidemics parts of the country. have been in effect since 1967. These preventive TRANSPLANTATION OF systems display the power in epidemiological sur- FOREIGN SPECIES SUITABLE TO THE veys in other epidemic diseases. For example, they JAPANESE TASTES estimated the critical temperature as 12°C for out- break of IPN. Concurrent with the reduction of rice production, Recently, the net culture of rainbow trout in shal- part of the fields will be changed to fish ponds. As low seavvater has begun in the northern part of this occurs, demand for a variety of cultured fish will

Japan. .\\\ attempts resulted in failure in southern increase. In anticipation of this situation, various

Japan, because the water temperature is too high for foreign species have been experimentally introduced rainhou trout to survive in seawater. The upper limit into our country. Examples are bluegill sunfish.

for survival in seawater is estimated to be 22°-23°C whitefish. German carp, and channel catfish. Chan- (72°-73°F). Water temperatures above 23°C lead to nel catfish attracts much attention because of the bacterial infections. An analogous phenomenon is ease of production: its taste is also suitable to the observed in ayu reared in seawater. Japanese people.

21 BUREAU OF STATISTICS. OFFICE OF THE PRIME REFERENCES MINISTER. JAPAN. 1969. Fisheries. [In Japanese and English] //( Bureau of

Statistics. Japan statistical yearbook, p. 145-166. 1971. Inland fisheries. [In Japanese and English.) In BROWN. E. E. Bureau of Statistics. Japan statistical yearbook, p. 160. 1969. The freshwater cultured fish industry of PREFECTURAL FISHERIES EXPERIMENT Japan. Univ. Georgia. Coll. Agric. Exp. Stn. Res. Rep. SHIZUOKA STATION. HAMANAKO BRANCH. 41, p. 57. 1%9. Hamana. Shizuoka Prefectural Fisheries Experi- Branch. 98. EGUSA. S. ment Station. Hamanako No. 1970. Branchionephritis prevailed among eel populations in 1970. Studies on the disease of eel culture. Shizuoka Pre- farm ponds in the winter of 1969-1970. Fish Pathol. fectural Fisheries Experiment Station. Hamanako Branch,

5(1 );5 1-66. No. 152. p. 26.

22 THE PRESENT STATUS OF SHELLFISH CULTURE IN JAPAN

HISASHI KAN-NO' and TOMOO HAYASHl-

INTRODUCTION Table 1. —Shellfish production in Japan, 1969.

Value in In 1969, shellfish production (including pearl oys- Landings million ters) in Japan was 561,132 tons worth 58,444 million Shellfish in tons of yen yen (Table 1). Types of shellfish products landed during the past decade have changed because of .Abalone iHaliotis discus luinai. certain effects on the environment and changes in H. discus, H. gijiantiea. H. commercial demands. Shellfish, like Meretiix. sicholdi) 6.463 5,692 which live along the coastal area, have decreased Top shell ( Turhu corneliis) 8.459 1,7L5 (Merelrix meretrix. remarkably in production because of the loss of their M. liisoriu) 7,081 966 habitat from industrialization. In 1969, the oyster Short-necked clam (Venerupis industry in the Seto Inland area seriously Sea was semidccussala) 1 16,572 3.025 affected because the oysters were heavily fouled by Common scallop (Palinopeclen the calcareous tube worm. Hydioides nonegica. yessoensis) 14,644 1.833

Surf clam (Spisula sachalinensis) . . . 4,050 948 For the past several years, production in the pearl Ark shell (Anadara suhcrenata) .... 38.289 1.918 industry has declined because of reduced demand Other molluscs 114.281 9.920 pearls. for On the other hand, landings of scallops, Oyster (Cnissosrrea gigas) 245,458 8.149 abalone, and top shell, so-called high grade prod- Pearl 97 22,600 ucts, have been increasing yearly both in tonnage Pearl molber sheW (PicUula fucalu) . 5,738 1.678 and value because of the demand by the consumer for fresh marine products. Production through Total 561.132 58.444 aquaculture has remained commercially stable in Japan. In the past, shellfish aquaculture in Japan was present status of shellfish aquaculture in Japan and limited, strictly speaking, to oysters and pearls. Re- its prospects for the future. cently, both scallops and abalone are being grown using aquaculture techniques. In general, aquacul- OYSTER CULTURE ture requires three important techniques: 1 ) to catch Production of oysters (Crassostrea gii^cis) has the juveniles in desirable places with collectors, 2) to rapidly increased since the 1950"s because of the produce seed for culture using hatchery (artificial) development of hanging culture. Strings of oysters techniques, and 3) to cultivate the seed to market are hung from racks, rafts, or longlines, depending size in the field. .Aquaculture techniques are being on water depth. Hanging culture makes good use of utilized to grow oysters, pearls, and scallops, and it the water column and is not limited by depth or is expected that abalone will also be produced in the nature of bottom. In 1969, production was 245,458 near future through aquaculture. tons (including shell) valued at 8.149 million In my presentation at the first UJNR (United yen (Table 1). States-Japan Natural Resources) Aquaculture Panel The first operation in oyster culture is to catch the meeting. I would like to explain briefly about the juveniles (seed). Strings of shells are suspended dur- ing the summer spawning season from racks placed

' Tohoku Regional Fisheries Research Laboratory. Shiogama. in coastal areas such as bays and inlets. After set- Mi\agi-ken. Japan. ting, is - National Pearl Research Laboratory. Kashikojima. Mie-ken. the seed hardened, a process of draping the Japan. strings over racks so that they are out of water for a

23 considerable period of time during each tidal cycle. In 1969, 14.644 tons worth 1,833 million yen were Hardening results in an increased percentage of harvested from natural grounds and approximately survival, better growth rates, and less fouling. In 5,0(X) tons were produced from hanging culture. northern Japan, almost all commercial oyster seed Seed scallops are caught in the spring. Several production takes place in Miyagi Prefecture. At kinds of cultch materials are used: vinyl fibre (used present, oyster seed production supplies not only gill net), vinyl film, branches of trees, etc. These are domestic uses, but also supplies some 30,000 to suspended from rafts or longlines. Three months 50.000 cases of seed per year to the Pacific coast after setting, the young scallops are transferred to of the United States and to parts of Europe, prin- nets where they grow to 3-4 cm by autumn. The cipally France. culture of scallops can then go one of two ways: Two met hods of hanging oysterculture are usually Either the seed can continue to grow in nets for l'/2yr practiced in southern Japan. In the first method, to market size or they can be released on the natural seed oysters are transplanted to the rafts about 1 mo grounds. As high as an 809? return has been obtained after setting to grow: no hardening is done. These from released seed on the coastal area of Hokkaido. In the future, a large-scale oysters are harvested at the end of I yr. This method near bottom farming of is characterized by a short growing period and low scallops can be expected along the coast of Okhotsk labor costs. In the second method, seed oysters are Sea, Hokkaido. This project will be made possible hardened until autumn orearly winter. They are then because large amounts of scallop seed are available. transferred to the rafts to grow and are not harvested The site once produced 60,000 tons of scallops annu- until the following year (known as 2-yr culture). ally. To make the program successful, systematic

The best oyster producing area in Japan is in the engineering and newly developed harvesting Seto Inland Sea where calm conditions exist. Here machines such as suction dredges and underwater there are wide areas which enable the growers to use bulldozers will be utilized. large size rafts, 20 m long by 10 m wide. The Tohoku region of northern Japan is also favorable for oyster ABALONE CULTURE culture and longlines are used in some of the rough water areas. It takes 2 yr for the oysters to grow to Considerable interest has developed in the cultur- market size. ing of abalone (Haliotis discus luinai in cold waters Oyster production is expected to remain stable and //. discus in warmer waters). These are very over the next few years. New species of oysters such important commercial species along the rocky sea as the European flat oyster, Ostrea editlis. and the bottom both in quantity and quality. Production has , Crassostrea aniiiilata. may enter remained relatively stable over the past years as a commercial production in the future if the problem result of good management practices such as the of pollution along the coastal areas can be over- transplanting of natural sets to areas of poor setting. come. In 1969, abalone landings totaled 6,463 tons valued

at 5,692 million yen (Table 1). SCALLOP CULTURE Two approaches are planned in the aquaculture of abalone —mass production of seeds in hatcheries The aquaculture of scallops. Patinopecten yes- and the artificial production of food in the field by soensis. has recently been developed in Japan. The seaweed afforestation. Artificial seed production production of scallops on natural grounds has re- was developed in the 1960"s. Seed production is mained poor during the past decade with annual expected to expand as studies are compjeted on the landings fluctuating between 5.000 and 15,000 tons. conditioning of abalone for spawning and as com- Since the development of the hanging method for mercial hatcheries are developed. Good returns can catching seed and culturing scallops, production has be expected from released seeds, 2-3 cm in shell increased rapidly during the past few years and will length, when they are harvested 3-4 yr later. continue to do so. Because considerable quantities There is a lack of knowledge about the food condi- of seed are being caught in Aomori and Hokkaido tions in the abalone's natural habitat. For this areas of northern Japan, the scallop fishery is cur- reason, research was initiated in afforestation in the rently expanding. Ihe seed is not only beingcultured field. .Afforestation could produce about 40 tons of in nets to market size but also released on the bottom food that could feed up to 4 tons of abalone. The where good returns are being obtained 2 to 3 yr later. seeds for this program will come from hatcheries.

24 PEARL INDUSTRY As the industry developed, culture grounds spread rapidly over the middle and southeastern

The pearl industry first began in 1906. The indus- parts of Japan. These areas were used mainly for the try has developed rapidly after World War II and production of mother shells. In 1956, 82% of all reached its peak of production in 1967 when 130 tons pearls produced in Japan came from the middle of pearls were produced by 4,701 culturist (called Pacific region; 73% of these came from rafts. Re- management units). The increase was related to cently, however, production in this area has declined techniques in artificially collecting seeds and rearing because of overcrowding and deterioration of cul- the mothershells (Piiutada sp.). The mother shell ture grounds. In 1964, 20% of the total pearl produc- industry has grown rapidly since 1952. In 1965. tion came from the Seto Inland region but, recently,

1 were harvested from production dropped to the other hand, 1 .000 tons of mother shells 10%. On pro- 69,000 rafts operated by 7,859 management units. duction in the southern Pacific and East China re- A rapid increase in the number of management gions has been on the increase, and over half of the units occurred from the postwar era to 1964. These total Japanese pearl landings now comes from these were mostly small-scale units using less than 30 two areas. rafts. In recent years, the number of units has not Until 1963, yields from pearl rafts were stable but, been increasing and many units are using more rafts, thereafter, production per raft has gone down. indicating an enlargement of the individual industry Reasons for this decline have been related to units. crowded conditions and to the use of unsuitable cul- The everlasting aim of the industry is to improve ture grounds. In the Seto Inland region, the deterio- the quality of the cultured pearl. In the 1920's, pearls ration of the waters caused by man-made pollution were small but, after developing successful tech- has caused a drop in yields from certain culture niques of transplanting mantle pieces in the gonad, grounds. Special provincial laws have been under- bigger pearls were produced. Between 1952 and 1969, the production of small pearls (less than 6 mm) taken to regulate production, recover the balance of decreased from 67% of the total production to 24%; supply and demand, and effectively utilize suitable those in the medium size range (6.0-7.6 mm) and culture grounds. The success of these regulations large pearls (7.6 mm) increased in total production will insure the steady foundation of the industry and from 24 to 58% and from 9 to 18%, respectively. the production of better quality pearls.

25

FISH FARMING AND THE CONSTRAINTS IN JAPAN

MASARU FUJIYA'

INTRODUCTION procedures used with salmon and trout. At that time the Inland Sea was regarded as a fish culture pond, Geographically and historically, utilization of and early stages of larvae were released directly marine products, which has been quite significant to from the operation centers without any care because the Japanese people and fisheries, is one of the most no effective technique had been developed for rear- important industries of the Nation. ing marine fish through their larval stages in captiv- Before the World War II, Japan expanded her ity. fishing area and Japanese fishermen worked all over Subsequently, it became apparent that more effec- the world to obtain their foods. The catch was tive utilization of artificially produced larvae was mainly consumed as the protein source for nutrition require!^, and some new techniques were developed of the people, and the expansion of production was for larval culture and for acclimation to natural wa- most important. This situation continued until about ters. Also, procedures were developed for maintain- a decade ago. ing a brood stock in captivity for earlier production During recent years the situation has changed re- of seedlings and production of more healthy seed- markably. The Japanese people have demanded lings. As a new idea, some civil engineering techni- greater variety of fishery products of high quality ques were proposed to rehabilitate growing and re- with improvement of their living standard. However, leasing grounds. high-quality species occur along the coast of our Thus, the present farming fisheries are really homeland, and these stocks had decreased because equivalent to agriculture in water areas. Artificially of overfishing and/or water pollution. Under these produced seedlings are held or planted in shallow circumstances, fish farming has become necessary. coastal regions, and these seedlings utilize natural ESSENCE AND SIGNIFICANCE OF productivity of these waters for their growth. Recap- FISH FARMING ture or harvest occurs within a certain period (Fig. 1) when the products are ready for market. In 1962, the Seto Inland Sea Farming Fisheries Association was established, and by 1966 five opera- SMdIing tion centers were completed and began operation. At present, the tasks of tlsh farming are expanding as scheduled, but some problems remain. Through Accltmalion cooperative research, biologists and fish farming Reformation specialists are searching for solutions to these prob- of Growing Growing Areas lems in order to advance the operations. Fish farm- Recapture or or Harvest Rearing ing is somewhat different from ordinary aquaculture. The differences are explained briefly and some con- straints are discussed in this paper. When the Seto fish farming operation was started,

it was planned to release the larvae following the Utilization of Natural Productivity

' Nansei Regional Fisheries Research l,ahorator\'. Maruishi.

Ohno-cho. Saeki-gun. Horoshima-ken. Japan. Figure I, — Fundamental conception of Ush tarming.

27 )

In this process, the utilization of natural produc- are transferred from the operation centers or hatch- tivity is an indispensable condition for farming eries to a temporarily constructed acclimation facil- fisheries which is different from ordinary aquacul- ity. This procedure allows the seedlings to adapt to ture in which the growth of species, such as trout and the environmental conditions of the recei\ing waters eels, depends almost entirely upon introduced and to naturalize their behavior while protected from foods. predators. After certain periods, they are released The following items are considered in selecting into natural waters forgrowth. In this case, the plant- suitable organisms for farming: ing sites are determined from the results of scientific investigation of the environments and distribution

1 They should adapt easily to farming operation. and behavior of natural stocks.

2) Their growth rate should be high. For example, when a shrimp release program is 3) They should have a reasonably high market planned, investigations are carried out in advance to value as a product. determine the suitability of various places for shrimp

4) The seedlings can be supplied easily from a growth and the best place is selected for the planting. hatchery or from natural reproduction. Places where natural shrimps thrive are likely to be 5) The feeding habits of larvae and/or young satisfactory release sites. should be clearly known ecologically and physiolog- When environmental conditions in an area are ac- ically. ceptable for the planned species and when results of 6) Foods for the organisms should be readily scientific investigations show that the adaptation available and cheap. and the naturalization are unnecessary, seedlings are 7) They should be resistant to diseases, or released directly into the waters. Otherwise, accli- disease-control methods should be available. mation techniques are applied. In the case of shrimp,

the seedlings are acclimated in net enclosures for 1 -3 The satisfaction of these requirements is espe- wk depending upon the situation. cially significant for a successful operation. How- The stock recruitment type of farming is practiced ever, if demand for a species is great and the market at present with prawn, blue crab, and several species value is high, greater efforts to develop farming of fin fish. techniques for the species will be justified, even though that species would be difficult to farm. The most important consideration in planning of fish Artificial Control Type farming may not be the technical problems, but the development of an economical system. Composite The artificial control type of farming is usually planning will be required from both technical and smaller in scale than the stock recruitment type, and economical points of view. frequently some facilities or mechanical equipment As a special case, geographical transplantation of organisms is ideal for some species. Rapid growth Fish Forming and greater production can be expected when north- ern species are transplanted to southern regions. ArTif iciol Stock Control Typ* Recruitment Some places isolated from a source of organisms Type sometimes have few native species, but have food and space capacity for additional species. So, when the investigation for farming is carried out. the idea Seedling Seedling Production Production of introducing a new species should be considered.

TWO TYPES OF FISH FARMING Acclimotion ^ Acclimotion Releasing i Present and/or proposed farming fisheries could Releosing be classified into two types: 1 ) stock recruitment and Nursing Ulilliotion ^ Growing 2) artificial control, as shown in Figure 2. of Noturol Productivity

Stock Recruitment Type Horveat Recapture

In stock recruitment type of farming, the seedlings Figure 2. — Brief diagram of fish r;irniing in Japan.

28 .

aquarium. For some species, matured adults are put are involved. The farming of oyster, abalone, clam, directly into the larval rearing tank and removed algae in Japan, and of milkfish in South Asian coun- after spawning. tries are of this type. zygotes are reared in tanks of still water, but A new experiment in the culture of red sea bream The to slow running water can be used for larvae after they is based on conditioning the fish to respond sizes. With some species, the larvae sounds. The seedlings, 20-50 mm in total length, are reach certain are transferred to floating cages until they reach kept in floating cages and trained with sound and size, but with shrimp, the larvae are kept in feeding of pellets. Within 2-8 wk, they are adapted to seedling tank till they reach seedling size. In this sound of certain frequency (100-600 Hz) and develop the same of population density to achieve the the habit of gathering around a feeding place every case, control numbers of final stage is important. The size time the sound discharges. After they obtain this desired seedlings varies depending on the purpose and habit, the fish are liberated into natural waters, and of conditions of receiving waters. most of them retain the habit and do not scatter. environmental planned numbers of seedlings to be produced Although a small amount of pellets is necessary to The centers in 1971 fiscal year are shown in Table feed them, they can eat more natural foods for their in five also producing some growth. Therefore, this idea could be categorized as 1. The prefectural centers are seedlings, but their main purpose is the development a tlsh farming. of culture methods. SEEDLING PRODUCTION Breeder Breeder Reoring Collection The first step and one of the key points of fish farming process is the seedling production. At the incipient period, zygotes, larvae, and young fish col- Spowning Stripping lected from natural waters are mainly used as seed- Natural Zygote Collection lings, but artificial seedling production techniques have been developed for important species and these techniques are applied for the actual farming opera- Natural Larva Collection tions. The process is briefly shown in Figure 3. Matured adults from wild stocks are still used to obtain eggs and sperm in most cases, but research to Natural Young Collection develop techniques for obtaining eggs from adults reared to maturity in captivity are in progress. In order to obtain zygotes, stripping and artifi- cial spawning methods are sometimes used, but most species can be induced to spawn naturally in artifi- cially controlled tanks. Matured adults are put in a tank of water, and the zygotes are collected after spawning and fertilization occur. Then, the eggs are 3. Seedling production process. transferred into a rearing facility such as a tank or Figure —

Table 1.— Planned production of seedlings in five centers of Farming Fisheries Association in 1971

Number of Organisms Season production Size

Prawn CONSTRAINTS AND PROBLEMS damental hypothesis that artificially produced seed- lings are equivalent to natural larvae. However, the results of farming trials along the coast of the Inland Although fish farming is in progress in Japan, Sea and surrounding districts have been variable. some problems and constraints remain. Successful results have not always been obtained in Technical constraints include problems concern- spite of the determination, based on preliminary in- ing seedling production, nutrition of larvae, disease vestigations, that these places were suitable for and parasite control, and feeding. Among these, farming. These circumstances raise doubts concern- seedling production techniques are being developed ing the validity of this hypothesis. rapidly, and experience with the successful culture The larvae reared under the ailificial conditions of several species should be applicable in the future are pampered. They are kept in optimal environmen- to other species. Among other problems, however, tal conditions as far as possible, with adequate food fundamental research for the advancement of tech- protected from competitors and pred- niques for nutrition of larvae and control of disease supply, and and parasites are the most important. Aquatic or- ators. ganisms go through several larval stages with selec- On the other hand, larvae in natural vsaters must tive food habits, and the most suitable food has to be survive the fluctuation of environmental conditions, found for each stage. At present, phytoplankton and effects of competitors and predators, and. in addi- zooplankton cultured and/or collected from natural tion, they must find food for themselves. Thus, they waters are fed to the larvae, but the supply fre- are hardened in nature. Therefore, it is likely that quently becomes the limiting factor for seedling pro- there are some differences in the biological charac- duction. Thus, the development of a stable supply of teristics of natural larvae and artificially produced in foods for larval stages is necessary for the advance- seedlings as diagrammed Figure 4. ment of seedling production. The development of In order to obtain more successful results of farm-

artificial foods is especially needed. ing, evaluation of suitability of the receiving waters As the history of aquaculture has shown us, dis- should include consideration of biological charac-

ease and parasite control is also significant. In fish teristics of seedlings. farming, disease control for larva! stage will have to There have been suggestions that comparative re- be developed. Usually, larvae are weaker than search should be carried out to define the difference ar- adults, and contagious diseases are most serious. It in biological characteristics between natural and this is is not unusual to have several millions of larvae tificially produced larvae. However, some- killed during a short-time period in actual farming. times impractical because of the difficulty in collect- In aquaculture, practical methods for treatment of ing samples of natural larvae. In some species, the diseases and parasites have been developed. For natural larvae have not been observed and. with the instance, chemotherapy has assisted the treatment present state of knowledge, could not be identified and prevention offish diseases. These kinds of ad- even if some larvae could be found. The best method vanced techniques should be applicable to fish farm- is to experimentally establish expected environmen- ing, but some fundamental problems such as resis- tal conditions and to observe the effect of these tant strains and human public health considerations conditions on biological characteristics, such as, re- remain. sistance to the fluctuation of environments, As an effective method for preventing disease physiological activity, avoidance reaction from

mortality, it may be possible to breed resistant predators, and ability of shrimp and crab to bury

strains but little research has been done for this themselves in the bottom sediments. purpose. Techniques for acclimating artificially produced The most significant constraint concerning the seedlings should be varied with the species and the

utilization of seedlings is the hypothesis that artifi- results desired. At present, almost standardized cially reared seedlings are equal to those from facilities and methods are used for acclimation of natural reproduction. As mentioned before, the re- seedlings without adequate consideration of objec-

lease of seedlings is based on the results of prelimi- tives. These include net enclosures and net cages for nary investigations on the environmental conditions shrimp and crab and floating cages for fish, in which of planting area and the behavior of natural or- seedlings are kept with feed for several weeks. Al-

ganisms. In most cases, the suitability is estimated though this procedure is helpful for adaptation to

from the presence of natural larvae indicating a fun- natural water conditions, it does not train the seed-

30 Usage Route for Seedlings

Characteristics of Naturol Larvae and Seedlings

Biological Characteristics of Natural Larvae \

Optimal Conditions for Natural Larvae

Acclimation including Optimal Conditions Noturalizotion for Artificial Adaptation Seedlings C onditioning and or Hardening Biological Charocteristics J of Artif iciol Seedlings Figure 4. —Some differences in the biological characteristics between natural larvae and seed- lings and artificial seedlings.

lings to find natural foods orto avoid predators. Con- As the mass production of seedlings is possible, a ditioning and training, based on biological require- limited number of hatcheries can supply the demand ments to achieve the intended purpose, should be for seedlings. Places chosen for hatching facilities tried in the acclimation facility; otherwise, success- should have the best environmental conditions in ful acclimation cannot be expected. unpolluted regions. Farming, especially of the stock The greatest problem connected with the future of recruitment type, requires extensive areas of unpol-

fish farming is the pollution of natural waters. Al- luted water for the production of large amounts of

though water pollution is a matter of concern among fish or shellfish. Complete water pollution control the people and plans for pollution control are being will be needed to keep released organisms safe. For

developed, the adverse effect on fish farming is not this purpose, the cooperative research will have to fully recognized. be carried out by fishery biologists and specialists on Some aspects of this biological problem have been pollution control. Without this cooperation the ad- investigated to find ways to reduce the effects of vancement and expansion of fish farming will be pollutants on fisheries, and water quality criteria and hopeless. water quality standards have been described for some aquatic organisms. However, most of the re- CONCLUSION search data are on adult organisms.

In fish farming, the situation is more severe. For The history of aquaculture in Japan is quite long.

example, the period of larval development is the Mariculture of oysters and algae was started some- weakest stage of the life history of organisms, and time before the beginning of science. Procedures even seedlings have lower resistance to pollution were established by fishermen, and the techniques than adults. Brood stocks require a high quality of have been developed and reformed year by year water to maintain healthy adults v\hich will produce based on their experiences. active larvae. Since the beginning of fisheries science about a

31 century ago. the scientists have verified the suitabil- artificial shelter or bank and fish farming could be ity of techniques developed by fishermen, though combined, greater fish production may be expected. some technical contributions have been offered. Therefore, the combination of differently v\ili Therefore, it cannot be said that scientists have de- categorized ideas or techniques accelerate the veloped the fundamental concepts for the advance- advancement of practical fish farming. ment of aquaculture. Fish farming is becoming of global interest and

Considering the period in which it was developed. Japan is considered as the most advanced country in the idea offish farming should be esteemed highly as this field. People concerned with fish farming and an epochal accomplishment. At the present time, aquaculture expect to obtain the information from however, ancient and new ideas of aquaculture in Japan, and sometimes they are apt to apply the Japan are mixed together. These ideas should be Japanese methods and techniques directly. Biologi- reorganized systematically to establish efficient op- cal techniques are so complicated, however, that eration plans and research projects. direct application in other environments may be un- Among the old aquaculture techniques, there are successful and some modifications will be required. some helpful ideas and methods for the development Certainly fish farming should be encouraged on a of new farming fisheries. For example, an artificial universal basis, but many problems remain to be

fish shelter of concrete blocks is an effective method solved. Greater advancement can be expected with to build a new fishing ground. A larger scale shelter the international cooperation of experts in this would form an "artificial bank." If the technology of specialized field.

32 LARVAL CULTURE OF PENAEID SHRIMP AT THE GALVESTON BIOLOGICAL LABORATORY'

CORNELIUS R. MOCK'

PRELIMINARY EXPERIMENTATION rected toward growing mass cultures of algal foods in natural seawater. Although samples of seawater The first larval culture experiments at the Na- were tested prior to each experiment with several tional Marine Fisheries Service Galveston Labora- types of fertilizers to determine which combinations tory were conducted to aid the identification and of nutrients should be used with that batch of seawa- description of the larval stages of penaeids found in ter for best algal growth, satisfactory growth did not the Gulf of Mexico. By 1966 the three commercially always occur. It soon became apparent that a more important penaeid shrimp (white shrimp. Peiiaciis reliable medium than seawater was needed. A setiferus; brown shrimp, P. aztecus; and pink number of media made with synthetic sea salts and shrimp, P. dtiorariim) had been reared to the post- tap water were tested. "'Instant Ocean"^ was cho- larval stage. The basic techniques used to culture sen from those tested for use at the Galveston larval shrimp were similar to those described by Laboratory along with a complement of nutrients, Hudinaga (1942) and Hudinaga and Miyamura trace elements, and vitamins (Mock and Murphy, (1962). 1971). With this medium dense unialgal cultures can During this period the following organisms were be grown and maintained. For example, 300 liters of tested individually as foods for the larval shrimp: Skeletonema costatiim can be cultured from an Skclctoiieina costatiim, Eiicampi sp., Gym- 8-liter starter culture to a density of 4-5 x 10" cells nodinhim splendcns. Tetraselmis sp., Tliiilassiosira per milliliter in 4 days. sp., a euglenoid protozoan, and Artemia sp. As a Additional algal foods fed experimentally in- result of this work, two suitable food organisms were cluded Cyclotella nana. Isochiysis galbana, and selected for use in subsequent experiments. These Cerataiilina sp.

were Skelctonemu costatiim, because it could be Based on observations made during this ex-

cultured easily, and Artemia sp., because it was perimentation the following conclusions were made:

readily available (Cook and Murphy, 1966; Cook, 1 ) the responses of Penaeiis aztecus larvae to differ- 1967). ent light intensities were inconsistent; 2) a tempera- Following the initial phase of this work, research ture range of 28°-30°C (82°-86°F) and a salinity range was directed toward developing methods of rearing of 27-35"/i]o were most satisfactory for penaeid larval penaeid larvae en masse in order to supply shrimp culture; 3) addition of several algal foods gave better grown under known conditions for physiological survival than additions of only a single species when studies and forexperimental pond culture. A variety comparable concentrations were used; 4) the omis- of specialized equipment was designed and tested in sion of antibiotics from the larval culture media was an attempt to perfect larval culture techniques. possible when the chelator EDTA (ethylene- diaminetetraacetic acid) was substituted at

concentrations of 0.01 per liter of seawater; and PROGRESS BETWEEN 1966-1969 g 5) postlarvae could be shipped successfully either by motor vehicle or air when placed in plastic bags filled From 1966 to 1969, considerable effort was di- with oxygen and seawater (Cook, 1965, 1966, 1968, 1969).

' Contribution No. .144 from the National Marine Fisheries ,Ser\ice. Galveston Laboratory. Galveston. Texas.

- Gulf Coastal Fisheries Center. National Marine Fisheries ' Reference to trade names does not imply endorsement hy the Service. NOAA. Fon Crockett. Galveston. TX 77550. National Marine Fisheries Service. NOAA.

33 RECENT EXPERIMENTATION under refrigeration the concentrate is placed in a plastic container and diluted to a volume of 6 to 8 Beginning in 1969, the major objective of the re- liters, then held at 5C and aerated gently. search at Galveston was to develop methods Freezing in a deep freeze at -19° to -22°C has whereby larval shrimp could be cultured more effi- also been a suitable method of holding algae. Frozen ciently and economically. It was realized that the algal concentrates have been held 7 mo without economic success of shrimp culture was largely de- apparent damage to the cells. Research has also been pendent upon the costs of producing larval shrimp in done on algal foods which are freeze-dried alone or quantity. Two key problems contributing to the in the presence of protectants. Brown (1972) re- costs were: I ) costs of food production and 2) costs ported that freeze-dried diatoms are suitable foods of labor. Research was initiated that was designed to for larval shrimp, although they are inferior to live reduce the investment required for the construction diatoms. of a shrimp hatchery, to increase the efficiency of The final modification in procedures made possi- algal and larval culture procedures, and to reduce the ble by the concentration of algae is the use of a amount of labor required in the hatchery. continuous feeding device consisting of a small The approach used has been to grow unialgal cul- peristaltic pump. Either freeze-dried, frozen, or tures separately from the larval shrimp and to add fresh concentrated algae is suspended and diluted only that number of algal cells needed to maintain the slightly so that it can be pumped into a larval culture shrimp population. However, when algal densities at rates as slow as a few milliliters per hour. Larval were low, large volumes of the culture had to be densities of 100-500 per liter have been maintained in transferred to the shrimp rearing tanks. This resulted tanks up to l,80()-liter capacity using this technique in changes in the temperature of the larval culture (Mock and Murphy, 1971). media which frequently caused mortalities. In addi- The entire procedure of centrifuging, freezing, tion, the medium in which the diatoms were grown and feeding automatically has been performed with was slightly toxic to the larval shrimp. For these cultu-res of Skeletonemu, Tetruselmis. Tha- reasons, it was decided to separate the cells from lassiosira, -and Cyclotella. Single species and mixed their culture medium. species of algal concentrations have been tested. In Separation with a centrifuge has been successful every case the algae used were reared in unialgal with several types such as a table model, a continu- cultures. Each step in this procedure contributes to a ous centrifuge, or a large cream separator. When a more efficient hatchery operation, and the freezing continuous centrifuge or cream separator is used, and automatic feeding reduce the labor requirements the algal concentrate accumulates within the cen- of the operation significantly. trifuge and is removed by disassembling the machine. If the speed of the centrifuge is adjusted so TYPICAL EXPERIMENTAL RESULTS that the cells are not damaged, the resulting concen- For purposes of demonstrating the value of re- trate is a satisfactory food. The cells are then sus- search conducted in small tanks, the results of two pended in a known volume of water and a series of experiments conducted in 1971 are presented below. counts made to determine cell density. The concen- The results of these experiments were not particu- trate is then measured into a number of suitable larly outstanding, but they can be used to illustrate containers in volumes predetermined to provide the type of information which can be obtained using appropriate feeding levels in the larval rearing tanks. this procedure. Experimentation with methods of preserving algal concentrates was initiated in an effort to increase the reliability of the larval culture procedure. Experiment I In the past it had been necessary to begin algal cultures several days before the gravid female Data are presented for a single tank from Experi- shrimp were captured to insure adequate volumes of ment I conducted March 31, 1971 (Table I). This the culture for feeding. Often cultures were ready, was the first use of frozen algae as food during the but gravid shrimp could not be captured, or if gravid protozoeal stages at the Galveston Laboratory. The shrimp were captured, the algal cultures failed. spawn from two brown shrimp were placed in a

Refrigeration has been used successfully to hold 1 , 520-liter fiber glass tank ( 1 .8 m in diameter, 0.9 m the concentrates for periods of 96 hr. For storage high. v\ilh a flat bottom) in a greenhouse. Twelve

34 . Table 1 —Experiment I. Use of frozen Skclelonema costatiim (S). Cyclotella nana (C), and freshly hatched and frozen Anemia by larval and postlarval brown shrimp, Penaeus aztectis.

1971 Algae Anemia Larval Larval Month Day Hour stage count Residual Feed Residual Feed

No. cells No. cells/ml fed/ml No. /ml

March 2145 April

April

April

April Table 1. —Continued.

1971 Algae Artemiu Larval Larval Month Day Hour stage count Residual Feed Residual Feed

April 7—continued

2045

April 8

April

April 10

April

April Table 2. —Experiment II. Tank 1. V'ae of fvozenSkclcloiwina coslutKni {S).Ti'rrciscliiiix sp. {T).andAi!ciiii

1971 Algae Anemia Larval Larval Day Hour stage count Residual Feed Residual Feed

No. cells No. cellslml fedlinl May Table 2. —Continued.

1971 Algae Anemia Larval Larval Month Day Hour stage count Residual Feed Residual Feed

May 31 0800 Mysis III

1030 1045

June —

Table 3. Experiment II, Tank II. Use of fresh concentrated and tVozen concentrdtedSkclc'i(}n('mti coslutiim and A rteniia by larval and postiarval brown shrimp. Fciuwiis aztcciis.

1971 Algae A rteinia Larval Larval Month Day Hour stage count Residual Fresh Frozen Residual Feed

Cell/ml Cells /ml Cells Imllhr No. /ml

May 20

May

May 23

May 24

May

May 26

May 27

May

May 29

May 30

May 31

June

June I%7. Identification and culture of shrimp larvae. /fiM.J. COOK. H. L.. and M. A. MURPHY Lindner and R. E. Stevenson (editors). Report of the 1966. Rearing penaeid shrimp from eggs to post- Bureau of Commercial Fisheries Biological Laboratory. larvae. Proc. Conf. Southeast Assoc. Game Comm. Galveston, Texas, Fiscal Year 1%6, p. 6-7. U.S. Fish 19:283-288. Wildl. Serv., Circ. 268. HUDINAGA [FUJINAGA], M.

I%8. and culture of shrimp larvae. In M. J. 1942. Reproduction, development and rearing ofPenaeiis

Lindner and R. E. Stevenson (editors), Report of the japonuiis Bate. Jap. J. Zool. I0:.1()5:.19.3. Bureau of Commercial Fisheries Biological Laboratory. HUDINAGA. M.. and M. MIYAMURA.

Galveston, Texas, Fiscal Year 1967, p. 7-8. U.S. Fish 1962. Breeding of the "Kuruma" prawn {Penaeiis Wildl. Serv., Circ. 295. juponUiis Bate). (In Japanese. English abstract.)

1969. Larval culture, //i M. J. Lindner and R. E. Steven- J. Oceanogr. Soc. Jap.. 20th Vol.. p. 694-706. son (editors). Report of the Bureau of Commercial MOCK, C. R., and M. A. MURPHY. Fisheries Biological Laboratory, Galveston, Texas, 1970. Technique for raising penaeid shrimp from egg to Fiscal Year 1%8, p. 5-6. U.S. Fish Wildl. Serv., Circ. postlarvae. Proc. Annu. Workship World Mari. Soc.

325, 1970. p. 143-156,

40 AQUACULTURE IN THE NATIONAL SEA GRANT PROGRAM

ROBERT D. WILDMAN'

INTRODUCTION of the funding is being provided by the universities, state agencies, and private industrial organizations The National Sea Grant Program was created by participating in these Sea Grant Programs. an Act of the Congress of the United States to accel- Due to the low level of past activity in the aquacul- erate the development and optimum utilization of ture field in the United States, very few research resources. This to be accomplished our marine was groups had any capability or experience on which to through the support of research and development, base an expanded effort. As a result, much of the education and training, and advisory service ac- early work under Sea Grant support has been de- tivities. Major emphasis was to be placed on the voted to the establishment of trained, experienced conduct of these programs through the establish- groups who are equipped and capable of conducting ment and operation of Sea Grant Colleges, the ocean the type of research necessary to solve the many and equivalent of our Land Grant Colleges which were varied problems encountered by anyone in aquacul- of the instrumental in making the United States one ture as a business venture. This includes studies on greatest agricultural nations of the world. economics and law, environmental quality, en- part of the The Sea Grant Program, originally a gineering, and technology as they relate to Foundation, is in the National National Science now aquaculture. Such studies are not described in this Administration of the Oceanic and Atmospheric paper even though they may ultimately provide the of Several require- U.S. Department Commerce. solution to the most critical problem faced by one or operation affect ments, restrictions, and methods of more aquaculture ventures. the Program in important ways. Sea Grant funds For the purpose of this paper, the Sea Grant not used for construction or maintenance may be aquaculture projects will be described by type of recipient of Sea purposes, or for vessel rental. Any organism being studied, except for a few projects of a least one-third of the Grant support must provide at general type. total cost of the project from non-Federal sources. All grantees are encouraged to develop cooperative CRUSTACEANS programs with other scientists from universities, Shrimp government agencies, and/or private industry. Many in this of our programs have, in fact, operated way. The first aquaculture project to be supported by When the National Sea Grant Program was created Sea Grant, the University of Miami program contin- the by the Congress, aquaculture was one of few ues to be one of the most advanced in experimental fields of research specifically identified for em- shrimp culture. Begun in cooperation with Armour phasis. In carrying out this mandate, the Sea Grant and Company, the United ( Fruit) Brands Company, Program has provided more support to this one area and Florida Power and Light Company, the main to any other. At the present time of research than objectives have been 1) to rear large numbers of over 209? of our research funds go into aquacultural shrimp from eggs to postlarvae (about 1 cm long) and over efforts. Asof 30June 1971, we were supporting 2) to grow these postlarvae to marketable size aquaculture. total 50 projects directly related to The quickly and at low cost. Since the first objective has cost of these projects was nearly S5 million with over been achieved for the most part, emphasis is now S3 million coming from our Program. The remainder given to the problems associated with the second.

Specifically, the work is now devoted to the further development of satisfactory foods and feeding ' Program Director. Office of Sea Grant. NOAA. Washington. D.c. :o:.\'!. methods which w ill provide rapid growth, high sur-

41 vival and yields in ponds, tanks, and cages, and to ranged from SO. 65 to 50.85 per pound, heads on further develop techniques for pond management, (465-608 yen/kg). In cooperation with Ralston including procedures for assuring adequate oxygen Purina, new feed rations have been developed. Har- supply and optimization of other pond conditions vesting of the 1971 crop, now in progress, should such as bottom material, depth of water, and fer- also reveal effects of pond fertilization on growth tilizer regimen. Other efforts are underway on rapid rates and survival. and efficient harvesting techniques, cage culture, Other shrimp research at Texas A&M includes and testing of the important variables in the culture studies on temperature and salinity etTects on post- system such as food types, stocking density, and larvae and feeding behavior, and diet preference of feeding methods. postlarvae. To date one phase of this research has A new rotatable cage for high density culture has provided information regarding upper incipient been designed. It is intended to solve the problem of lethal temperature, acclimation rate to temperature fouling of the mesh. Every portion of the cage is out change, and the influence of environmental salinity of the water for about half the time where it is ex- on heat tolerance of postlarval brown shrimp. Pres- posed to sunlight and drying and can be easily ent work will extend results to include white shrimp cleaned. It is not necessary to handle the animals in P. setifents. postlarvae. Differences have been order to clean the cage. Harvesting w ill also be great- demonstrated between the responses to diets of ly simplified by this design. postlarval brown and white shrimp. It was shown In a related project at Miami, attempts are being that shrimp responses to foods, including initial diet made to induce maturation of ovaries and oocytes m preference, survival, growth, and resistance to pink shrimp. Penaeus duororuin . This is a necessary high temperature may vary independently. step in the control of the life cycle of the animals in The 4.700 square miles (12. 17.^ km-) of brackish to captivity w hich will relieve the commercial culturist marine marshlands and 1.600 square miles (4.144 from his dependency on wild populations for gravid km-) of bays, estuaries, bayous, and canals in south- females as the source of fertilized eggs. The research ern Louisiana are potential sites for impoundments to date has included efforts to develop various mea- for mass culture of brown and white shrimp without sures of maturation and investigation of factors (light, supplemental feeding. A research program being temperature, salinity, and hormones) which enhance conducted by biologists from Francis T. Nicholls maturation by inhibiting molting. State University has been attempting to solve the Another project at Miami, aimed at the general many problems involved in demonstrating that such objective of life cycle control of shrimp, involves the a system is feasible. Two shallow. 10-20 acre (4-8 ha) development of techniques to attain in vitro fertiliza- impoundments containing water and Spartina tion of ova and sperm removed from ripe animals. patens marsh are being used to determine the basic Included in this investigation are in vitro studies of productivity (shrimp production) and for measure- maturation of oocytes and ovaries, effects of hor- ments of the effect of fish and crab predator control mones and ovarian extracts on maturation of ovarian on shrimp production. Natural stocking of ingress- cells, and development of cryogenic techniques to ing postlarval shrimp occurs on nighttime flood preserve viabilit\ of ova and sperm, fertilized eggs, tides across weirs in the impoundments. Large and cultured ovarian colls. Biochemical studies of shrimp and predators are prevented from entering by gonad maturation are underway using electrophore- hardware cloth screening. tic profiles to assess maturity. Predator control is exercised in the larger, test Aquacultural research at Texas A&M University impoundment by rotenone application for fish and is aimed at shrimp farming as a commerically feasi- baited wire traps for blue crabs. Efficient harvesting ble operation. Twenty '/2-acre ponds (0.2 hectares) of the ponds consists of draining surface water at are used for study of artificial feeds, shrimp stocking night across the weir into a net. Shrimp of commer- rates, mortality, and growth rates. Some ponds are cial size rise to the surface and migrate out o^ the stocked with hatchery-reared postlarval brown cstuarine areas and into the Gulf at night during ebb shrimp. P. (iztcciis. supplied by the Dou Chemical tides. With predator control the brown shrimp grew

Company. Yields from 1970 harvests averaged 2.'>0 to .^4 count (heads on) in 75 days and to 12 count in pounds of shrimp per acre (2S0 kg/ha), with some 200 days; the white shrimp grew to .^4 count in 60 ponds exceeding 450 pounds per acre (.'^04 kg/ha). days. The total harvest of both species for one sea-

The wholesale market price of the shrimp at harvest son was 125 pounds (57 kg) of .''4 count shrimp per

42 acre. In the pond with no predator control, the total ticated chemicals (hormones, antibiotics, stimu- harvest was 44 pounds (20 kg) of 70 count shrimp per lants, etc.). Use of the microcapsules will also re- acre, which is probably about the natural productiv- lieve the culturist from the tedious and expensive ity of unmanaged marshes. algal cultural systems now employed in most aqua- In a study of the penaeid shrimp, Pemieiis culture operations. ifiaifiinatus, aimed at developing techniques for in- Another study into the environmental and nutri- tensive cultivation under manipulated environmen- tional requirements of shrimp in culture is being tal conditions, investigators at the University of carried out at the Skidaway Institute of Oceanog- Hawaii have successfully spawned females and raphy in Georgia. Following a series of experiments reared the larvae through all stages. A new, which established a suitable water flow rate, type of intensive-culture enclosure is being built that will substrate, oxygen level, stocking density, and light boost production by vertically arranging the shrimp intensity, preliminary nutritional studies using in small cages on frames, so as to allow the use of the purified pelleted diets were conducted. Eighteen dif- entire water column. Also, a shrimp nutrition study ferent diets which varied in level and quality of pro- is underway. This project is to provide the technical tein, carbohydrate, lipid, vitamins, and minerals information needed for a commercial-scale opera- were evaluated by growth rate and percent survival. tion to be established and operated by a community Rates of ingestion under given environmental condi- group in Hawaii. tions, rates of assimilation of specific biochemical Biologists and food scientists at Louisiana State entities and calorie-protein relationships are now University are developing new rations (foods) for being investigated. To date, a semipurified diet, con- crustaceans in culture. Emphasis has been on the taining about 70% shrimp meal and 8% anchovy utilization of products such as crustacean meals, meal, fed at a rate of 15% of the total biomass daily single-cell protein (torula yeast), food processing has produced the best results (164% increase in "waste" fiber and cellulosic products, and other weight with 95-100% survival during a 3-mo period). products of the fishery processing industries. Spe- Crabs cial attention is being given to the evaluation of the nutritional value of sun-dried shrimp meal and Mass culture techniques to produce large numbers other shrimp meal prepared by various processing of larval stone crabs, Meiiippe mercenaria. and blue procedures. These rations will be tested for feeding crabs, Calliiiectes sapiclus, have been achieved in a efficiency rates, durability and acceptability, and the project at the University of Miami. However, tech- effect of various attractants to stimulate shrimp feed- niques must be improved to reduce and control the ing will be identified. A suitable ration which uses problem of cannibalism among larval stone crabs. alginates as a pellet binder has been developed and is The stone crab matures, copulates, and spawns via- being evaluated under a range of environmental con- ble eggs under conditions of captivity. P., offspring ditions. Other hydrocolloids and modified starches of blue crabs have also been attained in captivity. are also being evaluated as pellet binders. Experi- Investigations are now underway to improve techni- mental samples are being made available to inves- ques of larval culture and to test feasibility of rearing

tigators for testing on a range of economically valu- crabs to marketable size in cages placed in natural able crustacean species, i.e., penaeid shrimp, waters. freshwater shrimp, and crawfish. A Samoan or mangrove crab, Syclla seirata. has A part of this project includes work to prepare the been studied at the Hawaii Institute of Marine Biol- feeds developed as microcapsules in varying sizes ogy. The Samoan crab has been maintained in cages and densities according to the stage of development suspended from rafts and its growth rate measured. of the animal. Forexample. the feed forthe nauplius, This study indicated this crab could attain market-

- - zoea, mysis, and early postlarval stages will be small able size of 1 1 '/2 pounds (0.5 0.7 kg) in about 1 Vi and have near-neutral buoyancy, whereas that for yr at ambient temperatures (24°C). Tests at higher the late postlarval and juvenile stages would be temperatures (27°C) indicated that the time to reach

larger, would sink, and exhibit good water stability. market size could be reduced to 1 yr. Also, a diet of Although the microcapsules are expensive initially. artificial food resulted in faster growth than natural they should result in healthier animals and greater foods.

survival through provision of all nutritional require- In another crab culture project, efforts are under- ments and controlled amounts of expensive sophis- way at Humboldt State College in northern Califor-

43 nia to develop methods of growing the Dungeness ready completed has shown that it is possible to crab. Cancer nuii^ister, using locally produced fish produce a 1 pound (0.45 kg) lobster in 2 yr time wastes as food. The studies are being conducted in instead of the 7-8 yr it takes in the sea, by growing two different environments in Humboldt Bay, in them at 20°C and feeding them daily. pens—one using heated effluents from an electric Work on the American lobster at the University of power plant and the other in bay ponds at ambient Rhode Island is also directed toward reducing the temperatures. The diet preference, condition, and time required to grow the animal to market size. growth are determined and evaluated. This project Here the effort has resulted in the development of could provide a cheap source of food for an aqua- methods for accelerating the hatching of eggs and the culture operation as well as make use of what is mass culture of larvae to juveniles under controlled now a waste disposal problem. Early results indicate conditions. Work is now in progress for maximizing that a food mixture of rockfish, sablefish, Dover the growth rate of juveniles to market size under sole, and shrimp offal produced the best results. optimum conditions. Research is underway at Hast Carolina University Several parts of a multifaceted program of re- on the reproductive cycles and fungal parasites of the search at San Diego State College on spiny lobster, blue crab and will begin shortly on the American Pdniiliriis iiuerniptiis, and American lobster involve lobster, Honuinis cuncikaniis. Studies to date on aquacultural work. Juveniles of spiny lobster have the crab have included observations of the condition been studied with respect to the effects of elevated of the ovary as seen through the carapace, condition temperatures (20°. 22°, 26°, and 28°C) on growth and of eggs of ovigers, and occasion of spawning by metabolic energy budget. Studies of American lob- certain individuals. The crabs which ovulated were ster in progress are providing a comprehensive evalu- successfully induced to attach their egg mass, some- ation of the biological and economic feasibility as thing not previously reported for the blue crab. At- well as the potential benefits and dangers of estab- tempts to date to isolate La^enidiiim callinectes or lishing this species as a fishery resource in California other fungal parasites of crab eggs have waters. Part of this work is concerned with develop- been unsuccessful. ing and evaluating lobster culturing techniques, with In laboratory studies at Texas A&M University the primary aim of producing large numbers of young with young blue crabs (5-40 mm), a sand plus oyster suitable for stocking. shell substrate supported significantly better survi- Crayfish val than did either sand alone or bare glass. The suitability of various temperatures and salinity levels In a project to develop crayfish culture in the were also evaluated. Pacific Northwest, biologists at Oregon State Uni- versity are developing husbandry methods in con- Lobster trolling environments. A system for holding and One of the most highly prized seafood organisms breeding adult crayfish in captivity has been de- in the world, the American lobster, Homcinis veloped. anii'iicuniis, is being studied by geneticists at the Juveniles are raised singly in small cells to avoid

University of California at Davis. The intent is to cannibalism of soft-shelled animals. Several natural develop the technology necessary to grow large and artificial diets have been tested and research on numbers of edible quality lobsters, to marketable nutrition is now centered around a simulated natural si/.e, in a short period of time, at less cost than the diet versus a high protein vegetable pellet diet. The market value. The project is being conducted in role of temperature and salinity on growth and sur- cooperation with the State of Massachusetts Lob- vival is also under study. ster Hatchery on Martha's Vineyard Island. The work includes the improvement of culture facilities; MOLLUSCS development of an economically feasible form of Oysters tood; studies of the effect of selected environmental

parameters on growth; application of genetics tech- In a large multidisciplinary effort, scientists at the niques for the selection of fast growing lobsters: L'niversity of Delaware are working to improve our cvakialion of biochemical methods for controlling techniques in shellfish culture. .\ variety of prob- cannibalism, mating, molting, and disease ; and phys- lems are being attacked in both open and closed ical methods to control cannibalism. Research, al- 'ulture systems. Over 500 million oyster larvae were

44 reared at least to the straight hinge stage in 51 sepa- The second method delays the removal of the rate cultures during the past year. These larvae, the newly set spat from the substrate for 18-21 days. results of 40 spawning attempts, were used in a vari- Setting is induced on Frosted Mylar- or Herculene. ety of rearing and setting experiments. The algal A new setting tray was designed to hold the mylar culture facilities can now provide food on a year- upright. The spat set on the upright mylar sheets, round basis and are capable of producing 150 liters of thus avoiding most of the siltation and organic de-

dense algal culture every 24 hr. Research on the tritus. The spat is removed from the mylar sheet by

feeding of adult oysters in being conducted to show simply shaking it over a container of river water. It is how the oyster utilizes available food energy. Pre- then dipped up and down in the container, washing liminary experiements have determined the caloric the loose spat off. content of cultured algae and have shown that an A team of researchers at the Darling Center. Uni-

oyster can assimilate at least 859f of the energy con- versity of Maine, is investigating the feasibility of

tent in the food that it consumes. Research is also culturing several species of marine organisms in the being conducted on the bacteria associated with colder waters of that region. Although research is supplemental feeding of oysters in closed systems. being conducted on the deep sea scallop and blue and efforts to produce viable offspring from hybridi- , most of the experiments to date in this new zation of the Eastern (or American) oyster, program have been with cultchless European and Crassostrea virginica. and the , C. American oysters. Trays of the cultchless oysters gigas. are continuing. have been placed at many different locations in the

A pilot-scale oyster hatchery at Newport, Oreg. , is Damariscotta estuary (24 km long) and at 14 sites producing seed from Pacific and Kumamoto {C. along the coastline. These were selected to provide gigas). Olympid (Ostrea lurichi). and European fO. as good a geographic and ecological spread as possi- edulis) oysters on a routine basis. Peak production in ble and are being monitored for growth, survival,

the pilot hatchery approaches 1 million juveniles per and presence of fouling organisms. In the first year,

month. The seed is being raised by growers in growth response of European oysters was excellent

Oregon and Alaska, and is being used in a variety of (to 10 cm) in even the most exposed coastal studies by Oregon State University researchers. locations. The data will be utilized to develop a predictive model allowing assessment of the poten- Heritability studies have been completed on the tial of the Maine coast for economically competitive Pacific oyster, and parentage is controlled to selec- oyster culture. cooperative pilot hatchery is being tively breed for rapid growth, high meat production, A started at Newcastle which may result in the estab- and low mortality. The growth of hatchery seed oys- lishment of a commercial operation. ters in warmed ocean water from power plant ef- The Departments of Agricultural and Mechan- fluents is under evaluation. Successful cryogenic ical Engineering of the University of Maine are preservation of oyster sperm at -196°C has allowed working on oyster rafting systems which will be self-fertilization of the Pacific oyster after natural with sex reversal for genetic studies. Improved larval adaptable to this environment and compatible multiple use concepts. pilot model of a submers- feeding schedules and diets have increased the suc- A ible raft has been constructed and will be field test- cess of setting in the hatchery. ed in 1972. In their program to advance the state-of-the-art in Several problems inherent in the culture of oysters oyster culture, biologists at the Virginia Institute of Marine Sciences have developed two new methods and clams are being investigated at the University of Washington. of for obtaining free oyster spat (cultchless), one for The optimal horizontal spacing oys- ter cultches rafts in relation to relatively clear estuarine areas and one for areas suspended from growth, mortality, condition is being determined which ha\e heavy siltation problems. In the first and and local in method, the spat must be removed from the sub- the variation the degree and type of fouling organisms evaluated. The investigators are strate before sufficient new shell for permanent at- also attempting to determine if bacteria are responsi- tachment has been produced. The set takes place in ble for some of the summer oyster mortalities. They fiber glass salmon-egg hatching trays in complete are particularly interested in Vibrio and other types darkness, using filtered river water. The spat are removed from the tray bottom, to which they have temporarily attached, river by a strong stream of -' Reference to irade names does not imply endorsement by the water, yielding cultch-free spat. National Marine Fisheries Service. NO.AA.

45 of pathogenic bacteria which may be associated with with fiber glass window screen or plastic netting. In these mortalities. In related work, the gonadal de- one experiment, the scallops were grovs n from 1.3 to velopment of the Manila clam, Venerupis japonica, 5.7 cm in a net enclosure directly on a relatively hard

is being studied. Also, seed of this clam species is mud-sand bottom. The total growth time from egg to being planted in commercial growing areas to deter- market size was 6-7 mo. Work is continuing to de- mine the best annual planting density and minimum termine optimum stocking densities and optimum length of time seed must be held in the hatchery to depth for holding the scallop floats and to develop give optimum yields to the clam grower. other methods for holding scallops from about 2.2 In a companion program, a prototype continuous cm to market size. phytoplankton culture unit is being developed at the University of Washington to provide nutritious, effi- .\balone ciently grown feeds for the clam and oyster farm. The culture of four commercially important The prototype can produce at least 14 liters per day species of abalone is under study at the Scripps of Mo HOC hr}' sis liitheri with a total yield of 2 x 10" Institution of Oceanography. University of Califor- cells, consisting of 6. 8 gash-free dry weight, which is nia. Studies of spawning phenomena, early de- 22% protein. velopment, settlement, growth of settled juveniles, and hybridization are being conducted. Approxi- Clams mately 200, ()()() young red abalone, Haliot'ts nijes- A new hard clam culture method has been de- cens. were reared by the chief investigator in a com- veloped at the Virginia Institute of Marine Sciences. mercial venture. This resulted in the identification of The new method involves spreading shell, gravel, or the problems being attacked in this research pro- other material (aggregates) over the sand or mud gram. Primary attention is being given to the influ- bottoms before planting the seed. This type of bot- ence of temperature on larval development and tom protects the young clams from their chief pre- juvenile growth, and to the behavioral problem of dator, the blue crab, and other predators, such as substrate selection by settling larvae. Other efforts other crabs, boring , bottom-dwelling fish, and are being devoted to determine the causes of larval waterfowl. Other methods of protection tried in the mortalities and to identify micropredators of newly past included planting the young clams in screened settle juveniles. trays or boxes, within fenced enclosures, under or hardware cloth, in saltwater sheets of netting and tanks, and intertidally. These techniques were unre- rather unusual species of molluscs are being liable and expensive, caused silting and slow growth, Two studied by University of Hawaii scientists. Work on and thus are unsuitable for commercial use. large limpets, which are in great demand for Other work on molluscs at the University of luaus and which sell for as much as $70 per Hawaii has included efforts to develop pond culture Hawaiian gallon (6.000 yenVliter). is concentrating on the de- of the Japanese littleneck clam which was intro- velopment of an acceptable food source. Eggs have duced to Hawaii, but whose natural populations are obtained from females and artificially fertilized declining. Research to date has identified proper been successfully with the females producing several substrate as a key parameter with sand substratum thousand eggs each. However, further ecological yielding normal growth. Spawning was achieved is conditions under through temperature elevation (30°-3I°C) and addi- work necessary to ascertain which the early larvae can be reared to acceptable tion of sperm. size. Research on the Day Octopus, another Scallops specialized food that is highly prized in Hawaii, has The hatchery technicjues of conditioning, spawn- indicated a rapid growth rate with the animal reach-

ing, and rearing the bay scMop. Acqiiipcclen irrci- ing the marketable size of 1 pound (0.45 kg) in about 3

(lidiis. have been developed at the Virginia Institute mo and growing to 3-4 pounds (1.36-1.8 kg) in only of Marine Sciences. The scallop has been raised to 4-5 mo. Current efforts are directed toward the de- market size (5-6.5 cm) with the final growth phase velopment of an artificial food. Mating occurs read- taking place in wooden, rectangular floats (2.1 m x ily in captivity with the females producing an aver- 0.6 m X 15 cm) whose tops and bottoms are covered age of 500,000 eggs. Difficulty has been experienced

4(i in in the rearing of larvae since, while they are active not exhibit malformed yolks which are common and feed, they do not grow. hatchery chum salmon alevins. In the laboratory at Port Oiford, Chinook salmon are being exposed in rearing tanks to increasing salinities to determine the FINFISH feasibility of releasing juveniles directly to seawater Salmonids after only a brief period of adaptation. If successful this could significantly reduce the mortalities which One of the oldest research efforts in the United now occur in freshwater areas. States directed toward developing improved strains Other work at Oregon State University on salmon of seafood organisms is that at the University of includes attempts to: improve certain strains Washington under Lauren R. Donaldson. Over a through hybridization and selective breeding; de- period of 40 yr. through a selective breeding pro- velop methods for rearing in power plant effluents; gram, several species of salmon and hybrids of trout determine the effects of infection by the trematode, have been developed, and eggs from this program Nanophyetus scilmincoUi; and develop techniques have been provided to organizations all over the for cryopreservation of gametes. Sperm frozen for 7 world. Currently Donaldson and his co-workers are days at -I96°C were thawed and used to fertilize working with rainbow trout, rainbow-steelhead hy- 80% or more of fresh eggs from coho salmon and brids, and Chinook and coho salmon. Oncorliynchus steelhead trout, Salnio gtiirdnen. tsfunvyscha andO. kisiitch. Millions of eggs are pro- duced each year, some being used in the breeding Seafood scientists at Oregon State University are program, some irradiated for studies of the effects of working with several salmon diet formulations in radiation exposure, and others used or provided to order to develop new rations, as well as to learn more other organizations for other types of research or for about the nutritional requirements of the salmon. aquaculture. Experiments now completed indicate that a pelleted In an associated program, other University of fish food utilizing 40% dewatered and comminuted Washington fisheries biologists are attempting to shrimp wastes provide results as good as those ob- demonstrate the practicality of rearing salmonids in tained with the commonly used Oregon moist pellet. floating pens, in brackish water ponds, and in saltwa- Thus, a use for large quantities of raw shrimp wastes ter estuaries. In this work, which is being conducted has been identified. cooperatively with private industry, the salmon are Coho and chinook salmon are being reared in net being reared for two uses: 1 ) direct marketing and 2) enclosures in the open waters of Puget Sound in a release at an advanced stage for support of sport and project being conducted by a private firm. Ocean commercial fisheries. This same project also in- Systems, Inc. This project is an outgrowth of work cludes studies of the effects of environmental by the National Marine Fisheries Service whose parameters on the success of rearing salmonids in scientists continue working on associated problems. seawater, the training of salmon to come to an Assistance has also been received from the underwater sound source for effective feeding and Washington State Department of Fisheries and the harvesting, and feasibility studies on enhancing pro- University of Washington. The eggs were hatched duction of 20 species of flatfishes indigenous to and the fingerlings placed in a freshwater pond. Puget Sound by improved cultural techniques. When they reached the desired size, the fish were A team of researchers at Oregon State University transferred by truck to small net enclosures (7.5 x is investigating several problems associated with 7.5 X 4.5 m) in the Sound and later transferred to four salmon culture. New hatchery methods which simu- larger (15 x 15 x 7.5 m) growing pens which are late natural spawning beds are being developed. The attached to an anchored raft. The enclosures are system involves raising salmon alevins (larvae) in covered by a net to protect the fish from bird pred- darkness on a gravel substrate instead of on screened ators and surrounded on four sides and the bottom trays or smooth tank bottoms. Water velocity is by a 6.4-cm stretch mesh gill net to protect the fish similar to that in good quality natural spawning beds. from dogfish and other predators. Several hundred thousand chum salmon. O. keta, At the present time, approximately 230.000 coho are being produced annually by this method at an and 270,000 chinook salmon are growing in the pens. e.xperimental hatchery located at Netarts Bay. The They are fed a dry salmon pellet ration which is fry from the gra\el incubator are considerabh larger hand-cast over the enclosure. .Although some of the than frv from standard hatcherv incubators and do salmon have reached potential market size in 8 mo.

47 the average weight was 0.06 kg. The com- feasibility of commercial salmonid culture for food pany, working with the National Marine Fisheries fish markets. A projection of production costs for a Service, will begin test marketing the 0.2-0.34 kg fish model salmonid aquaculture facility has Just been shortly after the beginning of the year. Current ef- completed. forts also include an evaluation of the potential en- vironmental effects of a large-scale operation of this Striped Mullet type. In an effort to develop a controlled culture system In northern California, at Humboldt State College, for striped mullet, Miigil cephaliis. scientists at the fisheries biologists are in the early stages of testing Oceanic Institute in Hawaii have devoted consider- the efficacy of enriching brackish water and saltwa- able effort, with success, to the induction of spawn- ter rearing ponds with sewage etTluents for the rear- ing. Successful breeding of wild, adult fish has been ing of salmon and trout. The fish are released as fry accomplished with injections of salmon pituitary in and fingerlings into two ponds, one a control sea- conjuction with Synahorin. or with low doses of a water pond and the other contains a seawater and partially purified Pacific salmon gonadotrophin. sewage effluent mixture. The scientists hope to deter- Spawning was also induced in captive animals using mine if it is possible to rear fish to migrant size more a controlled photoperiod regime followed by injec- cheaply by this method than with standard fish cul- tions. Larval rearing studies are also underway using ture techniques. Harvest for human use would occur copepod adults and nauplii and gastropod veliger after the fish had been released and continued their larvae as food. The veliger larvae appear to be pre- growth in the natural environment. ferred by the striped mullet larvae and are produced

At the present time there are 40,000 coho salmon in the laboratory. (10,000 of them marked) and 2,500 steelhead trout In a companion project, the problems associated divided between the two ponds. Growth and mortal- with rearing the striped mullet in coastal ponds are ity studies are being conducted to evaluate the suc- being studied. Artificial seaweeds ("X" sheets of cess of this technique. plastic) are anchored in the ponds. Algae grow on Scientists at the University of Rhode Island are this plastic "grass" and are eaten by the fish, thus attempting to develop a new form of aquaculture, providing a cheap source of food for the fish in cul- based on a closed cycle, controlled environment ture. system, which will have almost no environmental Young striped mullet have been studied at Texas impact and be compatible with other demands on A&M University to determine high temperature re- coastal resources. Salmonids; Atlantic salmon, sistance and acclimation rates in laboratory tests.

Salmo scihir: pink salmon, Uncorhynclus goibiischa; Salinities of 1 and lO'Von were more suitable than 20 rainbow trout, bluefish, Pomatomus saltatrix; and and 30"/oo for temperature acclimation and heat resis- striped bass, Moronc suxcililis. are being grown in tance of young mullet. These findings may be useful the project. The work is intended to provide infor- in the development of pond stocking guidelines. A mation which will increase the operating efficiency two-factor laboratory study on the effects of salinity and capacity of present day salmon hatchery and and temperature on survival and growth of striped smolt production facilities as well as improve diets mullet has recently been completed. Statistical for fish in culture. Nutritional and physiological analysis of the results has not been completed, but studies are underway, with one study the effect of the the data suggest that striped mullet are tolerant to level of dietary protein and different lipids on the broad ranges of both factors. nutrition of rainbow trout adapted to an intermediary salinity (16"/(mi) just completed. Dolphin Studies are being conducted to determine the re- quirements for rapid activation of biological filters in Work is underway by North Carolina State Uni- both marine and freshwater systems. Also, alterna- versity biologists to determine the feasibility of tives to biological filters for water purification in the commercial propagation of the do\ph\n. Corypluicna closed circuit system are being evaluated. hippiinis. Successful efforts, being conducted at One key part of this work is aimed at solving the Hatteras. N.C., and Bimini, Bahamas, have been problems resulting from the accumulation of ni- directed toward developing artificial spaw ning tech- trogen waste products in the closed system. Another niques by use of sex hormones. Capturing and trans- part of this program is an analysis of the economic porting techniques have been developed, and growth

48 studies have yielded an average weight increase of I valuable bait fish in Texas has been studied at Texas pound (0.5 kg) per week with a maximum growth of A&M University to determine the effect of salinity 7'4 pounds (3.5 kg) in 6 wk. Larval rearing techni- on high temperature resistance and acclimation rates ques will be developed as dependable spawning is in the laboratory. At 10 and 20"/oo these fish fared

realized. better than at 1 or SO^/oo.

Miscellaneous SEAWEEDS Red Algae Several species of finfish (see appendix for names of species) have been studied at the Hawaii Institute One of the most advanced programs in seaweed of Marine Biology on Coconut Island to determine culture in the United States is being conducted by their potential for aquaculture. They were selected phycologists at the University of Hawaii. The pro- on the basis of their acceptability as food or bait and gram consists of the development of techniques for their ability to grow in captivity. Eggs, larvae, juve- growing the red alga, Eiicheuma (three species), as a niles, or adults were collected according to their carrageenan source. Small, pilot-scale farm opera- availability, and attempts were made to ascertain tions have been established and successfully demon- their environmental requirements in a variety of strated in the Philippines, the Trust Territory, and situations including small tanks, floating rafts, other Pacific areas. Hopefully, this project will lead ponds, etc. Investigations were made on nutrition, to full-scale commercial operations which will pro- growth, reproduction, and diseases of the various vide a reliable supply of raw material for the U.S. species. carrageenan industry. Research at Louisiana State University has been Other seaweed projects at the University of directed toward determining the various parameters Hawaii are investigating the culturing of other red controlling growth of several species of finfish in and green algae (Gnicilciria, Hypiieu, Cladopliora. culture. The effects of salinity and other water qual- and Ulva) and their potentially useful extracts. ity parameters on channel, blue, and white catfish Two projects aimed at expanding the source of

(htiiliinis piinctatiis, I. furcatiis, and/, cuius) and commercially valuable seaweeds in the United on Florida pompano (Trachinolus carolinits) have States are underway at the University of South been identified. One notable effect of brackish water Florida. One is a field and laboratory study of the on the catfish is that it prevented outbreaks of the carrageenan source, Eiicheuma isiforme. which in- protozoan parasites, Ichtyophthirius multifilis, volves studies of growth, reproduction, morphol- which is frequently a serious problem in freshwater ogy, and carrageenan content of tagged plants grow- catfish culture. Other studies have examined ing naturally in the ocean, plants suspended from

growth, development, and survival of the pompano lines 2 ft above the bottom, and plants under labora- and the Atlantic croaker, Micropogon undidatus, in tory culture. Results to date suggest that in the ocean, culture. growth rates are highest in the cooler months,

For the past 6 yr, Louisiana State University whereas carrageenan content is highest in the warm- (LSU), in cooperation with the Louisiana Wild Life est months. Morphology does not appear to be and Fisheries Commission, has screened a number easily influenced by environmental changes, such as of species for suitability for culture including: three would occur in transplantation, but may be greatly species of freshwater catfish (blue, channel, and influenced by nutrient levels. Reproduction appears white), pompano, mullet, croaker, crawfish, and to be limited to very brief times and may not even redfish. These species are also being stocked in vari- occur yearly. ous combinations, polyculture. In one study, the The other project consists of experimental cultiva- mullet-channel catfish combination showed prom- tion of about a dozen species of south Florida red

ise. Total production in ponds was increased. The marine algae in various habitats, during different

mullet, acting as a biological filter, helped to clean up seasons of the year, using three procedures: 1) veg- solid wastes produced by catfish, as well as adding to etative growth in net-covered frames or in, or upon, total production. LSU has consistently produced other forms of substrata: 2) the "seeding"" of

over 1 ton of channel catfish per acre in ponds with selected substrata with a given species, and obtain- salinities up to lO'Vuo total salinity. ing either gametophyte or sporophyte plants as de- The sheepshead minnow. Cv/«7//<)(/(w; vurici^atiis. a sired: and 3) the placing of solid substrata in areas

49 suitable for algal growth but lacking the necessary conducted at the Marine Laboratory of the Califor- substrata. nia Institute of Technology. During their early at- The most promising results with a potential for tempts of restoring the kelp beds off southern direct application in the production of quantities of California, the researchers simply transplanted adult taw material for industry have come from the first plants from an existing bed to an area where a new procedure. Growth of Hypnea musciformis and bed was to be established or a disappearing bed GraciUiriafolifera in net-covered cages, floatingjust strengthened. The adult plant then released spores

15 cm under the surface, during the warmer months \\ hich produced new plants. At the same time quick- of the year was very rapid, often doubling their lime was spread over the bottom to kill the heavy weight in 1 day. These plants, growing in a very grazing sea urchins. Attempts were also made to favorable environment and protected from grazers, protect the young plants from grazing fish with net increased their weight from lOto lOOgin 10-14days. covers. The culture of Eialwnma isifonne and E. acantho- Recent work has been devoted to the development chuliiiu. using some of these techniques, will be of techniques for raising Macrocystis plants in mass emphasized during the next year. culture from liberated zoospores, through the Methods to culture both benthic and planktonic gametophyte to the embryonic sporophyte. The em- marine algae are being developed at the University bryonic sporophytes which develop on an artificial of Washington. The phycologists have demon- substrate are scraped free and dispersed close to the strated that Iridaea cordalct, Gigartino exasperata. bottom in areas suitable for kelp growth. Preliminary dndAi^'dnlliii'lla teiu'ia vav. pacijka can be success- estimates indicate that about lO'* embryos must be fully transplanted to habitats in which they have not dispersed to yield one attached Macrocystis ']U\Qm\t previously grown, and have grown these three about 15 cm tall. species, plus Sarcodiotheca fitnaici, in laboratory The culture system now in use can produce 10^ to cultures. In a related effort, the investigators have 10" embryos per cm- of culture substrate. Thus, the completed a study on extracellular, water-soluble low survival rates following dispersal do not prohibit polysaccharides produced by various marine the use of this system for developing new kelp diatoms and isolated in axenic culture the unicellular stands. Out of five areas in which this technique red alga, Rhodosonis nuiriniis for subsequent was attempted, youngM curacy stis developed in growth experiments. three of them with hundreds to thousands of plants A multidisciplinary team at the University of resulting in two of the areas.

California at Santa Barbara is studying some of the varied problems encountered by the seaweed indus- MARINE PATHOLOGY try in the United States. Biologists and engineers are studying the settlement and growth of spores, includ- Several institutions have directed research efforts ing the effects of water motion on spore settlement toward the diseases and parasites of seafood or- and on reproductive stages. Transplants of ganisms, usually looking at several different kinds of Gelidiiim. Gnicilaria, and Maciocysiis are being animals. Most of the animals examined are being made for studies of growth and colloid production. cultured, at least experimentally, in the United As part of this program, economists are surveying States. Texas A&M University has established an the present and future status of the U.S. seaweed Aquatic Animal Medicine laboratory on its campus industry. An economic model is being developed for and is working with a wide variety of finfish and the agar weed Gelidiiim. which considers growth, shellfish, looking for many types of bacteria, vi- loss, and reproduction rates; production problems: ruses, and other infectious agents. They have iden- and agar content. tified the microbial fiora of Gulf of Mexico and Future work will include an evaluation of harvest- pond-grown shrimp and developed new techniques ing methods and packaging operations and the de- for detecting certain agents and diseases in finfish \elopment of a '"breeding stock"" of rapidly growing and shellfish. forms. Microbiologists at Georgetown University have been examining several Chesapeake Bay organisms Brown Algae for the bacterium, I'ihrio pciraliacituilyticiis.

One of the oldest programs in the United States in responsible for many cases of food poisoning in seaweed management is the kelp research now being Japan and some recent cases in the United States.

50 This bacterium has been isolated from dead anu pipe. Work is in progress toward establishingecolog- dying blue crabs from Chesapeake Bay and was ical and productivity baselines on the trophic sys- craters that are washed over by isolated from dead and dying cultured shrimp taken tems in two nuclear from Texas A&M University's ponds. the tides and have become invaded with marine or- Several other universities, including Oregon ganisms. In preparation, moreover, are efforts to of the reef and what State. Miami. Rhode Island, and Washington, have assess the water yield capacity during the seawater"s programs in marine pathology in which both w ild and changes the nutrients undergo formation. cultured animals are being studied. While it will be passage through the coral of scien- difficult, if not impossible, to solve disease and In a somewhat related program, a team parasitic problems in wild populations, this work tists from the Lamont-Doherty Geological Obser- could lead to solutions of problems with pathogens vatory of Columbia University is working on St. the encountered in aquaculture. Croix in the U.S. Virgin Islands to demonstrate feasibility of using deep, cold ocean water for aquaculture and. later, for other uses. The total sys- NEW AQUACULTURE SITES tem could involve multi-usage of the water: sea Two projects are underway at the University of thermal power production by the Claude process, air California to explore the potential of selected envi- conditioning, ice-making, cooling of electric power ronments for aquaculture. The first, at the Santa and desalination plants to avoid thermal and brine Barbara campus, involves the study of a California pollution, and condensation of atmospheric mois- coastal lagoon to determine its usefulness as a man- ture for freshwater production. The experimental ageable ecosystem for aquaculture. The inves- work to date, however, has been restricted to the tigators believe that it may be possible to increase aquaculture portion of the total system. productivity by shortening the normal food chains, A pilot-plant operation was established in which reducing predation and/or artificially fertilizing this water was pumped into small ponds from a depth of ecosystem. Initial efforts are devoted to a study of 830 m through an 1 .800-m long polyethylene pipeline the basic ecology of the lagoon, including of 7.5-cm internal diameter. The ponds are used to meteorological measurements, physicochemical de- grow diatoms (mainly Cyclotella nana ) which are fed terminations, and biological sampling. into tanks containing trays of Eastern oysters, Cras- The second, at the Scripps Institution of sostrea virginica, and hard shell clams. Mercenaria

Oceanography, is examining the feasibility of a mercenaria. Results to date have shown the system large-scale seafood production unit utilizing the nu- to produce unusually fast growth rates for both types trients contained in deep oceanic waters to enrich a of shellfish. However, some oyster mortalities have marine food chain. The pilot study is being carried been experienced. The culture of other types of sea- out on Eniwetok Atoll in the Marshall Islands, food organisms utilizing this technique will be ex- where the deep water may be brought up by drilling amined later and an expanded experimental system into the coral reef rather than by using a submerged is planned.

51 . .

APPENDIX

National Sea Grant Aquaculture Programs

(B> organization)

California institute of Technology 2. Ecosystem studies and mariculture Pasadena, C A 91109 potentialities of a coastal lagoon. Project: Robert W. Holmes. Department of Restoration, propagation and management Biological Sciences. of marine algae (Macrocystis pyrifera). Wheeler J. North. Department of Engi- Columbia University neering and Applied Science. Lamont-Doherty Geological Observatory I'alisades. NY 10964 University of California at Davis Project: Davis. CA 95616 Artificial upwelling. Oswald A. Roels, Projects: Chairman, Biological Oceanography.

1 The culture, selective breeding and gene- tics of the lobster, hotnanis anierlcti- University of Delaware nus. Robert Shleser, Department of Newark. DE 19711 Genetics. Sea Grant Program Director. Dr. William

2. Habitats for rearing of lobsters (//o/?;«/z/.v Gaither. Dean. College of Marine Studies: tele- ctnu'ikanus). Robert Shleser, Depart- phone (302) 738-2841. ment of Genetics. Projects: 1. System engineering and development of

University of California at San Diego, and commerically valuable marine shellfish. Institute of Marine Resources (Crassostrea virginica and C. gigas.) La Jolla, CA 92037 Donald Maurer, Department of Biologi- Sea Grant Program Director, Dr. George Shor; cal Sciences.

telephone (714) 453-2000, ext. 1094. 2. Closed environmentally controlled sys- Projects: tems for aquacultural production. 1. Abalone culture methodology and larval Oscar R. Harmon. Department of ecology. (Halioiis nifescens (red). H. Agricultural Engineering. conuiidta (corrugated), H. fiilgens 3. System engineering for shellfish (green), and H. soiensensi (Sorensen).) production. Frederick A. Costello. David L. Leighton. National Marine Department of Mechanical and Aero- Fisheries Service Laboratory. La Jolla. space Engineering.

2. Enhancement of natural marine produc- 4. Investigation of new shellfish species for tivity by artificial upwelling. Walter R. closed cycle mariculture. (Mercenaria Schmitt, Scripps Institution of Oceanog- mercenaria, Cullincctes spaiJii.s. raphy, l,a Jolla. etc.) Charles Epifanio, College of Marine Studies. University of California at Santa Barbara Santa Barbara, CA 93106 East Carolina University Project: Greenville. NC 27834

1. Continued studies of seaweed resource Project: management (cultivation). (Gclidiiim. Studies on reproduction and fimgal para-

Grciciliirid. and Miicrocystis.) Michael sites affecting reproduction in the lobster. Neushul and .Alexander Charters, Honuinis anwricdniis. and the blue crab. Department of Biological Sciences; Callinccles sapidits. in North C arolina and Walter J. Mead. Department of waters. Edward P. Ryan and Charles E. Economics. Bland. Department of Biologv . .

Georgetown University 2. The utilization offish wastes for rearing Washington. DC 20007 of crabs in salt and brackish water Project: (Cancermagister). James P. Welch. De- Vibrio parahaemolyticus in Chesapeake partment of Natural Resources. Bay - isolation, incidence and pathogenicity. Rita R. Colwell, Department of Biology. Louisiana State University Baton Rouge, LA 70803 Sea Grant Program Director, Jack Van Lopik, University of Hawaii Office of Sea Grant Development; telephone Honolulu. HI 96822. and (504) 388-1558. Hawaii Institute of Marine Biology Projects: Coconut Island

1 Culture of fish and crustaceans (Penaeus Sea Grant Program Director, Dr. Jack Davidson, sp. and Trachinotus carolinus). James Director of Sea Grant Program; telephone (808) W. Avault, School of Forestry and Wild- 944-7331. life Management. Projects: 2. Nutritionofpenaeid shrimp. Samuel P. 1 Production of food colloids from tropical Meyers, Department of Food Science marine algae. Maxwell S. Doty, De- partment of Botany. Honolulu. and Microbiology.

2. Seaweed agronomy. Ma.xwell S. Doty, Department of Botany. University of Maine 3. Algal food for aquatic organisms. Orono. ME 04401, and Maxwell S. Doty, Department of Ira C. Darling Center Botany. Walpole, ME 04573 4. Tropical animal aquaculture: Finfish - Sea Grant Program Director, David Dean; tele- omaka {Caranx mate), yellow ulua phone (207)563-3146. (Gnathanodon speciosus), moiiPoiydac- Projects: lyliis sexifilis), Japanese yellowtail 1. Laboratory spawning and rearing of deep (Seriola quinquiradiata), Nehu or Ha- sea scallops (Placopecten magellan- waiian anchovy (Stalephonis piir- icus). Herbert Hidu, Darling Center, piireus). iao (Pranesiis insulanim), Walpole. freshwater threadfm shad (Dorosoma 2. Adaptation of known cultural techniques pelenense). Molluscs - opihi or limpets for the european oy^iev (Ostiea edulis) to ( exarata and C sandwicensis), the Maine environment. Herbert Hidu, Japanese littleneck clam (Tapes philip- Darling Center, Walpole. pinariuin). Day Octopus (Octopus 3. Engineering assessment of hatchery cyanea). Crustacea - Samoan or man- mechanization; design and testing of grove crab (Scylla serrata). white or submersible rafts for oyster culture. haole crab (Portiimis saiiguinolentus), Richard Rowe. Department of Agricul- opae lolo (Penaeus inarginatiisj. tural Engineering; and Walter Schneider, Department of Mechanical Engineer- ing, Orono. Humboldt State College .Areata. CA 95521 University of Miani Sea Grant Program Director. Richard Riden- Miami, FL 33124 hour. Academic Vice President: telephone (707) Sea Grant Program Director, Wendell Mordy, 826-3632. P.O. Box 9178. Coral Gables. FL 33124: tele- Projects: phone (305) 350-7468.

I. Sewage fertilization of brackish and Projects: saltwater fish ponds for rearing salmon 1. Commerical culture of brachyuran crabs and trout. iOncorhyncluis kisHlch and (Menippe inercenuria and Ccdliiwctes Salmo gairdneii.} George H. Allen. De- sapidiis). W. T. Yang. School of partment of Natural Resources. Marine and Atmospheric Sciences.

53 2. Cryobiological preservation of shrimp Oregon State University sperm and ova. (Pciuieiis diiontniin.} J. Corvallis. OR 97331. and L. Runnels, School of Marine and Atmos- Marine Sciences Center pheric Sciences. Newport. OR 97365 3. Commercial culture of penaeid Sea Grant Program Director, Herbert Frolander, shrimp. (Penaeus diionirutn and Department of Oceanography: telephone (503) others.) Charles W. Caillouet, School of 754-2714. Marine and Atmospheric Sciences. Projects:

4. Induced maturation of ovaries and oo- 1. Physiology of developmental pro- cytes in Pcnaciis diioraniiii in cesses. Ronald H. Alvarado, Depart-

vivo. Charles W. Caillouet, School o\' ment of Zoology, Corvallis. Marine and Atmospheric Sciences. 2. Culture of Pacific salmon. William J. 5. Virology and protective factors. M. M. McNeil, Department of Fisheries and Siegel. Department of Microbiology. Wildlife, Newport.

3. Cultureof bivalve molluscs. Wilbur P.

Francis T. Nicholls State University Breese, Department of Fisheries and Thibodaux, LA 70301 Wildlife. Newport. Project: 4. Culture of crayfish, shrimp, and Effects of water exchange and blue crabs prawns. John R. Donaldson, De- control on shrimp production on Louisiana partment of Fisheries and Wildlife. salt-marsh impoundments, (Brown Corvallis. shrimp, Penaeus uztecus, and white shrimp, 5. Control of pests on oyster P. setifenis.) Alva H. Harris, Department grounds. Raymond E. Millemann. of Biological Sciences. Department of Fisheries and Wildlife, Newport. 6. Field culture of bivalve molluscs. North Carolina State University Howard F. Horton, Department Raleigh, NC 27607 of Fisheries and Wildlife, Corvallis. Project: 7. Heritability in oysters. Raymond C. Abundance, exploitation, migration and Simon, Department of Fisheries and propagation of the dolphin, Corypluiena Wildlife, Corvallis. liippiiici.s. William W, Hasler, Depart- 8. Cryogenic preservation of salmonid and ment of Zoology. molluscan gametes. Howard Horton, Department of Fisheries and Wildlife, Oceanic Institute Corvallis.

Waimanalo, H 1 96795 9. Hybridization of salmon. William J. Projects: McNeil, Department of Wildlife and !. Food resources studies of mullet (Miii^il Fisheries. Nev\port. cephaliis). Ziad H. Shehadeh, Food 10. Culture of algae for mollusks. Harry from the Sea Division. K. Phinney, Department of Botany and 2. Feasibility pilot project for a method of Plant Pathology. Corvallis. open water fish farming. Ziad H. II. Nutrition and waste utilization, Shehadeh, Food from the Sea Division. Russell O, Sinnhuber, Department of Food Science and Technology, Ocean Systems, Inc. Corvallis. Reston, VA 22070 Project: University of Rhode Island Pacific salmon aquaculture program. Kingston. Rl 02881 tOiicoilnnilnis lslitn\\r.\c lui and O. ki- Sea Grant Program Director, Niels Rorholm; siiicli.i Jon M. Lindbergh, Route #8, Box telephone (401) 792-2550. 848.V Bainbridge Island, \V.\ 98110: tele- Projects: phone (206) 842-5098. 1 . Nutrition of salmonids and other selected

54 species. (Chinook salmon. Onrorliyn- 2. Experimental rearing of flounder to mar- cluis tshawyisclui: coho or silver salm- ketable size in tidal flushed on, O. kisutcli: striped bass, Morone ponds. James W. Andrews, Life Sci- sa.xatilis; and American lobster. Honuuiis ences Division. iimericiuiiis.) Thomas Meade, Marine Experiment Station. University of South Florida

2. Commerical aquaculture of American Tampa, FL 33620 lobster. Akella Sastry, Graduate Projects: School of Oceanography. 1. Experimental cultivation of red algae of 3. Chemistry and microbiology of recir- economic value in Florida marine culating aquaculture systems. John waters. (12 species of red algae.) Sieburth, Graduate School of Oceanog- Harold J. Humm, Director, Marine Sci- raphy. ence Institute, St. Petersburg, FL 33701. 4. Marine pathology. (Protozoal infection 2. Ecological and culture studies on the red

of ocean pout, Macrozoarces america- alga, Eiicheitma isiforme. Clinton J. nus; fin rot in salmonids: epithelio- Dawes, Department of Botany and Bac- cystis disease of striped bass, Morone teriology. sa.xatilis, and white perch, Morone americana; effects of nitrosamines Texas A&M University on marine fish tissue.) Richard College Station, Texas 77843 Wolke, Graduate School of Ocean- Sea Grant Program Director, John C. Calhoun, ography and Department of Animal Vice President: telephone (713) 845-3854. Pathology. Projects:

5. Economic analysis of salmonid aqua- 1. Mariculture of commerical crustaceans culture. John M. Gates, Department and fishes on the upper Texas of Food and Resource Economics. coast. (Panaeus aztecus, P. setifenis, Callinectes sapid us. and Miigil San Diego State College cepluilus.) Kirk Strawn, Department of San Diego, CA 92115 Wildlife Science, College Station. Sea Grant Program Director, Glenn A. Flittner, 2. Mariculture pond demonstration. Bureau of Marine Science: telephone (714) (Panaeus aztecus and P. setifenis.) 286-6523. John E. Hutchison, Director, Cooper- Projects: ative Extension Service, College Sta- 1. Studies of recruitment and growth of tion. puerulus and juveniles of the California 3. Shrimp culture research. (Panaeus az- spiny lobster. (Panulirus interruptus.) tecus and P. setiferas.) William F. Deborah M. Dexter. Division of Life Mcllhenny, The Dow Chemical Com- Sciences. pany. Freeport, TX 77541. 2. Investigation and development of an 4. Bacterial and viral diseases and cell cul- American \ohsXeT{Homariis americaniis) tures of marine fish and shellfish. fishery in California. Richard F. Ford, George W. Klontz, Department of Division of Life Sciences. Veterinary Medicine, College Station.

Skidaway Institute of Oceanography Virginia Institute of Marine Sciences Savannah, GA 31406 Gloucester Point, VA 23062

Projects: Sea Grant Program Director, William J. Hargis, 1. A study of the nutritional, environmental Jr., Director: telephone (703) 642-2111. and economical requirements for the in- Projects:

tensive aquaculture of penaeid 1. Develop and demonstrate improved shrimp. iPcnaeiis setifenis. P. azieciis. methods of producing hard clams and and P. cliiorantni.) James W. Andrews, investigate the possibility of reviving Life Sciences Division. the bay scallop industry, i Mercenaria mercenaria and Aequipecten irra- 2. Aquaculture of Puget Sound fishes.

dians.) Michael Castagna, Eastern lOiicorhyncliKs iscluiwylsclui . etc.) Shore Laboratory. Wachapreague: and Ernest O. Salo, College of Fisheries. William T. Duggan. Gloucester Point.

2. Management of larvae, supply of 3. Development of a clam and oyster farm at food. John L. Dupuy, Gloucester Big Beef Harbor. (Venerupisjaponica Point. and Crassostrea f;igas.) Kenneth K. University of Washington Chew. College of Fisheries. Seattle. WA 98105 Sea Grant Program Director. Stanley R. Mur- 4. Algal culture as aquaculture feed. phy, Division of Marine Resources: telephone Frieda B. Taub. College of Fisheries. (206) 543-6600. Projects: 5. Aquaculture of marine algae. Ilridaea

1. Expanded program in salmonoid cordata, Gigartina exasperata, Agar- aquaculture. (Oncorhynchus ki.siilch, dhiella tenera, and Sarcodiotheca etc.) Lauren R. Donaldson. College of furcata.) Richard E. Norris. Depart- Fisheries. ment of Botany.

56 AQUACULTURE OF MOLLUSCS ALONG THE UNITED STATES ATLANTIC AND GULF COASTS

WILLIAM N. SHAW

INTRODUCTION the best yield on the bottom is 2.0 tons per acre per year (Ryther and Bardach, 1968). These yields are

Today I would like to take you on a tour of the east extremely low when compared to those of Japan and gulf coasts of the United States to review the where 23.3 tons per acre per year are being harvested past and present status of molluscan aquaculture. using off-bottom methods. Robert D. Wildman has already reviewed the cur- Not only are most of the U.S. methods of growing rent molluscan aquaculture projects under the Sea oysters extremely primitive, but so are our ways of

Grant Programs for this area, so I will cover these harvesting. In Maryland, the state that has the projects only briefly in my presentation. Because of largest annual production of oysters, oystermen the limited time. I plan to center my discussion catch oysters with hand tongs and patent tongs and around the culture of three species of molluscs, the in dredges pulled along the bottom by sailboats. , Crassostrea virginica; the hard Laws in this state prevent the use of more mechani- clam, Mercenaria mercenaria: and the bay scallop, cal means such as the hydraulic dredges, except on Aeqiiipecten irradians. Although there are other im- private leases. portant commercial molluscs found along our east Realizing that the production of oysters has been and gulf coasts, such as the surf clam, SpisuUi on the decline, many private companies, state and solidissima: ocean quahog, Articci ishindka; sea federal agencies, and universities have in recent scallop, ; sunray venus, years initiated programs in an attempt to modernize

Macrocallista nimhosa: calico sc^Wop. Aeqiiipecten the oyster industry. I would like to review some of gibhiis: and the soft-shell clam, Mya urenarici. these these programs at this time. species are being hunted. Little or no attempt is being made to farm these species at the present time. New Hampshire

I will review the fishery for the oyster, hard clam, and bay scallop and describe past and present at- Under the U.S. Government's Federal Aid Pro- tempts to farm each species. gram the State of New Hampshire has for 3 yr (1966-69) investigated the possibility of producing THE EASTERN OYSTER seed oysters and growing oysters using off-bottom techniques (Ayer, Smith, and Acheson. 1970). New

Hampshire is at the northern limit of the oyster's The Eastern oyster, Crassostrea virginica, (also natural range, and because of the cold waters, called the American or Virginia oyster) ranges along growth is slow. Still in certain areas, like Great Bay, the entire east and gulf coasts. Peak of production, the water warms sufficiently so that the natural oys- near 170 million pounds, was reached in the I890's. ter populations can spawn and setting does occur. It Since then, landings have been on the decline with an appears from their studies that a limited amount of apparent leveling off in the I960"s —around 50-60 seed could be produced annually, but intensity million pounds (Engle, 1966). Unlike Japan, oysters would vary greatly from year to year. along the east and gulf coasts are grown almost en- tirely on the bottom. The national average is re- ported to be only 0.004 tons per acre per year, while Massachusetts

Production of oysters in Massachusetts is small ' Middle .Mlantic Coastal Fisheries Center. National Marine Fisheries Service. NO.A.A. . MD 21654. and only 72,100 pounds of meats were harvested in

57 1970. Yet. during the 10-yr period from 1910 to have excellent consumer acceptance on the half 1919. an annual yield of 1.2 million pounds was shell. realized. Up to recent times, all oysters were grown An 8-ft high tower has been constructed adjacent on leased bottoms. Because of the cold waters, it to the Wareham River for growing oysters (Zahrad- takes up to 5 yr for oysters to reach market size. nik and Johnson. 1970). A series of 4 ft x 4 ft Massachusetts oysters are of excellent quality and tray-pallets containing up to 50 bushels of oysters are are eaten raw on the half shell. The wholesale price is in the tower. Water is supplied to the tray-held oys- as high as S22.00 per bushel (7,920 yen. 250 oysters ters through a pipe running up the center of the to the bushel). tower. It is planned to operate the tower for I yr. in 1956. the Bureau of Commercial Fisheries (now including a winter season. the National Marine Fisheries Service) initiated studies on the off-bottom culture of oysters in Mas- Rhode Island sachusetts. Because of the oyster's high price, it was felt that this method of culture may be commercially In 1910 over 15 million pounds of oyster meats feasible. were harvested from Rhode Island. In 1970 only 146 A log raft was constructed and moored in Oyster pounds of meats were landed. Although many fac- Pond River. Chatham. Mass. Oyster and scallop tors have contributed to this decline, pollution of shells, containing seed oysters, were strung on #14 Narragansett Bay is the probable leading factor. galvanized wire, each shell separated by a 3-inch At present, one company is attempting to grow piece of plastic tubing. The strings were suspended oysters suspended from rafts (patent pending) in a from the log raft for 1 yr, and then the oysters were small tidal pond. This is a small operation and only removed and planted on the bottom for an additional 800 bushels were expected to be harvested annual- year. ly- The results of the study showed that oysters grew Connecticut-New York almost twice as fast as those on the bottom. Survival of raft oysters was about 6 times greater than for the In the late ISOO's. Connecticut was producing bottom grown oysters. Meat quality was excellent. over 10 million pounds of oyster meats annually. In Finally, the results indicated that raft culture ap- 1970. only a little over 125,000poundsof meats were peared commercially feasible in Massachusetts landed. Set failures have contributed greatly to the (Shaw. 1962). drop in production. Loosanoff (1966) reported that Similar raft studies were conducted by Matthies- during the years 1925-60, a good commercial set has sen and Toner (1966) on Martha's Vineyard, Duke's occurred only 8 times. In addition, factors such as County, Mass. These results showed that suspen- slow growth, predators, siltation. pollution, and hur- sion techniques offered a promising method of oys- ricanes have all contributed to the decline of this terculture in the county. The authors felt that further once prosperous industry. refinement of suspended materials was needed and In an attempt to help the oyster industry of this that rafts which could be conveniently submerged area, a center for shellfish research was established below the surface should be developed because by the Bureau of Commercial Fisheries at Milford. many areas were exposed to storms and moving Conn. The Milford laboratory has become world ice. renown for its work in developing shellfish hatchery It was not until 1970 that off-bottom culture was techniques (Loosanoff and Davis. 1963). Shellfish attempted commercially in Massachusetts. Aqua hatcheries are now located throughout the United Dynamics Corporation. Wareham. Mass. has begun States and in many foreign countries. The use of lime to grow oysters suspended from iron-pipe racks (10 and Polystream- for predator control was also de- ft X 7'/2 ft X 5 ft) that rest on leased bottom. This veloped at the Milford laboratory. Unfortunately, year they plan to have 575 racks. Fach rack contains because of the current feelings about dumping chem- 154 5-ft strings which will yield approximately 60 bushels of oysters. The corporation hopes to market

their oysters, which will measure from 2 to 2' 2 in-

- .'\ polychlorobenzene product produced by Hooker Chemical ches, in I '2 \r. In a cooperative study with the

Corp . Niagara Falls. New York. Polystream is a registered National Marine Fisheries Service. Division of trademark. (Reference to trade names does not imply endorse- Marketing, it was learned that these small oysters ment b\ the National Marine Fisheries Service. NO.'X.A.)

58 icals in the water, the license for using Polystream New Jersey-Delaware has not been renewed. In 1968, the American Cyanamid Company of The leading area of oyster production in the New Stamford, Conn., developed a report entitled, Jersey-Delaware area is Delaware Bay. The once "New Engineering Approaches for the Production productive oyster beds in the Bay have been dev- of Connecticut Oysters." They attempted, through astated by increasing pollution, freshwater abate- a search of published literature relating to oysters, to ment, increased predation problems, and, most re- develop an oyster factory. The general conclusion cently, by massive mortalities from the disease, was that more research was needed (Calbo et al.. "MSX" (Miiichinia nelsoni). Landings in 1970 to- 1968). talled only 869,000 pounds. In 1950, the two states In New York, over 24 million pounds of oyster produced over 9 million pounds of oyster meats. The meats were landed in 1911. Since then production bay can be divided into two areas—the upper seed has steadily declined and reached an all-time low in beds and the lower leased growing grounds. Shells 1967 of only 101,000 pounds. From 1968 to 1970, are planted on the seed beds and later transplanted production has risen slightly to 534,000 pounds in by the private planters to their leased bottoms. Fol- 1970. New York like Connecticut has faced seed lowing the heavy mortalities in 1957 and 1958, New shortages. Three interesting developments have Jersey initiated a large shell planting program to taken place in recent years in an attempt to alleviate rehabilitate the oyster industry. Recently, heavy this problem. At Fisher's Island, N.Y., seed oysters oyster sets on these shells suggests that the oyster are being caught on scallop shells suspended from industry may recover. rafts in a 23-acre brackish water pond (Matthiessen, Both Rutgers University and the University of 1970a). In 1969, 150 rafts were moored in the pond and Delaware have been investigating disease resistance roughly 68.000 strings were suspended. This year of oysters to MSX. Also, at the University of Del- approximately 100,000 strings were used. In 7 yrof aware, extensive studies on the feasibility of semi- operation, only once was there a set failure. A por- closed and closed systems for culturing oysters are tion of the shells bearing the oyster spat are stripped now underway. This aspect of research is supported from the strings, loaded upon oyster boats, and under the Sea Grant Program described earlier by planted upon private grounds in Long Island Sound. Robert D. Wildman. The remainder of the shells are transported to Mas- sachusetts and suspended from the iron-pipe rack Maryland- Virginia described earlier in the talk.

Second is the development of commercial shell- Chesapeake Bay is one of the leading oyster pro- fish hatcheries in the Long Island Sound area. One ducing areas of the world. In 1880. nearly 125 million

of the largest is operated by the Long Island Oyster pounds of meats were harvested from the Bay. In Farms, Inc., in cooperation with the Long Island 1970. production was just under 35 million pounds or

Lighting Company. The hatchery is utilizing a 4-acre about one-half of the total U.S. production for that pond which receives warm-water discharge from a year. Yet. methods of oyster culture are extremely fossil-fuel power plant. The young trayed oysters are primitive with little or no change in either culturing placed in the pond for various periods of time before or harvesting methods since the turn of the century. being planted on the bottom in the natural waters of In Maryland, for example, the majority of oysters the Sound. Because of the quicker growth rates in harvested come from public bars. The tools used to the heated pond, the oysters reach market size in a harvest these oysters include hand tongs, patent year or so sooner. A marine museum adjacent to the tongs, and dredges pulled by boats under sail. Man- hatchery has been constructed for the viewing pub- agement consists mainly of planting up to 5 million

lic. bushels of shells for catching seed oysters and im-

Third is the New York State Department of En- proving or enlarging public oyster bars. Following vironmental Conservation project supported by fed- setting, the seed is replanted on public oyster bars

eral funds (PL 88-309) to produce seed oysters in a where it remains until harvested by oystermen, 3 or 4 natural pond in East Hampton. Long Island. To yr later.

date, little success has been obtained in their at- There have been several attempts in recent years tempts to catch seed on shells suspended from rafts to demonstrate new methods of oyster culture that or placed on the bottom. may be applied in Chesapeake Bay. These include

59 hatchery systems, raft production of seed oysters, North Carolina, South Carolina, and Georgia and culture of oysters to market size using off- bottom techniques. Two commercial shellfish The total production for the three south Atlantic hatcheries have been built, one at Urbanna, Va.,and states —North Carolina. South Carolina, and

the other on West River in Maryland. Both are pro- Georgia—was estimated to be 1 .4 million pounds in ducing cultchless oysters. Unfortunately these 1970. Methods of culture in these three states are single oysters are very vulnerable to predators and primitive, harvesting by hand is not uncommon. Lit- the handling of the juveniles is a formidable prob- tle attempt has been made, until recently, to investi- lem (Matthiessen, 1970b). The former company is gate new aquaculture techniques. In North Carolina, attempting to grow them to market size while the lat- a seed collecting project was undertaken under the ter is selling the small spat to private growers. There federal aid PL 88-309 program. Several varieties of are also two research agencies, Virginia Institute of cultch were tested. Because of heavy fouling, the Marine Science (Andrews and Mason, 1969) and cultch was lifted out of the water periodically. Using the Chesapeake Biological Laboratory (Hidu. 1971: the airing technique, good quantities of seed and Hidu cl a!., 1969), working on hatchery techniques. commercial size oysters were produced, but because Two agencies, the Maryland Department of of the excessive expense involved in the methods

Natural Resources (Otto, 1969) and the National tested, it did not appear commercially feasible (Mar- Marine Fisheries Service (Shaw, 1970), have been shall, 1969). studying raft production of seed oysters. Shells, The Coastal Zone Resources Corporation is at- either on strings or in chicken-wire bags, are sus- tempting to grow oysters caught on passenger car

pended from rafts. E.xcellent sets are being obtained tire beads (David Adams, pers. comm.). Eighty tons

using the off-bottom techniques, but to date it has of eight bead configurations (about 14,000) have not been adapted commercially in Chesapeake Bay. been planted in an area where oysters have the repu- The National Marine Fisheries Service has also tation for high quality and rapid growth. Each con-

been studying the off-bottom culture of oysters figuration is anticipated to yield about one-half (Shaw, 1969, 1970, 1971). Methods being tested in- bushel of oysters in 30 mo. clude raft, longline, and rigid-structure. Strings of Beginning in 1944, extensive studies were con-

spat-laden shells are suspended from each floating ducted in South Carolina on the cultivation of oys- device and maintained in suspension until the oys- ters in ponds. Initially (1944-45), excellent results ters reach market size —about 2'/i yr from time of were obtained and marketable single oysters were

set. It is estimated that 1 1 .9 tons of oyster meats per produced in 2 yr. In 1950, drought conditions de- acre per year could be produced using off-bottom veloped and salinities in the ponds rose. A sudden techniques. mass mortality among pond held oysters developed

In Virginia the majority of oysters are grown on probably by Dennocystidium. It was concluded that private leases. Power dredging is the common as long as wild oysters are available to the industry,

method used for harvesting although hand tonging is it is unlikely that pond culture will be economically also practiced. The majority of seed for the private practicable (Lunz, 1956). bed cultivation comes from the James River. Unfor- In Georgia, two members of the Japanese panel. tunately, in the late 1950"s and early 1960"s, heavy Atsushi Furukawa and Hisashi Kan-no, assisted in mortalities from MSX occurred among the oysters in an attempt to develop off-bottom oyster culture the high salinity waters which included the spawning techniques. Many problems were encountered in- stocks for James River seed. Since then little or no cluding fouling, heavy siltation, erosion, and retarda-

setting has occurred in the James River. tion of growth. It was felt that because of the cur- The Virginia Institute of Marine Science has been rent low price of oysters, off-bottom culture did not working on developing disease resistant stocks using appear commercially feasible in Georgia at the pre- hatchery techniques. In addition, spat collecting sent time (Linton. 1968). shells are being planted in Great Wicomico, Pian-

katank, and other rivers (Bailey and Biggs, 1968). It Florida is hoped that through the development of disease re- sistant stocks and managing around the disease, In 1970. Florida produced about 3.8 million the oyster industry of Virginia can come back to pro- pounds of oyster meats. The majority of oysters ductive levels. comes from the west coast of Florida. Ovsters are

60 harvested from public reefs either by tongs or picked excellent growth was obtained, he found the off- by hand, with dredging allowed on leased beds. The bottom culture was not economically feasible be- future of the Florida oyster industry lies in the culti- cause of high production costs and low market value. vation of the private leases (Ingle and Whitfield. The Alabama Marine Resources Laboratory at 1962). Dauphin Island constructed a '4-acre tidal pond to The Florida Department of Natural Resources study the commercial rearing of oysters. In 1968, has several research projects related to oyster oysters were placed in the pond and after 12 mo the aquaculture (Florida Department of Natural Re- oysters had increased in height from 18 mm to 101 sources, 1970) —one is oyster nutrition and the other mm. Ninety-one percent were legal size after SVd is oyster reef modification. Some success has been mo of growth. It is not known if studies were con- obtained in fattening oysters with finely ground tinued. commeal. These studies are continuing in conjunc- Mississippi tion with learning optimal conditions (temperature, salinity, and other parameters) for fattening oysters. The entire Mississippi oyster production comes Florida is presently studying the modification of public reefs acres), there are no natural reefs to improve their oyster production. from (about 3,000 private leases (Maghan, 1967). Annual production Artificial gaps are being cut in the reefs. Oysters fluctuates considerably because of adverse weather planted in these cut-out areas have shown excellent conditions, leveeing of the Mississippi River, pred- growth. Florida, through federal aid PL 88-309, is ators, and disease. As an example of these fluctua- also constructing artificial oyster reefs using oyster tions, production in 1968 was 3.8 million pounds of shells and limestone slag. Some excellent sets have been obtained on the planted cultch. meats while in 1970 only 547,000 pounds were landed. Except for extensive plantings of shells and One commercial company at Cedar Key, Fla., is seed oysters, there has been little attempt to moder- attempting to grow strings of oysters from rigid nize the oyster industry of Mississippi. structures (Robinson, 1971). Some problems have occurred resulting from the oysters falling off the strings. To solve this problem, portable racks have Louisiana been built with bottoms to catch the oysters that fall off In 1970, Louisiana produced 8. 1 million pounds of Similar to studies in Carolina, North attempts are oyster meats, second in the nation to Maryland. being made to catch and grow oysters on tire beads at Roughly 70-80% of the oysters are canned (Matthies- Cedar Keys. Fla. In this case the tire beads and sen. 1970b). Louisiana has a well-managed industry configuration have been patented. It is not known if based on privately owned or leased bottoms, approx- the operation is successful. imately 83,000 acres, plus state-owned areas (450,000 acres) set aside as a source of seed oysters Alabama (St. Amant, 1964). Growers are allowed to gather wild seed for planting on their leased grounds. All The oyster industry of Alabama is based upon oysters are grown on the bottom and no attempt has natural repopulations of public reefs which include been made to try off-bottom techniques. about 3.064 acres (May. 1971). In addition, there are The Louisiana Marine Laboratory on Grand approximately 2,000 acres of private bottoms, but Terre Island has several projects (federal aid PL they yield only 12% of Alabama's total oyster 88-309) related to oyster culture. These studies in- production (annual average from 1948 to 1968 was clude the reestablishment of historical seed grounds

1 .2 million pounds of meats). Lack of seed has kept and control of the Southern oyster drill, Thais

private production down. All of the oysters from haemostoina. Both projects are still in progress so public reefs are harvested with hand tongs; however, final results are not available. harvesting from private beds can be accomplished At Grand Terre Island. 16 '4-acre ponds were with dredges. constructed on existing marsh floor. The levees Very little attempt has been made to try to moder- were enclosed by two asbestos bulkheads that were nize the .Alabama oyster industry. May ( 1969) inves- supported by creosote posts and tied together by tigated the feasibility of off-bottom oyster culture. galvanized steel rods. Besides oysters, brown and Both rack and raft methods were tested. .Mthough white shrimp plus selected fishes are being cultured

61 in these ponds. Preliminary results with oysters with surprisingly little damage (Engle, 1970) to either were not promising when high water temperatures the clams or the clam beds. This gear is also used in resulted in excessive mortalities (Matthiessen, Chincoteague Bay, Md. 1970b). The hard clam fishery appears to be in excellent

condition although there is some concern over the increasingthreat of pollution. In New York there are Texas an estimated 450.000 acres of potential shellfish pro- ducing bottoms of which 156,892 acres or approxi- In 1970, 4.6 million pounds of oyster meats were mately 359f of the total are uncertified. Considerable harvested from Texas. The center of production is effort has been devoted by the New York Conserva- Galveston Bay. Harvesting has been confined al- tion Department to develop depuration techniques. most entirely to the 22.000 acres of natural reefs A PL 88-309 project entitled. ""Operation of a depu- (Hofstetter. 1959). although there are some 3.000 ration plant for hard clams {Merceiuirhi acres of leased bottom. Lack of good bottom for nwrrcncirid)." was completed in 1969 (MacMilian leasing has been a deterrent to oyster cultivation. and Redman, 1971). Results of the study, using a Considerable interest has developed recently in ""pilot"" scale depuration system, indicated that the the pond culture of oysters (More and Elam. 1970). depuration of hard clams is feasible, both economi- At Palacios, Texas, the Parks and Wildlife Depart- cally and bacteriologically when such shellfish are ment has built 21 artificial ponds ranging in size from harvested from restricted growing areas (Median a quarter of an acre to 4 acres. Studies on disease Coliform MPN range: 70-700). The successful oper- resistance to the fungal pardsile Labyrinthomi.xa sp. ation is greatly enhanced utilizing seawater obtained are being conducted. Attempts are also being made from a saltwater well. It was estimated that hard to relate water depth and type of pond construction clams could be depurated at a cost of $1.76 per to oyster growth and survival. bushel. The most intensive efforts towards propagation on THE HARD CLAM a commercial scale have been made on Cape Cod The hard clam, Mercenaria menenaria, (also and Long Island (Miller et al.. 1970). Clams are called quahog, quohog, and quahaug) is distributed artificially spawned to setting using methods de- along the Atlantic coast and the Gulf of Mexico. scribed by Loosanoff and Davis (1963). The seed They reached their peak of production in 1950 when clams are held in especially designed hatcheries and 21 million pounds were harvested. Production then then transplanted to controlled growing areas. dropped until 1955 when 14.2 million pounds were Heavy losses from predation have been a serious landed. Since then, production has remained fairly problem following planting on the growing grounds. stable fluctuating between 13.3 and 15.8 million To solve this problem the Virginia Institute of aggregates pounds, and in 1970 approximately 15.4 million Marine Science has developed the use of pounds of meats were produced. New York is the on the bottom to protect the seed clams from pred- leading producer (7.9 million pounds) while five ators (Castagna, 1970). Three types of aggregates states —Virginia, New Jersey, New York, Mas- were found successful: 1) crushed oyster shell. 2) sachusetts, and Rhode Island —accounted for 919^ crushed stone, and 3) stream bed gravel (pea gravel). of the total U.S. landings. The entire fishery comes An average of more than 809f of the seed clams from wild stocks although some attempts are being planted with aggregates survived compared to made to utilize hatchery stocks. 16-30% survival on plots without any aggregates.

In New York the center of the resource is on the Clams should be at least match-head size before southern shore of Long Island in the sheltered hays planting and should be scattered over the aggregate such as Great South Bay. Many types of gear have at a rate of about 25-50 per square foot. been used to harvest clams. These include tongs, One of the largest clam hatcheries is located in rakes, dredges, by hand, hoes, and grabs. In 1967, North Carolina (Tyler. 1970). Since early 1970. New York harvesting was divided among three Coastal Zone Resources Corporation has been en- types of gear—dredges, 2.6 million pounds: tongs, gaged in producing hard clam sets using hatchery 2.5 million pounds; and rakes, 1.9 million pounds. techniques (David A. Adams, pers. comm.). Ap- Introduced into this industry in recent years was the proximately 4 million clam larvae are produced each hydraulic escalator dredge which harvests clams week. Metamorphosis occurs in about 2 \\k. They

62 are then placed in shallow 2 ft x 4 ft plywood trays waters and placed in plastic coated wooden floats. mounted vertically in banks of 10 trays each. Here They reached an average minimum market size of 50 the set stays for an additional 8 wk. When the clams mm in 12-13 mo. The authors felt that bay scallops are about 10 wk old, they are transferred into run- appeared amenable to mariculture. ning seawater concrete raceways. Under ideal con- ditions, the seed clams measure 1-2 cm at about 14 FUTURE MOLLUSCAN AQUACULTURE wk of age. When the clams reach 2.5 cm, they are IN THE UNITED STATES either sold as seed clams or planted by the corpora- ATLANTIC AND GULF COASTS tion on nearby mud flats to grow to commercial size.

I have briefly described the past and present status THE BAY SCALLOP of molluscan aquaculture along the Atlantic and Gulf coasts. The next question is where do we go The bay scallop, Aeqiiipecten irrtulians. ranges from here? In your country (Japan), we realize that from Maine to the Gulf of Mexico (Belding, 1910). molluscan aquaculture is much further advanced Principal areas of abundance are the southern New than in the United States. One reason, of course, is England states; Peconic Bay, Long Island, N.Y.; your basic protein diet consists of aquatic products and the bay and inlets of North Carolina (Gutsell, while Americans eat basically land-grown products 1931). In 1970, approximately 865,000 pounds, val- (beef, chicken, etc.). To supply the Japanese people ued at 1.2 million dollars (dockside value $1.39/lb) with aquatic products, you utilize your inland waters were landed in two states. New York and Mas- considerably different than we do in the United sachusetts. The bay scallop rarely lives beyond 2 yr States. For example, almost all of your oysters are (Merrill and Tubiash, 1970). Because of its short life grown off-bottom in order to produce the maximum

span and high value, this species is highly suitable for numbers per unit of area. You have set priorities on aquaculture. Yet, very little attempt has been made the use of your waters—first, for food production; to farm this animal. second, for navigation; and third, for recreation. In Wells (New York Conservation Commission, the United States the waters are used mainly for 1927) was one of the first to artificially rear bay scal- navigation and recreation. The use of our waters for lops. Since then others including Loosanoff and food production is on a very low scale. For the Davis (1963) and Castagna and Duggan (1971) have United States to develop molluscan aquaculture in successfully spawned and reared the larvae to set- the future, we will have to change our philosophy on ting stages. water usage. This is going to be extremely ditTicult Several programs are presently underway in an and maybe impossible. attempt to farm the bay scallop. Under a federal aid A second point is that the development of mollus- project PL 88-309, the State of New York has just can aquaculture in the United States will only

begun studies on the growth of scallops during the succeed if it is done profitably. Already many

fall, winter, and spring in heated waters. Scallops companies which entered aquaculture have lost will be subjected to 40°, 50°, 60°. and 70°F respec- money and have quickly left the business. For this tively, and periodic growth measurements will be reason the development of aquaculture in the United taken. It is also planned to place scallops in cages States must depend initially on animals that have a placed in the effluent discharge from LILCO Elec- high market value. These animals must feed at a low

tric Power Station at Port Jefferson, N.Y. trophic level. Even using high valued crops, it is a Under a Sea Grant Program described earlier by question whether or not a profit can be made because Robert D. Wildman. the Virginia Institute of Marine of high costs of labor, materials, private leases, etc.

Science is rearing bay scallops to market size The third problem is that legal rights to conduct under controlled conditions (Castagna and Duggan, aquaculture must be defined. Only recently laws 1971). Scallops collected from Virginia and North were passed in Florida which made mariculture legal

Carolina were conditioned and spawned in the (Davis and Shields. 1971). Similarily. in Maryland,

laboratory. Follow ing setting, juveniles were held in until this year, it was illegal to grow oysters off- plastic trays in the laboratory for 1 wk. They were bottom. These are exceptions—in most states along then moved to outdoor tanks w ith flowing unfiltered the .Atlantic and Gulf coasts, there are no laws w hich seawater. They remained there until they were 2 mm protect the aquaculture investor or even allows in width. The scallops were then moved to natural aquaculture to be conducted.

63 .

The threat of pollution will hinder the develop- ENGLE. J. B. ment of molluscan aquaculture in the United States. 1966. The molluscan shellfish industry, cuirent status and No one wants to invest a great amount of capital, trends. Proc. Natl. Shellfish. Assoc. 56:13-21. 1970. Oyster and clam management. In N. G. Benson raise a product to market size, and then find that he (editor), A century of fisheries in North .America. Am. cannot sell his product because it comes from pol- Fish. Soc. Spec. Publ. 7:263-276. luted waters. One answer to this problem is to avoid FLORIDA DEPARTMENT OF NATURAL the use of waterways and to culture the animals in a RESOURCES. 1970. Current research. closed system similar to methods used to grow chick- Florida Department of Natural Resources, Marine Research Laboratory, St. Petersburg, ens. Unfortunately, our technology has not de- Fla., 19 p. far to this possible. Sea Grant veloped enough make GUTSELL, J. S. Programs, like the one at the University of Dela- 1930. Natural history of the bay scallop. U.S. Bur. Fish. ware, are working towards this goal. 46:569-632. HIDU. H. It is the hope of all of us at this Symposium, that 1971 The feasibility of oyster hatcheries in the Delaware- aquaculture will develop to the level of agriculture. Chesapeake Bay region. In K. S. Price. Jr.. and D. L. Your country has made great strides towards this Maurer (editors). Proceedings on the Conference of the goal. Through our state, university, and govermen- Artificial Propagation of Commercially Valuable Shellfish-Oysters-October 22-23. 1969:111-131. tal agencies, we in the United States are learning

HIDU. H . K. G. DROBECK. E. A. DUNNINGTON, more every day about aquaculture techniques. It is JR., W. H. ROOSENBURG, and R. L. BECKETT. hopeful that this knowledge can be applied in the 1969. Oyster hatcheries for the Chesapeake Bay future. It is our goal that someday, through the de- region. Univ. Maryland. Nat. Res. Inst.. Contrib. 382, velopment of aquaculture techniques, we may pro- 18 p. duce enough protein to help feed our increasing HOFSTETTER. R. P. 1959. The Te.xas oyster fishery. Tex. Game Fish world population. IT MAY BE OUR ONLY Comm., SALVATION!!! Bull. 40:1-38. INGLE, R. M.. and W. K. WHITFIELD. JR. 1962. Oyster culture in Florida. Fla. State Board Con-

serv., Educ. Ser. 5 (revised), 25 p. LITERATURE CITED LINTON, T. L.

1968. Feasibility studies of raft-culturing oysters in

ANDREWS, J. D., and L. W. MASON. Georgia. Proceedings of the Oyster Culture Workshop 1%9. Exciting new hatchery techniques cultchless seed July 11-13, 1967. Ga. Game Fish Comm.. Mar. Fish.

oysters. Va. Inst. Mar. Sci. 3. 2 p. Div.. Contrib. Ser. 6:69-73. AVER. W. C. B. SMITH, and R. D. ACHESON. LOOSANOFF. V. L. 1970. An investigation of the possibility of seed oyster pro- 1966. Time and intensity of setting of the oyster, Cras- duction in Great Bay. New Hampshire. N.H. Fish soslrea virf;inicii. in Long Island Sound. Biol. Bull, Game Dep.. Mar. Survey Rep. 2. Ked. Aid PL 88-309. (Woods Hole) 130:211-227.

Proj. 3-.32-R. 106 p. LOOSANOFF, V. L., and H. C. DAVIS. BAILEY. R. S.. and F. C. BIGGS. 1963. Rearing of bivalve mollusks. In F. S. Russell

1%8. Lets be oyster farmers. Va. Inst. Mar. Sci.. 59 p. (editor). Advances in marine biology, vol. 1. p. 1-136. BELDING. D. L. Academic Press. and New York. 1910. A report upon the scallop fishery of Massachusetts LUNZ, G. R.

including the habits, life history of PfcWri irradians. its 1956. Cultivation of oysters in ponds at Bears Bluff rate of growth, and other facts of economic value. Mass. Laboratories. Proc. Natl. Shellfish. .Assoc. 46:83-87.

Comm. Fish. Game. 150 p. MAGHAN. B. W. CALBO, L. J.. A. PERLUMUTTER. D. R. GOODRICH, 1967. The Mississippi oyster industry. U.S. Fish Wildl.

and R. B. WAINRIGHT. Serv.. Fish. Leafl. 607. 12 p. 1968. New engineering approaches for the production MacMlLLAN, R. B.. and J. H. REDMAN. of Connecticut oysters. \ problem analysis. .Amertcan 1971. Hard clam cleansing in New York. Commer. Fish. Cyanamid Company. Vol. 1. 140 p. Rev. 33(5):25-33. CASTAGNA. M. A. MARSHALL. H. L. 1970. Hard clam culture methtKl developed at VIMS. Va. 1969. Development and evaluation of new cultch materials Inst. Mar. Sci. 4. 4 p. and techniques lor three-dimensional oyster culture. CASTAGNA. M.. and W. DUGGAN. N.C. Dep. Conserv. Dev.. Div. Commer. Sports

1971. Rearing the bay scallop. Aeqiiipeclcii irnulians. Fish.. Spec. Sci. Rep. 17, 35 p. Proc. Natl. Shellfish Assoc. 6l:i«)-«5. MATTHIESSEN, G. C. DAVIES. C B.. and H. W. SHIELDS. H7()a. Seed oyster production in a salt pond. In H. W. 1971. Mariculture and the law. Pfoc. 1st .Annu. Work- Youngken. Jr. (editor). Food-Drugs from the Sea Pro- shop World Mariculture StK. l970;55-.^9. ceedings |969:87-m.

64 1970b. A review of oyster culture and the oyster industry in OTTO, S. V. North America. Woods Hole Oceanographic Institu- I%9, The Manokin River Project. Commercial Fisheries

tion. Contrib. 2528. 52 p. News, Chesapeake Bay Affairs 2(2):4. MATTHIESSEN. G. C. and R. C. TONER. ROBINSON, P. 1%6. Possible methods in improving the shellfish industry 1971. String-growing of Florida oysters has promise of of Martha's Vineyard Dukes County, Mas- heavy production. Natl. Fisherman, February, p. 4-c. sachusetts. The Marine Research Foundation. Inc.. RYTHER, J. H., and J. E. BARDACH.

138 p. 1968. The status and potential of aquaculture. Particularly

MAY. E. B. invertebrate and algae culture. Vol. I., Part I. The status 1969. Feasibility of off-bottom oyster culture in and potential of aquaculture. American Institution of

.Alabama. .Ma. Mar. Res. Bull. 3:1-14. Biological Sciences, Washington, D. C, 45 p.

1 97 1 . A survey of I he oysters and oyster shell resources of SHAW, W. N. .Mabama. Ala. Mar. Res. Bull. 4:1-53. 1962. Raft culture of oysters in Massachusetts. U.S. Fish MERRILL. A. S. and H. S. TUBIASH. Wildl. Serv., Fish. Bull. 61:481-495. 1970. Molluscan resources of the .Atlantic and Gulf coasts 1969. The past and present status of off-bottom oyster cul- of the United States. Proc. Symp. : Part ture in North America. Trans. Am. Fish Soc. in:925-948. 98:755-761.

MILLER. W. S., E. M. WALLACE. C. N. SHUSTER. 1 970. Raft production of seed oysters in upper Chesapeake JR.. and R. E. HILLMAN. Bay. Proc. Natl. Shellfish. Assoc. 60:11.

1970. Hard clam. . .the gourmet's delight. Atl. States 1971. Off-bottom growing techniques. American Fish

Mar. Fish. Comm.. Leafl. 4. 8 p. Farmer and World Aquaculture News 2(9): 16-21. MORE. W. R.. and L. L. ELAM. ST. AMANT. L. S. 1970. Salt water pond research 1970. Job 4-Oyster 1964. Louisiana leads in oyster production! Louisiana

research. Te,\. Parks Wildl. Dep.. Coastal Fish.. Aus- Wildl. Fish. Comm.. Wildl. Educ. Bull. 84. 11 p. tin, Tex., 9 p. TYLER, J. [STATE OF] NEW YORK CONSERVATION COMMIS- 1970. Raising clams for money. N.C. Tar Heel Coast SION. 6(12):l. 1927. Report of the experimental shellfish station. In ZAHRADNIK, J. W., and C. A. JOHNSON. State of New York Conservation Commission Sixteenth 1970. Proposed 50 bushel pilot plant for oyster

Annual Report: for the year 1926, p. 113-130. J. B. production. (Abstract.) Proc. Natl. Shellfish. Assoc. Lyon, .Mbany. 60:12.

65

FRESHWATER FISH CULTURE IN THE UNITED STATES

HARVEY WILLOUGHBY'

INTRODUCTION ernments, It is noted that the federal government operates 95 fish hatcheries and funds another 15 that

Freshwater fish culture in the United States is a are operated by states, while hatcheries operated by popular and fast growing business. Fish are reared the state governments number about 500. To get a for three main purposes: 1) for stocking public and picture of the total U.S. effort in fish culture, one private waters to support commerciai and sport fish- would add more than 2.000 private fish growers to ing or to be used as bait to catch sport and commer- the above list. cial species, 2) for marketing directly to the consumer for food, and 3) for home aquariums or LEVEL OF FISH PRODUCTION private tlsh ponds for ornamentation and pleasure. Rearing fish to augment depleted natural stocks, Fish produced at hatcheries operated by federal or to introduce new species into public waters has and state agencies are stocked primarily in public traditionally represented the greatest expenditure of waters to improve or maintain sport and commercial effort in America. The State of Massachusetts estab- fishing. The Bureau of Sport Fisheries and Wildlife lished the first government-owned hatchery in the and many state agencies also furnish fish, free of United States in 1868. It was followed by the States charge, for stocking waters owned or controlled by of Connecticut and New York, and in 1871 the fed- individuals. Much emphasis is on stocking sport fish eral government established a fish commission to since fishing is one of the most popular outdoor study the decline of native fish stocks and to recom- sports in the United States. In 1970, over 49 million mend remedial measures. This commission later be- sport fishermen fished in fresh and salt waters (U.S. came the U.S. Bureau of Fisheries the predeces- — Bureau of Sport Fisheries and Wildlife, 1971.) sor agency of the Bureau of Sport Fisheries and In addition to federal and state hatcheries, there Wildlife, which I represent, and the National Marine are well over 2,000 commercial hatcheries in the Fisheries Service, which employs my colleagues, United States. These are divided into three general William N. Shaw. John B. Glude. and Robert D. classes: bait minnow, catfish, and trout hatcheries. Wildman. This yearthen, 1971, marks the centennial The estimated production of freshwater fish pro- year ofour federal government's involvement in fish duced in 1965 by all hatcheries in the United States conservation. A series of celebrations and other was as follows: special events have been held throughout this year to commemorate our centennial year. The activities of the federal government in the field offish culture, fishery research, and manage- ment have been expanded greatly during the last one hundred years, but they have been outpaced by the indi\ idual state governments. As an indication of the relative level of effort by the federal and state gov- Table I. — Production cost of federal fish and hatcheries in 1947. 1956. I96X. and 1970. achieved by placing nylon fiber mats in the ponds to cial niche as efficient predators in shallow lakes. The serve as a place for the fish to deposit their eggs. muskellunge (or muskies for short) is particularly Experiments conducted at the Fish Culture De- prized as a trophy fish. Both species are reared in a velopment Center at Marion. Ala., during the past somewhat similar fashion as adult spawners are several seasons, have indicated a promising prefer- trapped in the wild and hand stripped. A certain ence for the use of the mats by the largemouth bass, amoimt of success has been achieved in speeding Micropterus sulmoidcs. After the eggs are depos- maturation of female northern pike by injecting dried ited, the mats are removed and placed in hatchery carp pituitary interperitoneally at a rate of 5 mg/kgof tanks where the required care and protection can be body weight. given them. This is nothing more than a modem Once the eggs have been fertilized and become adaptation of the ancient Chinese practice of placing turgid, they are incubated in jar batteries until hatch- brush mats in known spawning areas to collect carp ing and swim-up. The fry are then stocked into fer- eggs. tilized ponds and 5-cm fingerlings are harvested 3-5 A principal limitation to higher yield of warmwa- wk later. In the case of muskies, the fingerlings are ter species in hatcheries has been the problem of then stocked back into ponds at a reduced rate and providing natural food. To accomplish this, ponds fed forage fish until they reach a length of 25-30 cm. are fertilized. Intensive fertilization can produce At that size the fish are ready to be stocked back into enough natural food organisms in static ponds to rear the natural environment and good survival can be up to 550 kg offish from a hectare of water in a single expected. season. Supplementary feeding can increase this up In recent years, limited success has been achieved to about 2,500 kg. O.xygen limitations in lentic envi- in rearing muskies in concrete tanks on a diet of ronments prevent higher yields, but aeration devices forage fish. Indications are that there will be more should prove that higher yields are possible. tank culture of this species in the future. Efforts to hand feed largemouth bass have often been discouraging, but work toward this goal con- Bait Fishes tinues, and recent reports from the Development Center at Marion, Ala., tell of producing largemouth Bait fishes are raised in farm ponds, natural lakes, bass up to 20 cm long by supplemental feeding, with and other still waters devoid of predaceous fish. a conversion ratio of 1.4:1. Some of the more common species of bait fish reared Cultural techniques of other species reared at our in the United States are goldfish, Carassiiis auratiis: warmwater hatcheries are described as follows: golden shiners, Notemigoniis crysoleiicas: and fathead minnows. Pimephales proinelas. Once Walleye (Stizostedion vitreum vitreum) ponds are prepared, culture in the simplest form may

The walleye is one of our most valuable freshwa- be undertaken by merely introducing adult breeders.

ter sport fish. It also ranks high in the commercial The prolific nature of these fish generally results in a

harvest. In reclaimed lakes, that is lakes in which the rapid increase of the stock by natural reproduction. entire fish population has been deliberately poisoned Annual yields generally range from 1,300 to 4.500 out, this species has had the greatest success when kg/ha. stocked as fingerlings 5 cm long. Ictalurus It has not proved feasible to rear walleyes to Channel Catfish, punctatus maturit) under hatchery conditions. Consequently, For the past 10 yr channel catfish cultivation has adult fish must be trapped from the natural environ- rapidly increased in the United States. There are ment during the spring spawning run and hand strip- now approximately 24.600 hectares of ponds de- ped. The eggs are incubated, usually in ajar battery, voted to the growing of catfish. This can be com- and the sv\im-up fry stocked into fertilized rearing pared to 100 hectares 10 yr ago. The gross annual ponds. Under the best conditions, 5-cm fingerlings value to the farmers in 1971 was approximately $31 are harvested in about 4 wk. million from the 40.800 metric tons produced. To date, most catfish rearing has been done in Muskelliinjje iEsox masquiitongy) and large impoundments, many of them operated in rota- Northern Pike (E. Lucius) tion with rice farming. More recent entrepreneurs

The muskellunge and northern pike fit a very spe- into the catfish farming industry are large corpora-

69 tions which employ professional staffs of engineers, (Stevens. 1966). This accomplishment has resulted biologists, and business managers. These enter- in major attempts to establish striped bass popula- prises are beginning to use intensive culture methods tions with large-scale fry plantings. A final evalua- to rear cattish. Production levels of 9 kg/m^ are being tion of the success of these programs is not available realized in circular tanks. at this lime; however, it is the general consensus that Raceway culture at the Fish Farming Experimen- predation will prevent the establishment of desirable tal Station which the Bureau of Sport Fisheries and populations with this type of introduction. The al- Wildlife operates at Stuttgart, Ark., is producing ternative is to introduce fingerlings (6-15 cm) instead about 900 kg of catfish per year in 115 m^ of space of fry. At least six states in the southern United with a total flow of 35 liters/sec. Water temperature States have embarked on fingerling rearing pro- is 28°C. This is far below the potential for this grams. species in light of experimental data which reveal Production at federal hatcheries increased from that 9 kg/m^ are routinely held in circular tanks 90,000 fingerlings in 1966 to 1.500,000 in 1970. with a diameter of 2 m and with a water flow of

0.3 liters/sec. Intensive Fish Culture

Some of the more common species offish Striped Bass, Morone saxalilis reared by intensive culture method are; rainbow trout,

Striped bass culture, like channel catfish, is show- Salmo gairdneri; brook trout, Sahelinus fontinoUs; ing great promise, although the production of this brown trout, Salmo trutla: lake trout, Sahelinus

species is still in the development stage. The geo- nuinayctisli: golden trout. Salmo agiiahonira: graphical range of striped bass extends from the St. cutthroat trout. S. clarki: coho salmon, Lawrence River. Canada, to the large rivers of Oncorhynchits kisiiicli: chum salmon. O. keta; South Carolina and Georgia along the Atlantic coast Chinook salmon. O. tshawytscha: kokanee or sock- and along the Gulf coast from western Florida to eye salmon. O. nerka: and Atlantic salmon, Salmo Louisiana (Pearson, 1938). salar. Recent investigations indicate that the only sub- One of the basic advances in trout and salmon stantial fishery for this species in Florida is in the rearing is in the area of nutrition. Fish diets are now Apalachicola River, which empties into the Gulf of compounded as carefully and scientifically as diets Mexico. for domestic animals. The basic nutritional needs of On the F'acit'ic coast striped bass ranges from most species of trout and salmon have been defined southern California to the Columbia River. Oreg. by such workers as Phillips (1970) and Halver Introduction of this species to the Pacific coast was (1970). and diets are formulated to meet these accomplished with an initial stocking of 133 yearling needs. Proximate analysis of typical trout and salm- fish in San Francisco Bay in 1879 (Mason, 1882). on diets are as follows: These fish were seined from the Navesink River, N.J.. and transported to California by train. By 1899 the commercial catch of striped bass was

599 metric tons and by 1915 it had risen to 808 metric tons (Raney et al.. 1952). The establishment of landlocked striped bass populations in several inland reservoirs has gener- ated considerable enthusiasm in regard to the future potential of this species. Using striped bass on a put. grow, and take basis could prove to be a desirable management technique fi>r large freshwater im- poundments. In addition to its acceptance as a superb game and table fish, the striped bass also exhibits the ability to function as a biological control for gizzard shad. Doii>Si>i)i(i icpcilhiniim. The ability to produce millions of striped bass fry

through hormone induced spaw ning is nov\ a reality the precise quantities of feed at prescribed inter- lowing stocking. Water supplies, both entering vals. The more advanced of these devices monitors and leaving a fish pond, must be monitored for their water temperature, fish size, and adjusts the daily chemical content. Sufficient oxygen must be sup- ration accordingly. plied by the incoming water to permit the fish to use Where the pondfish culturist is basically an the food. The relationship between food eaten and ecologist. the trout and salmon culturist is a the oxygen required is so constant that many fish physiologist. He must know the requirements for culturists calculate the oxygen content of the water space, for the physical and chemical components of entering a pond as a means of determining the carry- the water, and for the nutritional requirements of ing capacity. Investigations indicate that 100 g of the fish. Through careful control of these factors, oxygen are required to metabolize 450 g of trout each kilogram of trout or salmon produced may pellets (1,200 calories) (Willoughby, 1968). This require as little as 1.2 kg of feed. 1.4:5 ratio should hold constant over the tempera- Growth rates can be calculated with utmost accu- ture range of 4°-16°C. racy. Haskell (1959) concluded that the increase in While oxygen is usually the first limiting factor in length of trout up to 25 cm in size is at a constant the hatchery environment, it is not the only one. As rate. He developed a ""temperature unit" theory in oxygen is used to break down foods for energy and which he states that the growth rate can be pre- growth, by-products are formed. Prominent among dicted for any temperature between 3.7° and these are carbon dioxide and ammonia. Carbon di-

!5.6°C. We have found it practical to restate oxide poses few problems. Ammonia, however, is

Haskell's hypothesis to include 0°C as the zero another matter, as it is very difficult to remove by

point for growth and consider it to be a straight line mechanical means. Thus, when water is reused

relationship when plotted against time up to 15°C. from one fishpond to another, it can be aerated to

This has proven a useful tool in projecting growth renew its oxygen content but ammonia continues to rates and forecasting the time when the fish will accumulate and soon reaches toxic levels. reach a given length. A recent development which has revolutionized

Fish densities in trout and salmon rearing ponds fish culture in the United States is the use of bacte- are not as critical as the quality and quantity of the rial filters, which convert free ammonia to more tol- water flowing through the unit. Ample exchanges of erable nitrates. This development has opened up 0° water between and 2rC.. free of to.xic metals possibilities for a tenfold increase in the quantity of such as zinc, copper, and manganese,- and from ex- fish that can be reared in a given water supply. This cessive levels of such gases as nitrogen, are essen- reconditioning system makes it possible to reduce tial. Oxygen levels must be maintained above 5 ppm the quantity of freshwater by as much as 95%. throughout the tank, and ammonia should not ex- The Dworshak National Fish Hatchery, ceed 1 ppm for long periods of time. If these water Ahsahka, Idaho, utilizes a water reuse system for a criteria quality are met, most salmonids can be part of its ponds. This hatchery began operation in reared at densities exceeding 50 kg/M^. 1968. There are 84 circulating ponds, 25 of which The raceway, a linear pond whose length is ap- operate on the water reuse system. In this system

proximately 10 times its width, has been the most approximately 10% of the water used in the ponds is popular type of rearing unit for salmonids in the added as fresh water after being filtered, disin- United States up to this time. Second in popularity fected, and either cooled or heated. The water goes

has been the circular pond. Many other types of through aerators for oxygenation and is supplied at ponds have been tried, but have not been widely the rate of 27 liters/sec to each pond. When water

adopted. In 1958 Burrows and Combs at Longview, returns from the ponds, it goes through biological

Wash., developed a circulating pond that is being filters where the pH is buffered and ammonia ox- widely copied in the northwestern United States. idizes to harmless nitrates. This pond is rectangular in shape, but employs turn- The hatchery was designed and built to replace ing vanes to cause the water to flow in a circular the spawning and nursery areas for the steelhead pattern. The merits of this pond are its higher water trout which will be lost by the construction of the \elocities and thorough circulation w hich give good Dworshak Dam. In addition to the rearing of distribution of feed and render the pond virtually steelhead trout for release into the north fork of

self cleaning. The increased velocities improve the Clearwater River, this station is also participat- stamina and result in better survival of the fish fol- ing in the management of the reservoir above the

71 dam. At the present time, the hatchery is rearing FISH TRANSPORTATION catchable size rainbow trout for stocking the reser-

voir. In addition, there is a limited number of cut- Fish hatcheries in the United States utilize many throat trout on hand which will be used for brood diversified types of distribution equipment from stock as a source of eggs for future stocking pro- 40-liter cans to elaborate tanks equipped with aera-

grams. In addition to these, it is expected that tion devices and oxygen equipment. However, this hatchery will also supply kokanee salmon for most hatcheries today generally use truck mounted the reservoir. distribution tanks. Hauling capacity is governed by volume of water in the tanks, design of tank, aux- The first year's operation of the Dworshak iliary equipment used, and size and species offish hatchery started with the collection of eggs from being hauled. Various materials such as wood, trout transported to the hatchery from the trap at plywood, fiber glass, steel, and aluminum are used the dam site during the period of October 1968-May for construction of tanks. Fiber glass-plywood 1969. The fish reared in the untreated water for 2 yr tanks are becoming very popular because of such from the 1969 brood year were released in the spring of 1971. At the same time, the 1970 brood advantages as lightweight, low cost, good insula- tion, and strength. Insulated units, having recir- year fish reared in the controlled environment of the reuse system were also released. The controlled culating water systems and an o.xygen supply, can be used to haul loads in ratios (unit weights offish environment of the reuse system made it possible to to equal unit weight of water) of 1.1:5 for trout and rear fish to migrating size ( 17 cm) in 1 yr instead of 1.2:4 for channel catfish, Maloy (1966). the 2-yr growing period that is required when the untreated water is used. There are reports of varying degrees of success in increasing hauling ratios by use of sedative drugs and buffer agents. Phillips and Brockway (1954) DISEASE CONTROL found that starvation of fish before shipment and the maintaining of low water temperatures were In 1968, the federal government of the United more effective than the addition of chemicals. States imposed regulations requiring that salmonid Ma.xwell and Thoesen (1965) reported on the fish and eggs imported into the country be free of successful hauling of large quantities of rainbow whirling disease, caused by the protozoan trout and largemouth bass fingerlings by airplanes Myxosoma cerehralis, and viral hemmorrhagic sep- equipped with water tanks. Sealed plastic contain- ticemia. The regulation is intended to protect the ers, 2 mil and thicker packed in insulated outer nation's fishery resources from fuilher introduction — cartons, partially filled with water, and inflated with of these two fish diseases. It may also serve as a oxygen—are used successfully by many hatcheries model for adoption by other countries similarly for surface and air transportation of fish. A typical concerned about protecting their own resources. shipment is 50,(K)0 bass fry in 3.8 liters of water for This regulation is included in Title 50, Code of Fed- a period of 48 hr. eral Regulations. Increased traffic in fish and eggs has spread the A recent development in the field of fish trans- virus disease, infectious pancreatic necrosis, in 10 portation is the "Tish pump." The fish pump is a yr from the nonheastem section of the country into modified fruit pump which was initially used to the trout and salmon producing areas of the West. transfer vegetables, fruit, dead fish, and seafood. The detection of this virus cannot be accom- The pump is especially designed to eliminate sharp plished by border inspections: consequently, control edges in the pump body and to allow unobstructed passage of had to be effected at the originating hatchery. Sev- water and produce. The water serves as a cushioning eral states now require that eggs or fish entering the agent. state be accompanied by a certificate of health. But The pump comes in two diameters. 12 and 15 cm. separate actions by the states can only be partially The 12-cm size is used for fish up to 15 cm in length successful, and to effect a coordinated nation-wide and the 15-cm size handles fish up to 47 cm in length. program, federal legislation has been introduced in The California Department of Fish and Ciame tested the Congress. If passed, the bill will regulate the this pump and found that 900 kg of trout could be interstate and foreign commerce of fish for pur- loaded into a tank truck in 6 min with slight loss of poses of disease control. time due to crowding racks. Other tests indicate that 200 kg of trout per minute can be loaded onto trucks this man-made habitat. They will migrate to the from concrete raceways. ocean to live and grow. Three to seven years later to the River as vigor- In addition to loading distribution trucks and they will return Sacramento fighting fish also valuable, nutritious transferring fish between ponds, the pump can be ous game and food. Some individuals may weigh 30 kg, and where attached to a grading device. With this device about 1 kg of fish migrated to sea from the spawning 200 kg of fish per minute can be sorted by size. channel, 50 kg will return. Most of the returning fish TRAINING SCHOOLS will be captured by either sport or commercial fishermen before they reach Tehama-Colusa, but sufficient numbers will reach the canal to assure The federal government operates three in-service perpetuation of the run. training schools for training fish culturists. These Operation of the spawning channel is both an schools are located in Spearfish. S.Dak.; Marion, engineering and a fish cultural challenge. The en- Ala.; and Leetown. W. Va. They were established gineering challenge will be in operating the mam- to provide essential technical training in the field of traveling bridge which will service the canal. fish hatchery management. Operation of the moth The bridge will span the canal, and travel its length schools is oriented to the activities of the Bureau of running on rails along the Sport Fisheries and Wildlife and includes such to- via motorized carriages of the canal. It will serve as a working plat- pics as nutrition, pathology and disease control, sides biologists engineers can ma- fish-cultural development, and general fish hatch- form from which and I nipulate the fish and their environment for ery management. In addition, strong emphasis is both placed on the use of hatchery fish in managing open optimum production. An underwater viewing waters. chamber will be suspended from the bridge to per-

Although the primary goal is to provide trained mit the observation of the movements and behavior fish culturists for the National Fish Hatchery Sys- of the fish. Elaborate gravel cleaning devices will tem, there has been increased interest in recent flush deposited silt from the channel after each years from state and foreign agencies in sending spawning season. Young fish will be sorted, trainees to the schools. The trainees may already counted, and representative numbers marked as a have a broad academic background in biology, but means of evaluating the contribution to the Pacific the art of application must be learned through prac- salmon fishery. tice. The training schools serve as a link between These and other changes that have taken place the academic world and the actual hatchery opera- during the last few years in fish hatcheries, reflect tion. In fact, T. Sana, a native of Japan, completed an emerging scientific approach to the ancient art of our fish disease course at the Leetown National fish culture. Fish Hatchery last year.

TEHAMA-COLUSA SALMON REFERENCES SPAWNING CHANNEL BOWEN, J. T. 1970. A history of fish culture as related to the develop- A totally different approach to intensive fish cul- ment of fishery programs. //; N. G. Bensen (editor). A ture is the Tehama-Colusa multipurpose water di- century of fisheries in North America, p. 71-9.1. Am. version project and spawning channel in California. Fish. Soc. Spec. Publ. 7. Built to divert water for irrigation purposes from the BURROWS, R. E., and H. H. CHENOWETH. Sacramento River, the upper 5.5 km of this canal 1970. The rectangular circulating rearing pond. Prog. Fish-Cult. 3::67-80. will function as a spawning channel for 60,000 BURROWS. R. E., and B. D. COMBS. Chinook salmon. 1968. Controlled environments for salmon propagation. Access to the spawning channel will be control- Prog. Fish-Cult. .M):I2.V136. led to allow optimum numbers to lay their eggs at DAVIS. H. S. one time. The eggs will incubate in the canal, and 1953. Culture and diseases of game fishes. University of California Press, Berkeley. 323 the resulting young fish will live and be fed there p. HAGEN. W.. and J. P. O'CONNOR. until they are ready to migrate to sea. 19.'i9. Public fish cuhure in the United States, 1958. A When the spawning channel reaches full capac- statistical summary. U.S. Fish. Wildl. Serv.. Circ. 58,

ity, up to 60 million chinook salmon will begin life in 44 p.

73 HAl.VER. J. E. PHILLIPS, A. M, JR.. and D. R. BROCKWAY.

1970. Nutrition in marine agriculture. Mar. Agric. p. 1954. Effect of starvation, water temperature, and sodium 75-102. amytal on the metabolic rale of brook trout. Prog. Fish- HASKELL, D. C. Cult. 16:65-68. 1959. Trout growth in hatcheries. N.Y. Fish Game J. RANEY, E. C. E. F. TRESSELT. E. H. HOLLIS. \ D 6:204-237. VLADYKOV. and D. H. WALLACE. MALOY. D. R. 1952. The striped bass, Rocciis sa.xalilis. Bull. Bingham 1%3. Hauling channel catfish fmgerlings. Prog. Fish-Cult. Oceanogr. Collect., Yale Univ. 14(l):l-55. 25:211-212. SPEECE. R. E. 1966. Status offish culture in the North .American region. 1973. Trout metabolism characteristics and the rational Proceedings of the FAO World Symposium on Warm- design of nitrification facilities for water reuse in hatch- Water Pond Fish Culture, p. 125-132. eries. Trans. Am. Fish. Soc. 102:323-334. MASON. H. W. STEVENS. R. E. 1882. Report of operations on the Navesink River. New 1966. A report on the operation of Moncks Comer Striped

Jersey, in 1879. in collecting living striped bass for trans- Bass Hatchery, 1%1-1965. South Carolina Wildlife Re-

portation to California. U.S. Comm. Fish and Fish., Part search Department, 25 p. [Mimeograph.] 7, Rep. Comm. 1879:663-666. TUNISON, A. V. MAXWELL, J. M., and R. W. THOESEN. 1951. Comparison of fish food costs in federal hatcheries 1965. Lake Powell stocking story. Prog. Fish-Cult. in 1945 and 1949. Prog. Fish-Cult. 13:121-128. 27:115-120. WHITE. J. T. (editor).

PEARSON, J. C. 1971. Live fish transfer pump reduces harvesting costs.

1938. The life history of the striped bass, or rockfish. Am. Fish Farmer and World .Aquacult. News 2(2):I2-14. Rocciis sa.xalilis (Walhaum). Bull [U.S.] Bur. Fish. WILLOUGHBY, H. 28:825-851. 1968. A method for calculating carrying capacities of PHILLIPS, A. M, JR. hatchery troughs and ponds. Prog. Fish-Cult. 30:173- 1970. Trout feeds and feeding. In Manual offish culture. 174.

Part 3.85,49 p. U.S. Bureau of Sport Fisheries and Wild- 1971. A new look at hatcheries. Sport Fishing US.A, p.

life. 359-369. GENETICS OF THE AMERICAN OYSTER, CRASSOSTREA VIRGINICA GMELIN

A. CROSBY LONGWELL'

INTRODUCTION successes in higher organisms. Interestingly, the fate of the fertilizing sperm can be followed from the The development of refined culture techniques time of its entry into the egg until the fusion of its for the commercial East Coast American oyster, chromosomes with the chromosomes of the female

Crassostrea virginica, at the U.S. government's gamete on the first cleavage spindle (Fig. 1). It Milford Laboratory (Loosanoff and Davis, 1963), should be noted that any cytogenetic examination of along with the opening of experimental and com- the eggs of at least this species of oyster must be mercial shellfish hatcheries in the United States, preceded by treatment of the eggs with methyl al- have led to an interest and modest support of genet- cohol and chloroform in a micro-Soxhlet apparatus ic research on the oyster (Longwell, 1969; Long- to remove interfering yolk granules (Longwell and well and Stiles, 1970). Our growers ofC. virginica, Stiles, 1968b). whether dealing with a wild oyster set in the field or There are 10 pairs of chromosomes at metaphase I with their own hatchery products, are faced with of meiosis in the mature spawned eggs of C. virgini- the dilemma of cultivating an organism which does ca (Longwell, Stiles, and Smith, 1967). Genes are either exceedingly well producing a superabun- linked together then in 10 different groups. At least dance or does very poorly, both for reasons seldom in the female the chromosomes indicate that there is known. Part of the hoped for process of bringing a small amount of recombination or crossing-over of this oyster under some greater measure of control the genes making for genetic variability without by the cultivator necessitates some information on which there can be no improvement by selective its genetic and breeding system. This is particularly breeding. There is no evidence for any sex chromo- so for profitable hatchery production and for the somes. This is in keeping with the protandric nature best pond culture. Knowledge of oyster genetics of this oyster. See Figure 2. would also be of value for the special stocking of The chromosomes of C. virginica are all short, decimated beds or for the introduction of stock to about the same length, and hardly any of them read- previously uncultivated beds in the wild. ily distinguishable from the others on any basis. This

makes for difficulty in their detailed study ( Fig. 3.4). CHROMOSOME BASIS OF C. VIRGINICA'S Also studied were the chromosomes of the BREEDING SYSTEM Japanese oyster, C. gigas; the Puerto Rican oyster, C rhizophorae: the European flat oyster, Ostreu An examination of the male gametogenesis and of editlis; the U.S. West Coast small Olympia oyster, the spawned and fertilized eggs of C. virginica O. liirida; and the horse oyster, O. equestris. All of revealed that its meiotic system, fertilization, and these species of both the viviparous Crassostrea cleavage are of the typical type found in most higher genus and of the larviparous Ostrea species have the plants and animals (Longwell and Sfiles, 1968a). The same number of chromosomes as C virginica. Also, oyster is not characterized by any anomalous insofar as can be discerned, the chromosomes of all chromosome behavior as, for example, is the honey these species are metrically and morphologically like bee, which would frustrate breeding plans based on those of C virginica (Longwell et al., 1967). Menzel (1968b) in Florida has examined several other species of these two oyster genera. He further found ' Milt'ord Laboratory. Middle Atlantic Coastal Fisheries Center. National Marine Fisheries Service. NOAA. Milford. no variation in chromosome number and morphol- CT 06460. ogy. At least at the chromosome level then there

75 %^

^ / <

' » ^^ Ten chromosomes

' oyster ^^ ^ V t ^'^ sperm

Ten chromosomes of female oyster gamete

Figure I. —The coming together on the tlrst cleavage spindle of the 10 chromosomes of the male and 10 chromosomes of the female gamete of the American oyster. Crassostrea virginicci. A } *d r V

Figure 2. — The 10 pairs of chromosomes of the mature, spawned egg of the American oyster. Ciass

76 -;

^ •

>;

#1 -»* >«

^« r

7 should be no barrier to the making of fertile hybrids far studied carefully, an average of 63*^ of the sib- between the species within these two genera or even crossed eggs remained unfertilized. Only \Wc of the between these two genera of oysters. No species of eggs of the contemporary between-line crosses or the third oyster genus, Pycnodonte, has yet been outcrosses to unrelated wild oysters remained unfer- examined chromosomally probably because of the tilized. Only 39? of cleavages in the sib-crossed eggs difficulties of obtaining these noncommercial forms were normal. In the controls 70% of the cleavages which occur as singles in deep water. were normal. Parthenogenesis averaged 109? in the To date, there have been no indications for any inbreeding crosses and 0.59f in the controls. See chromosome polymorphism in any of the popula- Table 1. Some of the inbreeding crosses were others there tions of C . virginka in Long Island Sound nor in any characterized by polyspermy. In was a other population thus far examined from as far north degeneration of the one or more sperm that had

as Prince Edward Island, Canada, to' as far south as penetrated the egg. the State of Virginia. Ahmed and Sparks (1970) may A second, more extensive series of sib crosses have uncovered a chromosome polymorphism in with their contemporary control interline crosses marine ; Staiger (1957) found extensive showed essentially the same crossing difficulties. polymorphism of chromosome numbers in a marine The incidence of ineffective fertilization was higher gastropod mollusk: and Battaglia (1970) has re- than in the first series. Only 469? of the fertilizations ported extensively on genetic polymorphisms in actually achieved with sibling sperm activated the marine copepods. Chromosome polymorphisms aid eggs to normal development, contrasted to 989? the population in making rapid adjustments to fluc- when the sperm of nonrelated oysters of other lines tuations in the local environment. was used. Parthenogenesis was also higher; only 7% In contrast to the population, species, and generic in the controls but 299? in the sib crosses. constancy of the chromosomes of the oyster, early Prolonged fertilization attempts increased the developmental stages of C. \iri>inica are marked by number of eggs fertilized in sib crosses by 20%. It, a high frequency of variation in chromosome number however, also led to more polyspermy, and there (Stiles and Longwell, unpublished data). Fertilized was more degeneration of sperm in the cytoplasm of and cleaving eggs from a series of about 15 mass- the eggs. Such late fertilizations seldom seem to be spawned groups, with a total of 835 spawning oys- effective. ters, had an average of about 269f postfertilization These crossing barriers are interpreted as meaning genetic abnormalities. Abnormalities of chromo- that a strong outbreeding system in C. viiffinica in some number were present in 129? of the eggs. It must, at least in some individuals some popula-

appears that the sensitivity of this oyster egg to all tions, be reinforced by a system of gamete cross kinds of environmental distresses results in acute incompatibility with a basis in genetic factors. This effects at the chromosome level. This should make system must operate to prevent the crossing of the oyster an excellent assay species for detecting gametes of closely related oysters with similar genetically damaging and zygote-destructive pol- genes. Inbreeding is thereby discouraged, and out- lutants (Stiles and Longwell, in press). breeding promoted. Incompatibility genes are known to be highly mutable. An increased cross- ability of C. virf^inica full- and half-sibs originating INBREEDING C. VIRGINICA, ITS EFFECTS from irradiated gametes so supports this interpre- AND THE SPECIES MATING SYSTEM tation.

Inbreeding to some extent will accompany mass Genetic systems of cross incompatibility prevent- selection in commercial hatcheries. More extreme ing inbreeding exist in an estimated 3,000 higher forms will eventually be used to develop lines for plants (Brewbaker, 1964; Williams. 1964). The only subsequent hybridization in hopes of so obtaining carefully studied case in animals though has been in a hybrid vigor. marine organism —the hermaphroditic ascidians Full-sib crosses of C.riri^inica made over a period (Morgan. 1924, 1942a. 1942b). Some of these are of a year gave consistently poor development to the self-fertile, others self-sterile, with some variability straight-hinge larval stage. An investigation into this between geographic races. Other groups having in- revealed that marked fertilization and early de- breeding incompatibility often shou interspecies velopmental failures were occurring in these crosses crossing barriers as well. From the pioneering work

(Longwell and Stiles, 1973). In 5 of 9 cultures thus of Imai in Japan ( Imai and Sakai, 1961 ) and the later

78 Table 1.—Fertilization failures, cleavage failures, and parthenogenesis in full-sib crosses of Crassostrea virginicci and in contemporary control outcrosses and between-line crosses. .

Comportion of Iht Growth RotO From the results of this analysis heritability esti- 0( Inb'Od onO OutOrtO Lorvot mates can be derived directly. Of Ifn ft«ntfico" 0>»tt'

This was attempted several times to estimate heritability of growth rate for laboratory-reared C virginicti larvae and spat. Unfortunately, in spite of

its merits, this method did not prove successful at the

.Milford Laboratory. This is because these very high larval mortalities experienced at the laboratory so much of the time seldom leave enough contem- porary culture families for statistical comparisons. However, in a commercial-scale pilot hatchery at the University of Oregon operating under better 6 B 10 12 environmental conditions heritability estimates for Ag« of Lorwoe

Figure 5. —Comparison of the growth rate/of inbred and obtained recently (Lannon, 1972). It is also proba- outbred larvae of the American oyster. Crassostrea vir- ble that C. gigas is more vigorous and easier to i;inicii. handle in artificial culture than C. virginicci.

virginica inbred oysters is undoubtedly attributable to the In one series of these diallel crosses of C. sporadically and unpredictable poor water quality at at Milford enough larval families did survive long esti- the Milford Laboratory, much of it represents the enough in sufficient numbers to obtain a rough severity of the effect of enforced inbreeding of this mate of heritability of larval growth to the larval age oyster. This is particularly significant in that the of 2 wk. This estimate, 24%, is in the medium-to- inbreeding cultures were initiated with unusually low range. large numbers of eggs, as compared to the far smaller Realized heritability estimates, as opposed to population numbers available for studies with such theoretical heritability estimates, can be ob- species of higher organisms. tained from selection experiments. Selection exper- Imai and Sakai (1961) detected and made some iments can also tell something about the duration of measurements of inbreeding depression in C. i,'i,i;as. the response to selection, and about the limits of Lines of C gii^'n-'i were lost in the third generation selection response for different coetTicients of in- of full-sib crosses. breeding, and selection differentials. Such experi- ments would fare better under the variable culture conditions at Milford than the diallel crosses of the SELECTIVE BREEDING OF C. VIRGINICA theoretical estimates. Quantitative, commercially important traits are controlled predominantly by large exceedingly BASIC FORMULA FOR SELECTIVE BREEDING numbers of either of two types ofgenes. The effect of one type is additive: the effect of the other is non- additive. It is the additive type that responds to Annual Progress for Trait molding and change by selective breeding. The herita- Being Selectively Bred For - bility of a trait is a measure of this additive genetic Heritability x Selection Differentiol variance as separated from the other type and from Generotion Interval the total phenotypic variance. Heritability estimates Heritability = can be used to predict progress by selection (see Variation Oje to Additive Genetic Vorionce Total PVienotypic Voriance formulae in Fig. 6). Theoretical heritability estimates should be read- Selection Differential - Difference Between Selected Oysters and Average of All Oysten ily obtainable in the oyster in one generation for any Fratn Which Selected number of commercial traits by crossing the divided Generation Intervol = lots of eggs of several females by several different Average Age of Oysters at Time of Reproduction males. Contemporaneous cultures of such crosses should provide full-sib. enough and maternal- and Figure h. — Basic formulu for selecli\e breeding paternal-half-sib families for an analysis of variance. of ov sler.

80 A large selection experiment is currently under- ters spawned. Of these spawners. 859? were from way for spat and juvenile growth rate of C vir- Long Island Sound and the rest from areas extending ginica. It is intended to keep this breeding experi- from Prince Edward Island, Canada, to Virginia. ment going at Miiford for an indefinite number of Several million eggs from 835 spawners were cul- selection generations to estimate the duration and tured, and the resulting larvae reared to metamor- extent of response for a particular inbreeding coef- phosis. About 8,000juvenile oysters were obtained. ficient and selection differential to upward and At the age of 1 yr a portion of the surviving downward selection for growth rate. It is hoped to juveniles was selected on the basis of their size. The keep the experiment going on a scale large enough population was divided into a large-selected group, a to provide seed oysters of known genetic back- small-selected group, and a nonselected population. ground for other projects The selection differential for the large juveniles was A carefully chosen collection of about 6.000 wild 18%; forthe small juveniles, 8%. The first generation C. virginica was set up for mass spawning. Some has been obtained from mass spawnings of the two nonlocal C. virginica were included in this group selected populations, and from the random- with the hope of increasing the base of genetic varia- breeding, unselected Fi control population. This

bility (Fig. 7). Of the approximate 6,000, 835 oys- first generation from selected parents is currently

Figure?. —Mass spawning of a group of .American ov>ters.(:ra.».s().\7;<'(/ \iri;inica. from different geographic areas.

81 being selected itself and spawned for the second increased reproductive capacity sometimes accom- selected generation of spat. panied by a reduction in another character: in- Larval data collected in the course of rearing these creased environmental range, or ability to live in a progeny of the tlrst generation to be selected are range in which either parent is unable to live: greater showing, as did the larvae from a prior spawning of uniformity among individuals. Often hybrid vigor is the same animals which failed to give set, a correla- concentrated in a critical stage of early life. Unfortu- tion between selection for juvenile oyster size and nately, there is no way of predicting for any species larval growth rate. This correlation could be a just how to obtain hybrid vigor. Inbreeding lines nongenetic one or a significant genetic one. might be test-crossed with one another each genera- First realized heritability estimates are being tion so that selection can be practiced in terms of the made on measurements of the spat from the first potential of the separate lines for producing selected generation of parents at 33 days postsetting. heterosis on crossing (see Fig. 8). Data are not yet fully analyzed. Nonetheless, pre- Hybridization for the sake of combining the desir- liminary calculations indicate the heritability for fast able genes of two different types sometimes takes growth to this age to be high, 93%. the form of upgrading practiced when the overall

Considering these estimates, and the possibility in performance of the import is better than the local, the oyster of very high selection differentials, hatch- but when the local is superior in some particularly ery breeders should be able to improve growth rate important traits related to local environmental con- of their oysters. This could be done by mass selec- ditions. The initial hybridization is followed by tion without recourse, for some cycles of selection, backcrosses to the import with either natural or arti- to family performance records or progeny testing ficial selection. Another way of combining the which are time consuming and costly. Problems will characteristics of two types is the introgression of probably arise from inbreeding. Commercial shell- special desirable foreign genes into the local stocks. fish hatcheries seem prone to start selection pro- This is accomplished by backcrossing the hybrid to grams with too few oysters. Because the spawn of a the local type again with either natural or artificial single, excellent cross might fill even a good-sized selection. commercial hatchery, the problem is accentuated. Hybridization of C. virginicu might supply a less Selection progress is being made for resistance to sensitive, more vigorous larval form better able to the microsporidian MSX disease of C. virginica in hold up to the vicissitudes of the hatchery. Hybrids the mid-Atlantic states U.S. by both natural selec- could furnish a diversification of the U.S. EastCoast tion on the wild beds and in a small artificially oyster crop. It is a fact that the close cultivation of selected experimental stock (discussion at 63rd Joint any species facilitates the spread of disease. Diver- Annual Convention between Shellfish Institute of sification can break the wildfire spread of a disease North America. Pacific Oyster Growers Associa- by the interdispersal of resistant types. It can assure tion, and National Shellfisheries Association. June some marketable crop when the disease toll of the 1971. Seattle, Wash.). Overa period of years the C. susceptible type is greatest. Were more known about virginicu oysters of Malpeque Bay, Prince Edward the genetics of different geographic populations of Island, Canada, slowly but certainly made them- C rirginica, some of the fear might be diminished of selves resistant to the Malpeque disease the through experimental transplantation of oyster set to com- agency of natural selection (Needier and Logic, mercial beds badly in need of seed from areas where 1947). it occurs in great abundance and goes to waste. C. rirginicti occurs extensively over an unusually wide range of temperature, from cold to subtropical, HYBRIDIZATION OF C. VIRGIMCA along the .Atlantic coast from the Gulf of St. Law- Plants and animals are artificially crossbred or rence to the Gulf of Mexico and farther south to hybridized in order to combine in the offspring some Panama, and around the West Indies. Ihere is evi- of the desirable characteristics displayed by either dence for a number of physiological spawning races set of parents. Another purpose of crossbreeding or within the species. Accumulated experience of hybridizing is to utilize the effects of hybrid vigor. In growers of C. virginicu indicates that these oysters different species, in addition to the general effects of transferred from one region to another often fail to hybrid vigor, there can be an increase in size some- thri\e in the new environment. No douht. as in C. times accompanied by partial or complete sterility; gigds (Imai and Sakai. 1961). there are real genetic

82 Reciprocal Recurrent Selection .

3. But outstanding peiformance of Maine hybrids Some of the methods used in plants and other ani- as larvae and early postselting spat. mals to break down gamete cross incompatibility 4. A hybrid growth rate of the spat in the first year barriers, as in inbreeding, would, no doubt, be useful slower than that of the local controls, but betterthan in accomplishing interspecific fertilization in the that of the nonlocal controls. oyster. The problem of hybrid inviability might be 5. Extremely poor growth of the older spat of overcome by crossing large enough numbers of indi- Maine hybrids and of the Maine x Maine controls viduals, carrying larger than usual cultures, by cross- with total mortality before the second year. Maine ing different races of the species involved, or with hybrids did better though than the Maine x Maine mutagenic agents, if direct hybrids between the de- control. sired species are not possible even then orare sterile, the use of a third "bridging"" species can sometimes Full fertility was found in some geographic hy- circumvent the barrier. brids of C. i,'/>rt,s. along with fertility of their Fi (Imai Currently the only reliable way to achieve pure and Sakai. 1961). Generally speaking, the hybridization in the oyster without any contaminat- crossbreds had a higher degree of hardiness, as com- ing nonhybrids is to make single crosses of individual pared to the inbred strains, and a greater adaptation oysters spawned separately, a tedious process not to environmental conditions. Morphological charac- commercially practical. This is so since the oyster teristics fell between those of the strains crossed as cannot be sexed until spawning and because the did growth, weight, index of meat weight, and oyster once sexed can reverse its sex. One male glycogen content. spawning in a group of intended female hybrid par- Some years ago H. C. Davis of the Milford ents would fertilize all the eggs before the desired Laboratory crossed C. viri>inica with C. ^igas hybrid cross could be achieved. This problem could (Davis, 1950). Fertilization took place readily, cell possibly be solved through the use of some sperm division was normal, and early veliger larvae were inhibiting agents in the mass-spawning population obtained. However, they all died before reaching intended for use as the pool of female parents in the the umbo stage. Imai and Sakai (1961) obtained the mass hybridization. same result. They further found both crossing bar- riers and hybrid inviability in crosses of C. gigas EFFECTS OF IONIZING IRRADIATION with C riviilaris and C. echinatu. More recently, ON C. VIRGINICA Menzel (1968a) reported obtaining a few spat from the hybrid cross of C. virgiiiica with C. gigas, and Mutation breeding has been scarcely attempted in some spat from crosses of other species with C economically useful farm animals. This is because of virginica. Interspecies crosses, at least those in- the high cost of culling out the large numbers of individuals volving C. virginica. in general, though appear dif- carrying the great numbers of lethal or ficult to obtain and difficult to culture successfully subvital mutations due to the low reproductive rate (Menzel, 1967, 1971). Recently, a cross of C. vir- of mammals. Because of the oyster's tremendously ginica with C. angulata. the Portuguese oyster, re- high reproductive rate and the insignificant worth of sulted in 209? of the eggs developing to the a single oyster, there would be no such limitations on straight-hinge larval stage (Stiles. 1973). All of the mutation studies, or breeding with mutations in the larvae, most of which were abnormal, died shortly oyster. after this. Cytogenetic examination of this inter- Some irradiation-mutation studies were mitiated species fertilization revealed 35% of the eggs to be inC. virginica for the basic information that could be unfertilized. Another I09f had a very delayed fer- derived, and to determine the radiosensitivity of this tilization. Polyspermy occurred in 35% of the eggs. mollusk. a member of a group about which there is Sperm nuclei were abnormally large and irregular in relatively little such information (Fig. 9) (Longwell.

259f of the eggs. Cleavage was irregular in y'r 1969; l.ongwell and Stiles. 1970: I ongwell and Nuclei of the early larval tissues were abnormally Stiles, unpublished data).' There is. of course, the vacuolated and highly irregular in shape. Adult oys- probability of practical application of such informa- ters were reared from the hybrid C. gigas x C. tion in the future. For example, irradiation might angulata made by Imai and Sakai (1961).

Difficulties in obtaining species ' hybrids of oysters Irradiation was carried oul at the Brookhaven National should not be viewed altogether pessimistically. Laboratory with the assistance and advice of A. H. Sparrow.

84 WAKWItO

00 NOT 10IT£«

ACXj-- % ^..i/a^-J^

\ \ r^. :\

Figure 9.- -Adult American oyster. Crassostrea virginica. set up for gamma-irradiation at the Brookhaven National Atomic Energy Commission Laboratory. have use in sterilizing highly selected strains of a and shell thickness. These oysters and spat were commercial hatchery to increase somatic growth and irradiated in the spring of the year as they were to prevent competitor companies from breeding the coming out of their winter dormancy. Germ-line strain. Irradiation might be used commercially to primordia were beginning active mitoses. induce parthenogenesis in obtaining instant, one- Gross cytological study of the gonads of the generation pure homozygous individuals. A mutant gamma-irradiated adults revealed that even the max- larval form with a larger mouth could increase the imum dose of 10.000 R did not adversely affect the types of algae an oyster larva would find acceptable production of gonadal material. Instead, the treated as a food since the larva would then be able to ingest group as a whole had roughly about 209? more larger sized algal cells. gonadal bulk than did the control group: also, there Gamma rays from a Cs'^^ source extending from were fewer sexually undifferentiated oysters in the 65 to 10.000 R administered to large, old wild adults treated group. in 1 hr. and from 220 to 20.000 R administered in 1 Spawning performance of the irradiated adults and 2 hr to wild spat about 9 mo old were not suffi- was better than that of the controls. Some adult cient to establish an LD.^dfor C.viri^inica. The lethal oysters receiving the maximum 10.000 R spawned. dose must be affected by the season of the year the However, none of the ju\eniles receiving more than oysters are irradiated, as well as by size of the oyster 8,000 R spawned.

85 Cytogenetic study of spawned eggs X-irradiated from the irradiation. Irradiation lines are also at a rale of 164 R/15 sec and then crossed with characterized by a greater crossability of sibs. as untreated sperm showed chromosome damage to mentioned earlier, and also by a greater success of begin at 500 R. By 2. (KM) R such damage was pro- the inbreds. Improved crossability of sibs can nounced. The highest dose used on the eggs was likewise be attributed to the increased heterozygos- 4,000 R. ity that results from induced mutations and to muta- In terms of the numberofset produced and surviv- tions of the cross-compatibility genes themselves as

ing for I yr from cultures of 500.000 fertilized eggs. well. There has been very little morphological even the lowest dose of 125 R of X-rays administered change in either the larvae or spat as a result of the at a rate of 199 R/lOsec to pooled sperm crossed with irradiation. untreated eggs had a slight effect. By 2,000 R the Fertilization and early cleavage stages of these number of these spat was reduced appreciably. At crosses have increased polyspermy, more spindle

3.000 R there was hardly any. and none at all at doses disturbances, more abnormalities of chromosome above this. From 4.000 R on there was a clear, strong number, more chromosome rearrangements, ab- drop in percent development of the eggs to some normal coiling of the chromosomes, and abnormal cleavage stage and percent development to the nuclei. These are all classic signs of irradiation dam- straight-hinge larval stage. There was an increased age to the genetic material. percent of abnormal straight-hinge or 2-day-old lar- vae. The highest dose used on the sperm was 10,000 R. See Table 2. LITERATURE CITED The overall performance of the larval and spat cultures from the Fi of the gamma-irradiated oysters AHMED, M.. and A. K. SPARKS. 1970. Chromosome number, structure and autosomal and from the Fa of the irradiated sperm lines has polymorphism in the marine mussels \t\liliis ectiilis and been characterized by an increased incidence of ab- Mytilus ctilifornianus. Biol. Bull. (Woods Hole) normal larvae at the straight-hinge stage, increased 138:1-13. mortality at all the early larval stages, heterosis of BATTAGLIA, B. the surviving larvae, and possibly heterosis some 1970. Cultivation of marine copepods for genetic and also in the young spat. This extra vigor must be due evolutionary research. Helgolaender wiss. Meeresun- to the increased genetic heterozygosity resulting ters. 20:385-392.

2. Table —Summary of the culture history of crosses of I wild adult x pooled irradiated sperm of 5 wild adult Cntsso.strea virginka. ters. Crassostrea virginica. Biol. Bull. (Woods Hole) BREWBAKER, J. 1-. 1964. Agricultural genetics. Prentice-Hall. Englewood 101:151-156.

Cliffs. N.J.. 156 p. MENZEL. R. W. DAVIS. H. C. 1967. Hybridization in species of Crassostrea. (Abstract.) 1950. On interspecific hybridization in Ostrea. Science Proc. Natl. Shellfish. Assoc. 58:6. 111:522. 1968a. CytotaxonomyofspeciesofclamsfMerrpnon'«)and

Mollusca, Part 1 . HILLMAN. R. E. oysleTs(Cras.wstrea). Proc. Symp. on p. 1964. Chromatographic evidence of intra.specific genetic 75-84. families of marine differences in the Eastern oyster. Crassostrea 1968b. Chromosome number in nine virginica. Syst. Zool. 13:12-18. pelecypod mollusks. 82:45-60. IMAI, T.. and S. SAKAI. 1971. The role of genetics in molluscan mariculture. Am. 1961. Study of breeding of Japanese oyster. Crassostrea Malacol. Union Bull., p. 13-15.

.WM.v. J. .Agric. Res. 12:125-171. MORGAN. T. H. 1924. Self-fertility in Ciona in relation to cross-fertility. J. LANNON. J. E. 1972. Estimating heritability and predicting response to Exper. Zool. 40:301-305. ascidian selection for the Pacific oyster Crassostrea 1942a. Cross- and self-fertilization in the Biol. Bull. (Woods Hole) 82:161-171. villus. (Abstract.) Proc. Natl. Shellfish. Assoc. Styela. and self-fertilization in the ascidian Molgula LONGWELL. A. C. 1942b. Cross- manhattensis. Biol. Bull. (Woods Hole) 82:172-177. 1969. Oyster genetics: Research and commercial applications. Conference on Shellfish Culture. April NEEDLER. A. W. H.. and R. R. LOGIE. in Prince Edward Island oysters 1968. at Suffolk Community College, Selden. Long Island. 1947. Serious mortalities N.Y. caused by a contagious disease. Trans. R. Soc. Can., LONGWELL. A. C. and S. S. STILES. Ser. 3. 4U5):73-89. 1968a. Fertilization and completion of meiosis in spawned NUMACHI. K. eggs of the American oyster, Crassostrea virgiiiica 1962. Serological studies of species and races in Gmelin. Canologia 21:65-73. oysters. Am. Nat. 96:211-217. STAIGER. H. 1 %8b. Removal of yolk from oyster eggs by Soxhiet extrac- tion for clear chromosome preparations. Stain Technol. 1957. Genetical and morphological variation in Purpura 43:63-68. lapillus with respect to local and regional differentiation of 1970. The genetic system and breeding potential of the population groups. Ann. Biol. 33:251-258. commercial American oyster. Endeavour 29:94-99. STAUBER. L. A. possible physiological species in the oyster 1973. Gamete cross incompatibility and inbreeding in 1947. On 99:614. the commercial .American oyster. Crassostrea virf;inica Ostrea virginica. (Abstract.) Anat. Rec. Gmelin. Cytologia 38:521-533. 1950. The problem of physiological species with special LONGWELL. A. C. S. S. STILES, and D. G. SMITH. references to oysters and oyster drills. Ecology 1967. Chromosome complement of the .'American oyster 31:109-118. Crassostrea virginica. as seen in meiotic and cleaving STILES. S. S. 1973. Cytogenetic analysis of an attempted inter-species eggs. Can. J. Genet. Cytol. 9:845-856. hybridization of the oyster. Incompatibility Newsletter. LOOSANOFF. V. L. 3. 41-45. Association P.O. 1%9. Maturation of gonads of oysters. Crassostrea vir- No. p. EURATOM-ITAL., ginica. of different geographical areas subjected to rela- Box 48. Wageningen, The Netherlands. tively low temperatures. Veliger 11:153-163. STILES, S. S.. and A. C. LONGWELL. in eggs from LOOSANOFF. V. L.. and H. C. DAVIS. In press. Fertilization, meiosis and cleavage 1963. Rearing of bivalve mollusks. In F. S. Russell large mass spawnings of Crassostrea virginica Gmelin. the commercial American oyster. Caryologia. (editor). Advances in marine biology, vol. 1, p. 1-136. Academic Press. London and New York. WILLIAMS. W. LOOSANOFF. V. L., and C. A. NOMEJKO. 1964. Genetical principles and plant breeding. Blackwell 1951. Existence of physiologically -different races of oys- Scientific Publications, Oxford, 504 p.

87

RECENT DEVELOPMENTS IN SHELLFISH CULTURE ON THE U.S. PACIFIC COAST

JOHN B. GLUDE'

OYSTERS meats from that time until 1965, and decreased somewhat in the following years, but again exceeded

Two species of oysters are produced in the States 1 million pounds in 1970. of Washington, Oregon, and Cahfornia in the bays Oyster production in Oregon reached nearly 1

shown in Figure 1. The small native oyster, Ostrea million pounds per year in 1950 to 1952 and then liirida Carpenter, 1863, is found in all three states,

but is raised commercially only in the southern part of Puget Sound. Wash. Production is low, but prices PUGEJ SOUND

are extremely high since this oyster is served as a specialty in seafood restaurants. N^^ BRITISH COLUMBIA The major species produced on the West Coast of GRAYS HARBOR — the United States is the "Pacific" oyster, Crassoslrea gigas Thunberg, 1793, which was first WILLAPA BAY , introduced from Japan about 40 yr ago. Except for the period 1941-46 seed oysters have been imported from Japan each year. Periodically local reproduc- tion occurs and U.S. growers are able to augment their seed supply by collecting spat locally. Major oyster producing areas are Willapa Bay, Grays Harbor, and Puget Sound in Washington; Tillamook, Yaquina, and Coos Bays in Oregon: Humboldt Bay, Tomales Bay, Morro Bay, and Drakes Estero in California. The major part of U.S. West Coast production

comes from Washington, as shown in Figure 2. Peak production of over 10 million pounds of shucked meats was reached in 1954 to 1956. Since that time production has decreased to a mean of 6.4 million pounds for the period 1966-70.

Oyster production in California increased rapidly

from 1954 to 1957, exceeded 1 million pounds of 900

eoo

700

600-

500

400

300

200

100 CALIFORNIA

Figure 3.— Production of clams on the U.S. Pacific coast.

Figure 2. — Production of Pacific oysters, Crassosslrea gigas. on the U.S. Pacific coast.

Clam production on the U.S. Pacific coast is cen- dropped to about one-half million per year, and con- tered in Washington with production ranging from tinues at about that level. 400.000 to nearly 1 million pounds of meats per year,

as shown in Figure 3. Although production has var- CLAMS ied during the past 20 yr. no clear production trend is evident from these records which include all species Several species of clams are harvested commer- of clams. Decreases in commercial production of cially on the U.S. Pacific coast. The razor clam. razor clams are largely offset by increased harvests Siliqini patiihi (Dixon. 1788), and the Pismo clam, of hard clams. Tivela stiiltorum (Mawe, 1823), occur on the open The few protected bays and inlets along the wave-swept ocean beaches. Although both of these Oregon coast produced between 100.000 and species were originally harvested commercially, the 200.000 pounds of clam meats per year for the period growing trend toward recreational fisheries has re- 1948-55 and have since dropped to a lelativeK low sulted in a disappearing commercial fishery. Only a level. few areas remain on the Washington coast where Commercial clam production in California was commercial harvesting of razor clams is still permit- never great and has been negligible in recent years. ted; but each weekend during the open season up to In both Oregon and California the tourist demand 25.000 recreational diggers attack the beaches hop- for hard-shell clams, as well as razor and Pismo ing to obtain their limit of 18 clams each. clams, has utilized an increasing proportion of the Other species grouped in the category of "hard" available supply. clams found in protected bays and inlets provide a significant commercial fishery. Species include the native littleneck or rock clam. Protothaca slamincci (Conrad. 1837): the butter ch\m. Sa.\:iJ(>iniis niiliali ANALYSIS OF TRENDS IN OYSTER

Conrad. 1837: and the introduced Japanese lit- PRODUCTION tleneck or Manila" clam. Tapes scnucleciisscita

(Reeve. 1864). There are several factors which help to explain the The commercial demand for hard-shell clams is decrease in production of Pacific oysters during the very good and prices are high in comparison to oys- past decade, as shown on Figure 4. .\ major factoi- is ters. Production does not meet the demand and sig- the limited U.S. market for oysters. The United nificant quantities of hard-shell clams are imported States per capita consumption of fisherv products from British Columbia. Canada. There is very little generally has remained nearly static for a number of "farming" of these clams is and production based on years at about 1 I pounds, and per capita cimsiimp- harvesting natural populations, principally upon lion of oysters during ihis period has acIualK de- privately-ow ned or privately-leased intertidal lands. creased. There has been little or no market promo-

90 Pacific oysters, tion by the oyster industry which is poorly organized Table 1. —Wholesale price of shucked Wash., cost index and oys- and made up of many small companies. Cntssostreii fii^as. in Seattle, adjusted to 1958 base. Although the quality of oysters produced and ter price marketed as a refrigerated, raw, shucked product is generally good at the time the oysters leave the plant, the delay in the distribution, especially to more dis- tant areas, results in a significant decrease in quality. Distribution to the Rocky Mountain and Mid- West states from the Pacific coast is more difficult now because Railway Express, which utilized rapid passenger trains, has become less available as trains are being discontinued because of the general trend toward air travel. Transportation of oysters by air to many of these locations is not economical because of the small volume to be shipped. All of this has re- sulted in curtailment of oyster markets in a large portion of the United States.

Another factor is the competition for the fresh- oyster market from East Coast or Gulf of Mexico, the American oysters, Crassostrea vir^inica Gmelin. Much of the production in these areas is from public beds which results in a low price when oysters are abundant, and a high price when oysters are scarce. Oyster production on the Atlantic coast was gen- erally low for several years following the major mass mortalities of oysters caused by the Haplosporidian Minchinnia nelsoni which began in Delaware Bay in 1957 and spread to Chesapeake Bay during the fol- lowing 2 or 3 yr. During this period the demand for Pacific oysters expanded and prices increased dur- ing the years 1960-61 and again between 1966 and 1967. More recently, production of low-priced oys- ters on the East Coast has increased, causing a re- duction in market demand for Pacific oysters. Mar- ket price of oysters on the Pacific coast has remained static for the past 4 yr even though costs generally In summary, production of Pacific oysters has of the United States. This is mainly because exten-

decreased to fit the present market. Marginal pro- sive intertidal areas have been available for oyster ducers have dropped out, and efficient producers culture and production of oysters on bottom is less have curtailed production. Prices have remained costly than production off-bottom. generally static, whereas costs have increased pro- Within the past 3 yr. however, several oyster ducing a generally unfavorable profit picture for the growers have begun oyster culture using rafts or Pacific coast oyster industry. Given increased de- racks, and those who have been able to market a mand at profitable price levels, production could be specialty product at a higher price have been quite greatly increased. successful. One company has constructed simple rafts using styrofoam for flotation and suspends seed oysters on wires below the rafts in a protected part of Puget Sound, Wash. After 15-18 mo those oysters NEW DEVELOPMENTS IN OYSTER which have reached commercial size are marketed, PRODICTION and the rest are placed on-bottom for another grow- ing season. These small oysters are well accepted in Specialty Products the Seattle market at higher than average prices, and

it appears that this production method will be Hidden in the statistics, because of low volume, is economical. a newly developed market for "specialty" oysters. Several Oregon growers in Yaquina Bay near These are partially grown Pacific oysters, usually Newport. Oreg., suspend Fiberglas- trays of oysters marketed under the trade name "yearling" oysters. below rafts and market these oysters at a small size These oysters are about 3 inches in length, similar to in restaurants in Portland, Oreg. These growers the size marketed in Japan, and are suitable for the have found that tray culture is somewhat more ex- raw half-shell trade, oyster cocktails, stews, sauteed pensive than "string" culture, and they may discon- oysters, etc. This product has a much better market tinue the use of trays. acceptance than large Pacific oysters which must be One company at Eureka. Calif, has an extensive blanched and cut into pieces before cooking. system of racks placed along the banks of channels in The market for yearling oysters is rather limited, Humboldt Bay. Oysters raised on these racks grow production costs are high and volume is low. but faster than those on bottom and are generally in these oysters sell for two to three time the price of better condition. standard-sized oysters. Turnover is rapid because of It has also been observed that mortality of oysters the short time required to grow marketable-sized suspended from racks is lower than that of oysters oysters. All factors considered, several small com- placed directly on the tide flats. Oyster mortality on panies have been able to improve their profit picture the beds in Humboldt Bay in 1971 was recorded as by producing this specialty product. 409c by pathologists of the C alifornia Department of Another development is a patented process which Fish and Game, whereas mortality of oysters sus- reportedly produces superior frozen oysters. This pended from racks was lO'/c. process consists of hand-shucking, partial cooking, Although rack culture generally is more costly breading, and rapid freezing. This product retains than "on-bottom" culture and requires special loca- the flavor well and resists oxidation during frozen tions, there is a belief that Pacific oysters raised storage. Although relatively expensive to produce off-bottom have a milder flavor than those raised because of the costs of hand-shucking, this product on-bottom. An organoleptic test to Compare the is finding good market acceptance. Frozen oysters flavorof oysters reared under various conditions will can be shipped by surface transportation which is be conducted by the Washington State Depailment cheaper than the air shipment required to deliver of Fisheries and the National Marine Fisheries Ser- fresh shucked oysters to distant markets. vice in Seattle during November 1971. Raft culture has many of the advantages of rack Increasing Use of Ofi'-bottom Culture culture and also provides more latitude in selection of locations since rafts can he anchored in waters of Although off-bottom culture of Pacific oysters has been used in Japan for many years, this method has - Reference to trade names does not imply endorsement by the only recently gained acceptance on the Pacific coast National Marine Fisheries Service. NOAA.

92 various depths. The principal requirements for raft Air Shipment of Anesthetized Oyster Larvae

culture are 1) shelter from storms, 2) sufficient depth, and 3) permits from local zoning authorities Pacific Mariculture, Inc. has recently patented a and Corps of Engineers for anchoring rafts. method for temporarily suspending activity of ma-

An anticipated development is a system of grow- ture oyster larvae. With this method it is possible to ing oysters on submerged rafts or racks. This system air ship large quantities of mature oyster larvae in will probably be necessary in areas where recrea- small containers from California to oyster culture tional use of the water surface for fishing, boating, areas. At these locations larvae are placed in tanks of etc. would make it difficult to obtain permission for warm water with suitable cultch materials. Attach-

raft culture. Engineering designs for structures ment is completed within 2 hr. This method avoids needed for this type of culture have not yet been the cost of shipping heavy "mother"" shells or other completed, but might be patterned after the sub- cultch materials since one-half million larvae can be merged racks which are used in French Polynesia for shipped in a '/2-liter bottle. Oyster growers can then pearl oyster culture to avoid storm damage and foul- "set"" the larvae on desired cultch materials and ing. plant them on their oyster beds. This method needs

further development to improve its reliability, but it Use of "Unattached" or "Cultchless" Seed appears probable that this will be accomplished in the near future and that this method will find applica- Pacific Mariculture, Inc. near San Francisco, tion in many places. Calif., has patented a process of producing indi- vidual seed oysters which have several advantages. Investigation of Causes of Oyster Mortality

This seed is readily available at any time of the year on the Pacific Coast and can be shipped economically by air freight. Sur- Mortalities of 10-70% during the second or third vival during shipment and after planting has been summer after planting Pacific oyster seed has been excellent and the individual oysters develop a un- observed at several locations along the Pacific coast. iform shape which makes a very attractive prod- The most severe mortalities have occurred in south- uct. ern Puget Sound and part of Willapa Bay in Washing- Disadvantages of "unattached" seed are that it ton, and Humboldt Bay in northern California. requires special handling in screen trays, and this Negligible mortality levels have been observed in requires a large amount of hand labor. Growth is British Columbia, northern Puget Sound and Hood generally poor in trays unless there is adequate circu- Canal in Washington, Oregon bays, and elsewhere lation of water which contains adequate food sup- in California. plies. These individual oysters must be quite large mortalities occur near the heads before they will stay in place on oyster beds which Generally, heavy with high nutri- are exposed to waves, currents, or storms. This of bays which are warm and muddy where oysters limits the use of this seed for traditional oyster farm- ent levels, abundant phytoplankton, Mortalities generally ing and requires development of new aquacultural grow rapidly and fatten well. weeks in midsummer when the systems. It appears that "unattached"" seed will be- occur during a few come an important factor during the next few years, oysters are in spawning condition. It has been ob- provided specialty markets can be developed for the served that mortalities have been more severe product. during warmer years. 5 yr by state During March 1971, I made experimental plant- Investigations during the past ings of ""unattached"" Crassosrrea ^sii^cis seed from fisheries agencies of Washington, Oregon, and the Pacific Mariculture hatchery at several locations California and by the laboratory of the National in the Fiji Islands. Survival ofthis seed was excellent Marine Fisheries Service in Oxford, Md., have and growth was satisfactory after the spat were failed to detect a specific cause for this mortality. cemented to fiberboard (Masonite or asbestos Tests for Lcihyiintli(>niy-\(i marina which causes ex- board) squares strung on wire or rope and suspended tensive losses of oysters in the Gulf of Mexico and below rafts. It appears that this method v\ill be ap- Minchinnia nelsoni which kills oysters in plicable any place where hydrographic conditions Chesapeake and Delaware Bays have proved nega- permit the use of rafts or racks and where labor costs tive. Although numerous microorganisms have been are low. observed in the thousands of oysters examined from

93 the Pacific coast, none have occurred consistently farming. Now a commercial hatchery in California enough to indicate that they are associated with the has successfully produced large quantities of young observed mortalities. Manila clams and has offered these for sale. Test In a new project, agraduate student at the Univer- plantings have been made in Willapa Bay, Wash.,

sity of Washington College of Fisheries in Seattle is and in some other locations, but it is too soon to investigating the relationship between the bacterium evaluate the success of these ventures. Vibrio anquiUaritm or V. ptiraluiemulyticiis and oys- I had the opportunity in March 1971 to obtain a ter mortalities. He has observed that Vibrio can kill small quantity of these seed clams from California oysters at elevated temperatures in laboratory ex- and to plant them in trays in the Fiji Islands. Survival periments, but field tests have not yet been of clams was excellent, but growth was not outstand-

made. ing. This experiment is still in progress, but it is

Efforts of Washington State Department of already apparent that the first step in the develop- Fisheries have recently been reoriented to develop ment of commercial farming forclams, availability of new oysterculture techniques which will circumvent seed, has been accomplished. With the large demand

oroffset mortalities. Forexample. transplanting par- for clams and the limited supply, it is likely that a tially grown oysters to low mortality areas before the new clam farming industry will develop in Washing- second summer when heavy mortalities begin seems ton State within the next few years. to be a practical solution. Also, of improvement Three new developments in the utilization of handling methods for seed to reduce losses would natural stocks of mollusks occurred in Washington. help to offset mortality which might occur during the Exploratory diving and population assessment by second summer. scientists of the Washington State Department of In summary, mass mortalities significantly reduce Fisheries have shown that less than 5*^ of the production profits in and specific locations, but clam, Fanope ^cnerosa Gould, 1850, are other areas remain unaffected. Research to deter- exposed at extreme low tide. Before this discovery it mine is causative factors still in progress. was thought that the geoduck was a scarce species which needed stringent regulation to prevent over- NEW DEVELOPMENTS IN CLAM harvesting. No commercial digging had been permit- PRODUCTION ted and the recreational or personal use limit was set at three clams per day. Ocean beaches on the Pacific coast are owned by Now Washington has surveyed subtidal beds and the states and held for public use. This prevents the established a system for leasing areas for commer- private commercial development of farming for cial harvest by scuba divers using suction pumps. species such as the razor clam or Pismo clam which The product is now achieving market acceptance occur only in this habitat. and a new industry has been established.

The inteilidal zone in bays or estuaries is also Another species of clams, Mya arenariu owned by the states, but much of this land, espe- Linnaeus, 1758, known as the soft-shell clam in New cially in the State of Washington, has been sold to England and Chesapeake Bay, is present in individuals who are usually the owners of the adja- Washington but has not been utilized commercially. cent upland. Large areas of intertidal zone have also This clam has a somewhat less attractive appearance been leased by the states to individuals or companies than the local littleneck and butter clams, and tradi- for special purposes, such as oyster and clam cul- tionally it has not been marketed in the Pacific ture. Subtidal bottoms also can be leased to indi- Northwest. Heavy concentrations of soft-shell viduals or companies for aquaculture. clams are found in muddy or sand\ beaches, usually Farming of clams has not reached the stage of at the mouths of rivers, but areas suitable for these development attained by oyster culture. The few species are rather limited. commercial clam farms on the U.S. Pacific coast still Recently several individuals or companies have depend upon natural setting to restock their beds. begun harvesting soft-shell clams using two types of Clam farming is still only selective harvesting of a hydraulic dredges to minimize labor costs. One type natural crop to obtain the greatest yield. similar to that used in Chesapeake Bay is operated

Until recently there has been no source of "seed" from a boat and consists of a digging head which is clams which might be used for planting on private forced through the bottom and a conveyor to bring lands and this has been a major deterrent to clam the clams to the surface. The second type is hand-

94 operated at low tide, but uses water pressure to wash for oyster culture in areas where shoreline residents the clams out of the bottom. want to use the water surface for boating, fishing, The quality of the soft clams in Washington is water skiing, etc. Even the installation of pilings or comparable to those from Chesapeake Bay or New stakes marking boundaries of shellfish beds or England. If harvesting and shipping costs are not wharfs for unloading the product are being ques- prohibitive, it is likely that a new industry for soft- tioned. shell clams will become established in the Pacific At the same time there is a majoreffort to maintain Northwest. or improve water quality in the bays and estuaries Large populations of the , Mytiliis and to eliminate sources of industrial and domestic edulis Linnaeus, 1758, occur in Puget Sound, Wash., pollution. These public effoils will help to assure but this species also traditionally has not been fully continuation and expansion of aquaculture which is utilized in the United States. Pugcl Sound mussels a "clean" industry. Furthermore, aquaculture pro- are comparable to the European mussels in quality vides a good economic justification for maintaining and the paralytic shellfish poisoning caused by their high water quality in inshore areas. feeding on the dinoflagellate Gonyaulax, which Federal and state legislation has been passed or is sometimes limits mussel harvesting along the ocean being considered to establish authorities and proce- coast, is not a problem in the inshore waters of dures for zoning the shoreline for special purposes. Puget Sound. If fish and shellfish farmers can present a convincing

Recently, through efforts of the marketing argument, it is likely that certain areas will be re- specialists of the National Marine Fisheries Service, served for aquaculture with assurance that water local restaurants have begun to serve mussels and quality will be maintained at acceptable levels. the product seems to be gaining acceptance in the Pacific Northwest. There are substantial natural CONCLUSION stocks of mussels which could be harvested if a In conclusion, oyster production on the Pacific market develops. Also, it would be possible to sup- coast is limited by demand, but the potential exists plement natural production by applying mussel farm- for greatly increased harvests through application of ing techniques used in Holland, Spain, and else- modern methods of aquaculture. where as the market expands. Clam production is limited by natural supply. Clam farming has not been developed but, now that COASTAL ZONING seed of at least one species is available, it is likely that commercial clam culture will develop rapidly in People in the United States are becoming increas- the Pacific Northwest. ingly aware of the need to protect the environment Water quality will not be a limiting factor if the from industrial or residential development. This present awareness of the importance of the envi- need is especially apparent along the shoreline ronment is translated into action to control pollution. where several classes of users compete for space. Coastal zoning is a threat to aquaculture in some Shellfish farmers are finding difficulty in obtaining areas but could protect those areas which are most approval from local "zoning boards" to anchor rafts important for production of fish and shellfish.

95

SEAWEED CULTURE IN JAPAN

ROBERT WILDMAN'

The culture of marine algae, primaril\ for human spores settled and grew, and the mature plants were consumption, is a large and expanding industry in harvested. The nori harvest grew gradually until the

Japan. At the present time, the growing and har- end of World War 11 and is now six times that of the vesting of Porphyra, "nori,"" is considered to be prewar level. Much of this increase was made possi- one of the most profitable fisheries in Japan. In con- ble by dramatic improvements in culture techniques. trast, seaweed culture is still in a research phase in Two other factors were the establishment of the United States. Our demand for marine algae is cooperative unions which increased the profit to the much more limited in terms of both total volume grower and increasing coastal eutrophication which and number of species. This is mainly due to the resulted in more fertile waters in many new areas, fact that few Americans eat the plants as such. Our while the latter is the less important factor. use of seaweed is almost entirely in the form of At first bamboo twigs replaced the tree twigs, then phycolloids extracted from the plants, and to a very these were replaced in many areas by nets which limited degree, as fertilizers and food. These uses of were still placed in the water to collect the spores. several species of marine algae and the recognition This use of net collectors is thought to be responsible that the U.S. possesses a limited supply of the three for a doubling of production, but the discovery by K. or four most used species has led to seaweed cul- M. Drew of the Conchocelis stage in the life history ture on an experimental basis in this country. How- o{ Porphyra enabled the Japanese to make the in- ever, we have not and, in the foreseeable future, creases in production to the current level. The will not place the amount of our coastal waters fisherman or cooperatives are now able to artificially under '"cultivation" as has Japan. Another impor- "seed" their nets through the controlled culture of tant difference between the United States and the Conchocelis stage, which in turn releases the

Japan is that the seaweed beds can be harvested spores to attach onto the nets in tanks or in the sea. only by fishermen's cooperative associations in (See Suto's paper in this report for a complete de-

Japan whereas in this country the harvesting is done scription of this process.) When the nets are "in- by industrial firms either directly or through con- noculated" in tanks, the nets are rotated slowly in tractors. The cooperatives are responsible for the the tanks containing the Conchocelis and then trans- management and protection of these resources ported to the growing area where they are attached while in the United States such efforts are rarely to the bamboo poles. This procedure allowed the required by the government but are usually volun- nori grower to control the seeding of his collectors tary. and thus, be more confident of his crop in areas with

a good natural population. It also provided a means PORPHYRA (NORI) of growing nori in regions which had experienced a shortage in natural spores, especially in western Culture Techniques Japan.

The most extensively cultivated seaweed in With the advent of the use of the Conchocelis Japan, nori. has been groun since about 1600 (Ta- —spore culture technique, the predominant species

mura. 1966). The earl v culture techniques consisted of used changed from Porphyra lenera to P. yczoensis setting bundles of twigs in estuaries on which the which could withstand higher salinities. In many areas P. tencra and P. yezoensis are grown in the inner parts of bays and estuaries with P. ' Prognim Director. OtTice of Sea Grant. NOAA. Washing- ton. D.C. 20:.\v p.seiiilollneari.s being grown in the deeper waters. In

97 )

the former situation, the nets (18.2 m x 1.3 m) are fishery. Briefly summarized, these problems and ac- stretched between bamboo poles stuck to the bot- tivities are as follows. (Again, see Suto's paper in tom, with the nets being tied at the mean water level. this report for a more complete description of them. The nets with P. pseudolineciris growing on them 1. Development of new nori grounds or improve- float on the water surface, anchored to maintain their ment of old ones, using the new net collector position, and kept on the surface by glass or plastic techniques, the floating net cultures and coastal floats. engineering works (pilings to protect growing Recent work by Imada and co-workers has areas, deepening such areas to increase water yielded results that could increase the production of exchange, etc.). This would bring new areas into nori. This research indicated that amino acids are production to replace old ones lost because of effective growth promoting substances for Porphym pollution and increase the productivity of existing and that the exposure of the fronds to air by tidal areas. fluctuations is a significant factor in disease control 2. Prevention of large-scale fluctuations (heavy (Imada, Saito. and Teramoto, 1971). Crossing ex- losses) yearly production primarily through dis- periments by Suto between different species of cul- ease control. This is done partially now by pre- tivated Porpliyra succeeded, the cross developing venting overcrowding of the nets in the growing to the Conchocelis phase. Other attempts at cross- areas and by refrigerating the "buds'" (juvenile ing monoecious and dioecious species, and between plants, 5-50 mm in length) at -20°C. This re- species with different chromosome numbers were frigerating procedure is applied to a large part of not as successful (Suto, 1971). the newly hatched fronds essentially for the pro- curement of frond stocks. These stocks are used Production and Use to replace poorer quality fronds in the growing areas. By refrigerating these buds, the '"weeds" The demand for nori in Japan and the increasing (such as Enteromorpha) and diatoms are killed, production capability have in a sig- resulted very and the development of a parasitic fungus is pre- nificant industry. In 1970. about 60,000 hectares vented. By 1970, one-half of all culture nets used (150,000 acres) of coastal waters in Japan were were refrigerated using this technique (Okazaki, for nori cultivation. being used This acreage pro- 1971). Most of the diseases or diseaselike prob- nearly 6 billion duced sheets of the dried product lems are not well understood, or. in many in- 70-80 worth billion yen per year (approximately stances, not even identified. Frequently, the million). paper-thin sheet is in- $230 Each 20 cm (8 plants appear to be infected by a fungus, but this ches square and weighs about 3 g. In addition, 200 could be caused by environmental or physiologi- million sheets are imported from Korea, a number cal conditions (temperature, salinity, malnutri- now limited by an import restriction and one which tion, etc.). Most of these conditions are called

could be increased to I billion in sheets the future various kinds and colors of "spot disease" or (see Suto). "rots," but the exact causitive agent is not iden- Approximately 60,000 fisheiTnen are now cultivat- tified. ing nori. setting about 10 million nets each year and Work reported recently by Ishio and his co- realizing the 509f (Furukawa, 1971) to 70% (see workers identified pollution from chemical plants Suto) net income for their efforts. This level of pro- as a cause of one type of algal disease. A "can- duction is required to meet the needs of the average cerous"" disease observed in Porpliyra in shallow Japanese 50-60 sheets who consumes of nori per coastal waters polluted by industrial wastes was year. price of nori, The up to $15 per kilogram dry shown to be related to contact between the fronds weight (nearly $7 per pound), is a major factor in and the contaminated bottom mud. The mud was making this the most profitable of all fisheries in extracted and it was found that the carcinogenic Japan. fraction contained a mixture of organic com- pounds discharged by a dye factor) which uses tar Problems and Needed .Advances distillates as raw materials (Ishio. Yano. and Nakagawa. 1972). In spite of the high level of productivity, the

Japanese recognize the need to increase their pro- 3. Mechanization of nori cultivation and processing. duction and improve the profit potential of this With the current labor shortage in Japan and other

98 industries drawing workers away from the Culture Techniques fisheries, with the resultant rising labor costs, as In the spring when the mature plants release the much of the growing, harvesting, and processing zoospores, "collector strings"" are hung in the water of the nori must be mechanized as possible. Even on which the spores attach and the sporophytes so, the nori fishery is not suffering nearly as se- grow. As with nori, this seeding now takes place in vere a problem as that facing the oyster fishery. tanks although in the past it was done in the sea near natural beds. Also, past efforts to expand the 4. Eutrophication in the coastal areas around beds have included creating new substrate surface Japan. This, in fact, is going on, and it may pro- by dropping rocks onto the bottom and exploding vide nutrients to the nori cultivating areas to existing rocks with dynamite in areas with natural some e.xtent, but most of the causative elements populations of Unclaria. A wide variety of other of coastal eutrophication such as industrial dis- techniques have been experimented on over the charge, domestic sewage, and agricultural run- past 55 yr with some success (Tamura, 1966). off contain undersirable constituents. Industrial However, currently the collector string method is pollution, particularly that which contains cad- used in which the mature sporophylis are partially mium, mercury, and other highly toxic elements dried, placed into the tanks of fresh seawater and poses a much greater threat to nori cultivation. the released zoospores settle on a lOO-m long string, Pollution of all kinds is now a very serious prob- previously wound around a vinyl plastic frame. The lem for Japan, but their heavy dependence on frame is removed after 1-2 hr and transferred to a seafood, much of which comes from their coastal l-m deep culture tank for the summer season. When waters, makes marine pollution a very real health the young plants reach about I mm in length (in the and economic threat. fall), the strings are transferred to rafts in the sea.

5. Potential for oversupply with its resultant The plants are harvested when they reach about 1 m economic effects. With the high prices, the in length. growers are obviously attempting to increase Attempts to produce hybrids of three species of their total production. The success of efforts to Undarin have met with some success, indicating expand the nori growing areas, solve the disease that at least closely related species can be crossed problems, eliminate pollution problems, and (Saito, 1971).

mechanize the industry will all lead to increased production. Further, the growing tendency of Problems separating the producers and processors into separate operations will cause the producers to If the strings are placed on the rafts before the grow more algae to maintain their income level. water temperatures have dropped to 15°C, serious fouling occur. Also, if the rafts are located in a Another possibility is that with the increasing can mechanization and increasing size of cultivation rough water area and left floating on the surface, the operations, fewer workers and separate young plants can be seriously damaged. In these operators will be needed. Thus, many nori areas the rafts can be anchored to a depth of 1 m to avoid this problem. Other problems which are not so fishermen will be moved into other types of em- easily bacterial diseases and ployment. remedied include some grazing of the young plants by isopods and gas- tropods. One last potential problem is the indication VNDARIA (WAKAME) that production is increasing to the point of equal-

Introduction ling, if not exceeding, the demand for wakame in Japan. In comparison to nori, cultivation of the brown alga, Utnhiriti. is of relatively recent origin. The amount of wakame grown is still significantly less LAMINARIA (KOMBU) than nori, but is increasing rapidly from almost zero Introduction production in 1963 to over 60.000 tons in 1970. This exceeds the amount being harvested in Japan from Many species of this genus are used by the natural beds. This alga, one of the Laminariales. is Japanese as food: several of them being cultivated at not native to .American waters. the present time. While important as a food and as a

99 source of alginic acid, kombu is still not in as great a GELIDIUM AND OTHER demand as are nori and wakame. AGAROPHVTES (TENGLSA)

Introduction Culture Techniques Perhaps the most familiar algal extract to Ameri- The cultivation, dating back 250 yr, is quite differ- cans because of its wide use as a component of ent than that for nori and wakame. Kombu produc- bacterial growth media in both educational and med- tion is increased primarily through the improvement ical facilities, agar is used for similar purposes in of available substrate and control of harmful Japan. It is harvested for both domestic and export "weeds"" such as PhyHospadix, a marine sper- purposes, including sales in the United States. matophyte. The latter is accomplished by dynamit- However, to meet the demand of the processors, ing to clear the PhyHospadix from areas suitable for Japan must now import about 5,500 tons of the growth oi Laininaria. The former involves the plac- 12.000 tons dry weight used in agar production. ing of additional large rocks on the seabed on which Many red algae belonging to the families the plants may grow or, in some instances, using Gelidaceae and Gracilariaceae serve as the source artificial substrate such as various shapes of con- of agar, but (Iclidiiim is the most important genus in crete. In addition, some cultivation has been done both Japan and the United States. using a hanging culture system (line and float). Culture Techniques Problems While much of the raw material for agar produc-

Liimiiuiria is one of the many valuable marine tion is harvested from natural beds, some artificial algae which have been plagued by the phenomenon propagation is practiced and has been for about 3(X) called "iso-yake"" by the Japanese which prevents yr. In the past, this has consisted largely of increas- the plant from adhering to the bottom. Apparently, ing the available substrate by throwing large rocks

the cause of this problem still has not been identified, into the coastal waters in areas near existing beds

but it usually occurs in areas where the bottom is where spores will be sufficiently abundant to seed covered with coralline algae. Some investigators the rocks. Other efforts to increase the supply of have advanced the theory that this results in a "des- agarophytes have included mechanical cleaning of

ert" condition with very little in the way of edible the rock surfaces, eliminating weeds (Ecklonici and

seaweeds available to shellfish in the area. Thus, if Eiscnia) from Gelidiiiiii beds, growing young plants juvenile plants of Lam in aria and other such algae to harvestable size attached to ropes hanging from begin to grow, they are grazed off rapidly. floating lines, and, more recently, fertilizing the In this same vein, the .lapanese have determined, coastal water in which the algae are growing as we have in California, that abalone are found only (Yamada, 1972). In this last effort, a lump of fer- where their primary source of food (brown algae- tilizer (in the form of urea, ammonium sulfate, or a kelps) is available (R. Burge, pers. comm.). In many "nitrogen/phosphate mixture"") is placed on the areas, the brown algae are completely lacking and, seatloor in the Gelidiiim bed and allowed to dis- thus, coastal waters in which abalone could grow, solve slowly. While this has succeeded on a com- are not usable for cultivation. A very large-scale mercial scale, the economic feasibility of this prac- experiment is planned to begin in 1972 which will tice has not been fully demonstrated as yet. involve the establishment of a large kelp bed in a bay. Problems if this is successful. 10 million abalone seed per year

for 3 yr will be introduced into the kelp bed. This Gelidiiim and its relatives are among the har- could lead to a new technique for expanding the vested seaweeds known to suffer from the iso-yake

capability of the Japanese for producing both phenomenon. To date it has not been possible to l.diiiiiKiriii and abalone (Hisashi kan-no. pers. control the release of spores from Gelidiiim as has comm.). been done with many other algae. Ability to do this Other possibilities being researched include the would make the establishment of nev\ populations

development of techniques for cutting the normal much more certain. Another potential problem is 2-yr growth period to harvest down to I yr Korea's growing production and export of agar (Hasegawa. 1972). This has been accomplished and v\hich could create an excess and result in a profit should lead to significant production increases. loss for Japan.

100 ANALYSIS OF SEAWEED CULTURE HASEGAWA. Y. Forced cultivation of l.iiniimiria. In I'roc. Seventh IN JAPAN 1972. Internatl. Seaweed Symp., Sapporo. Japan. Aug. 8-12.

1971, p. 391-.'!9.'!. Univ. Tokyo Press. Although the Japanese are still encountering many IMADA. O., Y. SAITO, and K. TERAMOTO. problems in optimizing the culture of the several 1972. Artificialcultureof laver. //I Proc. Seventh Internatl. species of marine algae, they are able to produce Seaweed Symp., Sapporo. Japan, Aug. 8-12. 1971, p. nearly as much as they need. Their real problems of .^58-363. Univ. Tol

lie in fields of I ) undesirable the future appear to the ISHIO, S., T. YANO, and H. NAKAUAWA. pollution, 2) oversupply with its resultant lowering 1 972. Cancerous disease ofPorphyra tenera and its causes. of price, and 3) idealizing the labor situation (im- In Proc. Seventh Internatl. Seaweed Symp., Sapporo, 8-12, 373-376. Univ. Tokyo Press. proved working conditions, keeping wages and pro- Japan, Aug. 1971, p. A. fits in line with other industries in Japan, keeping OKAZAKl. 1971. Seaweeds and their uses in Japan. Tokai Univ. Press, sufficient workers in the industry and finding ac- 165 p. ceptable employment for any excess over that SAITO, Y. which is needed, etc.). on morpholog- 1971 . On the effects of environmental factors in Japan could Many of the techniques developed ical characteristics of Undaria pinnalij'ula and the breed- be used by U.S. industry, but we face many problems ing of hybrids among the genus Undaria. Seminar on the which the Japanese do not. Our labor costs are al- Contributions of Culture, Laboratory, Field and Life His- tory Studies to the Systematics of Benthic Marine Algae ready so high that nearly all seaweed farming in the of the Pacific Abstracts, Jap. -U.S. Comm. on Sci. Coop., United States would have to be essentially totally p. 18-19. mechanized. Since the principal uses of seaweed in SUTO, S. America are for nonfood purposes, the price paid for 1971. Variation in species characters of Porphyra under cul- raw material will remain quite low. It is very ture condition. Seminar on the Contributions of Culture, doubtful that the public will allow the surface of our Laboratory, Field and Life History Studies to the Sys- coastal water to be covered with a bambo-net type tematics of Benthic Marine Algae of the Pacific Ab- stracts. Jap. -U.S. Comm. on Sci. Coop., p. 28-29. system used for Porphyra except in some very re- TAMURA.T. mote areas, such as in southeastern Alaska or on 1966. Marine aquaculture. 2nd ed. (Translated from the U.S. controlled islands. Japanese by M. I. Watanabe, p. C-1 —A2-30; available U.S. Dep. Commer.. Natl. Tech Inf. Serv.. Springfield. BIBLIOGRAPHY VA. as PBI94051T.) YAMADA. N. FURUKAWA. A. 1972. Manuring for Gelidium. In Proc. Seventh Internatl. 1971. OutlineofthemarineaquacultureinJapan.Jap. Fish. Seaweed Symp., Sapporo, Japan, Aug. 8-12, 1971. p. 385- Res. Conserv. Assoc. 390. Univ. Tokyo Press,

101

FRESHWATER FISH CULTURE IN JAPAN

HARVEY WILLOUGHBY'

INTRODUCTION that increases the salinity level in the rearing pond by approximately 10% per day. At a couple of points on Japanese Fish Cul- The following observations during the acclimatization period, salinities are held during field travel in Japan in the ture were made static for one or more days to let the fish become 20-27, 1971. period October adjusted to the change. Average survival is 70%. Growth in seawater is very rapid. Average size at CULTURE SALTWATER TROUT harvest after 10-12 mo in seawater is 1 .5-2.0 kg. This

is approximately double the growth rate in fresh My only observation of trout culture in seawater water, and the price is approximately double that of was at Ogatsu Bay in Miyagi Prefecture. John Glude freshwater-reared fish. Sea-reared trout were com- and I travelled to Ogatsu Bay in the afternoon of manding 600-800 yen/kg compared with the market October 20. with Akimitsu Koganezawa. Chief of price of 300 yen/kg for farm raised rainbow trout. Shellfish and Fish Research for the Migayi Prefec- tural Station. SALMON CULTURE The principal trout culture installation was a new From October 21 to 23, I visited the Island of commercial hatchery just getting into production at Hokkaido to view salmon management operations. Karakuwa. This is a commercial venture operated The organization of the Hokkaido salmon pro- by a Fishermen's Cooperative Association. The sta- gram is impressive. Overall program direction and tion consists of a small hatchery building and six principal research activities are conducted from the large circular rearing ponds. Each pond has a supply central headquarters in Sapporo. Regional field line for fresh water and one for seawater. supervisors at six locations direct the field work Each pond also is equipped with its own built-in carried on at 41 hatcheries and a number of fish recirculating system and filter. Since the rearing collection stations. facilities were completed too late to rear fish for the On October 22, I visited several chum salmon current year's stocking of the rearing pens in Ogatsu (Oncorhynchus keta) hatcheries on the Tokachi Bay, the fish were to be shipped in from another River in the vicinity of Obihiro. The annual spawn- location and acclimated to seawater at Karakuwa ing run of chum salmon was in progress, and I was before being transferred to the seawater rearing able to observe the seining of these fish at an irriga- pens. Koganezawa explained the procedure to be tion dam which blocked their upstream movement. used as follows: Approximately 100 million eggs were being incu- The trout are hatched in fresh water and reared in bated in the three hatcheries visited. the conventional manner until they are approxi- The following day, October 23, I visited the head- mately 150 g each. At this time they are separated as quarters of the Hokkaido Salmon Hatchery to sex and the females are acclimated to seawater. in where I met the Direc- The acclimatization process requires from 12-20 Fisheries Agency Sapporo in the day. Toshinobu davs. Seaw ater is mixed u ith the fresh water at a rate tor. .Ayahiko Hemmi. Later

Tokui and 1 travelled to Lake Shikotsu and visited

' Chief, DM^ionof Fish Hatcheries. BureauofSport Fisheries the kokanee salmon hatchery. and WildHI'e. L .S. Department of the Interior. Washington. D.C. Kokanee salmon fO. ncrkci kciiiwrliii are native to 20^40: piesent address; Bureau of Sport Fisheries and W'ildHfe. only two lakes in Japan, both on the island of Hok- L S Department of the Interior. P.O. Box l^ASb. Denver. CO s()::.s. kaido. They have, however, been widely trans-

103 salmon, On- planted and now occur in about 20 lakes. Lake populations of the native Japanese salmon, and various Shikotsu. a large natural lake on Hokkaido, contains c(>rli\)uliii.s mason, or cherry and brook trout. a population of kokanee salmon and is the site of a exotic salmonids such as rainbow Freshwater hatchery devoted to the propagation of the species. Scientists at the Nikko Branch of the Because of the low mineral content and consequent Fish Research Laboratory, are investigating the dynamics, the fish movements within the low productivity, it is difficult to maintain a satisfac- population of sal- tory commercial harvest of kokanee salmon in Lake lake, the characteristics of various species of Shikotsu without depleting the spawning population. monids, including hybrids, and the management streams. The interests of Officials of the Hokkaido Salmon Hatchery are trout in populations in those of searching for sources of kokanee salmon eggs with Yoshikazu Shiraishi and his staff parallel who are which to supplement their own supply. They have management biologists everywhere requested eggs from the State of Montana, but to charged with maximizing sport fishing yield in date have not been able to get any. fresh waters.

1 concluded my visit to Hokkaido by touring the Chitose Hatchery where an extensive expansion COMMERCIAL TROUT FARMS project is underway. 1 believe this is the oldest Soichiro Shirahata, biologist hatchery in Hokkaido. It rears chum salmon and Accompanied by Freshwater Fisheries rainbow trout iSalmo iiuinJneri). The capacity of the with the Nikko Branch of the visited trout farms and fish expanded hatchery will be about 13 million eggs. Research Laboratory, I processing plants in and around Fujinoyama City, In summary. I was impressed by the sheer volume of salmon released from the hatcheries in Hokkaido. Shizuoka Prefecture, on October 25. and laboratory These hatcheries incubate over 500 million eggs per The Shizuoka Prefectural hatchery rainbow trout eggs annually. year. The breakdown by species is approximately produces 30 million control time of S59c chum, 10% pink iOncorhynchus gorbuscha), They make extensive use of light to technique makes it and about 5% masu^O. mason). The chum salmon spawning. This management for their customers over a are fed for 70-90 days and released in early spring. possible to provide eggs manager, Matsuura, The return after 2 or 3 yr at sea is consistently be- period of several months. The stan- that in instance they were able to get tween 1 and 2%. an excellent return figure by reported one regulating dards achieved at Pacific salmon hatcheries in three spawns in 2 yr from a pond of fish by America. the photoperiods. his staff are faced with a formidable On Sunday afternoon of October 24, I visited the Matsuura and Tansui Fish Research Laboratory in Tokyo. labor problem of removing dead and infertile eggs by slides 1 Yamakawa and his staff showed me the laboratory manual means. They were quite interested in and explained their research projects. showed them of a mechanical egg picker in use at the in Idaho. This is a national laboratory devoted to the prob- Dworshak National Fish Hatchery fishing business is operated by the lems of freshwater fish culture. Their principal work A thriving sport Prefectural Hatchery. Some 10.000 fisher- is on the diseases and nutritional problems of eels, Shizuoka ayu. carp, and trout. The principal investigators pres- men per year participate in fee fishing in a stream

I under- ent during my visit were: Takeshi Nose who was running through the hatchery grounds. As fishing facilities is a working on the nutritional requirements of eels, stand it, the provision of sport hatchery license Hiroshi Kawatsu on disease and microbiology of condition of granting a commercial freshwater fishes, Shimadju on ayu culture, and Inui in some, if not all, prefectures in Japan.

1 assume on hepatic diseases of eels. Trout farms in Shizuoka Prefecture, and they are typical of Japanese trout farms in general, I visited the Nikko Branch of the Freshwater Fish

as any I have seen. The Research Laboratory, which is located on Lake are as modern and efficient with a high Chiizenji in Nikko National Park. The Chief of this fish are reared in raceway-type ponds dry laboratory was Yoshikazu Shiraishi, who passed rate of water exchange. The food is pelleted chemical away during his official travel to South America in food, commercially manufactured. Ihe the United 1972. analysis is very close to that used in ratio of food into fish Lake Chuzenji is one of the feu publicly owned States and a 1.4 conversion successful bodies of fresh water in Japan where public spoil tlesh also approximates that achieved at

fishing is permitted. This cold-water lake contains hatcheries in the United States.

104 The Fuji Rainbow Trout Breeders Association The culture of eels in Japan goes back 150 yr, and operates a processing plant in Fujinomiya City. The despite great effort by scientists, culture methods association president, Watanabe, and the plant man- have not changed much. Since the eel is catadro-

ager, S. Aoki, conducted me on a tour of the modern mous, spawning occurs at sea and the young migrate

facility that processes 1 ,000 tons of rainbow trout for to fresh water where they grow to adulthood. The

export each year. During my visit, trout were being Japanese eel culture industry is based on the capture packed in 5-lb packages for export to the United of young eel as they migrate to fresh water during the States. months of December to March. Size at time of cap- My impression of the Japanese trout farming busi- ture is about 3 inches in length. Introduced into

ness is that it operates on a very low margin of profit ponds, and fed a diet of either chopped fish or chop-

and is successful only by virtue of its operating effi- ped fish and pelleted feeds, they reach a market size

ciency at all levels. For example, the retail price for of 18-24 inches in 12-18 mo.

farm raised trout is approximately 300 yen/kg. This The principal restriction on the volume of eel cul- can be compared to the price of salmon which ranges ture in Japan is availability of fry. Scientists are from 550 yen/kg upward and tuna which sells at 600 attempting to overcome this problem by breeding yen/kg and upward. eels in captivity, but so far little or no success has Watanabe and his associates are quite concerned been achieved. over the restrictions of our salmonid import regula- tions. These require certification that all salmonid The Tokyo University of Fisheries operates an eel fishes entering the United States from foreign coun- culture research station on Lake Hamana in tries are free of the virus causing viral hemorrhagic Shizuoka Prefecture near the City of Hamamatsu.

septicemia and Myxosoma cerebnilis. the causative This well-equipped and well-staffed laboratory is

organism of whirling disease. I discussed these regu- conducting basic research on the problems as- lations with Watanabe, S. Aoki, and T. Sano, vi- sociated with the culture of eels, mullet, carp, and rologist at the Tokyo University of Fisheries, who various other species, including largemouth bass. serves as advisor to the Cooperative on Fish Dis- The shortage of native eels forculturing purposes

eases. These gentlemen feel that since neitherof the is compounded by other problems connected with

two diseases in question have ever been found in culture of the species. Principal among these is dis- Japan, our regulations requiring that certification as ease. In 1970, disease took an unusually heavy toll of to disease status be based upon specified sampling eels in Shizuoka Prefecture. That year the industry and analytical procedures, places an unnecessary was hit by an epidemic of a new disease, named hardship on exporters. After reviewing their prob- branchionephritis by S. Egusa, Tokyo University of lem and discussing it with our own experts in the Fisheries. This epidemic took 2,600 tons of finger- United States, it appears that Sano and the disease ling and yearling eels during the first half of the year. technicians at the prefectural laboratory had misin- Supplemental stocks ofA .japonicci are purchased terpreted our instructions and were indeed perform- from Taiwan and New Zealand, but these and other ing more laborious inspections than required. I have foreign sources cannot fulfill the need, and the attempted to clarify these points by letter since my Japanese are turning more and more to Europe for return to the United States. the Atlantic eel, /I. anguilla. In 1971, 34,000 kg of EEL CULTURE glass eels from Europe were imported. So far, the

results with/1 . anguilla have been less than satisfac- Eeh.AniiiiilUijciponicti. are an important species tory, because of disease and nutritional in Japanese freshwater fish culture. They command problems. premium prices at all times. For example, in 1969. when the production in Shizuoka Prefecture was I concluded my trip to Lake Hamana by dining on 15.000 tons, the price ranged from 774-1,400 yen/kg. smoked eel at the Prefectural hotel and dormitory.

In 1970, a year of low production, the price range I was so impressed by this product that I purchased was 1,037-1,718 yen/kg. cans of smoked eel to take home with me.

105

SHELLFISH CULTURE IN JAPAN

WILLIAM N. SHAW

INTRODUCTION production of seed oysters. Both scallop shells (northern and southern variety) and oyster shells are Japan has long been recognized as a leader in the used for cultch. Shells are strung on wires ('/2-inch aquaculture of molluscs. In 1969, approximately bamboo spacers are used to separate scallop shells) 560,000 tons (with shell) of shellfish were harvested and draped over racks. Following setting, the seed (Japanese Fisheries Association, 1971). Principal caught on scallop shells is used domestically while a species under cultivation include Pacific oysters, considerable portion on oyster shells is exported to Crassostrea gigas, scallops, Patinopecten yessoen- the United States and France. sis. and the abalone, Haliotis discus. Several species Twomajorareasofoysterproduction were visited of clams and snails also play an important role in the during the tour—Miyagiand Hiroshima Prefectures. total production figures, but these are mostly caught In addition, we visited Lake Hamana, the only from wild populations and are not farmed to any saltwater lake in Japan, where shallowwater rack extent. culture is being carried out. During my short tour of aquaculture sites in Ja- According to Furukawa (1971), Miyagi Prefecture pan related to the UJNR (United States-Japan Nat- produced 3,814 tons ofoyster meats in 1968,orabout ural Resources) Aquaculture Panel, I concentrated 9.3% of the total Japanese production. Matsushima my effort on surveying the areas where oysters, Bay has been one of the most important culture areas abalone, and scallops are being farmed. An over- in Miyagi Prefecture. In 1959, 1,456 tons of shelled view based on these visits is listed below. oysters were harvested. However, beginning in 1961 mass mortalities occurred in Matsushima Bay. Total OYSTERS annual losses from 1961 to 1964 were 62. 5, 41. 6, 42. 3, and 51.9%, respectively (Kan-no et al., 1965). Oyster production in Japan has shown a steady From our on-site visit of Matsushima Bay, it was increase in recent years. From 1958 to 1968, landings apparent that the Japanese had solved their oyster rose from 151,894 tons (with shells) to 265,881 tons mortality problems by converting the Bay's use from (Furukawa. 1971). Production declined slightly in oyster culture to seaweed culture. Very little oyster 1969 when 245.000 tons were harvested (Japanese culture in the Bay proper was observed. Fisheries Association, 1971). Yet, total oyster production for Miyagi Prefecture

A major reason for the increase in production is has declined only slightly. The Japanese have ex- the expansion of the hanging method of oyster cul- panded raft and longline culture in areas outside ture, raft, longline, and rack. By using the third Matsushima Bay.

dimension, the yield per acre is greatly increased One big industry in the Miyagi Prefecture is the over the bottom or sowing method. Furukawa (1971) exportation of seed oysters. On our tour, we had the estimates that the oyster yield from raft culture in the opportunity to visit this operation at Watanoha

Hiroshima Prefecture is 20 tons of oyster meats per as they were preparing seed for air shipment to

acre per year. These figures compare favorably with France. Oyster seed, which is hardened on racks

Ryther and Bardach's ( 1968) estimate of 23.3 tons for 3 mo, is brought ashore in small boats. The

per acre per year. seed (all caught on oyster shells) is removed from

The entire industry is dependent on the natural the galvanized wire strings, placed in baskets, and thoroughly washed. It is then culled into single pieces and examined for predators; all shells ' Middle Atlantic Coastal Fisheries Center. National Marine Fisheries Service. NO.A.A. Oxford. MD 21654. with six or less sp^t are discarded. The good shells

107 are placed in freshwater for 1 hr to kill flatworms. Several problems are facing the oyster industry of

P\eiid(>M\li>cluis sp. After a quick saltwater dip (5 to Japan. Of considerable concern is the increased 10 sec), 750 spat-laden shells are placed in shipping threat of both domestic and industrial pollution. In- cases. Before wrapping, a random sample of 50 dustries are located in areas adjacent to oyster grow- shells are taken out of the case and the number of ing and setting areas. Further expansion of such seeds counted. Within 48 hr after crating, the seeds industries could seriously affect the oyster industry. reach France. Because the bulk of oysters in Japan are grown

The French's interest in Japanese seed has come off-bottom, a considerable amount of labor is in- about only in recent years. Heavy mortalities have volved. In recent years, there has developed a seri- occurred among the Portuguese oyster. Cmssostrea ous labor shortage in the oyster industry. Young ani^iihita. in France, and the government has banned people do not wish to follow their parents in this line the importation of Portuguese oyster seed in their of work. Thus, simplification of techniques and de- country. In its place, they are now importing seed velopment of mechanization in the oyster industry is from Japan. urgently needed (Fujiya. 1970). The new competition for Japanese seed could have two implications in the U.S. Pacific coast oys- ABALONE ter industry: 1) the cost of Japanese seed to the United States could increase, and 2) because the Abalone production in Japan has increased from French have entered the market, there could de- 4.600 metric tons in 1964 to 6.500 metric tons in 1970. velop a possible shortage of Japanese seed for im- One possible reason for this increase is the effect of a portation to the United States. In 1972, heavy sets of large seed planting program. According to Sanders Pacific oysters occurred on the west coast, so the (1971). there are 16 laboratories in Japan artificially need for Japanese seed, at least in that year, was producing 2 to 3 million seed abalone annually. considerably less. A typical laboratory is the Kanagawa Prefectural About 77% of the total oyster production in Japan Fisheries Experimental Station located on the island comes from Hiroshima Prefecture (31,188 tons of of Joga Shima near the City of Miura. Their quota, meat out of a 1968 total of 40,928 tons). Furukawa which is set by the government, is to produce about (1971) states that a total of 10,962 rafts (9.1 x 18.2 m 300, OOA seed abalone annually. average size) are utilized in the Prefecture. At the Station, mature abalone are induced to During our tour of the area, seed oysters were spawn by first air-drying and then placing them in being strung on galvanized wire and suspended from shallow, standing water tanks which are exposed to bamboo rafts. Initially, 1.600 strings (wrens) are sunlight. Apparently as the sunlight heats the water, suspended. As the oysters grow, the number per raft the abalone spawn. is reduced to 800. On each string, about 15 m long, The fertile eggs are transferred to setting tanks spat bearing scallop shells are separated by a 9-inch located inside an adjacent building. These tanks are bamboo spacer. covered with black plastic sheeting to eliminate Each raft is constructed out of bamboo logs. A light. The larvae, which require no supplementary typical raft. 20 x 9 m, is supported by 25 styrofoam feeding, set in about 1 week on special plastic plates. floats, each the size of a 50-gal oil drum. Fifteen These plates have been previously exposed to run- floats are located down the center of the raft while ning seawater in order to obtain a film of diatoms, the two series of five floats are located along the outer food of young abalone. Since the larvae swim near edge. An iron cable runs down the center of the raft the surface, the water is slowly raised in the setting and is the connecting link between each series of four tanks so that the setting abalone are distributed as or five rafts. The rafts are held in place by six (5 tons evenly as possible on the plates. Once setting is each) concrete anchors. A typical raft, including over, the plates are transferred to outdoor tanks labor, costs about $350 and takes a crew of four 1 day where the abalone continue to feed on the diatom to build. film until they reach 5 to 10 mm in size. They are then As in Miyagi Prefecture, the entire industry is removed from the plates and placed on either tiles, dependent on natural setting. No attempt is being oyster shells, stones, or cross-shaped plastic config- made to supplement natural sets with hatchery- urations. At this stage, they are fed macroscopic reared stocks. The seed is caught in the intertidal algae such as Ulva and Laminur'ui. When the zone on scalli^p shells draped over racks. abalone are approximately 2.5 cm in size (about 8 mo

108 to 1 yrold), they are sold to the fishermen for 10 yen each. The growth rates in the area of the Kanagawa Station are as follows:

f;e in yr size 2 to 3 is obtained. The scallops are the surface. It is from this lower line that seed collec- until a of cm grow them sus- tors and cages for growing scallops are attached. then sold to local fishermen who approxi- Scallop spawning in Mutsu Bay begins in March, pended from rafts. When the scallops are size, the fisherman drills a hole in the peaks in early April, and is over by mid-April. The mately 5 cm in scallop, threads a nylon line through larvae life is about 35 days (temperature during this ear(wing)of the period ranges from 7° to 12°C). The fishermen put the hole, and ties it to ropes suspended from rafts. in yr (Cost- out their seed collectors in early May. They reach market size (12 cm) about 2 Initially, seed scallops were caught on suspended low, 1969). Cyprus branches, but now over 50% of the collectors consist of plastic web bags filled with used gill nets. Eventually, most collectors will be of this type. In LITERATURE CITED 1971. 2.3 million bag collectors were used and 40 billion seeds were collected in Mutsu Bay. AUSTRALIAN FISHERIES. Before the young scallops lose their byssal 1971. Australian studies Japanese fish culture techniques. Aust. Fish. 30(IO):3-7. 9. threads, they are removed from the bags and placed COSTLOW. J. D. JR. (editor). in pearl nets. As the scallops grow, they are transfer- 1969. Marine biology. Vol. V. Proceedings of the Fifth In- red to new pearl nets with larger mesh size. At about terdisciplinary Conference on Marine Biology. Gordon 4 cm, the scallops are either planted on the bottom or and Breach. New York. 606 p. placed in circular or book nets and resuspended from FUJIYA, M. 1970. in Japan. Helgolaender wiss. the longline. The suspended scallops reach commer- Meeresunters. 20:464-479. 10.5 to 1 1.0 cm, in about 2 yr. It costs the cial size, FURUKAWA, A. fisherman approximately 14 yen/scallop to raise it to 1971. Outline of the Japanese marine aquiculture. Jap. market size using the longline method. In turn, he Fish. Resour. Conserv. Assoc. Tokyo, .39 p. can sell the scallop for 30 to 60 yen apiece. IMAI, T.

1 967. Mass production of molluscs by means of rearing the Unlike the sea scallop fishery of the United larvae in tanks. Venus 25:159-167. save all the scallop shells. States, the Japanese JAPANESE FISHERIES ASSOCIATION. and shipped to the Inland Sea These are bagged 1971. Fisheries of Japan - 1971. Jap. Fish. Assoc. Tokyo,

where they are used as cultch for catching seed oys- 45 p. ters. KAN-NO, H., M. SASAKI. Y. SAKURAI. T. WATANABE. and K. SUSUKl. One of the principal laboratories involved in sea 1965. Studies on the mass mortality of the oyster in Mat- scallop research is the Aquaculture Center located sushima Bay. 1. General aspects of the mass mortality of Asamushi at the on Mutsu Bay near the City of the oyster in Matsushima Bay and its environmental condi- northern end of Japan's main island of Honshu. The tions. [In Japanese. English abstr.] Bull. Tohoku Reg. 25:1-26. Center is a new installation that opened in April Fish. Res. Lab. RYTHER. J. H. 1968. One of its largest programs is related to the 1%8. Invertebrate and algae culture. In The status and propagation of sea scallops. Their goal is to produce potential of aquaculture. particularly invertebrate and

1 million seed scallops annually using hatchery tech- algae cultures. Vol. I. Part U. p. 1-261. .Am Inst. Biol.

niques. Sci.. Washington. DC . ( Distrib. by: Clgh. Fed. Sci. Tech. The Oyster Research Institute is also culturing Inf.. Springfield. Va.. as PB 177 767.) R'l THER. J. H.. and J. E. BARDACH. sea scallops at their tank farm. 1968. The status and potential of aquaculture. In The status Scallops are induced to spawn using both natural and potential of aquaculture. particularly invertebrate and stocks. Over 200.000 seed scallops and conditioned algae culture. Vol. I, Part I, p. 1-45. Am. Inst. Biol. Sci.. are cultured annually. They are suspended from the Washington. D.C. (Distrib. by: Clgh. Fed. Sci. Tech. Inf.. tank farm in book nets, circular nets, and pearl nets Sprmgfield. Va.. as PB 177 767.)

110 CRUSTACEAN CULTURE

CORNELIUS R. MOCk'

SHRIMP, PENAEUS JAPONICUS shrimp culture has been expanded due to three im- portant factors: 1) the rising demand and costs for One of the most valuable marine species in Japan fresh food items to be fed to the shrimp: 2) the rising is the "kuruma-ebi," Penaeiis japonicus, shrimp wages of employees; and 3) disease problems en- fishery, which commands a price of 7-30 U.S. doUaFS countered. per kilogram, at the Tokyo Central Fish Market. Of particular interest is the use of a by-product of

Although this price is high compared to U.S. prices, soy sauce production, a cake which is ground into

it is due to the fact that the Japanese people demand powder to fertilize the water. Not only does it stimu- live shrimp for the preparation of a delicacy known late the growth of diatoms, but the larval shrimp also

as tempura. eat it. As the shrimp grow in size, this powder is Over the years much time has been spent develop- either extruded or pressed into a size suitable for ing methods of holding this species in ponds and eating. At the Kagoshima Prefecture Fisheries Ex-

rearing it to market size. Even though the Japanese perimental Station, the Director, K. Shigeno, re- have successfully reared shrimp through several marked that although the shrimp ate this artificial

generations, they explained that it was not economi- food and grew to market size, the consumer was not

cal to rear shrimp to sexual maturity because it was satisfied with the quality or color of the prawns. He time consuming and because the fecundity of the felt that the problem was primarily a vitamin defi- females was reduced. Therefore, gravid females are ciency. Artificial foods with a variety of additives purchased directly from the commercial fishing are being tested at Shigeno's laboratory.

fleets and then spawned. Research is also being directed toward rearing Once the eggs have hatched, the water is fertilized prawns to market size in a closed system. A 1,000-m^ to stimulate the growth of diatoms. Predetermined cement tank (23 m in diameter and 3 m deep) has amounts of fertilizer and seawater are added each been built at the Tarumizu Kagoshima Prefecture day to the tank until the larval shrimp have reached Fish Experimental Station. The water temperature

the last mysis stage. Brine shrimp nauplii {Artemia can be controlled, and a false bottom with airlift spp.) are fed from the last mysis stage through the pipes has been installed as an in-bottom filter. fourth postlarval stage. The shrimp are then fed Twenty-day-old postlarval shrimp have been

fresh meats of clams ( Venerupis philippinanini) and stocked in this tank and reared to market size with mussels (Mytilus ediiUs), which are crushed and dis- good results. However, during two recent experi-

tributed throughout the ponds. Because it is too ments a number of problems occurred, resulting in costly and time consuming to separate the crushed poor production. shell from the meats, the shell eventually covers the Circulation of the water mass within a rearing pond bottom, resulting in a substrate that hampers system was emphasized for either fish or shrimp the burrowing of the shrimps. Thus, ponds must be culture. At Tarumizu Kagoshima Prefecture Fish drained or dredged periodically to remove the shell Experimental Station the flow was maintained with debris. water jets, while a large mechanical stirrer was being .Although larval rearing techniques are primarily tested at Setonaikai Saibai Gyogyo Center. Tamano the same today as the> were 10 yr ago. research in Jigyojo. At the Nansei Regional Fisheries Research ' Contribution No. .'4.' from the National Marine Fish- Laboratory. H. Kurata spoke about the natural eries Service. Biological Laboratory. Galveston. Texas. waves of P. Ja[>(>iii(ii.s postlarvae that enter the es- - Gulf Coastal Fisheries Center. National Marine Fisheries tuaries. Monitoring of these waves now indicates Service. NO.'X.A. Fon Crockett. Galveston. TX 77.s.sO.

111 that recruitment is presently less than in previous Older stages are fed Anemia, chopped tlsh, and years. The total tonnage landed by the commercial crushed clams. Since crabs are active and ditTicult to shrimp fleet is also down. Therefore, the concept of maintain in a barren enclosure, a series of vertical seeding the system with (1.2 x 10") 20-day-old post- netlike structures were placed in the rearing pond. larval shrimp is being tested to see if the system is The growth of natural filamentous algae upon these still a suitable environment, if production of shrimp structures serves as a hiding place for the crabs. can be stimulated and ifnew areas can be used. Some Unfortunately, fighting over territories and food shrimp are released directly into the nursery results in a high rate of mortality in the pond. Har- grounds, while others are placed in a pen (30 x 10 x vesting is accomplished by draining the pond and 10 m) for 2 to 4 wk to acclimate them to estuarine raking the crabs, a process which is time consuming. waters. Although the price of these live crabs in United M. Fujiya, also of the Nansei Laboratory, began States is$l. 10 each, their culture is not yet economi- physiological studies to measure the ""quality'" of cally profitable in Japan. shrimp larvae reared in different ways, by observing A number of prefectural laboratories rear crabs to their reaction to anesthetics. His approach is to in- the megalops stage and release them into estuaries. sert electrodes into the brain of the shrimp and re- cord their brain waves on an oscelloscope. FRESHWATER SHRIMP, MACROBRACHWM SP. H. Hirata, at Kagoshima University, has begun work on the production of single-species mass cul- At the Tokyo University of Fisheries, Ogasawara tures of diatoms and their preservation. At present, and T. Sano discussed the culture of freshwater diatoms are concentrated and later frozen at 0°C. shrimp of the species Macrohrachiiim. Eleven dif- They can be held successfully for periods of 30 days ferent species were being studied. To rear the larval or less. Various other techniques are now being stages, they indicated that a medium of 50^ fresh tested. water and 50% seawater was necessary. A diet of

Table 1 is part of a statistical report, translated by Arteiniii. reared on a freshwater culture of

Jiro Tanaka. Of particular interest is the number of Chlorella. is fed during the larval stages along with tons of P. Jiiponiciis cultured. Since 1967, annual ground clam (Tapes sp.) meat. When the shrimp are production has been about 300 tons. Although some older, pieces of chicken egg shells are added to sup- live shrimp are imported, the tonnage is far below the plement the calcium in their diets. market demand. The importation of frozen shrimp Juveniles of Macrohrachiiim rosenheri^i have has no direct bearing on the live shrimp market. been reared on commercial trout pellets to market size in 6 mo at the Izu Branch Laboratory. Although results have been satisfactory, production costs CRABS, PORTUNUS TRIBERCULATUS were not made available.

Crabs, primarily Poriuniis trihcniiluins. have been reared successfully to the 5th generation at the SPINY LOBSTER, PANULIRUS JAPOMCUS Yamaguchi Fisheries Experimental Station. P.

trihcrciiUitiis is similar to the American blue crab. At Kanagawa Prefectural Laboratory, research Ccillinectes sapidus. Larval crabs in the zoea I-IIl on the spiny lobster, Panulirits japonicus, is being stages are fed rotifers, Brdchioniis plicatilis. which conducted. Of particular interest is the work of are maintained on freshwater cultures oiClilorclla. Inoue who has found that the phyllosoma larvae will

Table 1. —."XRHual production (in metric tons) of cultured, naturally caught, and \mipov\ed Penaeus japonicus. 1965-69.

Source feed on the arrow worm, Sagirta, which is collected Marifarms Incorporated, Panama City, Fla., my trip from the natural habitat. After a number of days, the was quite fruitful. Not only did he provide me with a larvae are then fed Artemici nauplii. Although phyl- list of places to see and letters of introduction, but losoma larvae have been reared in 180 days, their helped arrange for Jiro Tanaka to accompany me size is smaller than those found in nature. They have while in Japan. Jiro Tanaka's assistance was in- not yet reared the larvae to the benthic stage. valuable. Their pleasant attitude, cordial response, and vol- ACKNOWLEDGMENTS untary gesture of discussing their research clearly signified the willingness of the Japanese to cooperate Through the efforts and guidance of M. Miya- on this joint venture of mariculture. niura, Vice-President of Technical Operations.

113

MARINE FISH CULTURE IN JAPAN

JOHN B. GLUDE

INTRODUCTION

The concept of rearing fishes in floating net cages in sheltered bays or in fish ponds supplied with sea- water has been applied in Japan to several coastal species of high value, and commercial ventures are well established. In 1967 the production of cultivated marine fishes in Japan amounted to 27,103 tons in gross weight worth over $24 million and consisted of 98.6% yellowtails, 0.25% puffers or globefish, and 1.2% other marine fishes (Harada, 1970). Production of yellowtail has increased remarkably in recent years, as shown by the following table:

Yield of yellowtail culture iFiirukawa. 1970)

Year Tons

1961 supplied to all farms in the country from 28,363.000 of dipping must be shorter in the summer (3 min at to 30.780,000 per year (Harada, 1970). 26X ) than in the autumn (5 min at 16°C) to prevent The young yellowtail are reared in small net en- damage to the fish. Since this parasite grows very closures for 1-2 mo until they reach a length of 25-40 fast and becomes adult within 2 or 3 wk. the freshwa- mm. These seedlings are then placed in larger float- ter treatment must be repeated frequently during ing net cages approximately 6 x 6 x 2 m in which periods of infection.

1, 500-2. .SOO fish can be kept. By December the yel- Another monogenetic trematode. Av/'/ic iHeter- gills lowtail reach a size of 1 .0-1 .5 kg and are shipped to axine) helerocercd. infects the of yellowtail market. causing anemia which may kill the fish. Treatments, In southern Japan where the minimum tempera- according to Fujiya (1969). include 4-min bath in ture exceeds ITC, it is possible to hold yellowtail water containing 4% salt. 2) dipping in a 1% solution through the winter and sell them in April when they of "Tremaclean"" for 30 sec, and 3) oral treatment reach a weight of 2-3 kg. but winter temperatures by including "Bitin"" (4,5-dichlorophenol) in the farther north are too low for yellowtail. According to food. Fujiya (1969), about 95% of the yellowtail are ship- The bacteria Vibrio can cause extensive infections ped to market by December. Detailed descriptions in yellowtail populations. Treatments include incor- of yellowtail farming procedures are included in poration of sulfa drugs or antibiotics in the food. papers by Harada ( 1970), Furukawa (1970). and Fu- Virus diseases are suspected, but no information jiya (1969). is available concerning these.

Problems of the industry include 1 ) a stable supply The feeding of oxidized, unsaturated fatty acids of seedlings. 2) disease control, and 3) adequate food contained in fish used as food causes nutritional supply or development of suitable artificial diets. diseases of yellowtail. This can be prevented by feeding white-meated fish instead of anchovy, mack-

1 )Stahli' supply ofscedliniis. Production from yel- erel, and sand lance. lowtail farming is limited to approximately the pres- 3)Adeqiuitefo()cl supply or development of artifi- ent level because of government restriction on the cial diet. Farming of yellowtail in Japan depends on number of young fish which can be taken from availability of large quantities of cheap fish suitable coastal waters. According to Harada (1965), it is for use as food. These include mackerel, horse mack- highly desirable to produce seedling yellowtail by erel, anchovy, sand lance, and saury. With conver- artificial fertilization in a hatchery. This has been sion rates of 6: 1 to 8:1 the food must be obtained at accomplished recently on an experimental basis, but very low price in order to make yellowtail farming has not been perfected for commercial application. economical. Expansion of the industry or perhaps In the meantime. Harada recommends collecting the even continuation at the present level will require seed (larval or juvenile fish) at as early a stage as development of artificial diets which will provide possible and keeping them under careful manage- better nutrition for the fish and reduce dietary dis- ment to reduce mortalities. ease problems. Furthermore, the artificial diet must Although production could be increased by im- be available at a price which will permit economic proving growth rate, reducing mortality, or by ex- fish farming. tending the rearing time in places where winter water temperatures are not too low. ultimate development PUFFER CULTURE of the industry will require maintenance of a spawn- ing stock, collection and hatching of eggs, and rear- Puffers, also known as globefish or blow fish of the ing of larval stages to assure a dependable supply of genus Filial, are in high demand as a luxury food in seedlings. Japan even though certain species are extremely 2) Disease control. The monogenetic trematode. toxic. About 10 species of edible puffers occur in

Beneclenia seriolae. infects the skin of the yellowtail Japan, but one species. Fuiiti ruhripes nihripes. is causing an unsightly appearance, loss of appetite, used principally for farming ventures. The toxicity weakening or death of the fish. This parasite is con- of puffers changes seasonally, becoming the greatest siderably less resistant to low specific gravity than in the spawning season from May through June. The the host fish and consequently is easily controlled by toxic substance "Tetradotoxin" occurs mostly in dipping the infected fish in fresh water for a few the ovary, liver, intestines and skin, and rarely in the

minutes and then returning it to seawater. The time muscle. When prepared carefully by licensed cooks

116 in Japan, puffers are completely safe to eat. Production of puffers in fish farms has decreased during recent years because of a shortage of seed- lings, as indicated in the following table:

Yeur breams in Japan was nearly constant from 1965 to the flatfish. Paralkhlhys olivuceus. Ptiralichthys is 1967, butduring 1968 and 1969 decreased slightly to a in high demand at a price 4 times as great as for level of about 30,000 tons (Japan Fisheries Associa- yellowtail, so artificial propagation of this species tion. 1971). should be profitable. Harada et al. (1966) described Research on the farming and artificial propagation growth and rearing methods for the fry of the floun- of red porgy began in Japan over 70 yr ago but was der, Paralichthys olivaceus, obtained by artificial generally unsuccessful until recent years. In 1958 fertilization.

research on artificial propagation was intensified The silver sea bream. Spurns xarbci, is also being with more modern facilities are equipment and suc- studied at the Shirahama field station of Kinki Uni- cessful results were obtained on an experimental versity. scale in 1962. By 1965 an experiment in the propaga- Another marine fish Sehci.sticiis inarniorcitus.

tion of red porgy using artificially produced seed- known as the scorpionfish is artificially produced in lings succeeded at the Propagation Center in the Se- the hatchery of the Association of Marine Stock to Inland Sea. It now appears that a basis has been Farm of the Seto Inland Sea, and 125,536 juveniles established for expansion of red porgy farming, but were released into the Inland Sea in 1968. Similar this knowledge has not yet been commercially ap- releases of sea breams are being made by the Nansei plied (Fujiya. 1969). Regional Fisheries Laboratory, many of which are The Association of Marine Stock FarmoftheSeto tagged to evaluate the success of these plantings. Inland Sea was incorporated in 196.'^ to increase the fisheries resources of the Inland Sea of Japan by TROUT CULTURE releasing young marine fishes. In 1958, this Associa- tion produced 166,686 red porgy in a hatchery and Trout have been raised in Japan in fresh water for the Inland effectiveness released them into Sea. The domestic and export markets for many years and in natural stocks is of these plantings supplementing standard rearing methods have been developed. now being investigated. The success of this hatchery Recently, methods have been developed for cul- also portends the expansion of commercial farming ture of rainbow trout, Salino iiuirdneri irricleiis. in of the red porgy. the marine environment. Three Fishermen's to Fujiya (1969). larvae of the red According Cooperative Associations in Japan are now rearing 2 to in length, are usable seedlings. porgy, 3 cm as trout commercially in the protected waters of coastal They have been grown successfully in floating net bays and estuaries; the most recent a new venture at cages using fresh fish or pellets as food and meat Ogatsu Bay in Miyagi Prefecture. reach market size in 12 to 18 mo. Procedures for marine culture of rainbow trout described by Akimitsu Koganezawa, Chief of Shell- CULTURE OF OTHER MARINE FISHES fish and Fish Research for the Miyagi Prefectural Station, are as follows: Several other species of marine fishes are being Rainbow trout spawn in December in this part of cultured in Japan on an experimental or limited Japan and are raised in fresh water until the following commercial basis. These include amberjack, Seriola September or October. At that time they are accli- purpurescens, and the striped jack, Longirostniin mated to salt water over a period of 12-20 days by ch'licdtissiniiis. Both of these species can be cultured gradually increasing the salinity to that of the marine

by using the methods which are so successful with environment which is about 34"/(iii. Koganezawa has

the yellowtail. Teruo Harada of Kinki University is determined that mortality during acclimation can be conducting large-scale experiments in the culture of minimized by increasing the salinity lO'r each day these species at the University facility at Shirahama except at the levels of 409^ and SOCf of the salinity of in Wakayama Prefecture. Commercial culture of seawater which appear to be more critical. The fish these species is especialK attractive because there is are therefore held at least one extra day at these a demand at prices considerably higher than those salinities. for yellowtail. At the time of transfer to the sea the trout weigh Al the same research facilit\ Harada is studying 100-150gand are about lK-23cm in length. The trout artificial the culture of many other species of fish are harvested the following August at 1 .5-2.0 kg, but including the Japanese parrotfish, Oplciiiuithiis fas- some may reach a size of 3.4 kg. iititiis. and the spotted parrotfish. O. piincidtiis. and Maximum survival during the marine phase of this

118 aquaculture system is 90%; minimum survival is yellowtail Seriola. whereas smaller rainbow trout

60%; mean survival is about 709f . Bacteria of the which weigh 150-200 g each sell for 250-300 yen genus Vibrio are the major cause of mortahty, but ($0.81 to $0.97) per kilogram. In comparison, salmon infections can be controlled to a certain extent by the from natural production sell for 600-800 yen ($1 .95 to use of nitrofuran. sulfa drugs, and terramycin. In the $2.60) per kilogram. United States, nitrofuran probably could not be used One of the problems of raising rainbow trout in net

for this purpose since it has not been cleared for use enclosures is that they have tender skin and may lose

in treating food products by the Food and Drug some scales rubbing against the netting which may Administration. permit the entrance of the bacteria Vibrio. Japanese A new commercial trout farming project was ob- scientists have found that adding 10 jig of testos- served at Karakuwa at the head of Ogatsu Bay dur- terone per gram of food will increase the mucous ing October 1971. This project, which is operated by production in skin which will protect the scales from Fishermen's Cooperative Association with the gui- erosion. It is unlikely that testosterone could be used

dance of Koganezawa, included shore-based in the United States for this purpose because it is facilities for rearing trout and acclimating them to considered to be a carcinogen. seawaterand a series of net enclosures for culture of Another trout, Salreliniis pliivius, known as the

the trout in the marine environment. steelhead, is being reared experimentally in seawa- Shore facilities included six circular concrete ter at the Miyagi Prefectural Field Station at Ogatsu tanks, 12 m in diameter and 2.5 m deep, with four Bay. According to Koganezawa, S. pluvius spawns more to be built. The fish will be reared for approxi- in the headwaters of streams, is very resistant to

mately 1 yrin these tanks before they are acclimated changes in temperature, and can be successfully ac- to seawater and transferred to the floating net en- climated to seawater. Therefore, this is considered a closures. This year, since the project was just begin- good species for aquaculture, although it is not ning, the fish were raised at another location and reared commercially at the present time. were brought to Karakuwa for acclimation to salt water and transfer to growing pens. A system of SALMON CULTURE large plastic pipes makes it possible to drain each of the large round tanks to transfer the 14,000 trout The first Japanese pilot-scale experiments in cul- which will be acclimated in each tank into a long ture of salmon in floating net pens in the marine drainage channel which takes them to the shore environment are being conducted at Yamada Bay in where they can be transferred through pipes into the Iwate Prefecture. Yamada Bay is completely en- floating pens. closed except for a narrow entrance where the water The floating pens are anchored in Ogatsu Bay is reported to be 90 m deep. Hills protect the inner which is well protected from storms by steep hills. bay from storms making it an ideal location for

The water in this area is 10-30 m deep and varies in aquaculture. The Bay is about 60 m deep in the temperature from above 8°C during the winter to a center, but 15-25 m deep in the area where the maximum temperature of 23-25°C during the sum- salmon culture rafts were anchored. mer. The objective of these experiments at Yamada

The fish are fed ground raw fish and meal, making Bay which was visited in October 1971 is to perfect

a product similar to Oregon moist pellets which is methods which could be used commercially to rear used in U.S salmon hatcheries. This food has been salmon to marketable size in the sea. found to be better than dry pellets. The first experiments were with the chum or dog Only female trout are used in this type of culture as salmon. Oncorhynchus keta. which had been they are more disease resistant and are easier to hatched at Fishermen's Cooperative Association acclimate to seawater than males. Also, females can hatchery at Miyako Bay just north of Yamada. This

mature in the sea in 2 yr producing healthy viable hatchery which is located on the Tsugaruishi River

eggs, whereas males require fresh water to become has a capacity of 50 million eggs and is one of the mature. The sorting of male trout from female trout many hatcheries operated by local Fishermen's at a size of 18 cm is a time consuming operation. Cooperative Associations. These hatcheries take The price of marketable trout 1.5-2.0 kg in weight eggs from chum salmon in November, December, is 450-550 yen ($1.46 to Si. 79) per kilogram in the and January when the fish enter the streams, or

Tokyo fish market. This is about the same price as occasionally from those salmon which are caught in

119 trap nets in the bays. Afterthe eggs hatch, the fry are a coarse mesh to exclude birds and the sides and reared until April in an effort to reduce the mortality bottoms were made of about 8 mm square mesh. of fry which they estimate as 509f in the streams plus These enclosures contained 4,000 young salmon a significant mortality during the month which the which by October had reached a length of 20-25 cm. fry spend in shallow bays before going to the sea. Another similar pen contained 300 2-yr old salmon The eggs used in the experiment at Yamada were which appeared to be about 40-50 cm in length. lioka hatched on 22 February 1971 and began feeding on 8 reported that these floating surface pens were satis- April. They were held at the hatchery at Miyako Bay factory except that the nets had to be changed every until 10 May because the holding tanks at Yamada month because of heavy fouling by seaweeds. had not been completed. After transfer, the salmon The second type of enclosure was a middepth pen were held in fresh water at Yamada until 28 May which was located at a depth of 10 m to the top of the when the seawater system was completed. Transfer net. The enclosure was 10 meters square and 7 m to salt water was accomplished in about 24 hr with no with a top and bottom. Even at this depth the heavy significant mortality. growth of seaweed required changing the net about Because of the delay in completing the floating net every 3 mo. enclosures the small salmon were held in seawater in The third type of enclosure was a large octagonal tanks ashore until August when the temperature in net 55 m in diameter which extended from the sur- the tanks reached 25.8°C. They were then trans- face to the bottom and was anchored in position. The ferred to the sea. but even there temperatures net was supported by a series of floats at the surface reached 24.4°C. These temperatures were too high and held in contact with the bottom by a lead line. and the mean survival was only 42%, although A horizontal section of fine mesh at the surface individual lots had survivals as high as 90%. extended inward about 3 m from the vertical walls

According to Chikara lioka, who is in charge of and the inner border was supported by net floats this Iwate Prefectural Experiment Station, they will placed about 4 inches apart. lioka had found that the normally rear the salmon in fresh water until June or fish made no attempt to jump over the inner row of July and transfer them into floating net pens before floats and indeed found refuge and shade under the midsummer. Even so. it appears likely there will be floating section of the net which rapidly became significant mortalities from diseases such as Vibrio fouled with seaweeds. since surface water temperatures usually reach a Feeding was accomplished by rowing a boat over maximum of 22°C according to lioka. Furthermore, the top of the net into the center of the pen where the the thermocline is deep in this area, according to food was thrown into the water. lioka's measurements, and the maximum tempera- Predation by diving water fowl was prevented by

ture difference between the surface and a depth of 60 stretching twisted bright-colored plastic tape. I Vi to m is less than 4°C. In midsummer there appears to be 2 cm wide, across the enclosure at intervals by tying the only \°C difference between surface and bottom it to vertical supports so that it was about I m above at a depth of 15-25 m where the salmon culture pens the surface of the water. The apparent movement of are anchored. this tape caused by the wind seemed to scare the

National Marine Fisheries Service experiments birds away. The same system is used to keep birds with salmon culture in Puget Sound, Wash., have away from the rice fields. indicated increased mortalities due to i'ihrio when The young salmon were fed a dry pellet food that

scauatcr temperatures exceed 15^C. On this basis it had been developed for feeding rainbow trout in the appears likely that the high summer temperatures at sea. and this was found to be fairly satisfactory. The \'amada Bay will bo a limiting factor to salmon cul- fish were fed 3 times a day. and the pellets were ture imless methods can be developed for preventing mixed with water before feeding. The Japanese sci- or reducing Vibrio infections. entists stated it is important to mix the food with Three kinds of net enclosures were being tested by fresh water so that the fish have a source of fresh lioka and his associates. One type was a floating net water to replace that which the> would normally pen similar to those used for the culture of trout or receive by eating other fish. yellowtail. but with some refinements in the design. The objective of the Yamada Experimental Sta-

These enclosures were about 6 or 8 meters square tion is to develop methods for commercial salnmn

and about 3 m deep with nearly 1 m of the sides above culture soanumberofexperimentsarein progress or the surface of the water. The lops were covered w ith planned. Experiments by Koganezawa et al.. re-

120 ported in 1968, indicated that chum salmon grow HARADA, T.. H. KUMAl. K. MIZUNO. O. MURATA. M. more rapidly in brackish water than in fresh water or NAKAMURA. S. MIYASHITA. and H. HURUTANl. 1971. On the rearing of young bliicfin tuna. [In Japanese, salt water. These experiments are being repeated at English abstr.] Kinki Univ.. Mem, Fac. Agric. 4: 1.'53- 1.56. Yamada to develop procedures for increasing HARADA. [., K. MIZUNO. O MURATA. S. growth rate during the time that the tlsh are held in MIYASHITA. and H. HURUTANl.

tanks on shore. 1971. On the artificial fertilization and rearing of larvae in Also, ne.\t year lioka and his associates plan to yellowfin tuna. [In Japanese. English abstr.] Kinki Univ., Mem. Fac. Agric. 4:145-151. transfer chum salmon fry to salt water at various HARADA, T., S. UMEDA, O. MURATA. H. KUMAI. and ages from 9 to 90 days in order to determine the K. MIZUNO. optimum time. They also would like to test other 1966. On the growth and rearing methods of the fry of

species, such as the pink salmon, O. gorhushci, and \\\V2ime (Paratkhlhys olivuceus) obtained by artificial fer- the king or chinook salmon, O. tsluiwyr.sclia, from tilization. [In Japanese. English title) Kinki Daigaku Hokkaido, and possibly the coho salmon, O. Suisan Kenkyusho Hokoku (Kinki Univ., Fish. Res. Lab. Rep.) 1:289-303. kisutcli, from States. the United INOUE. M. In summary, the Iwate Prefectural salmon culture 1970. Possibility of tuna cultivation and propagation. [In station at Yamada is located at a delightful place for Japanese. English abstr.] Tokai Univ. Collect. Repr., experimental aquaculture. The only limiting factor Coll. Mar. Sci., Technol. 4:195-210. appears to be the high temperature of the water JAPAN FISHERIES ASSOCIATION. 1971. Fisheries of Japan. Jap. Fish. Assoc. 45 during the summer and the adverse effects of this p. KOGANEZAWA. A. may be overcome by selection of species or races of (No date but after 1%6.) Surface culture of salmon and

salmon, use of hybrids, or treatment to prevent or trout and some problems thereof. [In Japanese.] J. Fish. alleviate the effects of Vibrio and other diseases Oceanogr. Res. Soc 17:95-101. A.. N. ISHIDA. which are accelerated by high temperatures. Both KOGANEZAWA. and K. GOTO. 1968. Studies on several diseases of fingerling dog salmon domestic and export demands are excellent and it (Oncorhynchus kela). [In Japanese. English title.] Bull. appears probable that commercial salmon culture in Miyagi Prefect. Fish. Exper. Stn. 4:1-7. the marine environment will be economical. KOGANEZAWA. A., N. ISHIDA. K. SUZUKI. K. GOTO, and H. ABE. 1968. Studies on the growth ot fingerling dog salmon (Oncorhynchus kcla) in relation to salinity. [In Japanese, English title] Bull, Miyagi Prefect. Fish. Exper, Stn. BIBLIOGRAPHY 4:1-6. (No date.) Comparative study of surface and mid-depth FUJIYA. M. live pens for rearing chum salmon and rainbow trout. Fish. 1%9. Farming fisheries in Japan. Long Island Univ., Grad. Cov. Eng. 3(2):37-40. Dep. Mar. Sci. [Processed.] OKIYAMA. M. FURUKAWA, A. 1967. Study on the early life history of a flounder, 1971. Outline of the Japanese marine aquiculture. Jap. Paralkhlhys otivaceus (TEMMINCK et SCHLEGEL).

Fish. Res. Conserv. Assoc. Tokyo. 39 p. I. Descriptions of postlarvae, [InJapanese. English abstr.] HARADA.T. Bull, Jap, Sea Reg. Fish, Lab, 17:1-12,

196.'!. Studies on propagation of yellowtail (Seriola qiiin- 1970, Studies on the early life histor> of the rainbow runner.

) qiiertiiliiito T. & S. —with special reference to relationship Elagiitis bipinniilaliis (Quoy & Gaimard) in the Indo-Paci- between feeding and growth offish reared in floating net fic . [In English. Japanese abstr.] Bull. Far Seas crawl. [In Japanese. English abstr.] Kinki Univ.. Mem. Fish. Res. Lab. 3:167-186. Fac. Agric. Vol. 3. 291 p. UDA. M. 1970. The present status of marine fish cultivation research 1970. Recent advances in fisheries oceanography of Japan in Japan. Helgolander wiss. Meeresunters. 20:594- from 1967 to 1969. Jap. Soc. Fish. Oceanogr. Advan. Fish 601. Oceanogr. 3:171-185,

121

SOME IMPRESSIONS REGARDING GENETICS AND THE FISHERIES OF JAPAN

A. CROSBY LONGWELL'

INTRODUCTION Japan has had nothing at least in recent years equivalent to the symposium the Russians held in This report is based on a tour of Japanese 1968, "Genetics, selection, and hybridization of laboratories concerned with aquaculture or subjects fish," published in 1969 (Cherfas, 1969), and trans- pertinent to it, 8-13 October 1972; and on atten- lated in 1972 through the auspices of the National dance at the Second International Ocean Develop- Oceanic and Atmospheric Administration. (Nor has ment Conference, Tokyo, Japan. 5-7 October 1972. the United States.) It is relatively in recent years that Tour included: Oyster Research Institute at there has been a reinstatement of Mendelian, Kesen-numa on Mohne Bay; Pearl Research "Western" genetics in Russia after years of Laboratory of the Fisheries Agency at Kashiko- propaganda—serving Lysenkoism (which proposed jima, Mie-ken (Director, T. Hayashi); Ocean Re- that most of "heredity" was due to environment). search Institute of the University of Tokyo; Nikko Perhaps the Russians, with all vested interests in Branch of Freshwater Fisheries Research Labora- traditional fields ofgenetics disbursed, are now more tory at Nikko on Lake Chuzenji (Director, K. Ono- free to address the reestablished discipline of ge- dera); Tohoku University School of Fisheries; To- netics to the new research challenges of the time hoku Regional Fisheries Research Laboratory. of which aquaculture is certainly one. In any comparison of the application of genetics to BACKGROUND INFORMATION ON agriculture and to fisheries, irrespective of what

GENETICS IN JAPANESE FISHERIES nation's research programs are being discussed, it should be noted that even prehistoric man was work- There has been, in the past, no overall, concerted ing on the cultivation of land crops and domestica- effort at applying genetics to the aquaculture en- ting animals. Modem man, on the other hand, is still deavors of Japan which are without dispute the most for the most part content, correctly or incorrectly, extensive in the world. Now, however, in conjunc- with leaving marine organisms wild. University tion with a national research program on aquaculture schools of fisheries are dedicated to the advance- it appears that some special committee on the appli- ment of the science and art of fishing wild fish in the cation of genetics to aquaculture is being organized. wild. No doubt, this is partly the result of man's lack Since the advent of genetics at the turn of the of day-to-day familiarity with aquatic organisms, century, Japan has had a number of highly trained one measure of his failure to control the seas as he geneticists, many of world renown, invariably prom- does land. Also, the advance of civilization necessi- inent at International Congresses of Genetics. tated the promotion and ultimate success of agricul-

Breeding sciences and genetics are regarded impor- ture as wild crops and animals disappeared in its tant enough for school children to memorize the wake. In the same way pollution of the seas may names of famous Japanese (Kihara) and American assure the promotion of aquaculture over the span of (Sears) wheat geneticists. Genetic applications to the next few decades. breeding have, however, been with few exceptions Whatever the background reasons only presently in agriculture not in fisheries, the same situation as in is genetics beginning to be applied to the fisheries in the United States. Japan, which rank among the most important indus- tries of this island nation. By contrast triploid seed-

less in ' Milt'ord Laboratory. MACFC. National Marine Fisheries watermelons are bred Japan from sterile Service. NO.A.A. Milford. CT 06460. crosses made between special lines, and giant.

123 highly polyploid apples are sold at railroad station species exploited. Still of great importance, the food stands. Council believes, will be the switchover in the fish Until now there has been no pressing economic industry to farming-type endeavors. The necessity of breed improvement for success in such necessity in Japan to employ genetics to produce an maximum organism better able to perform in an intensive intensive culture under artificial conditions seems to aquaculture system. Aquaculture could be ineffi- be well understood. from the cient, depend on capture of young wild animals or At the same conference Akio Honma gravid females for a kind of semifarming. be labor Fishery Agency. Ministry of Agriculture and Forest- in intensive, and still be worthwhile as a means of pro- ry, gave a presentation on ""Fish farming Japan." ducing food and obtaining an income. This is no Honma said that in the fishing field, farming, along longer the case, and the change may be attributable, with concomitant management and breeding, has in part, to rising labor costs and to increasing de- been applied in the past only to a few freshwater mands for high quality seafood by a population with species and to a few species of seaweeds and crusta- a higher living standard. ceans. Over the years 1962-1966 the government's Fishery Agency established five Fish Farming Cen- EXPANSION OF INTENSIVE AQUACULTURE, ters to encourage coastal fishing in the Seto Inland A PREREQUISITE FOR GENETIC Sea. The entire Seto Inland Sea is being considered APPLICATION as one huge pond. Several important marine species are to be preserved and multiplied. Fry are bred at Certainly, the genetic study of wild fish popula- the centers and released to the prefectures for raising tions has some profound implications for fishery and releasing. In this program for the Seto Inland management. Genetic knowledge of wild popula- Sea a certain period of growth will be left to nature tions, in addition, makes for more judicious selection eliminating the necessity of using cheaper fish for the from such wild populations of the founding popula- farming of more expensive fish. tions used to breed hatchery stocks with particular Catching and releasing fry, as a source of seed, characteristics. The hatchery breeding of special, proved entirely inadequate. Seed breeding from arti-

though still undomesticated, stocks for release to the ficially spawned animals is now the work of the

wild represents still another area of genetics little project. It was found that, on the whole, breeding

considered in the fisheries. Such methods have been techniques were inadequate for the scope of the un- employed in forestry and grassland management, at dertakings. (Here, genetic improvement in repro- least, in the United States. However, the deliberate ductive performance under artificial conditions severe alteration of the genotype of the wild or- could lead to better breeding techniques in the ganism, which aquaculturists need to transform the hatcheries as an intermediate step in the total pro-

wild fish or invertebrate into a domesticated or cul- gram. Nothing was said of this. ) The main w ork of the

tivated form, requires, to begin with, intensive and center is now accordingly the development of mass fairly successful aquaculture of the organism. For production schemes. As the need arises, fishing ex-

that reason, it is important to note here the current periment station and university personnel work to- status of aquaculture programs in Japan. gether at the center.

At the opening of the Oceanoiogy Conference in It has become the policy of the government to Tokyo (Second International Ocean Development subsidize research work for seed production to some

Conference. 1972). it was indicated in a special talk nongovernment public corporation where they be-

that one of five major projects recommended by a lieve management is better. Seed production is the

special Council for Ocean Development created in area to which most money is now being directed. July 1969, as an advisory organ to the Prime Minis- Efforts are now being made to rear artificially ter, was the development offish culture with under- produced fish to maturity in larger tanks so that they

sea experimental farms. This is, it was explained, can subsequently be used to breed another genera- because Japan's coastal fishing has declined owing tion. When this is accomplished, of course, geneti- to pollution and overfishing, because of the exclu- cally controlled breeding will be possible. sion of Japan from some fisheries in their part of the Systematic work in the release and control of seed world by neighboring nations, and because of an has been limited since so much of the project had to intensification of the world "fishing race." New be aimed at developing seed and better seed-

fishing grounds will be developed and underutilized producing techniques. It was found that, if young

124 prawns are protected for a certain period and re- aquaculture under artificial conditions, or for "col- leased after adapting them to natural water, 5 to 10% onization" of a new area in the wild. of the released numbers can be harvested. As a result of this program, prawn has been pro- POLLUTION AND INTENSIVE AQUACULTURE duced on a commercial scale. Also red sea bream, WITH "SEMIDOMESTICATED " STRAINS , globefish, scorpionfish, sea-eel. blue crab, and abalone. The prawn project is emerging Possibly, even before breed improvement, with from its experimental to a semibusiness stage. concomitant genetic adaptation to the cultivated The prawn commonly cultured in Japan is Pen- state, aquaculture of some ""semidomesticated" aeiis juponiciis. It is one of the most expensive of forms will become a success with the disappearance in Japan. Artificial culture techniques for of their wild progenitors from Japan's coastal wa- this species have been developed over the last 10 yr ters, or when these wild forms accumulate enough by fisheries biologists and professional aquacul- contaminants to become unfit for human consump- turists. Despite a number of technical and tion. Oyster seed production has been eliminated socioeconomic difficulties in the commercial pro- from around the City of Hiroshima with implications duction of prawn in Japan, it is evident to the for the entire fishery. Yet. while pollution of wild Japanese that an increasing demand for prawn and stocks and their demise by marine contaminants may shrimp will stimulate the development of its culture make some aspects of commercial hatchery produc- as an industry wherever in the world it is at all tion more attractive, too widespread pollution would feasible. Culture should be particularly promoted in render even artificial production in natural seawater the untouched, widely ranging swamplands in the virtually impractical. The Japanese regard the future tropical zones. However, presently in Japan, poor success of artificial culture to be intimately tied to a culture techniques, defects in the present system of resolution of pollution problems. intensive culture, laborious rearing operations, ris- ing land costs, and unfavorable rearing conditions APPLIED AND BASIC GENETIC RESEARCH owing to pollution make for unstable costly pro- and TO SUPPORT FISH BREEDING duction on prawn farms. A decrease in artificial pro- duction is anticipated. Culturists wonder whether For many years Japan has emphasized applied prawn farms can even be maintained in Japan in research in the fishing fields. A system of extension competition with more productive enterprises. Yet, services for the fisheries is well established. In the an overwhelming demand continues to exceed pro- United States the Sea Grant Program stresses ap- duction even though at the Tokyo Central Fish Mar- plied research and extension services, but Japan is ket a kilogram of live prawn has been sold for as looking in the opposite direction. Unlike the Ameri- much as 8 to 30 U.S. dollars (Second International cans, the Japanese have made near maximum and Ocean Development Conference, 1972). efficient use of applied research. Now, Japanese The prawn fishery.justasthe shrimp fishery in the scientists actually carrying out the work and their United States, might well be the fishery that would research administrators alike are of the opinion that, benefit monetarily most quickly from a well- to increase further the productivity of their fisheries, integrated, sensibly supported genetics program. more basic research is required. In the past, such Experimental studies on the hybridization of the research has been largely confined to universities freshwater shrimp are being carried on at the Tokyo where it has not been well funded and to special Fisheries University (Uno and Fujita, 1972). Cross- national institutes. Basic research, they believe, is es of Macrohracliiiim nippoiiense x Q M. for- necessary to develop reliable means of carrying reg- luoscnsc -i" and reciprocal crosses were reared ularly large numbers offish from egg through sexual from the larval stage to sexual maturity. Morpholog- maturity, and this in the face of serious pollution. ical comparisons of hybrids to each parent were Such work should be deliberateh associated with made. These interspecies crosses were achieved by breed improvement programs, and the Japanese exposing the excised spermatophores to 50% seawa- recognize this. Even if the\ did not. some useful ter for 15 to 30 min. and then attaching them to the genetic selection would occur inadvertently. ventral thoracic part of the female of the other Food and disease appear to be presently regarded species just before she spawned. Such hybrids could as more important constraints on aquaculture gener- have advantages over nonhybrids for intensive ally than lack of special breeds. However, the

125 Japanese regard water quality —pollution —as the the FAQ ad hoc Working Party on Genetic Selec- current most serious point to consider in establishing tion and the Conservation of Genetic Resources of aqua-farms. In considering this ordering of pollu- Fish, which met in Rome in 1971 ( Food and Agricul- tion, nutrition, then disease, then genetics, in terms ture Organization, 1972). Their representative was of priority, it should be noted that: K. Suzuki, Chief Fish Culture Section. Ueda of Fisheries 1) Genetics will not succeed in accomplishing Branch Freshwater Research Labora- much of anything if the animal, to begin with, is not tory, Nagano Prefecture. The report published by reasonably easy to culture; this panel is an excellent statement. It is mostly, 2) but that genetics can in an early stage of however, oriented towards freshwater fish. In this aquaculture contribute to the development of types report the case for widespread utilization of genetics better able to utilize artificial foods, resist disease, in the fisheries is put more strongly than presented be more vigorous, and develop good gametes; here where emphasis is on genetics in the total per- spective. 3) so nutrition, disease, and genetics should not be regarded, either in the United States or Japan, as JAPAN'S NATIONAL INSTITUTE three separate research entities —they overlap. OF GENETICS STORAGE OF STOCKS AND COLLECTIONS Japan has an excellent National Genetics Insti- FOR BREEDING PURPOSES tute, which consists of 10 departments and was es- tablished in 1949 as the governmental institute for A directory prepared for distribution at the fundamental studies of genetics. One of its first di- Twelfth International Congress of Genetics, Tokyo, rectors was the now retired H. Kihara, world re- 1968, lists important genetic stocks of plants and nowned wheat geneticist. In the November 1972 animals and microorganisms being maintained in na- edition of Nature devoted to "Science in Japan" tional universities (Oshima. 1968). Tohoku Univer- there is an article by Kihara, "Activities of the Na- sity, Faculty of Agriculture, is named as holding tional Institute of Genetics." oyster stocks, but no other fish stocks are listed. One of the most active groups is the Department There are plans for establishing future "storage" of Developmental Population Genetics. The work centers to maintain genetic stocks. Fish are not men- of this group is currently all theoretical and not at all tioned in these proposals for storage of genetic concerned with fish. Training of this staff though stocks prepared by classic geneticists. "Stocks could be well utilized in fishery research. would be managed by an expert geneticist so that The silkworm is a much used organism for genetic uncontrolled, random breeding" of the closed stocks research at this Institute. Genetic mutations inter- would not result in genetic changes in the stocks fering with the feeding patterns of the silkworm lar- making them unrepresentative of the genotypes of vae are being studied. Such mutations no doubt also the wild populations or cultured lines from which present themselves in larvae of marine inverte- they were sampled for preservation. brates, as the oyster, which have delicate hirviil stages JAPANESE GENETICISTS often difficult to culture. Studies on radiation and chemical mutagenesis are being actively pursued

In this same directory, names of 944 Japanese using the silkworm. Emphasis is on dose-rate ef- geneticists are registered. Only four are cited as fects. (This is a very important area. There is a involved in research on fish: one was listed at the necessity internationally to clarify effects or lack of Nippon Institute of Scientific Research on Pearls, effects at very low doses of radiation, something two as working on the genetics of sexuality in fish, most difficult to carry out experimentally.) With em- and one on the genetics of invertebrate sex- bryonic death as a criterion, radio-sensitive and determination. An exhibit, "Genetics in Asian radio-resistant strains of silkworms have been iso- countries," at this Twelfth International Congress lated, differences being 6- to 9-fold. Using of Genetics," featured research on the origin, dif- Drosophila. induced mutations affecting viability ferentiation, distribution, and breeding of a number rather than simply inducing lethality have been of plants and animals especially associated with the found to occur 40 times as often as lethal mutations. life of Asian peoples: nothing was included on fish. This work in the field of mutagenesis might be di- Japan was represented by one of six members of rected toward establishing control standards for

126 .

marine contaminants as they affect the lethal gene importance. C gigas, C. rivitlaris. and Ostreci nip- load and reproductive cells of breeding fish popula- poini tions. Recently, workers at this National Institute of It is believed that C. lapcioitsi and C. ariaken- Genetics have developed a very sensitive test sys- sis. native Japanese oysters, reported some years tem for the detection of chemical mutagens in pol- ago by Kobayashi (1954) to have four more chromo- luted environments. somes than C. gigas, are really C. riviilaris. The

The Department of Cytogenetics is studying species C. riviilaris is not cross-compatible with C chromosome polymorphism in populations of the gigas (Imai and Sakai, 1961). Confusing here is the black rat around the world. With emphasis on the fact that American malacologists regard C. laper- Japanese population, the aetiology of Down's syn- oiisi and C. ariakensis as merely forms of the vari-

drome in humans is being studied. Expertise is cer- able C. gigas. tainly available then for breeding-related cytogenet- C. riviilaris. imported with seed of C. gigas. has

ic work. been planted in Puget Sound and, according to Galts-

Microbial genetics is also being pursued. Training off (1964), has established itself there. in such a field could be the basis for studying disease Some of this taxonomic confusion in classifying organisms of aquatic plants and animals. oysters may stem from the existence already of sev-

In the Department of Applied Genetics, rice is eral hybrid-type populations in the wild. Nothing

most extensively investigated - aquatic, marine or- was learned in Japan regarding the opinion of some ganisms not at all. A worldwide collection of rice U.S. workers that C. angiilata, the Portuguese oys-

species is maintained; there is a complete collection ter, and C . gigas are the same species. of wheat and its relative species. Lest an understanding of the nature of these

species be regarded as esoteric, it should be pointed out that such much publicized benefits of genetics, OYSTERS OF JAPAN, SPECIFIC USE OF HYBRIDS AND HYBRID VIGOR as miracle rice, resulted from a combination of two species or varieties. The characteristics of each of

There is a very real separation of Crassostrea these types of rice were clearly known and under- gigcis. commonly called the Japanese oyster, into stood by the breeders who test-hybridized them several distinct races (Imai and Sakai, 1961). initially along with many others which were not There may even be a variation in the chromosome "miracles" at all. number in some Japanese populations of C gigas. Part of the vigor of C gigas relative to the more This is at variance with all the recent reports of sensitive commercial East Coast American oyster, American workers (review, Longwell and Stiles, in C. virginica, may derive from a slow though steady

press). However, all the C. gigiis sampled in the rate of introgressive hybridization. That is. by the United States for chromosome analysis derive from addition of other species genes to C. gigas on a small

seed imported from Japan to the U.S. West Coast, scale over a long period. It could also derive from and most of the spat exported from Japan has been larger scale hybridization in various oyster popula- taken from one particular region. tions in the more distant past. Both of these prob-

C. gigas is collected widely in Japan in the shallow abilities can be checked experimentally. This is

waters on the coast from Hokkaido to Kyushu. Seed basic research, of course, but it would provide some

were, until recenth . collected most actively in information on how important hybridization pro- Hiroshima, where oyster culture is said to have grams are in developing vigorous hatchery stocks. begun 400 yr ago. The Miyagi district is next in Such would remove some of the present unavoidable production to Hiroshima. Main seed-producing beds guesswork as to the usefulness of wide species in Japan are Hiroshima, Miyagi, Mie, and crosses. Kumamoto Prefectures. The Miyagi Prefecture is Spat of C gigas are now being shipped to France famous for their export of oyster seed. This is most from Japan for planting on oyster beds once popu- likely where most seed imported to the U.S. West lated by C angiiUiiii. There is a chance of natural Coast has been originating. Hiroshima culturists sel- hybridization on the wild beds in France between dom bought oyster seed and seldom exported their imported C. gigas and the remains of the once plenti- seed to other prefectures or countries. ful C . angiilata populations. These two species read- There are 20 different species of oysters in Japan, ily hybridize in the laboratory, the hybrids survive all edible. Only three of these are of direct economic and are fertile (Imai and Sakai, 1961).

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It would be hard to overemphasize the importance lated from the Japanese through the auspices of the hybrid vigor will have in developing hatchery lines of National Oceanic and Atmospheric Administration. oysters, lobsters, scallops, fish and other marine At least for some considerable period of time adult, food animals, and algae. Hybrid vigor is so impor- fertile hybrids of the cross C. gigas x C. angulata tant because, unless artificial seawater is used, water were maintained at the Kesen-numa Laboratory. pollution will always be a threat to the commercial This Institute is now rearing the European oyster, success of a hatchery. Because a hatchery must Ostrea ediilis. which does well in Japan as a hatchery

carry its product through its most sensitive larval species. These oysters are sold as spat to growers stages, in smaller numbers than in the wild, and in and marketed. C. angiiUita is also being reared. No one spot as opposed to many in the wild, water genetic studies are now being conducted on the oys- pollution can have a more disastrous effect in a ter. hatchery than in the field. The sea scallop, Patinopecten, is also being Widespread use of artificial seawater would raised. The scallop fishery still depends on the cap- necessitate the breeding of lines commercially pro- ture ofjuveniles, not on hatchery rearing. However, ductive in such a media. Drastic changes in the at least in Mutsu Bay annual catches of P. yessoensis genotype would most probably be necessary. This is fluctuate widely. This is attributed to a natural insta- not a genetic improbability by any means, but bility of the reproduction of this species. Natural aquaculturists do not give the idea much thought. reproductive instability would make this scallop an excellent candidate for reproduction in the hatchery. LABORATORY VISITS Some of the scallops are known to be functional hermaphrodites. Use could so be made, for both experimental and commercial breeding work, of Even though there has been no general, broad their rapid inbreeding potential by self-crossing. program of fish or aquacultural genetics in Japan, Research at the Kesen-numa Laboratory is now some fine genetic research has gone on in various concentrating on the abalone. The market for this fishery laboratories. This work has not yet had a marine gastropod is excellent, and there is an urgent great deal of impact on the general fisheries. It is need to mass produce the young. Unlike the situa- related here along with comments and discussions tion for the oyster and scallop, mass collection of regarding aquaculture-related genetics. The re- wild abalone is fairly difficult. Young abalone escape search cited is a sampling of the sort of work that will from the collectors, and in their natural habitat, they most likely be conducted in the future on a larger shelter themselves under boulders or rocks. To in- scale. crease production it is, therefore, essential to pro- Oyster Research Institute at Kesen-numa on duce the young artificially. Mohne Bay—Oyster, Scallop, and Abalone In Japan 10 species of abalone are found. Only four of these species constitute the staple food

The Oyster Research institute at Kesen-numa products HuHutis haliotis discus hannoi, H . dis- (chief researchers now H. Kan-no and T. Seki) de- cus, H. sieboldii, and//, gigantea. Of the total catch

veloped, under the leadership of T. Imai, methods H . discus hannoi supplies 58%. for the artificial rearing of the Japanese oyster, C. At present, no genetic studies on abalone are

f;if>a.s. This Japanese work paralleled the prior work being conducted at Kesen-numa. However, there is of Loosanoffand Davis (1963) of the Milford Biolog- interest in possible genetic causes of the less than ical Laboratory, now part of the National Marine desired percent survival of the young larvae, in the Fisheries Service. From the Kesen-numa Labora- chromosomes of the abalone, and in genetic resis-

tory also came a breeding study on C. fiii^'us, which tance to disease. Disease is anticipated as a potential included the effects of inbreeding, hybridization be- serious problem in the very intensive system under tween members of different geographic races, and which the abalone will be reared. The intensive sys- interspecies crosses using the Japanese oyster as one tem includes a period of growth in the heated waters of the species parents (Imai and Sakai, 1961). Addi- of a nearby power plant at Shiogama. An above-

tional aquaculture and breeding information is con- ground running water tank system contains the

tained in a recent book edited by Imai et at., 1971, abalone at this time, and a hatchery with experimen- "Through culture in shallow seas (progress in shal- tal facilities has been built at the power plant near the

low seas culture)." This book is now being trans- tank farm.

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At the Iwate Prefectural Roes and Fries Distribu- cess would find application in numerous fields of tion Center the gametogenesis of adult abalone was fishery research. It would apply to work on this observed, as well as the normal development from epidemic MSX disease of the American oyster, fertilized egg to creeping stage larvae (Shibui, 1972). which just about devastated the oyster industry of Once the artificial production of abalone in Japan the U.S. mid-Atlantic states a few years ago (Sin- progressed to the commercial scale, interest de- dermann and Rosenfield, 1967). veloped in the potential of interspecies crosses. At Some inbreeding and some hybridization studies Chikura Branch of Chiba Prefectural Fisheries such are being conducted on the pearl oyster (K. Wada).^ hybrids were made and studied. These were between Also, some studies have been conducted on its H. discus and H. gigantea; between H. discus and chromosomes in spite of technical problems caused H. sieboldii; and between H. gigantea and H. by the presence of so much yolky material in the eggs sieboldii (Oba, Toyama, and Kaneko, 1972). All (K. Wada, see footnote 3). This latter work will were reared through metamorphosis in the labora- probably be published soon. It seems that some re- tory. Hatching, fertilization abnormalities, and shell search effort will be directed in the future towards form and structure were compared to the parental study of biochemical polymorphisms in the wild characteristics. Such hybrids could have advantages stock. over nonhybrids for intensive aquaculture under ar- Ocean Research Institute, University of Tokyo tificial conditions, or for colonization of a new area Genetic Polymorphisms of Wild Populations in nature. Some hybridization work was also conducted at In the division. Biology of Fisheries Resources, the Kesen-numa Institute (J. W. McBeth).^ studies are being conducted on enzyme variation in Pearl Research Laboratory of the Fisheries fish populations (Numachi, 1972a). Agency at Kashiko-jima, Mie-ken Shortage of genetic markers has been a handicap in the study offish genetics. Now variation in differ-

Research is confined exclusively to study of those ent enzymes can be used as genetic markers by em- mollusks used to culture pearls. Work is ultimately ploying gel electrophoresis followed by histochemi-

directed at improving the quality of the cultured cal staining methods. This method makes possible

pearl. All the research appears to be basic. It seems an examination of the structure of a population offish that, because the science and art of pearl culture are in genetic terms. Identification of self-sustaining well worked out, these researchers have more free- subpopulations of fish is a most basic problem in fisheries dom to pursue fundamental work. There is a persis- management. tent near 40% mortality of the pearl oyster, Pinctada Enzyme polymorphisms reflect a mutation in the fucata, in the trays and racks used to hold them in the structural gene of the enzyme concerned. A few pearl farming. Mortality appears to be accepted as years ago variants of enzymes were regarded as rare part of the business. The demand for pearls has events. It is now known that such variants are very dropped and there is now a government restriction common in most enzymes in various organisms. An on the amount of pearl farming to be conducted. increasing number of electrophoretically distin- There are no projects aimed at breeding disease re- guishable variants has been discovered in fish, as well sistant organisms, as those for the commercial as in other organisms. Marine mammals, such as Crassostrea virginica in the U.S. mid- Atlantic whales, dolphins, and seals, all contain five lactate states. dehydrogenase forms. Their enzyme "patterns" are

Research is being carried out on the artificial cul- similar to those of terrestrial mammals, including ture of this pearl oyster's mantle (A. Machii, pers. man.

comm.). Mitosis and cell proliferation have been Numachi (1971 , 1972b, c) has specifically reported obtained in vitro. American, European, and in the literature on interspecific and intraspecific Japanese workers can all generally attest to the fact variation of enzymes in fish species and on analysis that success in invertebrate tissue culture has been of the genetic control of such enzymes in fish—on most elusive. A persistent measure of culture suc- ^ Personal communication from a fellow staff member. K. Wada was away at a fisheries meeting at the time the laboratory - Communication through Japanese staff member acting as was visited, so more precise information on this work was not Director at the time. obtained.

129 electrophoretic variants of catalase in black rock- 1966: Kato. 1967: Suzuki and Fukada. 1971. 1972). fish, Sehastes inennis; genetic polymorphisms of Most likely, such programs will be stepped up as tetrazolium oxidase in black rockfish; genetic con- breed improvement is stressed in the future.

trol and subunit composition of lactate dehydro- It is believed that no fish populated Lake Chuzenji genase in Psciidorashuni puna (a cyprinoid fish): until 1873 when some local people volunteered to duplicate genetic loci and variant forms of malate stock the lake with such fishes as the char and carp. dehydrogenase in chum salmon. Oncorhyiu liiis Since that time, many species of salmonid fishes kt'tii. and rainbow trout. Saliiio iniinhieii. have been stocked frequently in the lake. Lhe eggs of Evidence has importantly been provided for the Sahelinusfontinalis, the brook trout, were imported tetraploid condition of salmon. This means that salm- in 1901 from the United States and fry released in the on, like many higher plants, basically have four of lake.

each chromosome instead of the usual two each It is well known that distinct species and genera of found in normal diploid organisms. Diploidy is the fishes hybridize frequently in nature. A considerable common stale in the animal kingdom. Further ex- number of natural hybrids has been reported, espe- amination of the evolutionary process of salmonids cially in the freshwater families —Cyprinidae and remains to be done. Already though recognition of Castostomidae: also, in Percidae. Centrarchidae, the tetraploidy of salmonids should be of intrinsic Poeciliidae, etc: and importantly in Salmonidae. importance in genetic studies. Because of the tetra- Natural hybrids seem to occur much less frequently ploid nature of salmon, big salmon obtained by selec- in marine fishes. Information about natural crosses tion are not a good general example of what might be is most useful in determining the relationship of expected by similar programs of breeding using truly groups of fishes. diploid species. Tetraploidy lends itself particularly Natural hybrids between 5. pliiviiis. the Japanese well to gigantism. char, and S. fontinalis were collected from a brook Study of enzyme variation in species transplanted flowing into Lake Chuzenji. They are estimated to and farmed in the not-so-distant future will be an constitute about 12% of the population at the area of important means of stock identification, and of de- the headspring. termining whether desired or unwanted hybridiza- Growth and survival rates of artificially produced

tion has occurred in the wild between the local and hybrids between .V. plnviiis and S. fontinalis were transplant type. This will be no small job since the studied from 6 mo after fertilization until they were 2 present most effective utilization of different genetic yr old and compared to the nonhybrid parents. This

characters of various populations is still by trans- was to determine their relative suitabilities for pond plantation of populations and species suitable for the culture. Best growth was in S. fomintilis followed by environmental conditions of the areas intended for the hybrid, then by S. pluvins. Survival rate was farming (Numachi. 1972a). highest in the hybrids. All the hybrids and S. fon- Another application of enzyme variants to genetic tinalis came to maturity during this time, but a third improvement of aquatic organisms may be as mark- of S. pluvius was still immature. Hybrids were fertile ers linked with economic characters. Economic and. in fiKt, produced a significantly larger number characters are usually polygenic and so are impossi- of eggs than did the nonhybrid parents. ble to study by simple Mendelian genetics as are With the hope of directly utilizing the information distinct, qualitative, morphological characters. obtained to increase annual trout harvests, hybridi- zation experiments with 62 combinations of Sal- Nikko Branch of Freshwater Fisheries monidae have been going on since 1965. The purpose Research I^aboratory on Lake Chuzenji of this work was to find F, hybrids suitable for pond culture and for stocking lakes or rivers. L'ntil a few Breed improvement is now regarded as one of the years ago the freshwater fishes of Japan were abun- main problems in the freshwater fish culture in dant in nature. They were used mostly by rural peo- .lapan. .Some selective breeding is underway at the ple as a main protein source. Due to a reduction in Nikko Branch of Freshwater Fisheries Research their natural habitats, such fish are now less plenti- Laboratory (for preliminary work on Stilino i^aircl- ful. At the same time the demand for them has gone iwri see Kato and .Sakamoto. 1969: Kalo. !97()), up. making them a luxury food. Presumably it was Extensive hybridization studies have been carried believed that genetic and breeding work would have out and reported in the literature (Suzuki and Kato. some bearing on this situation. It v\as further hoped

130 —

that some of these hybrid crosses would be sterile. species tested. Descendants from crosses of two Sterile hybrids might, because of their sterility, have dioecious parents and from two monoecious parents a faster rate of growth or greater ultimate size than grew normally. Those from dioecious-monoecious fertile nonhybrids. combinations died in mass at a young stage, but left a Hybrid development did occur in all combina- few survivors. The three dioecious species studied tions. There were, however, wide differences in sur- appear to be very closely related. At least in hybrids vival rates. Hybrids between 32 combinations of the dioecious species, there is normal reproduc- survived until they reached the free-swimming tion with typical genetic segregation. stage. Nine of these showed survival rates similar or Recently, some lines started from an interspecies better than those of parental species. Those combi- hybrid have yielded two and three succeeding gener- nations that did survive are currently being studied ations. Some of the lines grow more vigorously than at later growth stages. did their native parents. Among hybrid characteristics already ascertained This work demonstrates that new lavers, more is a heterosis against disease. This is an important suitable for commercial production than the present feature since prevention of epidemic disease is a wild lavers, can be bred. Probably the F, inter- serious problem in trout culture. species hybrids will first have to be subjected to a Even some intergeneric hybridization was program of artificial selection in the laboratory, or achieved. These hybrids though presented special one of natural selection in the wild before being used difficulties m cultunng and rearing. commercially. Introduction to Japan of foreign species of Porphyra, which may be disease resistant, for field Tohoku University School of Fisheries and trials and for use in hybrids with Japanese species, is Tohoku Regional Fisheries Research Laboratory regarded important. High quality species already Radiation Effects on Oyster; Seaweeds being utilized are, unfortunately, not the most pro- The effects of ionizing radiation on Crassostrea ductive, and disease is a factor in lowering produc- gigas are being studied at Tohoku University (L. tivity. Maeda, pers. comm.). This work may be similar in There is a likelihood of some natural hybridization nature to some done on C. virginica (Longwell and occurring on the wild beds between closely related Stiles, 1972). species. The genetic and other implications of this Recent advances in cultural techniques for the are recognized. seaweeds, like Porphyra and Undaria, have brought Some cytogenetic studies on P. yezoensis have substantial benefit to a considerable portion of been done elsewhere at Nagasaki University Fa- fishermen engaged in seaweed production in Japan. culty of Fisheries (Migita, 1967). There are three (At the same time once important nori grounds about chromosomes in vegetative and spermatogonial cells Tokyo have been irretrievably lost to pollution, and in the leaf thalli, and six chromosomes in fertilized nori products have come to contain mercury and carpogonia. The haploid chromosome number of cadmium.) Little attention though has been given to this alga is then three. Meiosis takes place in the cell the possibility of artificially crossing seaweed types division of the conchospore at the time of spore

to give a more productive, profitable strain. Since formation. Such information is pertinent to the mak- 1958, S. Suto has been making interspecies hybrids ing of artificial crosses. Also for the artificial somatic always using a local commercial species as one par- replication of a single plant for multiplication prior to ent. This work has been done with a view of obtain- larger scale commercial production. ing a new seaweed with good characteristics for Aside from the great commercial value of sea- culture (Suto. 1963; also see Suto, 1972). Fortunate- weeds in Japan (their most important fishery), the ly, self-fertilization rates are low, facilitating artifi- Japanese probably have here one of the most in- cial fertilization. However, much preliminary work teresting areas of the future field of marine genetics had to be done before artificial fertilization could with most promise of great commercial application.

be achieved with certainty. Also, the relationship This is because plants, in general, lend themselves between Porphyra species had to be clarified. so well to genetic study with subsequent genetic Artificial crosses were attempted between five manipulation and because so many genetic and species of the Porphyra genus, including four local breeding techniques are so well worked out for forms. Crosses occurred easily between any two plants.

131 .

LITERATURE CITED KOBA> ASHI, H. I9.S4. Uber die chromosomenzahl der zwei arlen von ja- panischen austern. Cytologia I9:.^71-.176. LONGWELL. A. CROSBY, and S. S. STILES. 1972. Breeding response of the commercial .American oys- C HERFAS, B. L. (editor). ter to ionizing radiation. Radiat. Res. .51:1-54.5 (He-5). 1969. Genelika selektisya i gibridizatsiya ryb (Genetics, In press. Oyster genetics and the probable future role of selection, and hybridization of fish). Moscow, Izd. Akad. genetics in aquaculture. Malacol. Rev. Nauk. (TransUited by Israel Program Sci. Transl.. 1972. 269 LOOSANOFF, V. L., and H. C. DAVIS. p.: available U.S. Dcp. Commer.. Natl. Tech. Inf. Serv.. bivalve mollusks. /;/ F. S. Russell (edi- Springfield. Va.. as TT-.SOl 12.) 196.3. Rearing of FOOD AND AGRICULTURE ORGANIZATION. tor). Advances in marine biology, vol. I, p. 1-1.36. .Academ- ic Press. London and New York. 1972. Report of the first meeting of the FAO ad hoc MIGITA, S. working party on genetic selection and the conservation of 1967. -Cytological studies on Porphyra yezoensis Ueda, genetic resources offish. FAO (Food ,\gric. Organ. U.N.) Bull. Fac. Fish., Nagasaki Univ. 24:55-64. Fish. Rep. 119. 9 p. NUMACHI, K. GALTSOFF. P S 1971 Electrophoretic variants of catalase in the black rock- 1964. The .American oyslcT rassostrea virginka Gmelin. C fish, Si'hostes inermis. Bull. Jap. Soc. Sci. Fish. vol. 480 U.S. Fish Wildl. Serv., Fish. Bull. 64, p. 37:1177-1181.

IMAl. T. (editor). 1972a. Genetic polymorphism in enzymes and its research 1971. Through culture in shallow seas (progress in shallow application in fisheries biology. In Second International seas culture!. [In Japanese.] Koseisha Koseikaka Pub- Ocean Development Conference 2:1813-1821. Sec- lishers. Tokyo, 4.S4 p. (English transl. by U.S. Dep. Com- retariat. International Ocean Development Conference mer., Natl. Oceanic Atmos. Admin., Natl. Mar. Fish. and Exhibition. Japan Management .Association. Serv.) Tokyo.

IMAl.T.. and S. SAKAI. 1972b. Genetic polymorphism of tetrazolium oxidase in 1961. Study of breeding of Japanese oyster. Crassostreu black rockfish. Bull. Jap. Soc. Sci. Fish. 37:1-789. control subunil lactate fiinas. J. Agric. Res. 12:I2.'!-17I. 1972c. Genetic and compositions of INTERNATIONAL CONGRESS OF GENETICS, dehydrogenase in Pseiidoroshora puna. Jap. J. Genet. TWELFTH. 47:193-201. OBA, T., T. TOYAMA, and S. KANEKO. 1968. Genetics in Asian countries. XII International Con- 1972. Studies on the experimental hybridization of gress of Genetics. Organizing Committee (D. Moriwaki. Haliotis. In Second International Ocean Development Chairman). 19-28 .Aug. 1968, Tokyo. [Brochure accom- Conference 2:1725. Secretariat, International Ocean De- panying exhibit.] velopment Conference and Exhibition. Japan Management INTERNATIONAL OCEAN DEVELOPMENT CONFER- Association. Tokyo. ENCE, SECOND. OSHIMA. C. (editor). 1972. Special lectures and rcpnnis. \ol. 2. Secretariat. 1968. Recent activities of Japanese geneticists. Idengaku International Ocean DevelopmenI Conference and E.xhi- Fukyukai. National Institute of Genetics. Misinia. hilion. Japan .Management Association. Tokyo. Shizuoka-Ken, Japan. KATO. T. SHIBUI.T.

1%7. Studies on the techniques of salmon - and trout - 1972. Biological studies concerning the mass production of culturing. 3. Growth and survival rate of Saheliiiits young abalone Haliotis discus hannoi ino. In Second In- pliiviiis, Sahelinns Jhnliniilis fnnlinalis and the hybrid, ternational Ocean Development Conference 2:1715-1724. Sahclinii.s pliiviii.K \ and Scilveliniis fontinatis Secretariat, Inlemational Ocean De\elopment Confer-

loiitiiHilis cJ . [In Japanese. English summary.] ence and Exhibition. Japan Management Association. \linalo-Ku Suisan Kenkuysho. Kenkyu Koku 16:59- Tokyo. M. SINDERMANN, C. J., and A. ROSENFIEl D. 1967. important m.irine 1970. Studies on the variation of growth in rainbow trout Principal diseases of commercially Crustacea. Fish Wild). Serv., Stilnio i-iiinliicrii-W. Regression line of satiation amount bivalve Mollusca and U.S. Fish. Bull. 66:335-385. on the body weight as an indication of food amount. [In Japanese. English summary.] Bull. Freshwater Fish. Res. SUTO. S. 1963. Intergeneric and interspecific crossings of the lavers 1 .ih. :():I1)|.|0". tPurphyra). Bull. Jap. Soc. Sci. Fish. 29:739-748.

KAIO. I .. and 't . .SAkA.MOIO. 1972. Variation in species characters of Porphyra under l')64, Suidicv on the variation of growth In rainbou tanit. culture conditions. //; J. .A. Abbott and M. Kurogi Siihiiii iiiiiiiliH'iii -1. The eflect of grading of body size on (editors). Contributions to the svstematics of benlhic the course of growth. [In Japanese. English summary .] marine algae of the North Pacific. Japanese Society of

Bull. Freshwater F ivh Rcv I .ih. 19:9-16 I'hycology. lok\.i klHARA. H. SL/L Kl. R.. and > I L K Al) \ 1972. .Activities of the National Institute of Cienclics. Na- 197|a. Survival potential ol 1 i hvhiids among s.ilmonid

ture (Lond.) 240:219-220. fishes. Bull. Freshwater I ish Res, I ,ib, :i:69-83.

132 1971b. Growth and survival of F I hybrids among salmonid UNO. Y., and M. FUJITA. fishes. Bull. Freshwater Fish. Res. Lab. 21:117- 1972. Studies on the experimental hybridization of fresh- '-^**- water shrimps. Miumhrachiitin iupp(ineii\c and M . for- SUZUKl, R., and T. KATO. mosense. In Second International Ocean Development 1966. Hybridization in nature between salmonid fishes Conference 2: 1762. Secretariat. International Ocean De- Scilvelimis pliniiis x Scilveliims Jontincilis. Bull. Fresh- velopment Conference and Exhibition, Japan Manage- water Fish. Res. Lab. 16:83-90. ment Association, Tokyo.

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370. Collecting and processing data on fish egps and larvae in the California Current 379. Fishery publications, calendar year 1969: Lists and indexes. By Lee C. Thorson and

iv 1 sale Superintendent of region. By David Kramer. Mary J. Kalin. Elizabeth G. Stevens, Jame« R. Thrailkill, and Mary Ellen Engett. April 1973, + 31 pp . fig. For by the James R. Zweifel. November 1972, iv + 38 pp.. 38 Cigi., 2 Ubles. For sale by the DocumenU, U.S. Government Printing Office. Washington, DC. 20402. Superintendent of Documents. U.S. Government Printinf; Office. Washington, D.C. 20402. 3B0. Fishery publications, calendar year 1968: Lista and indexes. By Mary Ellen Engett and Lee C. Thorson. May 1973. iv + 24 pp., 1 fig. For sale by the Superintendent of Documents. U.S. (Government Printing Office, Washington. DC. 20402. 371. Ocean fishery management: Discussions and research. By Adam A. Sokoloski (editor). (17 papers. 24 authors.) April 1973. vi + 173 pp.. 38 figs., 32 Wblea. 7 appendix Ubies. 381. Fishery publications, calendar year 1967: Lists and indexes. By Lee C. Thorson and

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378. Marine flora and fauna of the northeastern United States. Protozoa: Ciliophora. By 387. Marine flora and fauna of the northeastern United States. Crustacea: Stomatopoda.

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