The Feasibility of Enhancing Red Sea Urchin, Strongylocentrotus franciscanus, Stocks in California: An Analysis of the Options

MIA J. TEGNER

Introduction tially throughout the range of the fish­ Ui 25,000 ery, the alternatives are a reduced c: B 20,000 The red sea urchin, Strongylocen­ harvest and contraction of the indus­ .!'! ~ 15,000 trotus franciscanus, is the largest try, or stock enhancement to maintain §. echinoid in kelp forest communities populations above what is possible ~ 10,000 c: along the west coast of North America with current fishery practices. The =g 5,000 C\l and is fished commercially from Brit­ spectacular successes achieved with ...J o+--..:.....~---.---~~~ ish Columbia to Baja California some finfishes, notably the salmonids, 1970 1975 1980 1985 (Sloan, 1986). The California sea as well as the many recent advances in Figure I.-California landings of urchin fishery began in the early aquaculture, have led to widespread red sea urchins, 1971-87 (Calif. 1970's and grew very rapidly to total interest in the second and more eco­ Dep. Fish Game. Unpubl. data). landings of more than 20,000 metric nomically appealing alternative. Here, tons (t) in 1987 (Kato and Schroeter, I examine potential options for the en­ l 1985; Parker ). By 1987, this was the hancement of red sea urchin stocks, second most valuable fishery in Cali­ consider the conditions under which methods to enhance fishable stocks. fornia waters with a landed value of each might be appropriate, and make The success of all attempts to enhance $13,693,000. There are no unfished relative estimates of the costs and ef­ benthic invertebrate stocks by the re­ stocks left in southern California; only fort involved. lease of hatchery-reared juveniles will the development of a northern coastal The concept of stock enhancement be reviewed, as well as other methods fishery in the mid 1980' s allowed for valuable invertebrate fisheries is relevant to sea urchins. Because the the continued increase in landings not new. Transplantation of abalones, success of many Japanese approaches (Fig. 1). Haliotis spp., to better habitats for is related to the structure of their fish­ With the eventual elimination of un­ growth dates to the 19th century (lno, ing industry, this and the implications fished stocks statewide, and poten- 1966), and lobster, Homarus spp., of the American tradition of open­ juveniles were cultured for release on access fisheries for stock enhancement fishing grounds as early as the 1880's will be discussed. I D. Parker, Calif. Dep. Fish Game, 330 Golden (Van GIst et aI., 1980). The Japanese The success of any enhancement ef­ Shore #50, Long Beach, California 90802. Unpub!. data, 1989. in particular have explored a variety of fort will depend upon the answer to a critical question: What stages in the life history of the organism limit the production of fishable stocks? For red ABSTRACT-The California fishery for the extensive Japanese work, to enhance sea urchins, the limiting factors could red sea urchins, Strongylocentrotus fran­ fishable stocks of benthic marine inverte­ be larval supply, problems associated ciscanus, has undergone explosive growth brates, and consider the potential options with settlement, survival of newly set­ in recent years and is approaching full for red sea urchins at different points of exploitation. Thus, there is considerable limitation. These include collecting or cul­ tled to mid-sized animals, or adequate interest in enhancing stocks to maintain a turing seed for outplanting, physical habi­ high rate of landings. Fishable stocks of tat improvement measures, improving the Mia J. Tegner is with the Scripps Institution of red sea urchins in different areas appear to food supply, and conservation measures to Oceanography, A-OO I, University of California, be limited at three stages in their life his­ protect existing stocks until alternate San Diego, La Jolla, CA 92093. Mention of tory: By the availability of larvae, by the methods are proven and in place. The op­ trade names of commercial firms in this paper survival of newly settled to mid-sized ani­ tions are compared in terms of biological does not imply endorsement by the National Marine Fisheries Service, NOAA. Views or mals, and by the food available to support feasibility, capital and labor requirements, opinions expressed or implied are those of the growth and reproduction of larger ani­ and potential implications for change in author and do not necessarily represent the posi­ mals. Here / review other efforts, notably the structure of the fishing industry. tion of the National Marine Fisheries Service.

5/(2), 1989 food to support growth and/or gonad reported from late spring to early sum­ was highest on the southeastern is­ production. Enhancement efforts mer or even fall. The length of the lands, those most affected by the which do not address the stage which planktonic larval phase is temperature Southern California Eddy, the closed limits production are not likely to be dependent. Strathmann (1978) re­ gyralcirculation of Parrish et al. successful; e.g. seeding of juveniles ported a range of 62-131 days for (1981), which appears to aid in the will do little for a population limited larvae cultured at ambient tempera­ retention of larvae, and was very low by survival of mid-sized animals or tures (generally 7°-l30 C) in Friday on the northwestern islands until the food supply. Furthermore, these fac­ Harbor, Wash., and Cameron and 1982-84 EI Nino when upwelling tors are likely to vary on local and Schroeter (1980) found the earliest rates were extraordinarily low. While regional scales, e.g. the survival of settlement at 40 days and the peak at little red sea urchin recruitment data is mid-sized animals correlates nega­ 50 days after fertilization for larvae available from the region of maximum tively with the abundance of two warm cultured at l20 e. Whatever the tem­ upwelling, it is reasonable to assume temperate predators, spiny lobsters, perature, the length of the planktonic that stocks in central and northern Panulirus interruptus, and California phase indicates that the distribution of California are more likely to be limited sheephead, Semicossyphus pulcher the larvae is strongly affected by cur­ by larval supply than those in southern (Tegner and Dayton, 1981; Tegner and rent patterns. California. Barry2). The northern range limit of Current patterns, and thus the fate of The settlement requirements for red these two predators is normally Point sea urchin larvae, vary seasonally and sea urchin larvae are poorly under­ Conception, and both are character­ with latitude. Parrish et al. (1981) di­ stood. Hinegardner (1969) reported istic of bottoms with considerable ver­ vide the California Current System that both red and purple sea urchin tical relief; they will have little impact into four oceanographic regions on the larvae settle on an algal and bacterial on red sea urchins north of southern basis of mean geostrophic flow, film. Cameron and Schroeter (1980) California or in pavement habitats. Ekman transport, and wind stress curl observed no substrate specificity Finally, enhancement methods will patterns. California falls into two of among several filmed natural sub­ vary considerably in costs, in the these regions, the region of maximum strates and suggested that sea urchin length of time required to achieve re­ upwelling from Cape Blanco to Point larvae settle on any surface they en­ sults, and in how long the results will Conception which includes the north­ counter once they became competent last. western Channel Islands, and the to undergo metamorphosis. Rowley Southern California Bight. The region (1989) found that purple sea urchin Summary of the Life History of maximum upwelling is character­ larvae settle at significantly higher of Red Sea Urchins ized by strong offshore surface trans­ rates in response to crustose coralline The biology of S. franciscanus has port during the spring and summer, algae and red algal turf than in re­ recently been reviewed by Kato and whereas the Southern California Bight sponse to filmed rocks, but was not Schroeter (1985). Here I will sum­ is an area of minimal upwelling and a able to demonstrate density differences marize aspects of the life history rele­ closed gyral circulation (Parrish et aI., among natural substrates for newly vant to factors potentially limiting the 1981). These oceanographic patterns settled « I mm) red sea urchins. size of fishable stocks. appear to have major implications for Thus, evidence to date suggests that The timing and length of the spawn­ the transport of larvae. The Southern suitable substrates for settlement are ing season of red sea urchins are California Bight, the area of minimal not likely to be limiting as long as highly variable among locations (Kato upwelling, has the highest known rates excessive sedimentation or pollution and Schroeter, 1985). Seasonality may of red sea urchin recruitment (to the are not an issue. be related to the patterns of food avail­ population) throughout its range In contrast, the survival rates of ability (Bernard, 1977); red sea ur­ (Sloan et aI., 1987). Ebert and Russell newly settled to mid-sized animals do chins in the Point Loma kelp forest (1988) report reduced recruitment of appear to limit the size of fishable near San Diego, where food is gen­ intertidal purple sea urchins (S. pur­ stocks in some populations. While red erally abundant, are thought to spawn puratus) on headlands, predictable sea urchin larvae do not settle in re­ throughout the year although there is a sites of upwelling, compared with sponse to adults (Cameron and winter peak. North of southern Cali­ areas without predictable upwelling Schroeter, 1980), juvenile abundance fornia, where food may be primarily within the region of maximum upwell­ is often highest underneath the test or available from mid spring to mid fall ing. Roughgarden et al. (1988) found a spine canopies of conspecific adults (Ault, 1985), the spawning season is negative correlation between a (Fig. 2), especially where the substrate season's recruitment of barnacles, affords little cover or in the presence 2Tegner, M. J., and J. P. Barry. Size structure Balanus glandula, and the upwelling of certain predators (Tegner and Day­ of red sea urchin (Strongylocentrotus francis­ index at Pacific Grove. Tegner and ton, 1977; Sloan et aI., 1987). Breen canus) populations in southern California; ef­ Barry2 analyzed red sea urchin recruit­ et al. (1985) have shown experi­ fects of growth, recruitment, predation, and oceanography. Manuscr., 61 p. A-OOt, Scripps ment patterns on the Channel Islands mentally that the spine canopy associa­ Inst. Oceanogr., La Jolla, CA 92093. of southern California. Recruitment tion is a result of juvenile behavior;

2 Marine Fisheries Review juveniles chose shelter under adults over other protective locations. This association appears to be critical to the recruitment success of this species. Tegner and Dayton (1977) observed both significantly reduced settlement and survival of previously settled ju­ veniles on experimentally fished (all animals >95 mm were removed) reefs in the Point Loma kelp forest near San Diego. The spine canopy association provides juveniles protection from predators such as spiny lobsters (Tegner and Levin, 1983) and the young feed on drift algae snared by the adults (Tegner and Dayton, 1977; Breen et aI., 1985). Depending upon the size of the shelter provider and bottom topography, juveniles even­ Figure 2.-Juvenile red sea urchins shelter under the spine canopies of conspecific adults and share in the food caught by the larger animal. As the tually become too large for the spine recruits grow, they move toward the periphery of the spine canopy. (From canopy association and must move Tegner and Dayton, 1977; copyright 1977 by AAAS. away from adults. This size category (~ 25-30 mm) of red sea urchins is highly vulnerable to predation (Tegner and Levin, 1983) and Tegner and Barry2 have shown that survival of availability due to loss of algal stan­ 1976a). second year (~ 36-60 mm) animals ding stocks from such disturbances as Red sea urchins are highly selective limits the size of fishable stocks on the storms or El Niiios, urchins will leave in their choice of algal food and exhi­ southeastern Channel Islands. Red sea their protective habitats and forage on bit distinct species preferences. In urchins appear to attain a partial refuge attached plants. Moving sea urchins southern California, Leighton (1966) in size at about 90 mm from spiny may denude large areas of kelps and, found that Macrocys/is was signifi­ lobsters and sheephead, their major in extreme cases, grazing may elimin­ cantly preferred over other algae. predators in southern California ate and prevent the recovery of all Species of intermediate preference in­ (Tegner and Levin, 1983). However, algae except coralline algae. Sea cluded Gigartina armata (spinosa), red sea urchins of all sizes are suscept­ urchins in barren grounds may persist, Laminaria farlowii, Eisenia arborea, ible to predation by sea otters, but gonad development is poor, and Pterygophora californica, and Egre­ Enhydra lutris, the major predator in with time, the population may come to gia laevigata; least preferred was central California. consist mainly of small individuals. In Cystoseira osmundacea. In the San Finally, fishable stocks may be lim­ addition to their reproductive function, Juan Islands of Washington, Vadas ited by the amount of food available to sea urchin gonads function as the main (1977) found Nereocystis luetkeana to support growth and/or reproduction. nutrient storage organ (Giese, 1966); be most preferred, followed by The relationships between food availa­ as a result, starved sea urchins will Cos/aria costata and Laminaria sac­ bility, sea urchin behavior and physio­ resorb their gonads to stay alive (HoI­ charina; two species of Agarum were logy, and kelp forest community struc­ land et aI., 1967). Starved sea urchins actively avoided. Laboratory and field ture have been well studied in recent will not grow and they may even studies have shown that sea urchins years (Lees, 1970; Pearse et aI., 1970; shrink in size (Ebert, 1967). Thus, the eating their most preferred foods grow Mattison et al., 1977; Dean et al., relative size of the gonad, or gonad more rapidly, and have higher food 1984; Ebeling et aI., 1985; Harrold index (ratio of gonad to total body vol­ and energy absorption, growth effi­ and Reed, 1985). In a healthy kelp ume or weight), is a commonly used ciency, and reproductive potential than forest, red sea urchins feed on the estimate of urchin nutritional status animals feeding on less preferred abundant algal drift produced by Mac­ (Pearse et aI., 1970) which reflects foods. On the other hand, growth rates rocystis pyriferia and other laminar­ both the quantity and quality of food and gonad index of animals switched ians. When food is plentiful, the ani­ available (Lees, 1970; Vadas, 1977; to a diet of their least preferred food mals remain in cryptic habitats and Larsen et aI., 1980; Harrold and Reed, drop significantly, apparently because move little. When drift algae become 1985). Gonad color, a factor in the so little algae is eaten. While sea limiting, whether from an increase in salability of roe, is also dependent urchin feeding in nature is a compro­ grazing pressure, or a decrease in drift upon the type of food eaten (Mottet, mise between preference and availabil­

51(2), 1989 3 ity, preferential feeding appears to be a ment" section on p. 12) protection strategy designed to maximize growth 2<)0 depends upon the number and density and reproduction (Vadas, 1977; Lar­ S. franciscanus of sea urchins that have been left son et aI., 1980). 180 behind by the fishery. Significant

'60 .... densities are critical because fertiliza­ Enhancement of Fishable Stocks .. tion efficiency declines rapidly over Limited by Larval Supply § 140 '. distances as small as 20 cm between 1: .", en 120 spawners (Pennington, 1985), but Brood Stock Protection '0; , ". ;: ... where the numbers are adequate, this Brood stock protection is one of the "'C 100 :-­ may be a simple and effective ap­ c: , . '"o oldest fishery management approaches o 80 proach. to maintaining adequate larval supply. ; .. Because the actual period of spawn­ ' 60 .. In the early days of the red sea urchin -.- . ing is highly variable in both time and ....' harvest in California, fishermen focus­ 40 ... -.-'.. space, this may be impractical to legis­ sed on relatively few areas, typically ~ late but could potentially be controlled 20 ...... those close to ports and international at the level of the processor. This ap­ airports. Unfished areas continued to proach works in Japan because of the 70 90 110 130 150 produce larvae. With the expansion of high degree of local control over fish­ Test diameter (mm) the fishery in the last few years, Cali­ eries (Mottet, 1976a). The State of fornia can no longer count on unfished Figure 3.-Gonad weights of 138 Washington has also adopted a simple stocks to repopulate harvested areas. Strongylocentrotus franciscanus system of rotating fishing closures; sea While red sea urchins become sexually collected from one location in the urchin grounds are divided into three Point Lorna kelp forest in December mature between 40 and 50 mm (Ber­ 1975. (From Tegner and Levin, zones, one of which is closed each nard and Miller, 1973; Kato and 1983). year to foster repopulation (Kato and Schroeter, 1985; Tegner and Barry2), Schroeter, 1985). The Japanese ap­ small animals contribute few gametes proach of closing sea urchin recruit­ for the next generation. A plot of ment habitats permanently would not gonad weight as a function of test di­ work with S. franciscanus because of ameter (Fig. 3) shows that the increase allowing luxuriant algal growth and the spine canopy association; juveniles in gonad production is exponential presumably minimizing competition of are abundant in the same habitat as with size; the largest animals contrib­ juveniles with the adults for food while adults (Tegner and Dayton, 1977). ute a disproportionately large share of maximizing growth rates. These ani­ gametes to the population. Thus, mals are taken at the beginning of the Wild Seed Collection animals smaller than the legal mini­ next 3-year cycle. Mottet (1976a) re­ When natural recruitment rates ap­ mum size of 76 mm are not capable of ports that the resulting high density of peared to be the major factor limiting maintaining larval production at pre­ legal-sized sea urchins greatly in­ sea urchin population size, the Japan­ vious rates. creases the efficiency of harvesting. ese began experimenting with a variety To ensure brood stock protection of Implications for red sea urchins: of collectors on which larvae would their sea urchin populations, the Assuming that the existing minimum settle directly, thus presumably bypas­ Japanese have taken a threefold ap­ size limit will not provide adequate sing sources of mortality associated proach (Mottet, 1976a). There are larval production, what measures are with settlement in their natural habitat. minimum size regulations to allow re­ potentially available under the cate­ Some of the earliest collectors were production and to ensure adequate gory of brood stock protection? The apparently slate surfaces covered with product size. The actual spawning State of Washington has both a tufts of nylon thread (300 denier thread season is closed to fishing, ensuring minimum and a maximum size limit at a density of 30 threads/cm2) (Mot­ that reproduction will take place and (Sloan, 1986), and Kato and Schroeter tet, 1981). Eight months after being that sea urchins will not be harvested (1985) have suggested that this may placed in the sea, these collectors aver­ when the roe quality is poor. Finally, also be useful in California. Further­ aged 1,200 sea urchins of about 2 mm many sma]) sites are designated as "no more, the roe of the largest sea urchins test diameter per m2. Long (80 mm) fishing" areas, an action which also (> 125 mm) has been reported to be of tufts were found to be less susceptible protects recruits. Some sites, known as generally inferior quality3. The use­ to overgrowth by fouling organisms good recruitment areas from which fulness of a maximum size limit to than short (10 mm) tufts. young sea urchins migrate into fishing provide some degree of brood stock Biologists in Hokkaido, one of the areas as adults, are permanently and nursery (see the "Habitat Improve­ three major sea urchin producing areas closed. Other sites are fished in 3-year in Japan (Takagi, 1986), conducted cycles. Harvestable sea urchins are 3R. M. Harbo. Personal commun. cited in Sloan extensive studies on the collection of fished out in the first year of the cycle, (1986). wild seed of S. intermedius, their in-

4 Marine Fisheries Review termediate culture, and release back into the natural habitat (Department of Mariculture, Hokkaido Central Fish­ eries Experimental Station, 1984; Kawamura, 1987). Previous efforts in sea urchin propagation in Hokkaido had included policies for resource con­ trol, transplantation, and creation of fishing grounds, but it was felt that further increase required large num­ bers of seed. After observing that sea 30 em urchins settled abundantly on scallop culturing facilities, a decade-long re­ search project was initiated to pursue collection of wild seed. Extensive studies related the spawning period to the fall drop in water temperature, de­ termined the distribution of larvae of 1 various stages in time and space, in­ vestigated the direction and velocity of currents, and assessed annual variabil­ ity in larval availability. They found J that settlement was from December to January, and that by June, the density I.... 30 em ., of young-of-the-year sea urchins in na­ tural habitats on the coast was consis­ tently below 151m2 but usually greater Figure 4.-Diagrarn of a collector used in Hokkaido for settlement of sea than 100/m2 on a collecting apparatus. urchin larvae from the plankton. The corrugated (wave) plates are con­ structed of transparent vinyl chloride. Dimensions are in centimeters. Furthermore, there was a sharp de­ Dep. Maricult., Hokkaido Central Fish. Exper. Sta., 1984) crease in abundance (average mortal­ ity, 65 percent; range, 43-96 percent; n = 5 years) in the natural habitat from spring to fall which is attributed to predation by crabs and seastars and, when temperatures exceed 22°-23°C, 1.. 1. :, to thermal stress. 2.4m 2.8m / () A large variety of materials and de­ r () D 1m 7~ ..­ signs for collectors were field tested 1m I'sUSPE~SI using different suspension systems and ----­END ON LINE / LINE periods of installation in several loca­ tions. The most successful collector ANCHOR E was constructed from transparent vinyl LINE chloride plates with a corrugated sur­ "-... E face called wave plates (Fig. 4). The C\J C\J transparent plates allowed algae to I I COLLEC­ 0 grow on both sides, increasing the sur­ C\J ""TOR face available for settlement. Three square plates, 30 cm on a side, were suspended vertically in a layered con­ figuration with the corrugations run­ ning horizontally. Arrays of this ar­ b \ ~------..,I '\ .\"r rangement (Fig. 5) led to the ad­ ANCHOR CHAIN I SANDBAG 4 SANDBAGS herence of an annual average of 197 (50 kg) (5m) (60 kg) (240 kg) sea urchins per collector (range 42­ 836; n = 9 years) in January-February at one location in western Hokkaido. Figure 5.-Diagram of a fixed suspension sea urchin seed collecting facility. The numbers adhering were strongly (Dep. Maricult., Hokkaido Central Fish. Exper. Sta., 1984).

51(2), 1989 5 affected by depth of the installation; Table 1.-A comparison of onshore vs. offshore Intermediate culture of sea urchin seed (Department of Maricul­ 20-30 m bottom depths with the plates ture, Hokkaido central Fisheries Experimental Station, 1984). suspended at intermediate levels ap­ Item Onshore Offshore peared to be optimal. The plates were Preservation of facilities Easy Susceptible to wave damage most successful when installed 3 Management of culture Can be done intensively with a small Intensive management is difficult months before the settling season staff began. Capital costs High Low By April-May of all years studied, the number of adhering sea urchins Maintenance costs High Often low had decreased from earlier in the year; Stability of the culture environment Apt to become unstable, but artificial High stability, but artificial control is wave-induced oscillation of the collec­ (e.g., water temperature and quality) control is possible difficult tors caused animals to drop off once Seed health If control is deficient, apt to become Healthy in many cases they get to about 3 mm. The high pre­ weak dation rates on small animals during their first spring and summer in the natural habitat, combined with the drop-off problem from culture plates, necessitated going to intermediate cul­ of release into the benthic habitat. If urchins ~ 13 mm. Finally, the toler­ ture to ensure good survival rates. the seed are allowed to fall naturally ance to air exposure was determined to Intermediate culture may be carried from the collectors, or kept in interme­ be temperature dependent, and brief out in baskets in the sea or in tanks on diate culture until a size of about 5 mm (30-60 minute) exposures to low salin­ land. Net baskets (80 x 80 x 40 cm), (June), survival rate is less than 10 ity seawater impaired the vitality of the constructed of 1 or 2.8 mm mesh, percent by fall. As with the wild seed, seed as measured by the time required were designed to hold 20 seed collec­ this summer decrease is attributed to for animals to tum over. tors. In late March, before the drop-off predation. Survival was variable but Implications for red sea urchins: problem becomes serious but after the much higher for seed kept in inter­ The experience of the Marine Biomass sea urchins are large enough to be re­ mediate culture until fall. Averaging Project (North et a!., 1981) suggests tained by the mesh, the collectors are the results from three experiments that California sea urchins will readily inserted into the baskets. By the time where the seed were released at 15-20 settle on artificial substates. W. North4 the seed get to 5 mm, the food adher­ mm test diameter, the survival rate reports that thousands of red and pur­ ing to the wave plates is gone, so the was 60 percent 1 month after release, ple sea urchins settled on a large (32 m collectors are removed and algae is and in the three experiments, 24-75 diameter) structure designed to test the added to the baskets. With 5-6 months percent at I year. Thus, this study feasibility of growing Macrocystis in of feeding, it is possible to culture sea established the technical basis for na­ the open ocean. The "Test Farm" was urchins to release size of about 15 mm tural seed collection, intermediate cul­ deployed about 6 km off Corona del by October. A single basket can ac­ ture, and release of S. intermedius. In Mar, Calif., in about 550 m of water in commodate 2,000 sea urchins for the years 1980-82, a total of 4,068, September 1978. The arms supporting intermediate culture in the ocean and 700 seed were collected and processed the kelp plants were at about 20 m still allow good growth with survival through intermediate culture, but the depth but other structures of the farm rates up to 80-90 percent. In onshore impact on fishery landings 2-2.5 years extended to the surface. North reports culturing facilities, slightly smaller after release was not reported (Depart­ that sea urchins settled, probably very baskets were suspended in seawater­ ment of Mariculture, Hokkaido Cen­ soon after installation, all over the filled tanks with the incoming water tral Fisheries Experimental Station, structure. Some were on I-beams sprinkled on top. This arrangement 1984). which offered a ledge for support; and a 3 mm mesh allowed adequate Subsequent studies (Miyamoto et many others settled on smooth, cylin­ circulation to maintain water quality. a!., 1985) considered the characteris­ drical structures. By August 1979, the The comparative advantages and dis­ tics of juvenile sea urchins obtained sea urchins had grown enough to des­ advantages of offshore and onshore from collectors to minimize mortality troy juvenile Macrocystis colonizing culture are detailed in Table 1. In some during handling and after return to the the central buoy. There were more areas where algal food is not easily natural environment. Small (3.2 ± 0.5 purple than red sea urchins, but North available during the summer, experi­ mm) but not larger (>7 mm) animals estimates that the abundance of S. ments have shown that juvenile sea grew on microflora. Experiments with franciscanus was probably adequate to urchins grow very well on leaves of a predators showed that the smaller the warrant collections for stock enhance- terrestrial plant called knotweed, Poly­ sea urchin, the higher the predation gonum sachaliense. rate. Sea urchins> 10 mm were not 'w. North, Kerckhoff Marine Laboratory, 101 The survival rate of seed settled on consumed by the local seastar, and few Dahlia Street, Corona del Mar, CA 92625. Per­ collectors varies with the size and time of the tested crabs consumed sea sonal commun., 1989.

6 Marine Fisheries Review ment. It may be possible to minimize for several months to a year. Fur­ mm carapace length) Homarus gam­ the proportion of purple sea urchins thermore, as seeding in theory reduces marus (Wickins et aI., 1986). Tag re­ settling by manipulating the depth of the fishing pressure on wild stocks, it tention was 85-100 percent as the the collectors. may allow managers to avoid more animals passed through up to 29 molts painful restrictions on broodstock (90-102 mm carapace length) in cap­ Larval Releases harvest. tivity. Field releases of tagged individ­ While the seeding of hatchery­ uals were conducted in 1983 and 1984; Experience with Other Benthic reared abalones is practiced on a large tag returns from the fishery are ex­ Marine Invertebrates scale in Japan (Kafuku and Ikenoue, pected 5 years later (Walker, 1986). 1983), experiments in California do The earliest efforts to enhance fish­ Scuba divers captured five individuals not support this as a cost-effective ap­ able stocks of benthic marine inverte­ 1 year after release, suggesting that proach to stock enhancement (Tegner brates by the production and release of juveniles remain in the area and can and Butler, 1985, 1989). Problems in­ cultured juveniles apparently involved survive in the wild. French scientists clude the high cost of seed cultured for homarid lobsters. Van Olst et al. in Brittany are releasing hybrid Ameri­ about a year, high predation rates after (1980) report that between 1885 and can-European juvenile lobsters (which seeding, and low recovery rates of live 1920, more than 22 lobster hatcheries are easily distinguished from natives) animals. Furthermore, hatchery-reared were established in New England, the in another attempt to determine seed behave differently than wild aba­ Maritime Provinces of Canada, and whether hatchery-reared animals con­ lones of the same size, apparently in­ Europe. The method involved strip­ tribute to fishable stocks (Munro, creasing their susceptibility to preda­ ping eggs from gravid females and 1982). tion (Schiel and Welden, 1987; Tegner rearing the larval stages under presum­ Seeding of hatchery-reared juvenile and Butler, 1989). In an effort to de­ ably optimal conditions, i.e. the ab­ abalones to enhance fishable stocks, velop a more natural and less costly sence of predation, appropriate food practiced on a large scale in Japan, has seeding technique, experiments tested the temperature, and disease treat­ been reviewed by Grant (1981), the release of late stage, competent­ ment. However, it was eventually de­ Kafuku and Ikenoue (1983), and Uki to-settle larvae (Tong et aI., 1987; termined that the eggs were main­ (1984). After the loss of many abalone Tegner et al. ,5). Theoretically, this ap­ tained and hatched more efficiently by beds to overfishing, industrial and proach is appealing because of the the females than in culture. Further­ domestic pollution, or the loss of algal very low production and release costs, more, because of the problems of food, there was much incentive to en­ and inappropriate behavior patterns tagging lobsters, it was difficult to as­ hance stocks of this valuable gastro­ should not be an issue. Larvae were sess the results of the restocking pro­ pod. Abalone aquaculture has been released by waders into the shallow grams, and the effort was reduced con­ studied since the early 1960's and subtidal (Tong et aI., 1987) or into siderably. By 1980, there were only techniques for mass culture have been kelp forests with appropriate rocky two hatcheries seeking to augment na­ worked out. Advances in conditioning habitats by divers (Tegner et aI.,5). tural stocks by the release of hatch­ adults, spawning induction, control­ Both studies demonstrated enhance­ ery-reared animals (Van Olst et aI., ling fertilization and larval settlement, ment of existing populations at time 1980). and suitable food for the postlarvae periods ranging from 3 to 12 months Nevertheless, lobsters remain an ad­ have made culture very successful. By after larval release, but the results vantageous animal for culture (high 1979, 42 culture centers using stan­ should be considered preliminary until value; tolerance to temperature, salin­ dardized techniques produced a total better success rates can be achieved. ity, and water quality changes; large of 11,658,000 seed, almost all for re­ size of the larvae; acceptance of inex­ lease into the sea. However, despite Seeding Hatchery-Reared Juveniles pensive, dead foods), and recent field this large-scale seeding effort, Kafuku Seeding is an attractive approach to studies suggest that survival after re­ and Ikenoue (1983) report that "the stock enhancement for several lease is strongly related to habitat number released is too low to deter­ reasons. In contrast with nature, 100 suitability. Howard (1982) proposed mine whether there is any effect on percent fertilization can be achieved that rearing animals beyond meta­ (the total national) catches." These and heavy larval losses to predation, morphosis followed by placement on authors document a slow decline in the starvation, and transport to inappropri­ substrata (whether natural rock beds or national harvest from 1970 to 1979. ate habitats are avoided. Mortality of augmented with artificial structures) Published survival rates from aba­ highly vulnerable, newly settled indi­ with an appropriate number and size of lone seeding experiments in Japan, viduals is also presumably greatly re­ interstices would repay the expense of reviewed by Saito (1984), range from duces by holding seed in the laboratory longer time in culture. A new set of less than 1 to 80 percent. As many studies is currently underway in Great studies found decreasing mortality Britain. The internally placed micro­ with increasing seed size, fishing co­ 5M.J. Tegner, E.E. Ebert, and D.O. Parker, A-OOI, Scripps Institution of Oceanography, La tags developed for salmonids were operatives generally rear the 20-30 Jolla, CA 92093. Unpubl. data. adapted for use with juvenile (9-15 mm seed received from the hatcheries

51(2), 1989 7 in intermediate culture for an addi­ differences may be responsible for the The queen conch, Strombus gigas, tional year (to a size of 40-60 mm) poor survival of outplants; signifi­ has been harvested since prehistoric before release onto the fishing cantly more cultured than native ani­ times in the Caribbean and remains the grounds (Uki, 1984). Various habitat mals were consumed when predators area's second most valuable fishery improvement structures, such as bas­ were added to the laboratory studies (Berg and Olsen, 1989; Hahn, 1989a). kets or cement bins filled with (Schiel and Welden, 1987; Tegner and However, the fishery is in serious boulders or concrete blocks engraved Butler, 1989). danger of overharvest and has been with slits, are believed to enhance Ebert and Ebert (1988) recently de­ placed in the IUCN Invertebrate Red survivorship (see "Habitat Improve­ signed an abalone seeding module Data Book as a "commercially ment" section, p. 12) and allow for which acts as a temporary shelter, al­ threatened" species. The seeding of planting at a smaller size. In Hok­ lowing for acclimation to the natural hatchery-reared juveniles was pro­ kaido, both wild-collected and hatch­ environment before the seed are re­ posed in 1976 as a means to rehabili­ ery-reared seed are used for enhance­ leased. This approach also has the ad­ tate depleted stocks, and the appropri­ ment. Saito (1984) reports recapture vantage of greatly reducing the effort ate technology has been developing rates of 5-10 percent for hatchery required to plant seed, although the ever since. While culture of larvae seed and 20-25 percent for natural results of a predator encounter of such (from wild-collected egg cases) and seed. Research continues into rearing a dense concentration of prey could juvenile growout are feasible, mortal­ methods, including hybidization and negate this. The long term effects on ity after seeding is very high, some­ artificial diets for faster seed growth, seed survival are not known. times 100 percent. After a series of and techniques for intermediate cul­ Seeding studies have also been con­ experiments, Appeldoorn and Ballan­ ture and release (Saito, 1984; Uki, ducted with a variety of bivalves, nota­ tine (1983) estimated that only 0.1 per­ 1984). bly clams and oysters. Commercial­ cent of seeded 6-month-old juveniles The enthusiasm for seeding in Japan scale culture techniques have been (- 60 mm) would survive to enter the and a steep decline in abalone landings developed for important species, but fishery at an age of 2.5 years. Suscept­ led to a series of seeding studies by economics dictate that juveniles must ibility to predation apparently de­ biologists from the University of Cali­ be outplanted for growth to market creases with increasing seed size (Iver­ fornia and the California Department size, and adequate survival is a major son et aI., 1986), but seeding with of Fish and Game (reviewed by Tegner problem (McHugh, 1981; Castagna, large animals is not economically and Butler, 1989). Large-scale experi­ 1983). High mortality has been repeat­ feasible. Appeldoorn and Ballantine ments were conducted with two edly observed within a very short time (1983) conclude that seeding of unpro­ species (Haliotis rufescens and H. for seed clams planted without protec­ tected small conchs does not appear to fulgens) on both island and mainland tion from predators, e.g., Craig et a1. be a practical way to support a fishery sites. In each case, the estimated 1- or (1988) report 100 percent mortality and urge strong fishery management 2-year survival rate was 2.8 percent or within 6 months of Mercenaria mer­ measures to restore the stocks. Once less, unacceptably low for species that cenaria planted in unprotected trays, strong management measures are in require 10-15 years to enter the com­ whereas survival was high in trays pro­ place, it may be possible to use seed­ mercial fishery. Seed sizes ranged tected with gravel and a mesh cover­ ing to build up brood stocks in de­ from 10 to 80 mm but there was no ing. Techniques to increase clam seed pleted areas. evidence that survivorship increased survival include larger seed size, smal­ The top shell, Trochus niloticus, is with seed size. Estimations of survival ler mesh size, baffles to minimize the most economically important gas­ rates were based on censuses of plant­ wave disturbance, predator fences, tropod in the tropical Pacific (Nash, ing sites and their immediate surround­ crab traps, and poisoned bait for pred­ 1988; Hahn, 1989b). The meat is eaten ings; they do not take into account ators; combinations of various protec­ and the shell is exported for the pro­ possible larger scale migrations tive devices are more effective than duction of mother-of-pearl buttons. because of the problems of sampling any device alone (Kraeuter and Cas­ Sedentary in habit and found in easily rare, cryptic abalones. Shell recoveries tagna, 1985a, b). Similar results have accessible locations, top shell has been suggested that mortality related to the been reported for giant clams in the overfished virtually everywhere there stresses of the seeding process was not tropics: Small (10-20 mm) seed placed is a commercial fishery. Trochus nilo­ the major cause of the poor survival; in in unprotected trays on reefs rapidly ticus is an excellent species for culture one closely monitored experiment, suffer 100 percent mortality from because of its year-round spawning half of the shells recovered exhibited predation, but survival rates were which is spontaneous on a lunar cycle, growth up to 40 mm before death reasonable in sea floor cages (Munro, lecithotropic eggs, the short (3-4 day) (Tegner and Butler, 1985). Laboratory 1989). Finally, scallops and oysters pelagic period of the larvae, and feed­ studies found differences in behavior have been successfully grown in trays, ing by juveniles and adults on the and habitat selection between hatch­ rafts, or nets in the water column, or in algae which grow naturally in outdoor ery-reared abalones and natives of the protected plots on the bottom tanks. same size classes. These behavioral (Castagna, 1983). The only reported top shell seeding

8 Marine Fisheries Review Ulvella lens wave plate culture

Preparations for the culture of planktonic food

Culture of food

Collection of brood stock

Induction of spawning

Fertilization

Removal of unwantcd diatoms Egg washing

Hatching Larval feeding

Planktonic larval culture Water quality maintenance

Settlement

Controlling benthic diatoms Counting attached urchins

Changing wavc platcs Early-stage seed culture

Juvcnile fceding: knotwccd. Adding nutrient salts Sorting young kclp. Viva

Late stage seed culture Clcaning tanks

Sorting Offshore culturc

Release

Figure 6.-Steps in the laboratory culture of Strongylocentrotus intermedius seed as practiced by the Hokkaido Institute of Mariculture (Saito et a!., 1985; Saito, 1987).

experiment was conducted in Palau. In tality, microhabitat use, and move­ Sea Urchin Seeding in Japan this test, almost total mortality was ment of juvenile top shell should be observed within a couple of days of carried out before large-scale seeding Artificial culture of sea urchins outplanting; only crushed shell rem­ experiments are conducted. Similarly, began in Yamaguchi Prefecture in 6 nants were found . Hahn (l989b) Nash (1988) suggests that stock enhan­ 1968, and Japan produced a total of stresses that studies of sources of mor- cement through seeding of hatchery­ about 3.5 million cultured seed in reared Trochus may only be successful 1984. Techniques used to rear S. inter­ 6G. Heslinga. Personal commun. cited in Nash if areas of low juvenile mortality are medius at the Hokkaido Institute of (t988). identified. Mariculture (Fig. 6) have been de­

51(2), 1989 9 Figure 7.-Hokkaido Institute of Maricul­ ture abalone hatchery in Shikabe to be con­ verted into a sea urchin hatchery. A and B, tanks contain­ ing racks of wave plates; C and D, closeups of wave plates covered with juvenile sea urchins. Photographs taken by Christopher Toole, 1987.

tailed (Saito et aI., 1985; Saito, 1987). and the fertilization rate assessed. The vival to metamorphosis. Seed up to a Many of the techniques appear to have tanks are then left undisturbed until the test diameter of 3-4 mm consume been adapted from abalone culture; in larvae hatch at about 20 hours after benthic diatoms on the wave plates. fact, the Institute is converting an aba­ fertilization. Larvae are transferred to Once that size is attained, soft seaweed lone hatchery at Shikabe, Hokkaido, 600 L larval culture tanks at 3 days and fronds (e.g., VIva) are placed on top 7 7 to a sea urchin hatchery . Toole feeding is begun. The suitable temper­ of the wave plates for food (Saito et visited this laboratory in the spring of ature range is 15°-21°C. For larvae aI., 1985; Saito, 1987). 1987 and reports that the sea urchin cultured at 18°C and fed a diet of When the cultured seed reach a size hatchery is slated to produce 5 million Chaetoceros gracilis, metamorphosis of about 5 mm, they are placed into 5 mm seed a year. and settlement begin on the 16th day small mesh cages for intermediate cul­ Briefly, procedures followed in after transfer to the larval tanks. Wave ture in tanks on land or suspended in Hokkaido (Fig. 6; Saito et aI., 1985; plates which have been coverd with a the sea, as is done with seed settled on Saito, 1987) allow females to spawn culture of Vlvella lens, a species of collectors. Kelp or knotweed is pro­ naturally, releasing eggs into a round disk-shaped Chlorophyta, are installed vided as food. It is desirable to adjust 10 L tank. Sperm collected from sev­ in 5 m tanks to act as settlement sub­ sea urchin density and cage mesh size eral males is mixed and used for fertil­ strates, and the water and swimming as the seed grow. Release size is 15 ization. The zygotes are washed at larvae are transferred (Fig. 7). Settle­ mm or larger. With fertilization in least five times at 30-minute intervals ment of 70-80 percent of the larvae September-October and intermediate occurs within 3-4 hours, and the water culture offshore, sea urchins reach re­ 7c. Toole, Sea Grant Marine Advisory Pro­ gram, Eureka, CA 95501. Personal commun., can be exchanged within 24 hours. lease size the following autumn. In 1988. Toole7 reports about 60 percent sur- shore-based facilities where the water

10 Marine Fisheries Review is heated during the winter, the seed 1,040,000 Yen = 40,000 urchins x modifications, the same procedures are large enough to be released in 5 25 Yen + 20,000 Yen + 20,000 Yen work with S. franciscanus (Hinegard­ months (Saito et aI., 1985; Saito, ner and Rocha Tuzzi, 1981). Thus, 1987). Fishermen broadcast the seed Profit was calculated as income minus culture on a small scale is both feasible over the fishing ground from the sur­ expenditures divided by the number of and practiced. It may be possible to 7 face . fishing seasons: further reduce the larval period by cul­ ami (1987) reported the results of ture at higher temperature. The key to seeding experiments using cultured S. 378,560 Yen = (1,797,120 Yen production on the scale necessary for intermedius in Hokkaido. In each of - 1,040,000 Yen) -'- 2 seeding, however, will be the success­ two tests, 40,000 seed were released ful adaptation of mass culture tech­ into areas measuring 20 X 50 m in This estimate suggests a 36 percent niques such as those used for abalones water depths of 3 m. Seed were spread return on investment. If the sea urchins and sea urchins in Japan (McCormick uniformly over release sites by divers are allowed to grow for another year and Hahn, 1983; Saito et aI., 1985). and from boats. Survival rates were (assuming no further decline in num­ McCormick and Hahn (1983) stud­ assessed by divers with m2 sampling bers between years 2 and 3), the aver­ ied abalone aquaculture at prefectural frames. Released sea urchins were age gonad weight per sea urchin rises fish farming centers in Japan and esti­ generally distinguished from natives to 12 g, and the profit rises to 574,933 mated what it would cost to establish a by test diameter. The survival rate Yen for the same expenditures. ami Japanese-style abalone hatchery in after 622 days for the 1983 release (1987) does not appear to have ac­ California capable of producing 20 group was 38.7 percent, and 92 per­ counted for the capital investment in million juvenile (20 mm) abalones an­ cent of these had achieved the min­ the hatchery in these calculations. nually. Conversion of a Hokkaido imum legal size of 40 mm. For the Studies of Pseudocentrotus depres­ hatchery from abalones to sea urchins 1984 group, the survival rate after 597 sus in Yamaguchi Prefecture indicate clearly indicates that the two groups days was 22.6 percent, and 91 percent that sea urchin seed survival is better require similar facilities and treatment; were of fishable size. Other studies on gravel beds (65-76 percent) than on the major differences are that sea showed variation in survival rates be­ rocky substrates (38 percent), even urchin larvae are planktonic for a tween 10 and 40 percent, as well as in though food is much more (3-6 times) longer period of time and require feed­ growth rates, in different areas. The available on the rocky substrate ing. Thus, cost estimates for setting up seed spawning season was the same as (Takagi, 1986). Hybrids of P. depres­ an abalone hatchery are an appropriate that of the parent stock, which varies sus with Hemicentrotus pulcherrimus base for sea urchins; phytoplankton among different areas of Hokkaido, developed larger gonads with better culturing capabilities and extra tanks regardless of where they were planted. color than H. pulcherrimus, the fa­ for larval rearing would be additional. Agatsuma and Momma (1988) com­ vored species. McCormick and Hahn (1983) esti­ pared the growth of cultured and na­ mated capital costs for land (1 hectare, Culture of Strongylocentrotus tive seed. They found that the intro­ central California coast), buildings, franciscanus in California duced seed grew faster than the native tanks, culture plates, plate racks, seed during the first 14 months, but The importance of sea urchins as filters, two vehicles, emergency gen­ that the cultured seed growth rate de­ experimental animals for cell biology erator, water pumps, plumbing, air creased thereafter and was lower than has led to extensive studies of their pumps, water heater, UV sterilizer, that of the native stock after 3 years. larval development and culture. Hine­ brood stock, and cleaning equipment ami (1987) estimated the economic gardner (1969) developed the basic at $576,200. Operational costs includ­ benefits of sea urchin seeding in a methodology for culture of west coast ing wages, utilities, vehicle upkeep, 10,000 m2 area at a site which sup­ species on a laboratory scale, and var­ feed, telephone, filter upkeep, and ported excellent growth and survival ious refinements have been published generator upkeep were estimated to be rates. Income was calculated as the (Hinegardner, 1975; Hinegardner and $205,100 a year. Summing these two number of seed surviving (40 percent) Rocha Tuzzi, 1981; Leahy, 1986). with startup salaries and debt service, times the catch rate times the gonad Leahy et al. (1978, 1981) described a the funding required to produce the weight times the unit price: laboratory system for long-term main­ first 1 million abalones would be tenance of gravid sea urchins and dis­ $1,155,857 (McCormick and Hahn, 1,797,120 Yen = 16,000 seed x covered that ripe animals could be 1983). This estimate does not include 0.9 x 7.8 g/urchin x 16 Yen/g. found in the wild throughout the year additional expenses such as financial by collecting from deep-water popula­ and legal services, operating permits, Expenditures were calculated as the tions with good food supplies. Because taxes, depreciation, or replacement cost of the seed (produced by the Hok­ of their importance to cell biologists, costs. Given the huge increases in the kaido Institute of Mariculture) plus much of the focus has been on S. pur­ price of coastal land, inflationary in­ labor costs for the release operations puratus and the white sea urchin, creases on goods and salaries since plus transport costs of the seed: Lytechinus pictus, but with minor 1983, and the extra costs involved

51(2), 1989 11 with culturing sea urchins, the costs of breakwater blocks, designed to dis­ establishing a sea urchin hatchery of sipate wave action, are good for trap­ similar size in 1989 may be several ping drift or containing rock piles. If hundred thousand dollars more. high water movement leads to prob­ lems with kelp abrasion on the rock Enhancement of Fishable Stocks piles or substrate blocks, elevated Limited by Survival of Newly Settled frames may be installed as supports for to Intermediate-sized Animals stiff, plastic mesh pipe seeded with algae. The fastest way to increase kelp Habitat Improvement biomass is longline culture of Lami­ Mottet (1976a, b, 1981) has re­ naria. Typically such lines are 45-50 viewed the extensive efforts of the m long and buoyed above the bottom; Japanese to enhance sea urchin stocks usually a number of lines are em­ through habitat improvements. The ployed and spaced 3-8 m apart. A 50 use of rocks to improve the substrate m longline can produce nearly 1.5 t of for sea urchins dates to 1912 in Fukui Figure 8.-Futon cages, or mesh harvestable kelp in one season, while Prefecture and has spread through bags of rocks of 20-50 cm diameter, providing drift food for grazers and are used to create sea urchin habitat seeding nearby reefs. Many large­ much of the country. In areas of flat in areas of soft sediments. As these substrate, the addition of rocks may cages weigh 2.9--4.4 t, a crane and a scale development projects are de­ increase the yield of many marine sling supported by a steel frame and signed to maximize both kelp and sea species, especially kelp and sea ur­ logs are used to place the cages into urchin production, e.g., sea urchin chins, by providing algal attachment position. Dimensions are in centi­ habitats may be located in such a way meters (Mottet, 1981). sites, shelter for the sea urchins, and that drift entrapment is efficient but aid in drift entrapment. This is accom­ sand buffer zones protect benthic kelps plished either by importing rocks or from direct grazing. reef blasting. Generally rocks of 40­ Finally, one project from Iwate Pre­ 50 kg are placed in a layer 1-2 rocks high, and made of synthetic fiber net fecture suggests perhaps the ultimate deep with plenty of space between or coated mesh steel (Fig. 8). These in habitat improvement efforts (Mot­ rocks. It was estimated that it takes 50 are placed by cranes into areas where tet, 1981; Noma, 1983). In Japan, rocks weighing 40-50 kg each to in­ strong currents ensure circulation many edible seaweeds and grazers do crease the yield of gonads by 1 kg. At through the rocks. Sometimes the not grow well above the mean spring this rate, it took about 3 years for the cages are set on mats to prevent them low tide levels because of dessication operation to pay for itself (Mottet, from sinking into the sediments. As of in the summer and freezing in winter, 1976b). 1981, futon cages were the most but these same species prosper in na­ Historically, Japanese habitat im­ widely used sea urchin enhancement tural channels which cross rocky provement projects were funded by device, particularly in northern Japan benches. In this project, a total of 92 fisheries cooperatives and local gov­ where they were being placed by the channels (~ 100 m long x 4 m wide ernments (Mottet, 1981). The national thousands in many locations. Mottet x 0.6 m deep) were dug into rocky government began providing funding (1981) cites one example where intertidal platforms at 8 sites along 5 in the 1930's, and the level was greatly 10,000 futon cages were installed in a km of coastline. The channels were intensified in the mid 1970's. With the 27-hectare area in Hokkaido. Other designed in such a way that waves national government paying for 50-70 kinds of rock cages, ranging from passing into the entrances are funneled percent of the costs of selected pro­ bamboo baskets to steel or concrete up and over sills which then act as one jects, habitat improvement efforts be­ cribs, are also employed. way valves. Thus wave energy moves came much more complex and capital Mottet (1981) also described a vari­ the water shoreward until it reaches an intensive. ety of additional techniques which, excurrent drainage channel slightly Habitat improvement projects alone or in combination with other deeper than the culture channels, and spread to soft substrates (Mottet, habitat improvement methods, are de­ water circulation is ensured. The de­ 1981). In the simplest procedure, signed to enhance fishable stocks of sign achieved a water flow velocity of rocks are piled to a height of 0.4--0.6 grazers. Large concrete "substrate" 0.15 m/second with waves of 0.2 m m to provide habitat for kelp and sea blocks provide horizontal surfaces for height (Noma, 1983). Substrate blocks urchins. In areas of high water move­ the seaweed attachment and crevice were added to the culture channels to ment where the rocks would not be spaces suitable for sea urchins and maximize the surface available for stable, they may be piled in enclo­ abalones. As these are often used in kelp attachment and provide suitable sures. The most common structure is a areas with strong water motion, they habitat for grazers. Ten of these chan­ "futon" (mattress) cage measuring 4 m may weigh a ton or more but are no nels, with a combined length of 1,200 long by 1.2 m wide by 0.4--0.6 m higher than 1 m. Large, concrete m, were completed in 1975 at a cost

12 Marine Fisheries Review $326,087. The average annual harvest :; 30 UNHARVESTED (11177) CIl 80 UNHARVESTED (11fT7) of kelp, abalones, and sea urchins '0 ~ .~ 70 combined in the initial results was 2! 60 AdultN =79 20 'E 50 Recruit N = 547 worth $37,097, suggesting a pay-back 2 Adult N =79 <.> ~ 40 ~ Recruit N = 547 period of about 9 years. These obser­ o 10 .2. 30 vations suggested that the most profit­ <: ci> 20 ci> .it 10 able return would be from the com­ .it 0+-0~20'-----4~0 ~60-8~0 -1~00"-;12~0 -1~40~160 °4+-0-~-~~----~160 bined culture of kelp and sea urchins. Adult size class (mm) Laminaria seeded into the channels in 80 December had grown enough to :g 30 HARVESTED (11177) CIl HARVESTED (11177) N 70 provide a good source of sea urchin ~ 'iii 60 20 2! AdultN=37 0'5 AdultN =37 'c 50 food by May. Sea urchins were col­ <; Recruit N = 130 Recruit N = 130 ~ 40 ~ lected from areas of inadequate food .:!. 30 o 10 supply and transplanted into the chan­ <: ci> 20 ci> ...... it 10 nels; in a few months of fattening, the o .it 0+-0~20-=--4~0 ~60-8~0 -1~00--'---,12-0 -1~40~160 o 40 60 80 100 120 gonads increased from less than 7 per­ Adult size class (mm) Adult size class (mm) cent to 25 percent of the total body weight. The relative value of these two Figure 9.-Average number of re­ Figure IO.-Average juvenile red commodities and an experiment vary­ cruits per adult versus adult size sea urchin size vs. adult size class in class in spine canopy associations of spine canopy associations of ing sea urchin numbers were used to Strongylocentrotus franciscan us Strongylocentrotus franciscanus determine optimal stocking densities; populations on Santa Barbara populations on Santa Barbara an intermediate level of sea urchins Island, Nov. 1977. Island, Nov. 1977. The error bars allowed maximal gonad development represent ± one standard deviation of two crops of sea urchins each year and the boxes indicate the range of the data. with an annual profit of $5,217 per channel (Mottet, 1981). Noma (1983) compared the productivity of the rocky bench before and after the channels were built; profit in 1980 was 258 per­ lecting adults and any associated ju­ unharvested area was 12.20 mm and cent of the 4-year average before con­ veniles and placing each association in 10.98 mm in the harvested site; while struction. a separate bag. Data were collected on small, this difference was significant (t Santa Barbara Island, a site of consis­ test, P = 0.005). There was no in­ Protection of Juveniles tently good red sea urchin recruit­ crease in average size of juveniles with by the Red Sea Urchin 2 ment , in 1977 and 1978. In 1977 the increasing adult size, probably be­ Spine Canopy Association associations in an area where the cause most of the juveniles resulted Two papers (Breen et aI., 1985; size-frequency distribution indicated from a single settlement episode (Fig. Sloan et aI., 1987) have recently ex­ recent fishing were compared with a 10). In the unharvested site, 74 percent plored the biology of the S. francis­ nearby site where the abundance of of the recruits were found under canus spine canopy association in larger animals suggested that the site shelter providers 90 mm and larger British Columbia, where the minimum had not been harvested for some time, (Fig. 11). For the harvested popula­ size limit for red sea urchins is 100 if at all. At that time the fishery was tion, 29 percent of the juveniles were mm. Field data showed that the inner­ generally taking animals larger than 90 under animals 90 mm and larger, and most, under-the-test juveniles were mm. At the unharvested site, there was 62 percent were under shelter provid­ significantly smaller than more distal a significant increase in the average ers 60 mm and larger. Thus, faced but still under-the-spine-canopy number of juveniles sheltered with in­ with few large sea urchins under which young, and that juveniles not under­ creasing adult test diameter (r2 = to shelter, juveniles were associating neath adults, whether clustering 0.398, P = 0.037). There was no such with smaller shelter providers with nearby or not associated with an adult, trend at the harvested site where juven­ correspondingly smaller spine cano­ were significantly larger than juveniles iles were found under shelter providers pies and therefore less protection from under the spine canopy. This size­ as small as 30 mm, 20 mm smaller predators. In addition to there being related distribution pattern of young than in the unharvested area (Fig. 9). less space under small spine canopies, animals suggests that the smaller size Despite the sites being only about red sea urchins smaller than 90 mm limit in California has important impli­ 200 m apart, the average number of have not yet reached the size offering a cations for the survival of recruits. recruits per adult in the harvested area partial refuge from predation (Tegner To look at the role of different sized was only about half that in the unhar­ and Levin, 1983). This suggests that adults as shelter providers, individual vested area, 3.5 vs. 6.9. The average the associations based on shelter pro­ "associations" were sampled by col­ size of juveniles under adults in the viders less than 90 mm have a lower

51(2),1989 13 probability of survival regardless of canopies. If, as suggested by the re­ Q)~ .~ 'E UNHARVESTED (11/77) fishing. sults of Tegner and Dayton (1977), Ul Q) Samples from the same area of survival of recruits is depressed in '5.5 30 ~·2 _0 Santa Barbara Island collected in May fished areas, provisions should be o Q) 20 c:': AdultN =79 1978 contained adults up to 128 mm made to leave some portion of fishable .2.B Recruit N =547 '5.s 10 (data not shown). The average number animals behind to ensure future re­ :es of juveniles per shelter provider was growth of stocks. It is likely that a ZUl §~ °0000000000000000 5.0 and there was a positive relation­ maximum size limit of 125 mm is not o~ ~NMv~w~rom~~~~~~ ship between the size of the adult and appropriate in southern California; Adult size class (mm) the number of recruits sheltered (r2 = there are simply too few animals that 0.867, P = 0.0001). Again there was large left. Size-frequency data suggest HARVESTEDI'-(l'e.cI71CL)--~ no increase in the average size of ju­ that this may be a more useful ap­ 8 veniles with increasing adult size. proach in northern California , how­ Fully 84 percent of the sheltered indi­ ever. If there are too few animals 125 viduals were under adults of fishable mm or larger to provide spine canopy size. Sheephead are attracted to divers shelters, alternatives are to institute a and frequently feed on juveniles ex­ smaller maximum size limit, or to re­ posed upon removal of the adults. In a quire fishermen to leave some mini­ series of adult removal trials on San mum density of animals behind, a Clemente Island, some recruits were much more difficult regulation to en­ rapidly eaten while others managed to force. Figure ll.-Contribution in percent crawl out of sight to safety. The fate of of each adult size class to the total juvenile sea urchins exposed by fish­ Enhancement of Fishable Stocks sheltering of recruits in spine can­ ing depends in part on how much Limited by Food Availability opy associations of Strongylocentro­ tus franciscanus populations on cover, e.g., other shelter-providing Transplantation to Areas Santa Barbara Island, Nov. 1977. urchins, substrate rugosity, or foliose of Better Food Supplies The cumulative percent beginning algae, is available (Tegner and Day­ with the largest adults is indicated. ton, 1981). Mottet (1976a, b) reviewed the ef­ A number of smaller data sets col­ forts of Japanese fishing cooperatives lected in the late 1970's were ex­ to increase gonad development by urchin prices. The economic return of amined for the relationship between transplanting sea urchins from areas of this method of enhancing fishable the average number of sheltered re­ high density but poor food supply to stocks is suggested by the magnitude cruits and adult size class. Tegner and areas with rich seaweed populations. of the operation; in some localities, up Barry2 lumped samples from San Cle­ Although the animals may be out of to 20 t of sea urchins had been trans­ mente Island and from Santa Rosa and the water for 24-26 hours, there is planted by 1969 to improve gonad San Miguel Islands to consider the ef­ only a 1-2 percent mortality rate asso­ yield. Takagi (1986) reports cases fects of two different population struc­ ciated with transfer. Transplantation is where the fishery may depend exclu­ tures on juvenile sheltering. The rela­ generally done just before the sea ur­ sively on annual transplants. tionship seems most likely to be posi­ chins begin the period of rapid gonad Implications for S. franciscanus. tive when the average number of re­ growth. In Hokkaido, if food condi­ While food-limited animals can be cruits per adult is high. This degree of tions are good in the fall, sea urchins found in many areas, large red sea variability is not surprising given the can be transplanted then for harvest in urchins are subject to coelomic col­ gregarious behavior of juveniles the spring. Sea urchins transplanted in lapse if they are out of the water for (Breen et aI., 1985) and variability in the spring are ready for harvest about more than a few minutes. Once air gets recruitment rates and habitat structure. July. Transplanted animals exhibit into the coelom, survival is uncertain. However variable, the relationship gonad weights which are 4-5 times Kelc09 has found it possible to mini­ seems sufficiently compelling that those of nontransplanted controls and mize transport mortality by hanging these observations should be repeated, similar to the yields of animals origin­ sea urchins to be moved below the especially in southern California ating in the high food areas. A second surface in large mesh bags until it is where predation pressure is higher, to objective of transplanting is to move time to actually move the boat. determine the effects of a decade of sea urchins to high food areas which Reforestation of Areas intense fishing pressure. Ideally, re­ are also workable during winter per­ with Poor Food Supplies cruitment and spine canopy associa­ iods of bad weather and high sea tions should be assessed in both fished As in California, some rocky bot­ and nearby areas closed to fishing to Sp. Kalvass, Calif. Dep. Fish Game, 19160 S. evaluate the relative effects of brood Harbor Drive, Fort Bragg, CA 95437. Personal 9M. Otjens, Kelco, P.O. Box 13216, San stock reduction and loss of large spine commun., 1989. Diego, CA 92113. Personal commun., 1989.

14 Marine Fisheries Review tom areas on the northeastern coast of must be considered. First, the experi­ northern Channel Islands, a pulse that Honshu, the largest island in Japan, ment at Enoshima Island described was larger for purple than for red sea 2 are often observed to be nearly devoid above (and much of the longline urchins . Whatever the reason for this of large, foliose plants; encrusting mariculture in Japan) was conducted in reported increase, large populations of coralline algae cover the bottom 10. a relatively protected bay. Most of the S. purpuratus appear to be controlling These barren grounds, or isoyake in California coast is much more ex­ algal food supplies in some areas, Japanese, are often characterized by posed. Second, the kelp farming notably on the northern Channel unfishable (small and/or starving) pop­ industry, still in its infancy in Cali­ Islands 12, and this situation will inhibit ulations of sea urchins and abalones fornia, is primarily involved with the regeneration of red sea urchin which prevent the regeneration of kelp research and development, suggesting stocks. populations. A 5-year experiment that commercial longline production Purple sea urchins are similar in size demonstrated that it is possible to re­ may be prohibitively expensive. A pri­ to the species harvested in Japan so establish a kelp forest and productive vate company in Goleta has studied there should be no acceptance problem fishery without killing the grazers. The Macrocystis test farms (Neushul and for the export market. However, their experiment was conducted in a 3­ Harger, 1985), and is currently operat­ smaller size makes harvesting and pro­ hectare V-shaped bay on Enoshima ing longline farms for a study of cessing prohibitively expensive 13. Island which contained dense popula­ marine farm engineering that deals Less expensive harvesting methods tions of urchins (S. nudus) and aba­ with storm resistance. Neushul 11 esti­ such as dredging or air pumps or lones (H. discus hannai). To provide mated that it would cost about $600 to mechanical processing may make fish­ food for the grazers, Laminaria produce a 50-foot (15.2 m) longline ing for purple urchins financially feasi­ japonica was cultured on longlines ar­ seeded with macroalgae. This estimate ble. Alternate uses, such as for animal ranged in a grid with 2-3 m spacing does not include the cost of the line, feed or soil supplements, are also and buoyed off the bottom. This floats, shackles, anchors, or shipping. under investigation 14. proven methodology had already been In Japan, longline cultures are pro­ The Feedlot Approach worked out for the production of edi­ duced by the fishing cooperatives. ble seaweed. In 1972, longlines total­ Kelco, a San Diego-based kelp har­ The Problem of Competition ing 3,825 m produced 33.3 t of kelp, vesting firm, has been experimenting and in 1973,4,200 m produced 41.5 t. Widespread areas within southern with enclosing and feeding red sea As a result of the increased availability California are reported to have under­ urchins in barren areas of the Point of algal drift, the sea urchin gonads gone large increases in the number of Loma kelp forest as part of their kelp 9 were well developed and the annual purple sea urchins in recent years, and management activities . Their objec­ increase in abalone body weight was 4 these animals can also cause overgraz­ 'tive is to reduce grazing pressure suffi­ times that of animals in control areas ing. There are several, nonexclusive, ciently that kelp will grow in formerly without supplemental feeding. In potential explanations for this apparent productive areas. After trying several 1973, over 3.4 t of sea urchins and 3.2 increase. First, red and purple sea different net configurations, their cur­ t of abalones were harvested. The re­ urchins have similar food (Leighton, rent model consists of nylon cargo net duction in herbivore numbers and the 1966; Vadas, 1977) and habitat with 3.5 x 4.1 cm mesh. The netting release of spores by the cultured (Schroeter, 1978) preferences. is cut to dimensions of 0.3-0.6 m by Laminaria led to a large natural bloom Schroeter (1978) reported that red sea the length of the enclosure. Lead core of algae in the spring of 1974. It was urchins exclude the shorter-spined pur­ line (0.64 cm diameter) is threaded estimated that the standing crop of ple sea urchins from the most desirable through the bottom of the net to act as suitable food for the sea urchins and habitats by spine fencing. The harvest­ a weight, and 0.95 cm polypropylene abalones was more than 100 t, elimin­ ing of thousands of tons of S. francis­ line is threaded through the top of the ating the need for further longline cul­ canus may thus represent a release net to provide flotation. The leadline is ture. Kito et al. 10 believed that this from competition for S. purpuratus. anchored to the substrate using mush­ amount of seaweed was enough for a Furthermore, the large red sea urchin room-head, nylon cement anchors and gross annual production of 6.6 t of fishery has undoubtably reduced larval urchins and 3.1 t of abalones. production in this species; there has Implications for California: Kelp been no comparable reduction for pur­ J2G. Davis, Channel lsI. NatI. Park, 1901 Spin­ culture to improve fishable stocks of ple sea urchins so these animals may naker Dr., Ventura, CA 93001; R. McPeak, Kelco, P.O. Box 13216, San Diego. CA 92113; red sea urchins is certainly a possibil­ be recruiting at a higher rate. Finally, B. Steele (commercial sea urchin fisherman), ity in California, but several factors the 1982-1984 EI Nino led to a large P.O. Box 91609, Santa Barbara, CA 93190. Personal commun., 1988-89. pulse in sea urchin recruitment on the 130. Rudie, Catalina Offshore Products, 4537 JOKito, H., S. Kikuchi, and N. Uki. Seaweed as Mt. Henry PI., San Diego, CA 92117. Personal nutrition for marine life: Technology for artifi­ commun., 1989. cial marine forests. Pap. pres. at Int. Symp. "M. Neushul, Neushul Maricult. Inc., 475 Kel­ J4A. Chadwick (commercial sea urchin tender), Coastal Mar. Life, Western Wash. Univ., Oct. log Way, Goleta, CA 93117. Personal com­ Box 3033, California Valley. CA 93453. Per­ 1979, p 55-66. mun., 1988. sonal commun., 1989.

51(2),1989 15 nylon cable ties. Materials cost for this Knotweed leaves supported faster water population was equally fertile all enclosure is estimated at about $0.50 growth than kelp for sea urchins up to year round. D. Rudie l3 reports that red per linear foot (30.5 cm). Observa­ IS mm; for larger animals, the two sea urchin roe yields were higher dur­ tions suggest that the sea urchins are feeds produced similar results (Depart­ ing the 1988-89 period of colder than reluctant to cross the net which is kept ment of Mariculture, Hokkaido Cen­ normal temperatures. While more re­ in motion by surge; the few escapes tral Fisheries Experimental Station, search is needed, these observations were by animals that managed to get 1984). suggest that increasing the nitrogen under the net. Nitrogen is a critical element in the content of the food, whether by collec­ Kelco has tried several pens ranging survival and growth of all organisms ting kelp from below thermocline in circumference up to 130 m, as well due to its central role in metabolism, depths, fertilizing warm water kelps, as linear barrier fences to prevent sea cell structure, and genetic coding. or using terrestrial plants with a high urchins from entering areas where kelp Plants experience shortages of inor­ nitrogen content, would increase was recruiting. About 2,000 red sea ganic nitrogen; herbivores encounter growth and gonad development rates. urchins per pen were transplanted with shortages of organic nitrogen, often in Structure of the Japanese Fishing a very low mortality rate. The sea ur­ the presence of abundant calories Industry and Implications for chins were fed chopped Macrocystis (Mattson, 1980). Russell-Hunter Enhancement of Red Sea taken from the surface canopy about (1970) calculated that all animals Urchin Stocks in California once a week, and gonad development (except ruminants) have adult nutri­ was rapid. Two months after these bar­ tional requirements for protein Marine fishes in the United States ren ground animals were penned, 100 amounting to about 16.5 percent dry are traditionally common property re­ kg of sea urchins were harvested and weight of their diet. This corresponds sources. An individual fisherman has found to have good quality roe. Kelco to a diet with a ClN ratio below 17: I . little incentive to conserve or enhance forsees using this technique to reduce The ClN ratio of Macrocystis varies the resource because of the likelihood grazing pressure during the optimal seasonally following ambient nitrate that someone else will reap the bene­ spring season for kelp recruitment and concentration (which is inversely re­ fits of his actions. In contrast, local 9 to control sea urchin fronts . lated to temperature and negligible control of the fishing grounds was This technique appears to be low above 16°C (Jackson, 1977», and may established in Japan during the Toku­ cost and have considerable promise for vary from less than 10: 1 to greater than gawa feudal period (\603-1867) (Mot­ short-term enhancement of fishable 40:1 (Wheeler and North, 1981). tet, 1980; Sato, 1987). These rights red sea urchin stocks where sea urchin While the role of nitrogen limitation were codified, democratized, and populations are limited by food availa­ of kelp forest herbivores is poorly redistributed to assure greater control bility. While it is not yet clear how understood, there are indications that by the working fishermen during the long these nets will last, Kelco's data nitrogen strongly affects both growth 20th century. A fishery right (near­ suggest that each net could produce and reproduction. Ogino and Kato shore fisheries are managed by the several "crops" per year. Furthermore, (\964) found a strong positive correla­ fishery rights system) is the exclusive the environmental results could be tion between growth of abalones and right to conduct certain types of fish­ long term; where sea urchin densities the amount of protein in artificial ing operations in a specific area under are reduced, kelp is likely to recruit diets. Shifts of feeding preference pernlit from the prefectural governor. and end the problem of food limita­ toward more protein-rich foods have A 1948 law required fishermen to form tion. been observed; sea urchins selected cooperatives to receive priority in ob­ L. Romina 15 reports that Japanese bryozoan-encrusted kelp (Bonsdorff taining fixed net (which allows fishing brokers are encouraging Mexican sea and Yahl, 1982) or artificial food by placing fishing equipment in a de­ urchin fishernlen to establish pens for made with animal protein (McClintock signated area) and common (which feeding red sea urchins to increase et al., 1982). Evidence for the effect of allows joint use of a designated area their gonad yield, in a manner analo­ nitrogen limitation on reproduction for fishery purposes) fishery rights and gous to the feedlot approach widely comes from the work of Leahy et al. allowed cooperatives to engage in a used for cattle. This method, now ap­ (\981) who compared oogenesis in variety of activities ancillary to fish­ parently practiced in Japan, involves shallow (4-6 m) water populations of ing. Now the common fishery right is terrestrial forage such as alfalfa. We S. purpuratus with that of animals col­ only granted to fishermen's associa­ do know that the Japanese have experi­ lected from a deep (\5-21 m) water, tions composed of fishermen posses­ mented with knotweed and other easily subthermocline habitat where tempera­ sing certain qualifications; there are obtained terrestrial plants in intermedi­ tures are more favorable for nitrate some 3,000 fisheries cooperatives in ate culture of seed during periods availability. The shallow population Japan eligible for common fishing when algae are not readily available. produced few gametes from August rights (Sato, 1987). Many fishery reg­ through November, when nitrate con­ ulations are instituted at the prefectural

15L. Romina, Ins!. Nae. Pesea, Ensenada, Baja centrations tend to be low (Wheeler level, but fisheries cooperatives often Calif., Mex. Personal eommun., 1989. and North, 1981), whereas the deep­ further restrict access, e.g., limiting

16 Marine Fisheries Review the number of days and the number of provided new government subsidies of that are described in the application for hours per day that a certain fishery is $1 billion to increase coastal produc­ the lease and produced in the area are open, gear restrictions, etc., to con­ tion. This effort was directed at areas owned by the lessee. The lessee has serve their stocks (Mottet, 1976a; of the continental shelf less than 50 m the exclusive right to cultivate and Takagi, 1986). in depth and included diverse activities harvest the aquatic organisms in the While the law does not give fish­ such as improving spawning and lease site. Thus, a lease would make it eries cooperatives priority for demar­ nursery areas, release of seed and fry, reasonable for a fisherman to invest cated (aquaculture) rights, many gov­ construction of artificial reefs and the time and resources to plant collec­ ernors allow the local cooperatives to habitats, wave reducing facilities, bot­ tor-caught or cultured seed, to grow administer these rights as well to tom improvements, and predator con­ kelp, or to feed hungry animals. Ex­ permit all of the necessary compro­ trol. As Mottet (1981) summarizes: clusive rights would also provide in­ mises between culture areas and other centive for a fisherman to follow con­ fishing rights to be made without "Even with these intense research servative fishing practices such as government involvement. The cooper­ efforts, the results from the prelimin­ leaving behind some minimum density atives which receive these rights then ary studies always appear grossly in­ of adult red sea urchins to provide treat them as income and divide the adequate for justifying the projects. spine canopy protection for recruits. profits among members. If native The fact that the projects are still A major problem with water bottom stocks and aquacultural sites are fully funded probably rests less on biolog­ leases in California may be enforce­ exploited, new memberships in a co­ ical and economic data than on the ment; there are simply too few Fish and operative may be all but impossible to political situation which has resulted Game Department wardens to police obtain. Cooperatives frequently spon­ from the worldwide introduction of leases. If fishermen (and processors) sor projects to increase productivity of 200-mile fishing zones. It seems that were to further follow the Japanese the fishing grounds for the benefit of Japan is determined to increase its own model and to enter into agreement over all members. These projects com­ coastal fisheries production, no matter rights to the local fishing grounds, it monly include bottom improvements, what the cost, so it will be less suscep­ may be possible to ensure the dividends artificial reef construction, or predator tible to manipulation by foreign gov­ of each individual's efforts. As leases control. Some cooperatives are also ernments." are subject to public comment, addi­ very involved in the operation of tional potential obstacles to this ap­ hatcheries and/or seeding projects Other important aspects of the fish­ proach are other sea urchin fishermen (Mottet, 1980). ing/culture infrastructure include gov­ who may feel that their rights are being In addition to control over the fish­ ernment subsidies through low-interest infringed upon, or other users of kelp ing grounds, a variety of other institu­ loans and culture insurance (Mottet, forest resources such as recreational tional factors favor and support en­ 1980). The fishing cooperatives take fishermen or kelp harvesters. Such con­ hancement activities. The Japanese care of many business aspects such as siderations underscore the importance have the highest annual per capita fish marketing, purchasing, financing, and of an information campaign and in­ consumption of any major nation, and insurance, leaving the fisherman or volvement of all concerned with the they consume one-seventh of the culturist more time to devote to his resource before leases are applied l6 world output of fisheries products primary activity. Finally, Japan has an for . (Mottet, 1980). With the increase in extensive network of research, educa­ Fish and Game Commission water fuel prices of recent years, the nearly tion, and extension services. There are bottom leases do not, however, allow full exploitation of the world stocks of fisheries high schools and college pro­ for modification of the bottom 16. Such table-grade species, increasing compe­ grams. Research is supported by every habitat improvement approaches as the tition from other countries in high sea level of government as well as by the addition of rock piles or habitat struc­ fisheries, restrictions or loss of access cooperatives themselves, and much is tures would have to go through the associated with extended fisheries heavily subsidized by the national gov­ same approval process as required for jurisdictions, and the loss to pollution ernment. artificial reefs-approval or permits of some domestic coastal fishing In California, it is possible to obtain from the U.S. Army Corps of En­ areas, Japan has been forced to im­ some degree of control over nearshore gineers, California Coastal Commis­ prove the productivity of her remain­ water bottoms. The Fish and Game sion, State Lands Commission, De­ ing coastal waters to maintain supplies Commission leases state-owned tide­ partment of Fish and Game, and the of valuable species. Insecurity over lands for aquaculture. The primary local Regional Water Quality Control sources of supply have led to a po­ lessees to date have cultured bivalves, Board. Any potential conflicts with litical consensus which makes it possi­ but in recent years leases have been existing sport or commercial fisheries ble for fisheries to receive a dispropor­ given for abalones, a group ecologic­ tionate amount of government aid. For ally similar to sea urchins. The Cali­ 16R. Collins, Calif. Dep. Fish Game, 1416 example, the 7-year Coastal Fishery fornia Fish and Game Code provides Ninth Street, Sacramento, CA 95814. Personal Development Project funded in 1976 that all lawfully cultivated organisms commun., 1989.

51(2), 1989 17 must be resolved. The importance the Table 2.-Comperlson of Strongylocentrotus IntermedIus seed collection in the 88a and culture In land-based feclllties In Hokkaldo. Both methods require Intermediate culture with feeding to obtain seed of a suitable size for Japanese place on locally produced relea88 In natural habitats (Kawamura, 1987). seafood is not apparent in California where esthetic and recreational uses of Subject Seed collected in the sea Seed cultured in land-based facilities the nearshore environment often take Collecting technique Planktonic larvae attach to collectors hung Larvae are cultured from fertilized eggs. in the sea. The system is simple and re­ The process is complex and requires spe­ precedence over mariculture. While quires little training. cialized training. artificial reef construction is common Collecting facilities Collector construction, suspension. and Complex facilities are required for supply­ and establishes precedent for some protection from waves are relatively simple. ing water, culturing larval food and young types of habitat improvement, major sea urchins. modification of a multiuse resource Operations Minimal labor is required for placing long­ Labor intensive on a daily basis. such as cutting channels in rocky inter­ lines and retrieving the collectors. tidal benches is likely to meet with Obtaining consistent num­ Great variation. As techniques are perfected, the supply bersof seed may stabilize. serious opposition from the Coastal Commission and others. Vitality of seed Natural selection occurs. Gene pool is Natural selection does not occur. Gene large. pool is small.

Discussion Region Limited to areas of good larval availability. Possible in any ice-free area. Thus, there are several biological options for enhancing fishable stocks of Strongylocentrotus franciscanus which vary widely in cost, the amount of labor required, duration of the I, results, and effects on current land­ meters south of the present day Point seen as an attractive solution,for many ings. While all these approaches offer Loma kelp forest in San Diego) or species, but as Hahn (l989a) observes, some biological potential for success, those living seaward of the kelp zone "There is little, if any, evidence that none has been adequately field tested in central and northern California hatchery production has ever had any in California. These options raise (e.g., Pearse and Hines, 1979) are measurable effect on natural fishery questions about who will pay for obvious candidates. It may also be populations of any marine inverte­ enhancement, who will do the work possible to increase the period of time brate." Conversion of an abalone and reap the benefits, and whether any during which sea urchins from seem­ hatchery to sea urchin culture and the of the approaches will be cost effective ingly non food-limited habitats are of data reported by Omi (1987) suggest now or in the future when wild stocks fishable quality by increasing the that managers in Hokkaido are encour­ are likely to be smaller. quantity or nitrogen content of their aged about the prospects for sea urchin Enhancement of stocks limited by food. This approach is clearly not seeding, but until more results are food availability apears to represent capable of supporting all California provided, they must be regarded as both the highest biological probability sea urchin fishermen, but it may prove preliminary. Hatcheries are capital of success and the shortest time inter­ productive for several individuals to intensive and operational costs are val before efforts payoff. The capital establish water-bottom leases and high (McCormick and Hahn, 1983). investment for nets or pens is likely to feeding regimes in each area. Collection of settling larvae from the be relatively low compared to other It should be noted that the California plankton followed by intermediate cul­ approaches to enhancement, but oper­ Department of Fish and Game requires ture in the sea is much less capital ation will be labor intensive. This a permit to transplant animals. There is intensive but is subject to the vagaries approach is basically short term in its also a question of the legality of penn­ of current patterns and larval supply effects, although areas where grazing ing sea urchins which are a common (Table 2). Presumably these are the pressure is reduced sufficiently are property resource (in contrast with reasons that led to the sea urchin likely to regenerate kelp populations seeded sea urchins which have been hatchery in Hokkaido. and improve the conditions for the produced by the owner)16. Tegner and Barry2 have identified next generation of sea urchins­ Increasing the supply of juvenile sea the southeastern Channel Islands, assuming that larval supply and/or urchins, whether by collection of seed Santa Barbara, and especially San immigration of the desired species are from settlement plates, release of cul­ Clemente Islands, as sites of steady adequate. Unless purple sea urchin tured late-stage larvae, or culture of and high S. franciscanus recru,itment densities are reduced, however, some seed in hatcheries, would seem to be due to the influence of the Southern habitats are unlikely to regenerate. the most efficient way of enhancing California Eddy. However, these same This approach is also clearly affected fishable stocks in areas where popula­ islands are also areas where survival of by the supply of food-limited sea tions are limited by larval supply-if mid-sized red sea urchins is poor due urchins, which may vary considerably any of these approaches can be shown to intense predation pressure. Thus, it among areas. Animals from barren to work in California. Seeding of may be beneficial to establish arrays of grounds (such as several square kilo­ hatchery-reared juveniles has been collectors on these islands for trans-

18 Marine Fisheries Review plantation to other sites. Northwest mains one of the major hurdles to and Southward, 1985) and Barbados Harbor, a semi-protected site on San successful culture of mollusks (Jory et (Scheibling and Mladenov, 1987) have Clemente Island, may be ideal for aI., 1984), and no doubt crustaceans collapsed. It seems prudent to adopt a placement of seed collectors. and echinoids as well. Jory et al. conservative approach now to prevent Whatever their source, seed survival (1984) reviewed how predators can further deterioration of existing stocks rates are likely to be very area-specific decimate unprotected mollusk seed until alternate methods of enhance­ and will have to be determined em­ and the many different devices which ment are tested and put in place. pirically in California. Miyamoto et al. will provide protection---often at con­ In these days of budget deficits and (1985) found that predation was min­ siderable cost. They suggest the im­ limited government means, the cost of imal on seed larger than 15 mm in portance of planting seed at a size of any approach to enhancement must be Hokkaido. In contrast, seastars in decreased vulnerability and adequately considered in concert with its biolog­ southern California commonly con­ dispersed to minimize predation. As ical and economic effectiveness. A sea sume sea urchins up to 50 mm (Tegner there may be considerable seasonal urchin hatchery is a very expensive and Dayton, 1981). Spiny lobsters variability in predation pressure, proposition, especially since it is not feed heavily on sea urchins to 60 mm studies should determine the optimal clear that seed survival will be ade­ and will consume animals as large as time of planting as well. quate in California ecosystems. The 90 mni in aquaria (Tegner and Levin, Physical habitat improvements, sea urchin industry has levied a tax on 1983). There are apparently no inver­ such as the addition of rock piles to landings to fund research and develop­ tebrate-feeding fishes such as wrasses pavement habitats or even soft sedi­ ment of enhancement methods, but a in Hokkaido. Sheephead are major sea ments, represent considerable initial several-fold increase in funds would urchin predators and the senorita, outlay, but there are no operational be required to finance a hatchery. A Oxyjulis california, another common costs and the results are long lasting. logical first step would be to obtain wrasse, has been observed picking This approach may be especially im­ seed from collectors in the ocean, juvenile sea urchins out of coralline portant for populations of red sea increase their size in intermediate algae and having small sea urchins in urchins limited by the survival of culture, and then conduct experiments its gut contents (Tegner and Dayton, mid-sized animals. The enthusiasm for to assess survival rates in benthic 1977, 1981). The effects of lobster and physical habitat improvement shown habitats. While research may be re­ sheepliead predation are apparent in by the Japanese suggests its effective­ quired to adapt Japanese methods of the population structure of red sea ness, but their cost calculations appear seed collection to California condi­ urchins on the southeastern Channel to include substantial government sub­ tions, seed obtained in this manner 2 Islands . sidies. The major obstacle to this will be relatively inexpensive and still Thus, the Japanese method of approach in the United States may be useful for determining whether seed broadcasting seed from the surface is opposition by other users of the same survival is adequate to pursue this clearly inappropriate for southern Cali­ environment such as net fishermen 16. approach. Tegner and Barry2 have fornia, and protective habitats such as Broodstock and nursery protection identified San Clemente and Santa adult spine canopies and rock piles require no capital outlay but they do Barbara Islands as optimal sites for will be critical for seeding to be entail a cost; some landings must be seed collectors; mainland locations successful. Given the apparent lack of sacrificed now for the sake of future such as the Point Loma kelp forest are a reasonable size threshold beyond harvests. Where it is not possible to likely to produce lower but still useful which there is a significant reduction accomplish this with a maximum size numbers of recruits (Tegner and Day­ in predation, it may well be more limit, there is also the risk that the ton, 1981). If seed collection proves to cost-effective to seed a large number animals left by one fisherman will be be an efficient method for obtaining of relatively small seed. Seeding may harvested by someone else. The results juveniles, then there are a number of well be more applicable to northern of leaving a minimum density of adults options regarding who funds the col­ California where predation pressure behind are likely to be modest, but lections, distribution or sale of the appears to be lower. When evaluating they may prevent the loss of some seed, and who owns fishing rights the Japanese results, it is also impor­ fishing grounds, especially on the after growth to harvestable size-in tant to consider that they harvest sea southeastern Channel Islands where short, will enhancement require 2 urchins as small as 40 mm which may predation pressure is high . Rotating changes in the structure of the fishery? .be only 2 years old (Omi, 1987). The area closures should also be tested. Capital-intensive approaches to en­ minimum legal size in California is 76 Despite their high fecundities and hancement such as a hatchery or phys­ 2 mm, about 3 years of age . Thus, red recruitment rates, sea urchin fisheries ical habitat improvement projects may sea urchins in California are exposed can be over-exploited. Taki (1986) require the financial backing of the to predation for a year longer than sea described a case where a fishery for S. entire industry. This can be practical if urchins in Hokkaido before they enter intermedius exceeded recruitment based on landing taxes. Labor-inten­ the fishery. leading to stock deterioration, and sea sive projects such as enhancing food­ Predation during field growout re­ urchin fisheries in France (Southward limited populations are likely to be

51(2), 1989 19 difficult to organize on an industry­ Literature Cited Giese, A. C. 1966. On the biochemical constitu­ wide basis but may be ideal for a few tion of some echinoderms. In R. A. Boolo­ otian (editor), Physiology of echinodermata, individuals if seafloor leases can be Agatsuma, Y., and H. Momma. 1988. Release of cultured seeds of the sea urchin, Strongy­ p. 547-576. Interscience, N.Y. obtained. Broodstock and nursery pro­ locentrotus intermedius (A. Agassiz), in the Grant, J. F. 1981. Abalone culture in Japan: tection needs the support of all fisher­ Pacific coastal waters of southern Hokkaido. Development and current commercial prac­ I. Growth and reproductive cycle. Bul!. Hok­ tice. Tasmanian Fish. Res. 23:2-17. men, but the incentive to conserve is kaido Fish. Res. Sta. 31:15-25. [In Jpn., Hahn K. O. 1989a. Culture of queen conch, likely to be greater where there is local Eng!. abstr.1 Strombus gigas, in the Caribbean. In K. O. control of the water bottom. Appledoorn, R. S., and D. L. Ballantine. 1983. Hahn (editor), Handbook of culture of aba­ Field release of cultured queen conch in lone and other marine gastropods, p. 317­ Sea urchins have been an important Puerto Rico: Implications for stock restora­ 331. CRC Press, Boca Raton, Fla. part of the Japanese diet for hundreds tion. Proc. Gulf Caribb. Fish. Inst. 35:89-98. ___. 1989b. Culture of the tropical top shell, Trochus nitoticus. In K. O. Hahn of years and are intensively harvested. Ault, J. S. 1985. Some quantitative aspects of reproduction and growth of the red abalone, (editor), Handbook of culture of abalone and National landings averaged 25,000 t Haliotis rufescens Swainson. J. World other marine gastropods, p. 301-315. CRC for 1978-82, and there was remark­ Maricult. Soc. 16:398-425. Press, Boca Raton, Fla. Berg, C. 1., and D. A. Olsen. 1989. Conserva­ Harrold, C., and D. C. Reed. 1985. Food avail­ ably little variation among the years tion and management of queen conch (Strom­ ability, sea urchin grazing, and kelp forest (Takagi, 1986). In a country where bus gigas) in the Caribbean. In J. F. Caddy community structure. Ecology 66:1160­ there is little or no distinction between (editor), Marine invertebrate fisheries: Their 1169. assessment and management, p. 421-442. Hinegardner, R. T. 1969. Growth and develop­ fishing and marine farming, the stabil­ Intersci., N.Y. ment of the laboratory cultured sea urchin. ity of the sea urchin harvest appears to Bernard, F. R. 1977. Fishery and reproductive BioI. Bull. 137:465-475. ___. 1975. Care and handling of sea urchin be based on both traditional fisheries cycle of the red sea urchin, Strongylocentro­ tus franciscanus, in British Columbia. 1. eggs, embryos, and adults (principally North management measures such as effort Fish. Res. Board Can. 34:604-610. American species). In G. Czihak (editor), restrictions, size limits, etc. and var­ ___. and D. C. Miller. 1973. Preliminary The sea urchin embryo, p. 10--25. Springer­ investigation on the red sea urchin resources Verlag, Berl. ious enhancement activities facilitated of British Columbia (Strongylocentrotus fran­ - __, and M. M. Rocha Tuzzi. 1981. by the structure of the fishing industry. ciscanus, Agassiz). Fish. Res. Board Can., Laboratory culture of the sea urchin Lytec­ As the California red sea urchin will Tech. Rep. 400, 37 p. hinus pictus. In Laboratory animal manage­ Bonsdorff, E., and O. Vah!. 1982. Food prefer­ ment, marine invertebrates, p. 291-302. Natl. soon, if it is not already, be fully ence of the sea urchins Echinus acutus and E. Acad. Press, Wash., D.C. exploited and the landings will start to esculentus. Mar. Behav. Physio!. 8:243-248. Holland, L. Z., A. C. Giese, and J. H. Phillips. 1967. Studies on the perivisceral coelomic fall, the long-term success of the Breen, P. A., W. Carolsfeld, and K. L. Yam­ anaka. 1985. Social behavior of juvenile red fluid protein concentration during seasonal Japanese is something for Californians sea urchins, Strongylocentrotus franciscanus and nutritional changes in the purple sea to consider. (Agassiz). J. Exp. Mar. Bio!. Eco!. 92:45­ urchin. Compo Biochem. Physiol. 21:361­ 61. 371. Cameron, R. A., and S. C. Schroeter. 1980. Sea Howard, A. E. 1982. Lobster 'seeding'-a Acknowledgments urchin recruitment: Effect of substrate selec­ promising approach to the problem of increas­ tion on juvenile distribution. Mar. Ecol. Prog. ing natural stocks. In Proc. 13th Annu. Shell­ I thank R. Collins, W. North, M. Ser. 2: 243-247. fish Conf., p. 14-22. Shellfish Assoc. Great Otjens, D. Parker, D. Rudie, B. Castagna, M. 1983. Review of bivalve culture Britain, Lond. Ino, T. 1966. [The abalone science and its prop­ Steele, C. Toole, and K. Wilson for methods. J. World Maricult. Soc. 14:567­ 575. agation in Japan]. Propag. Mar. Prod. Ser. providing infornlation and P. Parnell Craig, M. A., T. 1. Bright, and S. R. Gittings. 11, p. 2-105. Publ. by Jpn. Fish. Resour. for preparing figures. The California 1988. Growth of Mercenaria mercenaria and Conserv. Assoc. Fish. Res. Board Can. Mercenaria mercenaria texana seed clams Transl. Ser. 1078,209 p. Department of Fish and Game pro­ planted in two Texas bays. Aquaculture Iverson, E. S.. D. E. Jory, and S. P. Bannerot. vided ship time and helped gather the 7 I: 193-207. 1986. Predation on queen conchs, Strombus spine canopy association data. Thanks Dean, T. A., S. C. Schroeter, and 1. Dixon. gigas, in the Bahamas. Bull. Mar. Sci. 1984. Grazing by red and white sea urchins 39:61-75. are also due to Madelon Mottet and the and its effect on the reclUitment and survival Jackson, G. A. 1977. Nutrients and production Washington State Department of of giant kelp. Mar. BioI. 78:301-313. of the giant kelp. Macrocystis pyrifera, off southern California. Limnol. Oceanogr. Fisheries whose translations and re­ Department of Maticulture, Hokkaido Central Fisheries Experimental Station. 1984. [On the 22:979-995. ports about Japanese fisheries were natural seeds collection, intermediate culture, Jory, D. E., M. R. Carriker, and E. S. Iversen. critical ,0 this analysis. I am very and release of the sea urchin, Strongylocen­ 1984. Preventing predation in molluscan trotus intermedius]. J. Hokkaido Fish. Exp. mariculture: An overview. J. World Maricult. grateful to S. Kato for his critical Sta. 41:270--315. Can. Transl. Fish. Aquat. Soc. 15:421-432. review of the manuscript. D. Parker, Sci. 5200, 48 p., 1985. Kafuku, T., and H. Ikenoue. 1983. Abalones. D. Rudie, and R. Rowley also pro­ Ebeling, A. W., D. R. Laur, and R. J. Rowley. In T. Kafuku and H. Ikenoue (editors), 1985. Severe storm disturbances and reversal Modern methods of aquaculture in Japan, p. vided comments on the text. This of community structure in a southern Cali­ 172-182. Elsevier Sci. Publ. Co., Arnst. research was sponsored in part by the fornia kelp forest. Mar. BioI. 84:287-294. KalO, S., and S. C. Schroeter. 1985. Biology of California Department of Fish and Ebert, T. A. 1967. Negative growth and longev­ the red sea urchin, Strongylocentrotus fran­ ity in the purple sea urchin, S. purpuratus ciscanus, and its fishery in California. Mar. Game, and in part by the National (Stimpson). Science 157:557-558. Fish. Rev. 47:1-20. Science Foundation and NOAA, ___ and M. P. Russell. 1988. Latitudinal Kawamura,K. 1987. Techniques for obtaining National Sea Grant College Program, variation in size structure of the west coast sea urchm seed on offshore longlines. In purple urchin: A correlation with headlands. [Summary lectures for 1986 of the Fisheries Department of Commerce, under grant Limno!. Oceanogr. 33:286--294. Culture Research Society: Techniques for col­ number NOAA 04-8-MOI-189, pro­ Ebert, T. B., and E. E. Ebert. 1988. An innova­ lecting sea urchin seed and results of re­ tive technique for seeding abalone and prelim­ leases]. [Public Corp. Promot. Aquacult. ject number RJF-36 through the Cali­ mary results of laboratory and field trials. Hokkaido]. Transl. (extended summ.) fornia State Resources Agency. Calif. Fish Game 74:68-81. Madelon Mottet, Jpn. Sci. Liason, 595 Tuck-

20 Marine Fisheries Review er Ave., No. 39, Friday Harbor, WA 98250. vironment for fisheries and aquaculture in tures for 1986 of the Fisheries Culture Re­ Kraeuter, J. N., and M. Castagna. 1985a. The Japan. Compl. Rep. to Dep. Commer., search Society: Techniques for collecting sea effect of clam size, net size, and poisoned bait Wash. Dep. Fish., 176 p. urchin seed and results of releases]. [Public treatments on survival of hard clam, Mer­ Munro, A. L. S. 1982. Prospects for enhancing Corp. Promot. Aquacult. Hokkaido]. Transl. cenaria mercenaria, seed in field plots. J. British fishery resources by release of cul­ (extended summ.) by Madelon Mottet, Jpn. World Maricult. Soc. 16:377-385. tured juveniles. Scott. Fish. Bull. 47:32-39. Sci. Liason, 595 Tucker Ave., No. 39, Friday ___ and . 1985b. The effects of Munro, 1. L. 1989. Fisheries for giant clams Harbor, WA 98250. seed size, shell bags, crab traps, and netting (Tridacnidae: Bivalvia) and prospects for ___, K. Yamashita, K. Tajima, A. Obara, on the survival of the northern hard clam, stock enhancement. In J. F. Caddy (editor), Y. Nishihama, M. Sawasaki, K. Kawamata, MeStrongylocentrotidae. settlement processes? Mar. BioI. 100:485­ mercial fishing. Science 196:324-326. Wash. Dep. Fish., Tech. Rep. 20: 1-66. 494. ___and . 1981. Population struc­ ___. 1976b. The fishery biology of sea Russell-Hunter, W. D. 1970. Aquatic produc­ ture, recruitment, and mortality of two sea urchins in the family Strongylocentrotidae. tivity: An introduction to some basic aspects urchins (Strongylocentrotus franciscanus and Compl. Rep. to Dep. Commer., Wash. Dep. of biological oceanography and limnology. S. purpuratus) in a kelp forest. Mar. Ecol. Fish., p. 67-176. Macmillan Co., Lond., 306 p. Prog. Ser. 5:255-268. ___. 1980. Factors leading to the success Saito, K. 1984. Ocean ranching of abalones and ___ and L. A. Levin. 1983. Spiny lobsters of Japanese aquaculture with an emphasis on scallops in northern Japan. Aquaculture and sea urchins: Analysis of a predator-prey northern Japan. Wash. Dep. Fish., Tech. 39:361-373. interaction. J. Exp. Mar. BioI. Ecol. 73: 125­ Rep. 52: 1-83. ___. 1987. Techniques for the artificial ISO. ___. 1981. Enhancement of the marine en­ culture of sea urchin seed. In [Summary lec­ Tong, L. 1., G. A. Moss, and J. Illingworth.

51(2), 1989 21 1987. Enhancement of a natural population of Van Olst, J. c., 1. M. Carlberg, and J. T. Wheeler, P. A., and W. J. North. 1981. Nitro­ the abalone, Halioris iris, using cultured Hughes. 1980. Aquaculture. In J. S. Cobb gen supply, tissue composition, and frond larvae. Aquaculture 62:67-72. and B. F. Phillips (editors), The biology and growth rates for Macrocysris pyrifera off the Uki, N. 1984. Abalone culture in Japan. U.S. management of lobsters, Vo!. II, p. 333-384. coast of southern California. Mar. BioI. Dep. Commer., NOAA Tech. Rep. NMFS Acad. Press, N.Y. 64:59-69. 16:83-88. Walker, R. S. 1986. The first returns of tagged Wickins, F., T. W. Beard, and E. Jones. 1986. Vadas, R. L. 1977. Preferential feeding: An juvenile lobsters [Homarus gammarus (L.)] Microtagging cultured lobsters, Homarus optimization strategy in sea urchins. Eco!. after release to the wild. Aquaculture gammarus (L.), for stock enhancement trials. Monogr. 47:337-371. 52:231-233. Aquacult. Fish. Manage. 17:259-265.

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