Confidential FISHERIES RESEARCH BOARD OF CANADA REPORT of the ATLANTIC . BIOLOGICAL STATION for 1951 by A. W. H. NEEDLER, Director With Investigators Summaries as Appendices à DEC 26 1951 1 / `_d _firdrEfir OF fe---d 4 M. V. "Mallotus" Built early in 1951 for the Atlantic Biological Station by VI. larren Robar, Upper LaHave, N.S., on plans developed by the Nova Scotia Department of Trade and Industry in co-operation with him and modified slightly for our pur- poses. Length overall 55.5 feet; beam 14.2 feet; gross tonnage 29.11; 106 h.p. Cummins diesel engine. Ordinary crew includes Captain, Engineer and cook-deck- hand with special observers frequently aboard. In 1951 the "Mâllotus" has been engaged in exploratory dragging in the upper Bay of Fundy and south-eastern Gulf of St. Lawrence, in scallop investigations and other minor work. The vessel is suitable for inshore work of many kinds, including dragging with various types of gear, long-lining, and general scientific and fishing operations. A varied program for 1952 includes participation in groundfish, herring, lobster and tuna- billfish investigations. REPORT FOR 1951 OF TEE 4 ATLANTIC BIOLOGICAL -STATION ST. ANDREWS N B By A. W. H. Needier, Ldrector 44 14 414 44 de * * 414 * 414 * * 044 ' -- The general failure of other sources of animal pro- teins and fats to keep pace with the rapid growth of human ' populations is producing a world-wide intensification of use of the fishery resource.- In the waters off the Atlantic coast of" Canadafishing.is steadily Increasing not only by our own . fishermen but by those of other countries, some of them thou- sands of miles away. There is'every•reason to believe that this trend will continue both in our own inshore fisheries and in the international offshore fisheries; it will affect species as yet little used as well.as those already fished intensively. The problem of obtaining the best use of our resources can be solved intelligently only with the help of information which can be obtained neither easily nor quickly. It is the impor-' tant and interesting job of biological fisheries Investiga- tions, by. this and others of the Fisheries Research Board's -- Stations, to Obtain this information and pass it on - to the fishing industry and the administration. t e A few of our commercial species are very intensively . and the yield can be maintained at its most profitable . fished -level only by careful regulation; others are intermediate„._ '— perhaps fished intensively in some areas but not in others; . still other species, and apparently the majority, do not yet yield nearly as much as they could with more intensive or effective fishing. On the whole we must regard our fisheries as under-developed and, while regulating some and holding a ' watching brief on others, put emphasis on development rather . than on restriction. We must learn how to regulate intensive fisheries to the best advantage but must also help tà obtain better use of the resource by more positive means such as exploration for new stocks and improvement , of methods of find- ing and catching some species and of cultivating others. Our efforts in all these directions depend on bettering our * knowledge of how fish behave, survive, reproduce and grow in relationfto the conditions around - them. EM.1=112n0 The discovery of new stocks of fish, whether to extend well-eStablished fisheries or to develop new ones, depends to a high degree on better knowledge of the physical conditions in'our waters and how the various species react to them, and on the use of fishing methods new to us. This branch of our work suffers from the limitations inherent in any attempt to cover such a wide field with a very few boats and men. Exploration is, however, very important in the long run.and can sometimes yield fairly immediate bene- fits. Whether or not these are forthcoming we must improve - 2 - our knowledge of the fish stocks available to our industry if it is to have its full share of the long-term expansion which is taking place. Work in this field must continue and should be extended, both through hydrographie and general biological in- vestigations and through exploratory fishing. Exploratory work in 1951 included, in addition to hydrographic investigations, a number of particular attempts to find new stocks reported in greater-detail below. Among them were continued search for , soft-shelled clams, scallops, shrimp, bait-worms and,flounders, more exploratory drift-netting for - high-quality summer herring, encouragement of the first commer- cial use of razor clams and some minor investigations on tuna. Improvement of-fishing methods. Most of the fish .' which we attempt to catch are out of sight and must be found and caught by a great variety of mechanical means developed - slowly over the centuries by trial and error. The development of fishing methods is - hindered by our ignorance of how the fish 'react.t6 them and, since our knowledge of the abundance and . movements of fish depends entirely on catching or seeing them, it is very important to thellsheries biologist as well as to the fisherman to improve fishing Methods and to understand more about how they work. Progress In this field is slow, being plagued by the infinite variety of gear, fish and circumstances and by the indirect and remote observation which is often the • best we can do. It is, however, important for us to improve our knowledge of fishing gear - sometimes as a direct attempt to introduce a better method in our fisheries, and sometimes as a prerequisite for sound interpretation of our aen observations or of changing commercial catches. In 1951 the study of fishing methods has been an integral part of many of our investigations, including the development of "savings gear" for scallops, introduction of commercial Danish seining for'flatfish, further experiments with mid-water trawls for herring, exploratory drift-netting for herring; studies on the operation of small otter trawls, - and assessment of the-effects of hydraulic means of taking' soft-shelled clams. A proper attack on these problems needs the combined critical and open-minded attention of biologist and engineer, and the employment of an engineer, Mr. C. E. Petite, on the Station's staff is already bearing fruit. Regulation of intensive fisheries. A number of our fisheries are'highly intensive; in some areas, for example, two thirds or more of the lobsters of Marketable size are ' caught each year. In some of these cases it is believed possible for properly designed regulations to maintain the catch at a more profitable level than it would otherwise reach.' The fisheries administrations and public, especially on this 'continent, have shown an unaccountable willingness to , believe that restriction of fishing is necessary to preserve fisheries and that it can be made to increase the catch, and undesirable restrictions seem to have resulted in some cases. -j Close study of intensive fisheries is necessary to determine 4 ■ -whether restriction would probably make them> more profitable - and, if so, what kind and degree of restriction is likely - to be - beneficial. A great deal of investigation Is needed in order.to give a sound opinion on these cases. Tut crudely, it is necessary to know what expectation there is of the fishery.having a second chance.to_catch and_keep any-fish- the „ restriction prevents - it from*using', and'whether the increased' : of the fish will.make -Up for the possibility that there *size will be no second chance. This requires knowledge of the.' growth, abundance, movements and survival of the fish and of - the proportion caught by the fishery. In 1951 investigatioàs of this kind were continued on ,the intensive and impbrtant lobster fishery and a number of -recommendations were made on its regulation. Periodic closure Of clam flats is emerging as a possibly beneficial:measure, though further study is required. Work was also continued on the smelt and scallop fisheries. We continue to hold a watch ing brief on the important groundfish fisheriés to recognize over-fishing should it occur and much effort is being spent on 'a study of the fishery and'thé - fish populations. A second attempt to estimate the 'size of the harp seal population by • 'aerial,ph6tography confirmed the 1950 estimate of its order, - the increased take In. 1951 led to the view that.som9 Fe- but - striction would be desirable, especially on the killing,of 'adult. seals. An increasing effort is being.madé to discover the complex background for regulation of the commercial and sports fisheries for Atlantic salmon. Increasing production bv positive cultural measures. Only in sheltered inshore waters and in fresh waters is it possible to improve*the conditions for reproduction, growth or survival enough to increase the production of valuable species of fish or shellfish. The measures used are often -cdmplex themselves and their success - is always affected by the many and very complex ways in which an animal -reacts to the condi- tions under which it lives. A great deal of investigationls, therefore, needed to develop the best cultural - procedures or "farming- methods", but the fact that these procedures and - their effects are more readily observed than in the cases of .fishing or fishery regulation in the deep sea, makes them :more easily:investigated by the scientist and understood by the layman, who also sees in them analogies with the more familiar agriculture. The Station'S work in thiS very varied field in7 eluded in 1951 continued experimental farming of oysters with its'associated_investigations, studies on the pond culture ot. trout and the use of predator control and fertilization to increase troUt production, study of the effects of predator - control (both birds and eels) and of various planting pro- cedures on Atlantic salmon production, continued observation of the effects of better access to spawning areas on the production of smelt and limited observation of the few - 4 - -remaining attempts at profitable clam farming.