472 Lionel A. Walford 



America, since history is longer and the facihties for keeping records go back further 

 there; universities and museums are more ancient, great fisheries and fishery 

 researches have been longer established, and there has been more opportunity to 

 observe the habits of fishes and to record the vagaries of fisheries there than in other 

 sections of the country. Thus over the course of over 300 years there has accumulated 

 a great store of knowledge about western north Atlantic fishes — about the charac- 

 teristics of their environment, their seasons and places of spawning, the structure of 

 their eggs and larvae, their food habits, routes of migrations, anomaUes of occur- 

 rences, and many other matters relating to normal patterns of life history and to 

 the deviations therefrom. 



Natural History has been unappreciated for a long time, and is now at last again 

 coming into its own, though perhaps under a different label. During the 1920's and 

 1930's the extraordinary growth of new fisheries such as for haddock in New England, 

 for sardines in California, and for shrimp in the Gulf of Mexico, aroused concern 

 for the future productivity of those natural resources that were being subjected 

 to unprecedented exploitation. It was logical that these fisheries should be regulated 

 as promptly as possible in order to safeguard them from extermination, and that to 

 be effective, the regulations must be based on scientific information. It transpired 

 from preliminary inquiries that a special kind of information was required which 

 in fact did not exist. Although there was a large store of facts, none of it was suitable 

 for calculating estimates of the sizes and ages at most profitable capture. Under 

 the impetus of the demands of the time, therefore, biologists whose interests might 

 otherwise have been natural history took up the study of fishery biology. At first they 

 were preoccupied with determining the effect of fishing on the abundance and pro- 

 ductivity of populations of fish. For this they paid the bulk of their attention to 

 founding useful systems of commercial statistics and to the analysis of the quantities, 

 sizes and ages offish caught in relation to the amount of eff'ort required in the catching. 

 They tended to limit biological studies to those features of life history required for 

 scientific regulation, i.e. rates of growth, death and replacement. 



• Fishery research might have remained so for a much longer time had it been proved 

 unequivocally that fishing alone causes depletion, which can always be corrected 

 simply by controlling the catch. However, one of the principal results of studies 

 over the past 30 years has been to bring out that, although fishing certainly does 

 affect the abundance of fishes, so also do events which happen in the ever changing 

 environment. Long period trends in climate and hydrography, for example, affect 

 distribution and abundance of all species, whether they are fished or not; and they 

 affect different species in different ways. Thus there is continuous change in the 

 numerical interrelations among the many species inhabiting an environment, perhaps 

 with some kind of pattern of oscillations which has yet to be deciphered. 



Fishery researchers had first thought to speed their progress towards practical 

 results by limiting the scope of their studies to the species of greatest importance 

 and to the problems of greatest urgency. Every study about those species, however, 

 has made it more evident that they can not be understood out of context from the 

 intricate system of their biological environment composed by their predators (includ- 

 ing man), their competitors and their prey. So it is that fishery researchers have been 

 finding it necessary to rediscover natural history (now called ecology), and to enlarge 

 the scope of their programmes in order to establish a proper balance between studies 



