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shore fisheries, except for the plaice and the halibut. But acute 

 ajyprehensior. is nor fslt for the haddock in iVtr.erican waters, because 

 its concentration on grounds v^here stearc trawlers can easily work 

 ciakes it especially vulnerable to a rapidly expanding fishery. 



With the stock of any species of fish in the sea likely at any 

 time to diminish, and to stay at a low ebb for years, from natural 

 causes, as well as standing in danger of depletion by man, it is 

 economically of great importance to be able to state whether a shrink- 

 age in the catch falls in the one category or in the other, because 

 the procedure proper for the industry to follow is quit_- different in 

 the one case than in the other. If depletion is taking place, regula- 

 tion, as already remarked, is in order, for it is certain that we 

 cannot maintain any of the true marine fishes by artificial propogation 

 if tney be overfished. Boast as we may of the billions of young cod, 

 haddock or pollock that are dumped into the sea by the government 

 hatcheries, these are less than a drop in the bucket: the product of 

 only a handful of parents in populetions to be numbered by the million. 

 But if fish dim.inish as some one dominant year class dies off, before 

 another year of abundant production has come, the fishery itself needs 

 to be safe-guarded against the disastrous results of the sudden 

 cessation of the supply. Theoretically, extensive protective regula- 

 tion might seem called for in this case also: practically however, 

 this has not proved to ce the case, because we know of no instance, up 

 to the present, where the stock of a species that has shrunk from 

 natural causes has failed to recover from, such a decline in spite of 

 the drain upon it by the fishery. When fish are scarce there is less 

 fishing done, so that this side of the picture takes care of itself, 

 ^nd the oceanographer stands in the best position to guard the fishery 

 (and the con3um.ing public) against fluctuations of this sort for he 

 alone has the opportunity to discover a rational basis for predicting 

 such events in advance. Until that can be done, we can only proceed 

 "hit-or-miss" . 



The basic fisheries problem, then, is to make the greatest 

 possible use of the food recources of the sea that is compatiole (a) 

 with avoiding the danger of overfishing; (b) with safeguarding the 

 industry against the disastrous effects of unpreventable fluctuations 

 in the available supply of fish. 



Although the problems involved in these two cases are fundamen- 

 tally distinct, in each case the solution can only come from investi- 

 gations of the life histories of the fishes involved, and of their 

 reactions to their environment, animate and inanimate, combined with 

 statistical study of the commercial catch. In other words, the 

 technique of oceanic biology must be employed, whether the aim be 

 protection or prediction. 



Whenever any fishery increases greatly in intensity, as is now 

 hapT^ening with the American haddock fishery, the immediately practic-i.l 

 task is to estimate the strain of fishing that the species in question 

 may reasonably be exp-^cted to withstand; or when any fishery shows a 

 serious decline, to determine whether this reflects overfishing, or 

 results from a natural decrease in the stock in the sea. In either 

 case the species concerned must be studied as populations, not as 

 individuals, by m.ethods similar to those developed, in the science of 

 Vital Statistics, This part of the economic fisheries problem is 



