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do not know at what aa^e it is wisest to catch and market ths crop of 

 any species, i.e. '.-hetn^r the beet yields will result in the long run 

 if. the fish are taken near the loTier limit of marketable size, or 

 whether they should be allowed to grow larger and to spawn several 

 tines. 



Obviously, if a species is to persist so.me individuals .must grow 

 to breeding age. But as only a fraction of each year's crop can do so 

 in any event (else the universe would be a solid mass of fish) in some 

 cases' it may be wise for the fishermen to utilize the smaller sizes, 

 .most of which could not mature. For instance, we are totally in the 

 dark as to whether the great destruction of immature fish, too small 

 for the market, that is^wrought by the otter-trawlers, and by the 

 pound nets along our A.tlantic coast, so often heralded by calamity- 

 criers, does any real dgmpge to the stock; it may conceivably be a 

 benefit, paradoxical though this may seem. To be more specific, there 

 is no positive evidence that the annual capture of a billion or more 

 of small herring in the Gulf of Maine, to be packed as "sardines", 

 year after year7 has had any effect whatever on the numerical strength 

 of the stock of adults breeding there. Could a large catch of the 

 latter have been made with equal impunity? Te cannot answer. 

 Similarly, it is now a moot question whether it is wiser to protect 

 the small lobsters and market the large, or vice versa ; nor can this 

 be settled correctly/ by acrimonious argument, any more than can the 

 question whether large catches of small plaice in the ITorth Sea are 

 really as destructive to the stock as has often been supposed. 



For few species can we yet so much as glimpse an answer to the 

 question "Where ought the fish to be caught", though this may be an 

 important one in the maintenance or development of any given fishery. 

 Practical fisherm^en have long feared the results of hsrd fishing on 

 the sparming grounds, especially in the case of the flat fishes, 

 though economic pressure has forced them to do just this for it is 

 often on the spawning grounds tht-t drift-netting and otter-trawling 

 are the most productive. Certainly it is safest to kill breeding 

 fish just after, rather than just before sp-iwning, so ensuring at 

 least that one crop of eggs. But to translate this academic theory 

 into practical regulation calls for a kno^^'ledge of spawning grounds 

 and seasons which can only be gained in sufficient detail by intensive 

 study at sea. 



On the other hand, we already know that there are certain 

 grounds where no a.mount of fishing for certain species (even to the 

 verge of temporary extermination) will have any permanent effect upon 

 the general stock. This applies in cases where there is a regular .• 

 emiigration away from the spawning areas to grounds far distant, with 

 no return migration. Thus the lobsters that stray to the Bay of 

 Fundy cannot reproduce in the low te.mperatures prevailing there, 

 though they find these cool conditions favorable to mature growth. 

 It would be pure econo.mic waste not to catch the.m. The case is 

 similar for the Rose Fish (Sebastes) off the west coast of Greenland, 

 which are recruited fro.m fry produced in higher temperatures in the 

 Atlantic to the south, with no r'=turn movement. In instances of this 

 sort the only sound lim.it to fishing is the economic one. But the 

 understanding of such cases involves a knowledge of the lines of 

 dispersal and migrations in general, which in turn dem.ands long 



