230 SUMMARY AND CONCLUSIONS. 



have little fear on this account, however loudly its doom might 

 be pronounced. 



In areas constantly harassed there can be no doubt that the 

 fishes become more wary and thus more difficult of capture. 

 A tiny larval or post-larval cod will avoid the forceps intended 

 to capture it, and it is very probable that the adults will move 

 from ground that is constantly fished. The same holds with all 

 the food-fishes. Hence when fishermen find that their captures 

 — on what was rich ground — seriously diminish, such may be 

 due to increased wariness as well as to decimated ranks \ Marine 

 fishes differ in habits from fresh- water forms, such as the trout 

 in streams. Instead of from day to day frequenting nearly the 

 same spot with snouts directed to the current, or hiding under 

 the same stones or ledges, the majority of the oceanic round fishes 

 roam hither and thither in vast swarms, consorting with those 

 of a similar size and bound to no locality, for their food is 

 universally distributed. Even the more sedentary flat fishes 

 in their life-cycle often show many changes of habitat, and 

 additional information has lately been given by Dr C. G. J. 

 Petersen from the Limfjord^ into which the young plaice yearly 

 migrate from the North Sea, and are fished up without a chance 

 of returning in adult life to the open ocean and of reproducing 

 their species. 



The larger forms of the food-fishes for the most part are 

 thinned for the time in areas of the open sea closely fished, but 

 the fishes are not extirpated, and if circumstances are favourable 

 they, as a rule, repeople the depleted waters. There are 

 differences however in regard to species. Some, such as the 

 cod, roam after prey, coming inshore in numbers during the 

 winter months and towards the spawning season. Bays have 

 been pronounced as "fished out," yet a single boat, with 

 suitable bait, will at the season mentioned capture 80 fine cod, 

 and others in smaller number. Adult halibut frequent deep 

 water, and appear to become much scarcer when eagerly fished. 

 The smaller forms again are generally found in shallow sandy 



1 Vide " On the Memory of Fishes," Journal of Mental Science, April, 1898. 



2 " The yearly immigration of Plaice into the Limfjord from the German 

 Sea." Fisk. Beret. 1895—96. 



