Pelagic Fauna of our Shores. 145 



It is probably the profusion of crustacean life close inshore 

 that tempts the shoals of green cod, common cod, whiting, 

 and pollack to seek the rock-pools and inlets at low water j 

 there they pursue their active prey amongst the olive-green 

 seaweeds and forests of tangles, and likewise seize on many 

 of the smaller Mollusca browsing on the algge. These large 

 forms also to a considerable extent feed on the young mussels 

 just as they are quitting pelagic life to fix themselves by their 

 byssi to the seaweeds, zoophytes, and rocky surfaces ; and no 

 food is more eagerly sought after or is more nourishing than 

 this. Their enormous numbers, for instance in St. Andrews 

 Bay, make them important elements in the food of the younger 

 fishes ; and though perhaps their presence is not so vital as 

 that of the minute crustaceans in the early larval stage, still 

 any serious injury to the fine mussel-beds of the Eden or of 

 the Tay would be detrimental to the prosperity of the fisheries. 

 Man has this much in his power ; but he is impotent in regard 

 to the vast and never-failing supply of minute crustaceans and 

 other forms wliich Nature provides in the open sea for the 

 sustenance of the delicate and translucent young of the food- 

 fishes. No ordinary atmospheric change can materially modify 

 this wealth of pelagic life, though it is true that in some 

 seasons its appearance and that of the young fishes which 

 prey on it may be slightly varied. 



The importance of the pelagic element in the food of our 

 fishes cannot readily be over-estimated. Without it the 

 young fishes, after the absorption of the yolk-sac, would 

 become emaciated and perish. Moreover the minute size of 

 certain of the constituent forms is eminently adapted for the 

 needs of the most tiny fishes ; while the adults of the same 

 crustaceans, or those of more bulky species, fit in as suitable 

 sustenance of young fishes of larger size. The interchange, 

 again, taking place between the bottom-fauna and the surface, 

 viz. of eggs and early larvas passing upward, and of older 

 forms going downward, keeps up a constant stream of food 

 for the young fishes, which have a similar migration. But 

 they do not, unmolested, thus levy a tax on the lower types. 

 The larger food-fishes prey perpetually on the smaller ; indeed 

 certain stages in the development of the rarer fishes have 

 hitherto been procured only from the stomachs of predaceous 

 pelagic fishes, such as the various tunnies. In the same way 

 early stages of haddock, whiting, and herring drop from the 

 mouths of cod when landed on deck from the trawl. Thus a 

 check is kept on the enormous powers of reproduction so 

 characteristic of the food-fishes — powers of reproduction which 

 have hitherto been, and doubtless will continue to be, of great 

 benefit to man. 

 Ann. & Mag. N. Hint. Ser. 5. Vol. xix. 10 



