402 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



"feeding" migrations and the spawning migrations, 

 and the feeding migrations depend upon the plankton. 



3. Bearing of Putter's Views. — The experiments 

 and arguments of Professor Putter in regard to 

 the nutrition of fishes and other aquatic animals 

 need not lead to any change of opinion as to 

 the economic importance of the plankton. If, as 

 seems likely in the light of the recent experiments of 

 Henze and B. Moore, Putter's figures require consider- 

 able modification, then the argument as to the 

 insufficiency of the plankton as a food material falls to 

 the ground. But even if Putter's figures are correct, or 

 partly correct, that consideration must if anything lead 

 to an enhanced estimate of the importance of the 

 plankton from the fisheries point of view ; as, if Putter 

 has shown anything new and true, it is that such an 

 animal as a fish could not be nourished by the amount of 

 plankton in the water if the material were merely 

 strained out of the average water of the sea area in 

 which the fish was living. In order to get an adequate 

 quantity of planktonic food the fish must seek out and 

 capture the Copepoda, for example, just as fish on 

 occasions can be seen to do. In other words, the fish 

 must go where the plankton is abundant, and must in 

 its movements follow the movements of shoals of 

 plankton. It is the very poverty of the plankton in 

 some sea areas, insisted on by Putter, Lohmann and 

 others, which makes it necessary for plankton-eating fish 

 to move about in search of more abundant supplies. 



4. Association of Fish with Plankton. — This 

 association of shoals of fish with abundance of plankton 

 is in agreement with many observations that have been 

 made by naturalists in the past. It is well known that 

 in coastal waters favourite line-fishing localities are 

 where strong tides run through narrow channels or over 



