74 EEPORT OF COMMISSIONER OF FISII AND FISHERIES. 



weirs for herring at Grand Manan. Fastening on the exterior, they eat 

 off the bark in circular spots. ' 



There is, therefore, no difficulty whatever in establishing the exist- 

 ence of vegetable matter in the sea in sufficient quantity to serve as the 

 basis for the stupendous mass of animal food derived from it. 



Starting thus from the vegetable kingdom the chain of succession 

 of animal life furnishes in oue or other of its links food to all the ani- 

 mals of the sea, in the process of such assimilation enormous numbers 

 of distinct organisms being consumed for the support of a single indi- 

 vidual. Nor is there any definite ratio between the size of the food 

 used and that of the animal raised upon it, since the baleen or bone 

 whales are believed to live almost entirely upon shrimps, floating mol- 

 lusks, and upou the smaller fish whenever they can be obtained in suf- 

 ficiently large schools. It is well known that herring are devoured in 

 multitudes by whales, such as the finback, &c. 



Sixty thousand copepods (Temora longicomis), by actual count, have 

 been taken from the stomach of a single herring, while many thousands 

 of herring have been taken from the similiar receptacle of the whale, 

 which shows that this miscroscopic shrimp may be regarded as one chief 

 source of the subsistence of the whale — another case of the relation 

 between the infinitely small and the infinitely great. 



Some fishes are believed to feed very largely upon the organic mud 

 of the sea-bottom, this of course being rich in some of the smaller forms 

 of animals and the diatoms. The examination of stomachs of large 

 numbers of the common menhaden, by Professor Yerrill, revealed no 

 other substances than the mud in question ; the fish being provided with 

 very thick, muscular walls to its stomach, a so-called gizzard, for the 

 special purpose of utilizing it. The J)orosoma, or gizzard shad, of the 

 rivers of the Atlantic coast, has also a similar provision. 



A favorite implement of the naturalist is that called the towing-net. 

 This is simply a bag of gauze, the mouth of which is held open by a 

 ring or brass frame, which is towed behind a boat or vessel so as to take 

 a skimming of the surface of the water. This can never be used in any 

 part of the ocean without very soon obtaining a greater or less number 

 of the minute animal organisms, such as the adult shrimp, the larval 

 stages of certain crabs, embryos of mussels and other mollusks, and 

 small fishes. 



Around floating sea-weed in mid-ocean are always congregated great 

 swarms of minute animals. The presence of whales, dolphins, albicores, 

 and other species of animals in mid-ocean also proves the occurrence of 

 food in vast quantities; as although all these species may not them- 

 selves devour the lower order of animals, they yet feed upon fishes 

 which do find their sustenance therein. 



It is not probable that any fish feed directly upon purely inorganic 

 matter. It is through plants that mineral substances of any kind are in- 

 troduced into the system, especially that which is required for the for- 

 mation of bone. 



