THE SEA FISHERIES OF EASTERN NORTH AMERICA. 75 



Except iii the earlier stages of life, as already explained, the chief 

 sustenance of fishes in the sea consists of animal matter, either dead or 

 living. While some hinds of fish are believed never to feed upon any- 

 thing but living animals, otbers are, to a very great extent, scavengers, 

 being especially appointed to devour dead or decaying substances, such 

 as offal or the so-called gurry, &c. The cypriuodonts of the coast are 

 particularly active in this direction. Sharks also exercise the same func- 

 tion in a very marked degree. There are probably but few of the bot- 

 tom fish that will disdain such substances, consuming living forms with 

 the same readiness. In the business of clearing out refuse fish they are 

 assisted largely by crustaceans, certain mollusks, echini, &c. 



The living food of fishes may be divided into two sections : first, eggs 

 and embryos; second, fishes and marine invertebrates of more mature 

 and advanced ages. 



The earliest form in which the fish serves as food for its fellows in the 

 sea is in that of the egg, and it is for this reason that with the enormous 

 fecundity of certain fish there is so little apparent increase in their 

 schools. It may safely be assumed that only a small fraction of 1 per 

 Cent, of the total number of eggs laid by fishes ever develop embryo 

 fish, by far the greater part being devoured in a very short time. The 

 young fish, also, after birth, is for a certain time immature and to a con- 

 siderable degree helpless and only able to take food for itself after the 

 absorption of its yolk-bag and the accompanying development of its 

 fins. Before it assumes the shape of the perfect fish and is able to care 

 for itself, it becomes a prey to innumerable enemies; and if of the orig- 

 inal deposit of eggs one fish becomes able to care for itself by feeding 

 and hiding to every ten thousand eggs hatched, it may be considered a 

 very satisfactory yield. The proportion, however, doubtless varies with 

 the species. 



Under the rate of the fecundity of fishes will be found a table of the 

 numbers of eggs laid by particular kinds of fishes, partly copied from 

 Buckland and partly original, from which we understand that even 

 with this percentage of loss there is still a margin left for the main- 

 tenance of the species. 



Although the percentage of loss after the embryonic development of 

 the fish is complete is less than before, there is still a very great drain 

 upon the numbers of the species, there being at every step an enemy 

 lurking in wait to devour. 



To the large fishes of course there comes a time of comparative 

 immunity, when nothing but the rarer and more powerful inhabitants 

 of the sea can interfere. Even then, however, numbers of smaller ene- 

 mies may combine together for the overthrow of the monsters that 

 would be more than a match singly for any antagonist, and thus while 

 fish of the known voracity of the cod, haddock, &c, may consume 

 readily species of a smaller size, they have as their antagonists the 

 sharks, the various porpoises, and other cetaceans, and the rarer 



