THE SEA FISHERIES OF EASTERN NORTH AMERICA. 79 



Here, according to some writers, it has been ascertained that, while it 

 may require 1 pound of flesh to increase the weight of a trout from 3 

 ounces to 6, the addition of the next 3 ounces to the weight requires at 

 least 2 pounds of flesh; for the next 3 ounces, 3 pounds ; for the next, 4 

 pounds, and so on in a constantly increasing ratio. Finally, when the 

 fish has attained the maximum development possible in the given limits 

 of the pond or stream, comparatively little effect is produced by any 

 amount of feeding. 



In this point of view, therefore, and in reference to a future supply 

 of food, the capture of all the old and fully matured fish is especially 

 desirable, apart from their own greater commercial value. 



Worms, mollusks, &c, feed on the organic mud of the sea bot- 

 tom, caused by the decomposition of sea- weeds, eel-grass, and land or 

 fresh- water plants carried down. Other animals and fish feed on this. 

 Infusoria eat diatoms ; larger forms consume infusoria. 



Apart from the consumption of shrimps and other crustaceans the 

 stomachs of mackerel are not unfrequently found to contain small sand- 

 lance and what the fishermen call all-eyes. These are said by them 

 to be the embryors, quite recently hatched, of fishes, in which the body is 

 transparent and the eyes very conspicuous, indeed, almost the only 

 portion visible. In summer, schools of all-eyes are found on our coast, 

 sometimes in immense quantities. Captain Hulbert informs me that in 

 July the stomachs of the mackerel were fou nd loaded with these fish 

 which were seen also on the surface of the water, forming extensive 

 schools. On one occasion he went out seaward from Block Island for 25 

 miles without getting through the schools, and they were equally abun- 

 dant to the right and left of him, so thick, indeed, that a dozen at a 

 time could be scooped up in the palm of the hand. 



To what species these belong is uncertain, although the fishermen 

 surmise that they are young mackerel. It is, however, quite probable, 

 after all, that they may be the young or zoea-stage of crustaceans.* 



Fishermen inform me that they frequently find mackeral apparently 

 feeding on the jelly-fish, their method of attack being from below, com- 

 ing upward and striking through the center and making a hole in it. 

 It is very common to find the jelly-fish floating on the surface torn to 

 pieces in this way. 



* I have frequently found young mackerel — blinks — several inches in length in the 

 stomachs of mackerel. These are sometimes as large as they are able to swallow. 

 Without doubt they also feed to .some extent on the smaller crustaceans. As is well- 

 known, a variety of these forms grow on floating sea-weed, and many fishermen con- 

 sider it a good sign of mackerel in the vicinity when they see floating eel-grass broken 

 into small fragments. They assert that the cause of the eel-grass being "chopped 

 up" in such a manner is because it is bitten into by mackerel. This is perhaps true> 

 and, if so, is doubtless done by the fish while feeding on the small shell-fish with 

 which the grass or sea-weed is generally covered. J have observed mackerel attack- 

 ing Jelly-fish, 



J, W, COLLINg, 



