296 



U. S. BUREAU OF FISHERIES 



proved to be an excellent food for yoimg whitefishes, also. By feed- 

 ing at first on herring roe and afterwai'ds on the larvae of mosquitoes, 

 the aquarium has succeeded in carrying whitefish through the period 

 of infancy and has reared many specimens to the age of 10 years. 

 The larvae of mosquitoes are excellent for feeding whitefish fry and 

 yearling trout and are, in fact, devoured by many kinds of small 

 fishes, but this food is now less available than formerly, when 

 mosquito-breeding pools about the city were neglected. 



Nearly all fish food from the markets is headed and sometimes 

 eviscerated before being cut up. The cost of the market food used 

 at the aquarium during the past five years has averaged about 

 $2,800 a year. The various kinds of live food procured in connec- 

 tion with the work of capturing specimens for exhibition might be 

 valued at a quarter of that amount. Fresh menhaden, always 

 abundant in coastwise pound nets in summer, is fat and should be 

 used sparingly as food. Its cheapness makes it a desirable food for 

 large animals kept in floor pools. 



The sea cow, or manatee, which is a hearty feeder, eats some lettuce 

 and cabbage trimmings but greatly prefers a diet of salt-water eel- 

 grass. The manatee can also be fed a limited amount of fresh bread. 

 One manatee consumed exactly 90 bushels of eelgrass and 20 of pond- 

 weeds during the five months that it lived in the aquarium. Carp are 

 largely vegetable feeders but will eat all of the foods provided for 

 other kinds of fishes also. They are fed to some extent on soaked 

 corn or wheat, cooked corn meal, and the trimmings of vegetables. 



The sea turtles are fed chiefly on cut fish but will eat clams and 

 small mollusks. Sometimes they are supplied with cabbage leaves, 

 seaweed, sea lettuce, and eelgrass. Sea turtles are fond of whelks 

 and other large mollusks, the shells of which should be crushed. 

 Fresh-water turtles will take cut fish, meat, and pond snails and 

 should also be supplied at times with pondweeds. 



A useful guide in the woi'k of feeding at the aquarium is a care- 

 fully compiled catalogue of the natural foods of fishes and other 

 aquatic vertebrates. Many of these foods are not available during 

 the winter months, and the living exhibits suffer for lack of them. 

 The quantity and cost of the food used depend, of course, upon the 

 number and size of the specimens exhibited. These items rise in. 

 proportion to the number of heavy-feeding animals in floor pools, 

 such as seals, porpoises, and manatees. The accompanying table 

 shows the cost of food at the New York Aquarium during recent 

 vears : 



Fishes in captivity have rather limited space for exercise and can 

 not assimilate as much food as they might if at liberty. A number 

 of large fishes lost at various times were found, upon dissection, to be 



