ZOOLOGICAL SOCIETY BULLETIN. 



1-35 



.Iqiiarium. 



White Perch as Destroyers of Mosquito 

 Larvce. — During the last week of May some of 

 the emplo3'ees of the Aquarium were sent to the 

 lake in Prospect Park, Brooklyn, to collect 

 specimens of black bass and white perch for ex- 

 hibition at the Aquarium. The large seine 

 which was used brought in hundreds of young 

 perch, a few of which were injured by being 

 "gilled" in the meshes of the net. Mr. W. L 

 DeNyse, who was in charge of the collecting 

 party, observed the young perch to be distended 

 with food which on examination was found to 

 consist chiefly of the larvae of mosquitoes. 



This observation is important in view of the 

 increasing interest taken in fishes useful in com- 

 bating the mosquito nuisance. The white perch 

 is a fish of the coastal waters, ascending streams 

 to spawn. Although chiefly a marine species, 

 it can be kept permanentlj- in fresh water, 

 where, however, it does not attain so large a 

 size. As it is an excellent food fish, the fact 

 that the young are active feeders on mosquito 

 larvae will be of special interest to persons se- 

 lecting fishes for private ponds. 



Attendance. — The winter attendance at the 

 Aquarium has been larger than ever before ; the 

 number of visitors from January 1 to April 30 

 inclusive having been 666,525, an average of 

 over 5,500 a day. Heretofore the attendance 

 for the first quarter of the year has but once 

 exceeded half a million and has seldom exceeded 

 450,000. This winter's record serves to indi- 

 cate that the year's attendance will far exceed 

 the two-million mark passed two years ago. 



Increasing Use of Carp. — The carp jjroblem 

 in this country is being gradually solved by 

 the commercial fishermen who are sending this 

 fish to market in greater quantities each j-ear. 

 The statistics of the U. S. Fisheries Bureau 

 place the annual catch of carp at about twenty 

 million pounds. 



The greater part of the catch of carp is made 

 in the Mississipj^i River and its tributaries, 

 where the annual yield exceeds twelve million 

 pounds, half of this total being derived from 

 the Illinois River. 



Over four million pounds of carp are taken 

 from the Great Lakes, three and a half millions 

 coming from Lake Erie alone. In other parts 

 of the country the carp is not yet being taken in 

 verv large quantities for market purposes, al- 

 though the Middle Atlantic States contribute 

 over a million pounds. 



The greatest development of the carp fishery 

 is taking place in Ohio and Michigan, the fish 

 being taken from Lake Erie and Lake Michigan. 

 The fishermen of Illinois have been making 

 money out of the carp for several years and 

 have been sui^plying a large part of the seven 

 or eight million pounds used each year in New 

 York City, There are now several other good 

 markets for carp, which the fishermen are sup- 

 plying at a fair profit. In many places along 

 the Ohio shore of Lake Erie the fishermen are 

 enlarging the ponds they have for some years 

 been using for retaining carp taken from the 

 Lake. The carp are caught in immense quan- 

 tities, Mhich makes it profitable to liandle them 

 at a low price and are shipped whenever the 

 conditions of the iish market are favorable. 



Large Sea Turtle. — On June 3, the Aquarium 

 received a large Leather-back turtle, (Der- 

 mochelys coriacea) from Baj-head, New Jersey, 

 where it was captured. The specimen weighed 

 750 pounds and measured six feet and five 

 inches from beak to tail. The top shell, along 

 the median ridge, was five feet long. Unfor- 

 tunately it did not reach the Aquarium alive, 

 although apparently without external injuries 

 of any kind. 



The Leather-back is the largest of all the 

 marine turtles. Unlike most of the other spe- 

 cies it does not live long in captivity. 



The New Salt Water System.— The New 

 York Aquarium is now using its new salt-water 

 system kno%vn as the closed circulation. Pure 

 sea water, brought in tanks from the ocean, and 

 stored in a reservoir, is pumped to the distribut- 

 ing tanks on the upper floor, whence it flows 

 through the exhibition tanks and then through 

 gravitj^ filters back to the reservoir. 



The new reservoir — holding 100,000 gallons 

 of stored sea water — and the new filters, have 

 been quietly under test for three weeks, and 

 have given entire satisfaction. 



This is the most important change that has 

 yet been made by the Zoological Society in 

 methods of operation at the Aquarium, It 

 means that the exhibition tanks containing 

 marine species will hereafter be supplied with 

 real sea water instead of the brackish, sewage- 

 laden water of the Harbor. It means also that 

 the high death rate among the sea fishes and 

 invertebrates due to polluted water, will be done 

 awaj' with, and that the exhibition of many 

 forms of marine life new to our collections will 

 be made possible. During the month of July 

 the marine exhibition tanks will be re-stocked, 



C. H. T. 



