FISHES IN RELATION TO MOSQUITO CONTROL 
IN PONDS.’ 
~~ 
By SamueEt F. HitpEBRAND, 
Superintendent, U. S. Fisheries Biological Station, Key West, Fla. 
INTRODUCTION. 
The United States Commissioner of Fisheries, in response to a 
request from the United States Public Health Service for an ichthy- 
ologist, detailed the writer to cooperate with the public health 
authorities of the extra-cantonment zone of Camp Hancock, Augusta, 
Ga., 10 an antimalarial campaign. The duty assigned to the author 
was an investigation of the effectiveness of fishes as eradicators of 
the aquatic stages of the mosquito, and the conduct of such opera- 
tions as would promise secure “‘ fish control” in the extra-cantonment 
zone, where there were many swamps, ponds, and small lakes in 
which control by oiling was impracticable. This area covers a terri- 
tory approximately a mile wide surrounding the camp, the city of 
Augusta, and a belt about a mile wide surrounding the city limits. 
The swamps, fortunately, were nearly all drainable, but the ponds 
were mostly so situated and of such a nature that draining was either 
impracticable or impossible. The ponds, however, presented a situ- 
ation which offered excellent opportunities for testing the practical 
value of fishes as eradicators of mosquito larvee and pupx. Experi- 
ments were at once started and observations were continued brea 
March, 1918, to November 8, 1918. Much credit for the success of 
the work is due the local authorities of the United States Public 
Health Service for their excellent cooperation in furnishing labor, 
transportation, and other facilities for conducting the investigation. 
Quite a number of species of fishes have been mentioned by writers 
in connection with the mosquito problem. The usefulness of some of 
these in aquaria and small pools, at least, is well known, but accurate 
information as to their effectiveness in larger bodies of water, and 
especially in places where the immature mosquito finds protection 
among plants or débris, is largely wanting. The summer’s investi- 
gation was almost wholly devoted to the determination of the practi- 
cal value in antimalarial work of the top minnow, Gambusia affinis 
(Baird and Girard). 
The experiments were conducted in a large series of ponds which 
afforded many different conditions. It is the writer’s intention to 
relate how the investigation was conducted and to mention results 
and conclusions. It is hoped that the value of the top mimnow may 
a This report embodies the results of investigations conducted by the Bureau of Fisheries in cooperation 
with the Public Health Service and was published originally by the United States Public Health Service 
in Public Health Reports, Vol. 34, No. 21, May 23, 1919. 
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