THE MOSQUITO FISH, GAMBUSIA AFFINIS (BAIRD AND 

 GIRARD), IN THE PHILIPPINE ISLANDS 



By Alvin Seale 



{From the Section of Fisheries, Biological Laboratory, 

 Bureau of Science, Manila) 



ONE TEXT FIGURE 



In 1905 I was commissioned by the Hawaiian Government to 

 secure and transport to the Hawaiian Islands a shipment of 

 fish that would live in areas infested by mosquitoes and feed 

 on the larvse and eggs of these pests. 



At that time practically nothing was known regarding any 

 species that might fill these requirements, nor was it known 

 if such a fish, when found, could be successfully transported a 

 great distance. Helpful suggestions were received from various 

 friends, and I proceeded to Seabrook, Texas, to look for the 

 desired fishes. 



At that place I noticed a number of small top-minnows, or 

 killifishes, feeding on mosquito larvse. An examination was 

 made of the stomach contents of several species in order to 

 ascertain which had eaten the greatest number of mosquitoes. 

 This resulted in Gambusia afflnis being selected, and there has 

 been no reason to regret the choice. This species is now known 

 throughout the Orient as the "mosquito fish." 



About 400 specimens of this species were transported in 

 ordinary 10-gallon milk cans and landed at Honolulu September 

 15, 1905. When the fish were liberated in small breeding ponds, 

 which were stocked with mosquitQ larvse, they at once made 

 a vigorous attack upon these pests, suggesting a pack of wolves 

 ravaging a flock of helpless sheep. 



Two years later Dr. D. L. Van Dine, entomologist for the 

 Hawaiian Government, wrote as follows regarding these fish : ^ 



They have multiplied rapidly and from the few hundred introduced, 

 several hundred thousand have been bred and distributed. Where they 

 occur they effectively clear the water of mosquito larvse, feeding likewise 

 on the eggmasses of Cvlex pipiens on the surface. 



At the present time (1916) there are millions of these fish 

 in the Hawaiian Islands, and two men of the health department 



'Press Bull. Hawaii Agr. Exp. Sta. (1907), No. 20, 10. 



177 



