THE FISH CURE FOR MOSQUITOES

Dominion, Volume 16, Issue 89, 11 January 1923, Page 5

THE FISH CURE FOR MOSQUITOES

SUCCESSFUL EXPERIMENTS IN AMERICA.

During the past fpw years tho prob* lem of fiow to destroy mosquitoes has engaged vlie attention of scientists, who m particular have been investigating tin? capacity of fish for eating mosquito larvae. Experiments lately, carried out in Norfolk by an export from the Natural History Museum led to a suggestion for the stocking of ponds with, carp; but as yet the suggestion has not been extensively adopted. A fresh impetus was given to research the other day when Professor Dubois, of Lyons, in a report which he submitted to the Academic des Sciences, advocated the stocking >.f ponds with young eels, on the ground.' that eels breed easily and • have a voracious appetite.

In England, where the mosquito danger is small, the science of combating it is naturally not far advanced. By contrast the use of fish for this purpose has become an established practice in Central American States. A serious epidemic of yellow fever broke out in Peru, for instance, in 1920, and spread rapidly. In February of last year- extensive measures were organised along vhe Pacific coast-, notonly to stamp out the mosquitos in. the infected zone, but to create a bf.rrier zone to prevent the further spread of the disease. Fish was distributed —■< two to four small fish to a container holding tan to fifteen gallons—and all ponds and water-bins were stocked. By July tho epidemic had been stamped out. A total of 750,000 fish had been distributed. As a precaution against the recurrence of the epidemic, tha fish “drive” was restarted this year along a front of 500 miles from Ecuador to Callao. This is a typical example of what is by now a commonplace operation in public health along the Pacific coart. Since 1900 the United States. Bureau of Fisheries has been experimenting, with the top minnow as a fish for desltjroying mosquit-cnes, and valuable results have been obtained in many parts of the world——for instance, in New Jersey, from 1902 to .1911; m Arkansas, in Georgia, and in sippiAmong the chief epidemics that have been stamped, out by the use of fish, may he mentioned, that of Guayaquil (Ecuador) in 1920, of Peru 1920-1921, Mexico 1920-1921, where it is calculated that an 80 per cent, degree of control was achieved; of Nicaragua, 1919 ■ of manv towns in tho Southern States, 1920-1921. All authorities # agree that an matgenous fish is bes’t. In the alternative an imported species must be thoroughly acclimatised and allowed to adjust itself gradually to its tiew home before use. Small fish of the family Poeciliudae are the ones most extensively used throughout tropical tmd temperate zones.