South Seas

How Gambusia Were Introduced Into

Larvae-Eating Fish Check Mosquito Breeding.

A YOUNG official of Sydney City Coun cil (Mr. W. O. Vogwell, F.I.S.E., M.R.

San. I., Chief Health Inspector) has performed a service of great value to all the people of the South Seas. He has carried out his work so quietly and un ostentatiously that very few realise what has been done. Posterity, however, will do honour to the name of Health Inspec tor Vogwell.

Mr. Vogwell was on a holiday trip abroad in 1926 and he inquired about modern methods of guarding the public’s health. It was then that he heard about a small larvae-eating fish, Gambusia affinis. It appears that this fish had come under notice in the West Indies, owing to its habit of eating the larvae of mos quitoes. It was a voracious little crea ture, living in fresh water and attack ing all other living things in the water, such as insects and other small fish.

Mr. Vogwell learned that the Govern ments of Italy and Spain had recently brought over a consignment of Gam busia from the West Indies, with a view to propagating the fish in the ponds and swamps of their respective countries, to check the mosquito pest. He learned that the Italian consignment died, but the fish were satisfactorily established in Spain, and a quantity were then sent to Italy.

Thereupon Mr. Vogwell went to Italy and continued his investigations. He learned that the result of the liberation of the fish in the mosquito infested swamps of Italy had been very marked.

Italian officials were kind and helpful, as a result of which Mr. Vogwell, at his own expense, had a container con

structed, wherein he placed a consider able consignment of the Italian Gam busia. Mr. Vogwell took his container aboard the mail steamer at Naples and gave the fish his personal care during the voyage to Sydney.

The fish were liberated in a pond in the Sydney Botanical Gardens, where they flourished. Within a few years there were millions of the savage little creatures available, and they were liber ated all over the Sydney district, where they had a marvellous effect in clearing stagnant and semi-stagnant water of mosquito larvae. It was found that they were very hardy, were propagated easily, and could live and flourish in water of extreme stagnancy even in mud puddles. They were liberated, for in stance, in the high, square, water-pres sure tanks which may be seen above many big buildings in Sydney, and which previously were breeding-grounds for mosquitoes. The Gambusia has lived for years, now, in some of these tanks and, of course, the mosquito larvae has been destroyed therein.

The Gambusia was widely distributed from Sydney and the establishment of the fish in stagnant water all over the Commonwealth is now a recognised duty of the various health authorities.

One day, early in 1930, Health In spector H. O. Plummer, of the New Guinea Department of Public Health, called on Mr. Vogwell in Sydney and became interested in Gambusia. As a result of this, Mr. Vogwell and Mr.

Plummer introduced the fish to Rabaul.

The first consignment arrived there in March, 1930, and it was successfully pro

pagated in a pond in the Rabaul Botani cal Gardens. The Territory’s Health De partment quickly perceived the value of Gambusia, with the result that, in the succeeding three years, the fish has been distributed over much of the Mandated Territory and has had a most satisfac tory effect in checking the breeding of mosquito larvae. Gambusia was liberated, for instance, in the Lakunai swamp, near Rabaul, and undoubtedly cleaned that breeding ground of the Anapholes.

The Chief Health Officer reported in 1931 that the fish showed a decided pre ference for the Anapholes larvae. The effect of Gambusia in checking malaria among natives in New Ireland has been truly remarkable.

The New Guinea health authorities sent a consignment of Gambusia to Papua and there, again, the fish has been propagated and distributed with satisfactory results.

It is interesting to note that the 12 youths who have been sent to the Syd ney University for special training for public health work in Papua have been introduced to Gambusia. They are being shown how to care for and propagate the fish, and its distribution in Papua will be part of the duties which the young Papuans will undertake upon their return.

A consignment of Gambusia was sent from Sydney to Suva, and it is under stood that in Fiji also this useful crea ture is being made use of to an increas ing degree in combatting the mosquito pest.

It is, however, as a factor in the war against the Anapholes (the carrier of malaria) that Gambusia will be most valuable; and it is likely that in the years to come the name of Mr. Vogwell, who brought Gambusia to the South Seas, will be praised in all those Pacific Territories where malaria in the past has taken so heavy a toll of native and European life.

Government health officers are not given to rhapsodies in their official re ports; but it can be said that the Chief Health Officer of New Guinea, in his re ports for 1931 and 1932, has permitted a note of enthusiasm to creep into his re ferences to Gambusia, and his descrip tion of how the distribution of the vora cious little fish is helping in the great work against malaria. (An article in the “P.I.M.” of January, 1933, containing quotations from the official medical reports, showed that the use of Gambusia had had extraordinary results in reducing the incidence of malaria among New Guinea natives).