In the previous couple of months, numerous authorities and non-governmental organisations in Andhra Pradesh, Odisha, and Punjab have launched mosquitofish into native water our bodies to handle a mosquito menace that locals have complained about. In truth, officers in Visakhapatnam are set to launch a further six lakh mosquitofish after having launched some 20 lakh just a few months in the past.
The world’s local weather and habitats have modified noticeably within the final century, accelerating the unfold of mosquito-borne ailments. Today, these ailments prevail in additional than 150 international locations worldwide, affecting greater than 500 million individuals. In India alone, round 40 million people contract mosquito-borne ailments yearly, and mosquito-borne sicknesses have remained a persistent public well being concern for a lot of many years.
What is mosquitofish?
In this milieu, the organic management of mosquitoes assumes significance. In the Sixties, such approaches – together with introducing mosquitofish in freshwater ecosystems to feed on mosquito larvae – turned outstanding as alternate options to chemical options like pesticides, which have been discovered to have dire hostile results on each human well being and the ecosystem. The uptake of those alternate options elevated within the Nineteen Eighties and Nineties.
Many of them have been thought-about to be environmentally pleasant and sustainable. Among mosquito predators have been two species of mosquitofish, Gambusia affinis and Gambusia holbrooki. In international locations with governments that had accepted this technique, the authorities launched them into freshwater ecosystems.
What they didn’t plan for, nonetheless, was that the fish started to proliferate right here, with their populations ultimately spreading far past their unique habitats.
These species of mosquitofish originated within the U.S. however in the present day have turn out to be international inhabitants. They are infamous for his or her detrimental ecological affect, together with displacing and preying on native fauna, main to the extinction of native fish, amphibians, and numerous freshwater communities. As such, Gambusia stands out as a number of the most generally dispersed freshwater fish, aided by their strong adaptability and excessive tolerance for fluctuating environmental situations.
Is mosquitofish ‘used’ in India?
The Indian Council of Medical Research (ICMR), India’s nodal medical analysis organisation, performs a major position in mosquito administration within the nation – significantly within the context of controlling mosquito-borne ailments and conducting analysis to develop efficient methods.
In 1928, Gambusia was first launched in India throughout British rule. Later, numerous governmental organisations, reminiscent of the ICMR, the National Institute of Malaria Research (NIMR), native municipal firms, the Fisheries Department, and the Health Department, alongside different personal organisations in India, took over as a part of their efforts to fight malaria.
The thought of this scheme was that the newly launched species would prey on or compete with mosquito larvae, decreasing the latter’s inhabitants. The authorities additionally entrusted a number of municipal firms, district administrations (and their well being departments), fisheries departments, tribal improvement companies, native aquaculturists, and most of the people with introducing these fish throughout India.
Today, as within the American story, Gambusia, has turn out to be widespread in India as effectively, establishing self-sustaining populations in numerous habitats across the nation.
The technique was well-intentioned however it backfired, main to extreme ecological and environmental issues.
What results has mosquitofish had?
The authors not too long ago investigated the range of haplotypes and genotypes inside Gambusia species in India. (Haplotypes are DNA variants possible to be inherited collectively; the genotype is an organism’s total genetic materials.) Our efforts revealed the widespread distribution of G. holbrooki and, to a lesser extent, G. affinis, the latter particularly so in Northeast India.
Wildlife biologists and conservations take into account mosquitofish to be among the many hundred most detrimental invasive alien species. Aside from their resilience, these fish even have voracious feeding habits and have demonstrated aggressive behaviour in habitats to which they’re launched. India’s Gambusia story thus underscores the significance of cautious consideration, analysis, and monitoring when utilizing organic management strategies to handle pest species.
Studies performed in different international locations have constantly revealed the dangerous penalties of the presence of Gambusia in water our bodies. For instance, in Australia, launched mosquitofish have led to the native extinction of the red-finned blue-eye (Scaturiginichthys vermeilipinnis), an endemic fish species. They have additionally been noticed preying on the eggs and larvae of native fish and frogs. A research from New Zealand highlighted the menace posed by Gambusia to their native aquatic biodiversity. In India, some stories have indicated a decline in Microhyla tadpoles following the introduction of Gambusia.
For these causes, the World Health Organisation stopped recommending Gambusia as a mosquito management agent in 1982. In 2018, the National Biodiversity Authority of the Government of India additionally designatedG. affinis and G. holbrooki as invasive alien species. But each authorities and non-governmental organisations in India have continued to introduce these species for mosquito-control.
How can mosquitofish be managed?
At this time, extra stringent enforcement measures are essential to stop the species from persevering with to be launched to freshwater ecosystems and to handle the implications of previous introductions. Both additionally embody the duty of safeguarding our indigenous aquatic biodiversity and the well-being of native species.
Put in a different way, the issue in the present day is each wolf on the door and termites on the base, and the optimum resolution wants practitioners to deal with the issue from a number of angles. The first has to do with the National Centre for Vector Borne Diseases Control (NCVBDC) – of the Ministry of Health & Family Welfare – displaying a advice on its web site for the usage of Gambusia and Poecilia (guppy) fishes to handle mosquitoes. This advice have to be eliminated.
Second, for efficient mosquito management, alternate options to Gambusia ought to come from native options. Experts have urged a collaboration between mosquito biologists/entomologists, invasion ecologists, and fish taxonomists, with a concentrate on river basins. Together, they’ll compile lists of native fish species in every basin which are able to controlling mosquito larvae. Then, based mostly on these lists, authorities can launch the related species into the pure atmosphere, sidestepping the chance of ecological repercussions posed by invasive alien species.
The authors are with the Ashoka Trust for Research in Ecology and the Environment, Bengaluru.
