Mosquito Pesticide Suspected in Lobster Deaths
(Beyond Pesticides, October 7, 2011) Commercial lobster fishers operating in Long Island Sound off the coast of Connecticut have begun to suspect that the mosquito killing chemical methoprene, sprayed by neighboring New York State as part of its West Nile virus (WNv) control program, is contributing to widespread deaths of lobsters in the sound. Believing that a large amount of the chemical flowed into the sound in late summer due to heavy rains from Hurricane Irene, the lobster fishers are asking New York to follow Connecticut’s example and switch its WNv control method to the less toxic bacillus thuringiensis.
Late summer declines in the sound’s lobster population have been alarmingly common throughout much of the last decade, devastating fishers and the local economy that depends on them. A number of factors have been blamed, but the lobstering community has increasingly been pointing to mosquito pesticides for several reasons. Methoprene has a tendency to sink to the bottom of the ocean water, where lobsters live and feed. Additionally, lobsters are a distant cousin of mosquitoes, and the methoprene acts on them in much the same way that it does the insects. Finally, the western part of the sound was the hardest hit. Not only is this the area that is closest to New York, but it is also one of the areas more protected from ocean currents that would normally help to wash the chemical out into the open sea.
In 2003, it was determined by researchers at the University of Connecticut that methoprene was deadly to lobsters at concentrations of only 33 parts per billion. The research was seized upon by the lobstering community as part of its quest to seek legal recourse against chemical companies whose pesticides they blamed for widespread lobster deaths in 1999.
The fishing community has been pushing state lawmakers in Connecticut to open a dialogue around the issue with their counterparts in New York. One state Representative, Terry Backer (D-Stratford), has taken up the fight, arranging meetings on the issue and gathering affected parties. Backer also directs a local non-profit organization that works on issues of water quality in the sound.
The WNv control plan adopted by one county on Long Island, Suffolk County, was highly controversial when first passed, partly over its planned use of methoprene. Despite major objections from other county agencies, environmentalists, and members of Suffolk’s Council on Environmental Quality (CEQ), the County Legislature passed the plan in 2007. The CEQ advises lawmakers on the environmental impact of proposed county projects and while their recommendations are non-binding, the legislature has generally followed the group’s advice. Approval of the plan caused several members of the CEQ to resign in protest.
The effect of mosquito pesticides on marine life, especially lobsters, has repeatedly come under scrutiny over the years, in Connecticut as well as in other northeastern waters, such as the Bay of Fundy. Some of the other mosquito killing chemicals suspected of causing damage to aquatic life include cypermethrin and malathion. Both are already known to be toxic to many aquatic species, including crustaceans.
Communities and agencies in New York have taken a stand against unnecessary pesticide spraying in the past, in areas such as pesticide free state parks and safe school playing fields. Some would argue that the states’ outdated mosquito management scheme is inconsistent with these past actions, and that it is time to bring it in line, not only with other policies in the state regarding pesticide use, but also with the wealth of knowledge and evidence concerning the harmful effects of pesticides on human health and the environment, as well as nearby local economies.
Other municipalities around the country have consistently proven that dangerous pesticides are not necessary to effectively control mosquitoes and prevent outbreaks of West Nile virus. Prevention strategies, such as removing standing water and using least-toxic larvicides only as a last resort, have been adopted in such densely populated areas as Shaker Heights, OH and the District of Columbia. To learn more about safe and effective mosquito management strategies, visit Beyond Pesticides page on Mosquitoes and Insect Borne Diseases.