Many Connecticut lobstermen have long suspected that mosquito pesticides are the culprit in the massive lobster die-off that began in 1999 in Long Island Sound.
After all, it was in the late 1990s that Connecticut and New York started using larvicide "dunks" in storm drains, as well as aerial spraying, in order to control the mosquitoes that carry West Nile virus — however both states have recently cut-back their use of the chemicals.
Now, a joint study by the Connecticut Department of Energy and Environmental Protection and University of Connecticut’s Veterinary Medical Diagnostics Laboratory has turned up traces of the pesticides in Long Island Sound lobsters, according to a DEEP news release.
DEEP officials sent nine "weak" lobsters caught in an area in the middle of the Sound, south of Norwalk, in September, 2011 for testing at the UConn lab. First the lobsters were tested for the presence of bacteria or parasites that are sometimes present when the creatures become stressed due to warmer than normal water temperatures. These tests "provided no evidence of a consistent pattern of tissue injury that would explain the mortalities," according to the DEEP.
But when the lobsters' tissues were tested for the presence of three common mosquito pesticides — malathion, methoprene, and resmethrin — "the tests showed some lobsters collected in the mid-Sound waters were exposed to resmethrin and at least one was exposed to methoprene. Malathion was not present in any of the samples," the release states.
The DEEP, however, cautions that the testing is only preliminary and therefore not conclusive.
"Given the preliminary nature of these tests and the small sample size, it is not yet clear what the presence of the pesticides in the lobster tissue means to the relative health of the lobster population," the release states.
As such the DEEP is "undertaking a comprehensive study seeking reasons for the continued decline in the lobster population of Long Island Sound," which will, said DEEP Commissioner Daniel C. Esty, employ "sophisticated laboratory tests to obtain a better understanding of why this species — and an industry it has historically supported — is now in danger of collapse."
The DEEP hopes to have the results from the next round of testing this fall.