NOAA releases study on pesticide impacts on oysters and clams

Four of the most common mosquito pesticides used along the east and Gulf coasts show little risk to juvenile hard clams and oysters, according to a new study by the National oceanographic and Atmospheric Administration.

The study sought to address a lack of toxicity data for mosquito control pesticide effects on shellfish early life stages.

Commercial shellfishing has a large economic national impact. 

NOAA Fisheries estimated that U.S. oyster and hard clam landings for 2010 were worth nearly $118 million and $41 million, respectively.

Shellfish growers, however, are concerned that pesticide spraying near the coastlines may contaminate both their hatcheries and source waters.

The research team examined the toxicity of four mosquito control pesticides (naled, resmethrin, permethrin, and methoprene) to larval and juvenile life stages of hard clams and Eastern oysters.

However, the study also determined that lower oxygen levels in the water, known as hypoxia, and increased acidification actually increased how toxic some of the pesticides were.

Overall, clams were more susceptible to mosquito control pesticides than oysters.

Naled, an organophosphate chemical, was the most toxic compound in oyster larvae, while resmethrin was the most toxic compound in clam larvae.

Decreased swimming activity was observed after four days in larval oysters and decreased growth was found in juvenile clams and oysters after 21 days.

The study did not address the impacts of the pesticides on other shellfish such as shrimp or lobsters.

http://live.oysterradio.com/