Reducing impacts of hopper dredging on marine turtles in the northwestern Gulf of Mexico
Sundin, Gary W.
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Three species of threatened or endangered marine turtles are sometimes harmed or killed by hopper dredges in U.S. shipping channels: loggerhead (Caretta caretta), green (Chelonia mydas), and Kemp’s ridley (Lepidochelys kempii). The U.S. Army Corps of Engineers manages dredging in these channels and works to monitor and mitigate negative impacts on turtles. I analyzed Corps of Engineers data to examine turtle behavior and relative abundance in shipping channels in the northwestern Gulf of Mexico, and provide information to reduce dredge-turtle interactions in the region. Turtles were taken by dredges and captured by trawls more frequently in southern channels relative to northern channels. Dredge take and trawl capture rates were greatest during March-June relative to other periods. Projects using relocation experienced fewer takes, on average, than projects without relocation trawling. Dredge hopper size and drag arm configuration, sea surface temperature, and period of day also affected rates of take and capture.