Evers, D. C., BioDiversity Research Institut, Gorahm, USA, david.evers@briloon.org
Graham, R. T., Wildlife Conservation Society, Punta Gorda, Belize, rgraham@wcs.org
Perkins, C. R., University of Connecticut, Storrs, USA, christopher.perkins@uconn.edu

SHARK MERCURY LEVELS IN BELIZE

Mercury (Hg) loading in global aquatic ecosystems is a growing concern. Compelling evidence of widespread adverse effects in fish and wildlife populations indicates the rate of transformation to methylmercury is problematic. Long-lived, apex predators such as sharks are at high risk to Hg toxicity. We investigated the occurrence of Hg in sharks from coastal waters of southern Belize. In our pilot study, 89 sharks representing 8 species were analyzed for muscle Hg levels in 2007. Highest Hg levels were recorded in blacktip, hammerhead, and nurse sharks. Lowest Hg levels were recorded in bonnethead, sharpnose, and lemon sharks. Over 88% of the sharks sampled exceeded USEPA human health consumption standards. Muscle Hg strongly correlated with size for blacktip and nurse sharks. Such models provide a tool for confidently predicting muscle Hg levels in some shark species used for human consumption. Mercury levels measured in hammerhead and nurse sharks exceeded known adverse effect thresholds for fish. An assessment of the potential negative impacts from Hg on shark survival and reproductive success is needed to support global shark conservation efforts.

Poster presentation

Presentation is given by student: No
Session #:187
Date: 03-03-2008
Time: 17:30 - 19:30