UNLV scientists plan study of Lake Mead fish

Two scientists have proposed studies of Lake Mead fish tissues to determine if they are safe for eating.

James Pollard of the Harry Reid Environmental Research Center and Shawn Gerstenberger of UNLV's Environmental Studies Department say they expect fish such as large-mouth bass and stripers to show no evidence of chemical pollution or cancer.

But no one has looked at fish caught for sport from Lake Mead since the U.S. Geological Survey discovered the highest levels nationwide of endocrine disruption in male carp and pesticides in bottom-feeding catfish during a 1996 study.

Pollard has tentative funds up to $100,000 from UNLV and the Nevada Division of Wildlife to conduct a general study of about 400 fish. Scientists would look for lesions or cancerous tumors and then test the liver, brain and blood for heavy metals or industrial pollution from phosphates and carbon-based chemicals.

Gerstenberger outlined an ambitious detailed study starting with a questionnaire to be filled out by those fishing at Lake Mead. People fish near Las Vegas Bay and Hemenway Harbor, but who eats their catch and their ages are critical details, he said.

How fish are cooked can change the concentrations of chemicals, as well, he said.

Gerstenberger is interested in seeking polychlorinated biphenyls (PCBs), mercury and other heavy metals in fish. Effects from these substances are subtle, possibly affecting hormones, intelligence and behavior.

Once the survey is complete and fish are collected, 40 pounds of fish samples will be fed to pregnant laboratory rats. Then the babies will be studied to see how they behave, move, open their eyes and walk, Gerstenberger said.

The study would take three years, he said. Gerstenberger said he was interested in pursuing specific chemicals and metals after one 7-pound catfish showed high levels of the pesticide DDT during the USGS study.

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