Environmental contaminants in blood, hair, and tissues of ocelots from theLower Rio Grande Valley, Texas, 1986-1997

The ocelot (Felis pardalis) is an endangered neotropical cat distributed wi thin a small range in the Lower Rio Grande Valley (LRGV), in Texas, U.S.A. Studies of the impacts of environmental contaminants in wild cats are few. Approximately one fourth of the estimated population (about 100) of ocelots in the LRGV was sampled to evaluate the impacts of chlorinated pesticides, polychlorinated biphenyls, and trace elements on the population. Hair was collected from 32 ocelots trapped between 1986-1992, and blood was collecte d from 20 ocelots trapped between 1993-1997. A few blood samples were obtai ned from individuals recaptured two or three times. Tissue samples from 4 r oad-killed ocelots were also analyzed. DDE, PCBs, and Hg were some of the m ost common contaminants detected in hair and blood. Mean Hg levels in hair ranged from 0.5 to 1.25 mu g g(-1) dw, Se from 1.5 to 3.48 mu g g(-1) dw, a nd Pb from 0.56 to 26.8 mu g g(-) (1) dw. Mean DDE concentrations in plasma ranged from 0.005 mu g g(-1) ww to 0.153 mu g g(-1) ww, and PCBs ranged fr om 0.006 mu g g(-1) ww to 0.092 mu g g(-1) ww. Mean Hg levels in red blood cells ranged from 0.056 mu g g(-1) dw to 0.25 mu g g(-)1 dw. Concentrations of DDE, PCBs, or Hg, did not increase significantly with age, although the highest concentrations of DDE and Hg were found in older animals. Overall, concentrations of DDE, PCBs, and Hg were low and at levels that currently do not pose any threat to health or survival of the ocelot. This is further supported by good reproduction of the ocelot in the LRGV, where adult fema les averaged about 1.5 kittens/litter. Thus, it seems that the current majo r threat to recovery of the ocelot in the LRGV may be habitat loss, althoug h potential impacts of new generation pesticides, such as organophosphorus and carbamate insecticides need further study.