Preliminary results on ecotoxicological investigation on gray whales (Eschrichtius robustus) in the san Ignacio lagoon (Mexico)

The main objective of this pilot project was to investigate for the first time the ecotoxicological status of gray whale (Eschrichtius robustus) in the San Ignacio Lagoon (Mexico). The differences in CYP1A1 and CYP2B expression, and contaminant levels (OCs) were investigated in two different period of the breeding season and between mothers and calfs using skin biopsy as diagnostic tool. The DDTs level were slightly higher in calf blubber in comparison to the mother, despite the PCB concentration are similar, suggesting the maternal transfer of POPs trough lactation. In conclusion these preliminary data point out that there is an accumulation of chlorinated POPs in gray whale calves resulting from the lactational transfer of these compounds from their mothers. Exposure to POPs (such as DDTs) at early life stages may have toxic impacts on their developing endocrine, immune and neural systems. However, the impact of these contaminants on health and development of gray whale calves is currently unknown.