Whale shark Rhyncodon typus exposure to organochlorine pesticides in the Southern Gulf of California, Mexico.

Organochlorine pesticides (OCPs) are persistent organic pollutants (POPs), characterized by their high mobility and environmental persistence, bioaccumulation, and trophic transfer. Considering the highly migratory nature and longevity of the whale shark, this species can be considered as an early warning bioindicator of regional contamination from the marine environment. This work investigated the concentration of twenty OCPs in thirty whale shark skin biopsies, collected between 2014 and 2015 in Bahía La Paz (Gulf of California, Mexico). Mean detected OCP levels were 33.99 ± 105.23 ng/g dw (dry weight), and ΣChlordane, ΣDrin, and ΣHCH showed the highest concentrations. Statistically differences in mean OCP concentration were not found by sex and size. PC1 and PC2 accounted for 68.1 % and 16.1 % of the total variance, respectively. The presence of higher levels of some pesticides than their corresponding metabolites suggests recent applications related to agricultural activity in the surrounding areas of Baja California peninsula.