Mercury (Hg) contamination of oceans is rapidly increasing, however Hg bioaccumulation in pinnipeds has been understudied. Here, we report for the first time Hg concentration in liver tissues of South American fur seals (Arctocephalus australis) in South and Southeast Brazil. Hg concentration was determined in twenty-five fur seals’ specimens found stranded along the coast of the Southwestern Atlantic Ocean. Samples were digested using the microwave technique and quantified by cold vapor generation atomic fluorescence spectrometry technique. The average Hg concentration was 6.37 mg kg-1 (wet weight), with a minimum concentration of 0.09 mg kg-1 and the highest concentration of 15.58 mg kg-1. No correlation between biological variables (sex, total length and weight) and Hg concentration in A. australis liver were found. The results presented here are of great importance to establish baselines for future evaluations of Hg contamination in marine mammals and the effects of this environmental problem in animal health.

ABSTRACT This study describes the diversity, distribution, richness, abundance and species composition of the deep sea Chondrichthyes (1,000-2,250 m) of the south Patagonian Archipelago, including Cape Horn, Diego Ramirez Islands and the northern area of the Drake passage, south eastern Pacific Ocean (52°43'S-57°05'S). The chondrichthyan fauna analyzed corresponds to the southernmost not Antarctic of the planet and consisted of 7 species belonging to 3 orders and 5 families. The species are the skates Amblyraja amblyraja frerichsi, Bathyraja cousseauae, Bathyraja meridionalis y Bathyraja macloviana and the sharks Somniosus pacificus, Squalus acanthias and Lamna nasus. The highest species richness was represented by the order Rajiformes, with 3 species of Arhynchobatidae and one species of the Rajidae, followed by the order Squaliformes, with one species of Squalidae and one species of Somniosidae. The order Lamniformes was represented by Lamnidae. The biomass was dominated by Rajidae and secondly by Somniosidae. Diego Ramirez Islands had the highest abundance and species richness, Desolation Island presented the greatest diversity and equity. The chondrichthyan fauna detected in deep waters of the southern area of the southeastern Pacific shows a strong similarity with South West Atlantic waters, even more than the one existing at mid-latitudes of the South Eastern Pacific, which corroborates the biogeographic patterns observed for coastal fish in the same area, for deepwater chondrichthyans.

The finding of two specimens of Bathyraja cousseauae (Batoidea; Rajiformes; Arhynchobatidae) caught off Diego Ramírez Islands and Cape Horn, southern Chile, is reported. Both findings correspond to the first record of this species in Chile and southeastern Pacific. This species is distinguished from all other softnose skates species of Bathyraja by the lack of thorns and interspace between dorsal fins in females whereas the clasper morphology, rod-shaped not expanded at proximal section of glands are distinctive features in males.

Se informa el hallazgo de dos especímenes de Bathyraja cousseauae (Batoidea; Rajiformes; Ar-hynchobatidae) capturados en las cercanías de las islas Diego Ramírez y el Cabo de Hornos, sur de Chile. Ambos especímenes proveen el primer registro de esta especie en Chile y en el Pacífico suroriental. La especie se distingue de otras especies de Bathyraja por la ausencia de espinas y espacio entre las aletas dorsales y, en especímenes machos, por la morfología de clásper, en forma de vara no extendida en la región proximal.