Two female Northern fur seals (Callorhinus ursinus) (NFS) and two female California sea lions
(Zalophus californianus) (CSL) from the Mystic Marinelife Aquarium, the Smithsonian National Zoological Park, and Seneca
Park Zoo died with similar clinical and pathologic findings. Livers showed necrosis and/or nodular regeneration with cirrhosis
associated with high levels of iron within hepatocytes, Kupffer cells, and macrophages. Livers from these and other captive and
wild otarids were compared histologically using hematoxylin and eosin stains and Prussian blue stain for iron. Histologic iron
content was subjectively graded from 0-4+ with the following results: captive adult animals with histologic and gross lesions had
levels of 3+ - 4+. Captive seal pups had levels from 1+ to 3+, and wild cases had levels from 0-2+.
Paraffin-embedded liver samples analyzed for iron and copper content by atomic absorption spectrophotometry
varied from 10,700-27,000µg iron/g dry weight in captive adults. This compared with ranges of 364-872 µiron/g dry weight
in wild harvested fur seals with histologically normal livers. Copper levels ranged from 6-193 µcopper/g dry weight in captive
NFS and from 61-111 µcopper/g dry weight in wild harvested NFS with histologically normal livers.
Serum iron profiles from sixteen fur seals and three sea lions in adult females ranged from 72-341µg/dl of
iron, with total iron binding capacity (TIBC), from 100-286µ/dl, and % saturation from 31-100%. In males and NFS pups, serum
iron levels ranged from 77-162µ/dl; TIBC from 198-368µ/dl; and % saturation from 22-72%.
These data indicate that in captive female otarids iron accumulation is a pathologic process that may lead to
hemochromatosis. Further evidence suggests that increased dietary bioavailability of iron may result from a higher proportion of
fish fed than cephalopods in captive otarid diets.