Premature Parturition in the California Sea Lion

Abstract

Twenty percent of the California sea lion pups born on San Miguel Island die due to premature parturition. Specimens collected from premature-partus animals resulted in recovery of a virus, San Miguel Sea Lion Virus, indistinguishable from Vesicular Exanthema of Swine Virus, and Leptospira pomona from some of the premature cows and pups. The age range of 10 females delivering healthy pups in June was 10-14 years. With one exception, the ages in 10 aborting females was 6-8 years. The p,p'-DDE levels of the premature parturient cows' blubber and liver were 7.6 and 4.8 times greater, respectively, than corresponding tissue concentrations in the full-term animals. Polychlorinated biphenyls residues were 4.4 and 3.8 times greater in aborting animals' blubber and liver than in the same tissues of full-term sea lions. Premature-partus females had tissue imbalances of mercury, selenium, cadmium and bromine. Pathology, parasitology, serum enzyme and hormone results are also presented. These data suggest an interrelationship of disease agents and environmental contaminants as the cause of premature parturition.

The Role of Domoic Acid in Abortion and Premature Parturition of California Sea Lions (Zalophus Californianus) on San Miguel Island, California

“…1). In the late 1970s, a high proportion (20%) of California sea lion pups born on the island were reported to die following premature parturition (Gilmartin et al, 1976). Higher concentrations of the organochlorine contaminants dichloro-diphenyl-trichloroethane (DDT) and polychlorinated biphenyls (PCB) were found in tissues from premature parturient dams and their pups than those measured in full-term dam-pup pairs (DeLong et al, 1973).…”

Variable Nucleotide Tandem-Repeat Analysis Revealing a Unique Group of Leptospira interrogans Serovar Pomona Isolates Associated with California Sea Lions

“…California sea lions are persistently exposed to serovar Pomona during nonoutbreak years (15). Intermittent exposure of California sea lions to the same L. interrogans serovar Pomona clonal population from another host species through accidental exposure over a 37-year period is unlikely (1,4,6,7,(10)(11)(12)(13)23). We conclude that California sea lions are maintenance hosts of L. interrogans serovar Pomona.…”

Organochlorine-Associated Immunosuppression in Prefledgling Caspian Terns and Herring Gulls from the Great Lakes: An Ecoepidemiological Study

“…Subsequent laboratory studies showed that HAHs increased susceptibility to bacteria (42,48,61), viruses (26,50,62), and protozoan parasites (26). Several investigators suggested associations between epizootics and elevated organochlorine exposure in beluga whales (Delphinapterus leucas) in the St. Lawrence Estuary (63), California sea lions (Zalophus californianus) on San Miguel Island (64,65), harbor seals (Phoca vitulina) in Europe (66)(67)(68), and bottlenose dolphins (Tursiops truncatus) in the Atlantic Ocean (69). At highly contaminated sites in the Great Lakes, doublecrested cormorants (Phalacrocorax auritus) had increased rates of eye infections associated with Pasteurella multocida (70).…”