Mortality in California Sea Lions. The pathologist's Impact on a Public Relations Problem
Patricia A. Gullett, DVM
Wildlife Pathologist, CDFG, California Department of Fish and Game, Wildlife Investigations Laboratory, Rancho Cordova, CA
Forty-two California sea lions washed ashore on a 2 mile stretch of Monterey Beach between 6-5-82 and 6-9-82. These animals died during the latter half of May. Due to extensive postmortem degeneration, no definitive cause of death could be determined. Seven carcasses were x-rayed. All were negative for metallic objects or bullet fragments. Many round holes were evident on the beached carcasses. These were due to postmortem sea bird scavenging. Skull fragmentation was due to decomposition. No signs of antemortem trauma were observed. No evidence exists to suggest illegal or purposeful killing. Of ten carcasses examined, all had ample body fat. There is no evidence to indicate starvation. Stomach contents in 90% of the animals yielded whole undigested squid. These animals died during or shortly after feeding. No lesions suggestive of an infectious disease process were noted. The most likely explanation for these losses may be accidental entanglement and drowning of unwary individuals' fishing gear during legal fishing activity. This explanation, although plausible, is conjectural in nature and could not be substantiated by hard evidence.