Causes of death and pathological findings in marine mammals stranded along the Oregon coast

• Main Author: Stroud, Richard K.
• Other Authors: Koller, Loren D., School of Veterinary Medicine, Oregon State University. Graduate School
• Format: Master Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Marine mammals > Oregon; harbor seal
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/2j62s861d

Fifty-seven stranded marine mammals representing seven species were examined over a period of three years. The primary cause of death along with contributing factors, incidental pathology and parasites is reported for each animal examined. Gunshot wounds directly or indirectly caused the death of 14 of 44 seals and sea lions examined. Predation by large sharks and killer whales was evident in five animals examined. In all but one case, the prey was debilitated prior to attack. Traumatic injury such as received in falls, boat collisions, intraspecific fighting, etc., was evident in ten of 57 animals examined. Reproductive failure manifested by dystocia and neonatal mortality was the cause of death in four of six harbor porpoises. Verminous pneumonia was a significant cause of stranding in immature animals. Parasites were identified and listed. Bacterial pneumonia, peritonitis, dermatitis and other septic conditions were diagnosed as the primary cause of death in ten animals and secondary causes in seven others. Bacterial pathogens were cultured, identified and listed along with pathological observations attributable to the bacterial infection. Evidence of a recurrence of leptospirosis in marine mammals was not observed in the animals examined. Lymphosarcoma in a harbor seal was reported.