Poster

From 1986 to 1996, 348 cases of human interaction related injuries were observed in pinnipeds admitted to a rehabilitation center in central California. Of these animals, 84 had lesions caused by entanglement with marine debris, 25 with fishing tackle, and 3 from boat related trauma (Table 1). Although cases were observed throughout the year, the month in which the most cases were seen was June. Typical lesions caused by entanglements were seen around the neck and head. The material was usually embedded in granulation tissue and muscle, causing swelling and deep suppurative wounds. An obvious scar developed once the debris was removed and the wound healed. Fish hooks were most often found embedded in the mouths, esophagus, stomachs and flippers of animals and were most commonly diagnosed with radiographs. In the cases where trauma was suspected due to boat propellers, diagnosis was made based on the presence of multiple deep smooth edged lacerations. Of the animals in this group, 77 were released, 29 died and six were euthanized.

Wounds caused by gunshots were the most common, accounting for 236 cases, with the majority occurring in California sea lions (Zalophus californianus). A total of 204 gunshot cases were seen from 1992-1996 (Table 1). All were California sea lions except for two Pacific harbor seals (Phoca vitulina), four northern elephant seals (Mirounga angustirostris) and one Stellar sea lion (Eumetopiasjubatus). In 1992, the prevalence was the highest (16%), with the mean for the last five years of the study (1992-1996) being 11% in contrast to 5% for the first five years (1986-1991). Yearling sea lions stranding in the Monterey area were the most affected age class, with June being the peak month for admission of these animals. Clinical presentation of animals suspected of gunshot included paralysis or paresis, signs of central nervous system damage such as blindness or seizures, ocular lesions, lesions typical of bullet entry or exit wounds, deep draining abscesses from puncture wounds or multiple small dermal wounds from shotgun pellets. The majority of wounds caused by gunshots were found in the head (139), then less frequently in the spine (39) and fewer in the thorax (24), shoulders (17) and abdomen (2). The most effective way of diagnosing these gunshot cases was with radiographs. The common types of ammunition found were shot gun pellets (66), followed by bullets (63)--mostly 0.22 in caliber. Of these 204 gunshot animals, 101 were euthanized, 92 died, 42 were released and one was placed in a captive facility as it was deemed unreleasable. This data suggests that extensive pinniped-human interactions do occur in central California, and that the predominant interaction is shooting of California sea lions.

Click on the table to see a larger view.