Postmortem pathology investigation of the wounds from invasive tagging in belugas (Delphinapterus leucas) from Cook Inlet and Bristol Bay, Alaska

Abstract

Wildlife researchers need to understand the effects of biotelemetry tags in order to better weigh benefits versus risks. We describe tag-site healing and pathology of three beluga whales, Delphinapterus leucas, found dead in Alaska. The tags were secured with two or three nylon rods that pierced the dorsal ridge, and one beluga also had a LIMPET tag. The tag wounds in one Cook Inlet beluga featured a normal healing response with minimal inflammation ~12 years posttagging. Photo-ID studies of another Cook Inlet beluga demonstrated degeneration of the tag wounds over several years. It died ~12.8 years posttagging of bronchopneumonia and septicemia due to Staphylococcus aureus that also infected the tag wound. A Bristol Bay beluga died 4 months posttagging. Although it may have been predated by a killer whale attack, Orcinus orca, the tag site was inflamed and infected with Streptococcus uberis which spread to an abscessed lymph node. To reduce the risk of infection, researchers should adopt strict sterilization protocols for all implanted parts of tags and continue research into improved tagging methods. Clinical and behavioral assessment of potential preexisting conditions before tag deployment, as well as posttag monitoring, could help reduce tag-associated mortality and identify immediate impacts and mortality.