Satellite tag placed on orca contributed to L95's death
A necropsy of the killer whale L95 implicated the placement of a satellite-linked limpet-style tag in its death. The site of the tag, which was placed on its dorsal fin five weeks before its death, was the source of a fungal infection.
This fungal infection contributed to illness in the whale and played a contributory role in its death. According to National Marine Fisheries Service, limpet-style tags have been deployed on more than 500 cetaceans, including seven other killer whales, without any documented mortalities.
The death of the 20-year-old whale, part of the endangered Southern Resident Killer Whale pods, was investigated by National Marine Fisheries Service, Department of Fisheries and Oceans, Canada and the Animal Health Center, British Columbia Ministry of Agriculture and Lands, Canada.
There were several factors in this case that predisposed this whale to a fungal infection at the tagging site, according to the necropsy. NMFS is reviewing the findings from this case and developing mitigation factors to limit the impacts of future tags and tagging on southern resident killer whales.
The experts suggested some possible mitigation measures to use in future tagging events of killer whales including:
• Implantable tags that are exposed to seawater during tagging should not be used and should be brought back to the laboratory to investigate the electronics and tag attachment viability and re-sterilized at the laboratory prior to use. For researchers working with non-ESA species and working in remote locations where lab re-sterilization is not feasible, tags exposed to seawater should be soaked in appropriate fungicidal disinfectants for appropriate contact times (~10-20 mins) prior to re-deployment.
• Consultation with cetacean anatomists to determine the optimal location for tag placement in relation to dorsal fin vasculature is recommended to minimize the possibility of spread of pathogens from localized infections at the tag site.
• The process by which whale body condition is evaluated and criteria for target animal selection prior to tagging should be re-evaluated so as to minimize the chance of tagging an animal nutritionally compromised or in poor health.
• The panel strongly recommends re-evaluating tag designs for killer whales to minimize impacts to the tagged individuals, currently a tagging workshop is planned by the International Whaling Commission (IWC) in spring 2017 and presentation of this case at that workshop would be of value. Additionally, discussions should be conducted with the tag manufacturer to determine if there was a change in manufacturing that could have contributed to tag failure.
• Some of the panel members felt that if the southern resident killer whale population is being impacted by environmental factors that are causing population-wide malnutrition and the overall population is in relatively poor general health, then the idea of implanting tags in these animals should be revisited, whether or not this tag cause the death of this particular individual. It may be prudent to not resume invasive tagging and use noninvasive assessment tools such as photogrammetry over multiple seasons as a less risky source of useful information if the population is truly in a fragile state.
• Lastly, the panel strongly recommends that NMFS will utilize the above recommendations and those from the IACUC review now, and others from the IWC tagging meeting (or other reviews) later, to modify current tagging methods and evaluate appropriate mitigation measures for future tagging of ESA species.
Recovery Plan for Southern Resident Killer Whales