Infectious diseases have the potential to play a role in the decline of threatened wildlife populations, as well as negatively affect their long-term viability, but determining which infectious agents present risks can be difficult. The southern resident killer whale, Orcinus orca, population is endangered and little is known about infectious diseases in this species. Using available reference literature, we identified 15 infectious agents (bacteria, viruses, and fungi) reported in free-ranging and captive killer whales, as well as 28 additional infectious agents reported in free-ranging and captive odontocete species sympatric to southern resident killer whales. Infectious agents were scored as having a high, medium, or low ability to affect fecundity or reproductive success, to cause disease in individual animals, and to cause epizootics. Marine Brucella spp., cetacean poxvirus, cetacean morbilliviruses, and herpesviruses were identified as high priority pathogens that warrant further study. Using identified pathogens to develop a standardized necropsy and disease testing protocol for southern resident killer whales and sympatric odontocetes will improve future efforts to better understand the impacts of priority and non-priority infectious agents on southern resident killer whales. This model can be used to evaluate potential infectious disease risks in other threatened wildlife populations.
In this newsletter:
Collaborative research: How can scientists, anglers, SCUBA divers and others best work together?
New initiative to support peer-reviewed publication.
Mapping Killer Whale foraging.
Decision on octopus protection.
Legislature funds derelict gear removal.
Jonna Mazet joins board of Morris Animal Foundation.
New research published in the journal PLoS ONE by Katherine Ayres and collaborators shines light on the sources of stress in Southern Resident Killer Whales. Ayres used fecal matter to find markers of nutritional and psychological stress in the whales. Her results support the hypothesis that inadequate prey (Chinook salmon) is a larger cause of stress for the whales than is vessel traffic.
Note that the paper does not say there are no impacts from boats, only that the impacts from lack of food overshadow those impacts.
Best quote (from the Seattle Times piece): ""I like to call it my buffet-in-a-bar example," said Katherine Ayres, lead author of a paper on the study published in PLoS ONE, released Wednesday. Patrons in a noisy bar won’t mind the racket if all their favorite foods are piled high on the buffet. "But you go there and they are only serving rice and potatoes, and it’s super noisy and crowded, then it’s, ‘I am not getting a good meal and these boats are driving me crazy.’ "
An interesting section of the full paper: "The temporal trend in T3 concentrations within and between years suggest that the sampled SRKWs might be feeding on a nutritious early spring food source acquired prior to their arrival in the Salish Sea. The trend further suggests that the whales become somewhat food limited during the course of the summer. This result is somewhat unexpected, because the more confined waterways of the Salish Sea, combined with large runs of salmon returning through the area would seem to provide easier foraging opportunities for the whales than the outer coast. Nonetheless, the declining trend in T3 levels at least suggests the possibility that the early spring period when the whales are typically in coastal waters might be a more important foraging time than was previously believed."
As always, we encourage you to read the research for yourself. With PLos ONE it’s easy to do, because the journal is free and open to the public. Here’s the link to the full research report:
Photo by Kat Kellner via Flickr.