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    BeringWatch observations contribute valuable information to 2015 large whale unusual mortality event

    Dead Gray Whale

    Dead gray whale filmed by King Cove fisherman Daniel Mack near Pankoff and East Anchor on the south side of the Alaska Peninsula.

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    Dead juvenile female humpback whale sighted by Darien Uttecht from the F/V Northern Star outside of Dolgoi Island.

    On June 10, 2015 Dakota Walker, the BeringWatch Sentinel Program coordinator for the Agdaagux Tribe of King Cove, Alaska received a report from fisherman Daniel Mack that he had seen a dead whale located near Pankoff and East Anchor on the south side of the Alaska Peninsula. Mack, a crew member of the F/V Echo was participating in a project designed to conduct community based ecological monitoring by fishermen in the King Cove/Aleutian Region funded by the North Pacific Research Board. The video and screen captures taken by the crew of the F/V Echo were forwarded to BeringWatch collaborator Kate Wynne of the Sea Grant Marine Advisory Program for identification and confirmation. The carcass was identified as a gray whale (Eschrichtius robustus) and a Level A Marine Mammal stranding Form was filled out to report the sighting to the National Marine Fisheries (NMFS) Marine Mammal Stranding Program. The observation was immediately added to a growing number of dead whale sightings that had recently been designated as the 2015 Gulf of Alaska Large Whale Unusual Mortality Event or UME. A UME is defined under the Marine Mammal Protection Act as a stranding event that is unexpected, involves a significant die-off of any marine mammal population, and demands immediate response. Wynne and the NOAA researchersĀ  emphasized the extreme importance of information from the members of the public such as BeringWatch Citizen Sentinels. During a UME it is especially important to have quick reporting when dead or distressed whales are spotted so that researchers can get to the animals, document them and, if possible collect samples either at sea or on the beach if the whales strand. Over the course of the summer four more dead whale sightings were reported to the Agdaagux Tribe by fishermen participating in the BeringWatch Citizen Sentinel program. These included two sightings of humpback whales (Megaptera novaeangliae) which were confirmed and added to the list of dead whales in the UME.

    From May to mid-August 30 large whales were reported including 11 fin whales (Balaenoptera physalus), 14 humpback whales, 1 gray whale and 4 other unidentified large cetaceans. Additional reports of dead whales also occurred off the coast of British Columbia, Canada. Scientists in the United States and Canada have yet to determine the cause of the 2015 large whale UME, however the investigation is ongoing. Unfortunately many of the whales were floating at sea or in an advanced stage of decomposition. Scientists were only able to obtain samples from one dead whale in Alaskan waters. Because all of the dead whales were species that feed by filtering water through plates of baleen in their jaws, one possible cause under investigation is that the whales may have ingested biotoxins present in harmful algal blooms such as red tides. Since the mid-1990s, UMEs associated with biotoxins from harmful algal blooms have become more common, the majority of which have been attributed to toxicity from domoic acid or brevetoxin. Toxic algal blooms can be caused by unusually warm ocean conditions, such as those observed in the eastern North Pacific since 2013 in conjunction with a sea surface temperature anomaly that has been nicknamed “the blob.” The unusually warm ocean conditions linked to the blob can have a variety of impacts on the marine ecosystem and have also been implicated in the 2013 California sea lion UME and increased strandings of Guadalupe fur seals.

    The unusualĀ  events occurring in the marine ecosystem in recent years highlight the importance of sightings documented by projects such as the BeringWatch Citizen Sentinel Program. With effective monitoring tools and training, local community members can provide reliable and important environmental information, especially on threatened or endangered species and unusual observations in the local environment.

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