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SC/68C/ASW/02
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Resource ID
19190
Access
Open
Document Number
SC/68C/ASW/02
Full Title
Two Aboriginal Subsistence Whaling Stocks Remain in Tested Parameter Space
Author
G.H. Givens and D.W. Weller
Publisher
IWC
Publication Year
2021
Abstract
The 2019 abundance estimate for Bering-Chukchi-Beaufort Seas bowhead whales and 2019/20 abundance estimate for eastern North Pacific gray whales both were notably lower than previous estimates. We examine the parameter spaces used during the development and testing of the Strike Limit Algorithms for these stocks to determine whether additional simulation testing is warranted. For bowheads, the new lower estimate is believed to be attributable to bias, and perhaps also ordinary statistical uncertainty. In terms of both bias and variation, the 2019 estimate falls within the range of what could be expected given the scenarios tested. For gray whales, the new lower estimate is believed to be attributable to a recentunusual mortality event, similar to the one that occurred in 1999-2000. That prior mortality event motivated a variety of testing scenarios that explored the impacts of similar future events. What was tested bearsaremarkable resemblance to what has now occurred. Thus, for both stocks, we conclude that—despite the lower new abundance estimates—the respective Strike Limit Algorithms remain fully tested for present circumstances. We also list several future contingencies that might warrant additional testing, should they occur.Lastly, we note the importance of continuingto collect and review the necessary datato monitor the status of these stocks.