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SC/68D/CMP/08
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Resource ID
19481
Access
Open
Document Number
SC/68D/CMP/08
Full Title
Gray whale?s body condition in Laguna San Ignacio, BCS, M?xico for winter breeding season 2022
Author
M. Valerio-Conchas, S. Mart?nez-Aguilar, S.L. Swartz and J. Urb?n R.
Publisher
IWC
Abstract
The Eastern North Pacific (ENP) gray whale population (Eschrichtius robustus) feeds during the summer in the Bering, Chukchi, and Beaufort Seas, and migrates along the Pacific coast of North America to the breeding areas on the Baja California Peninsula in Mexico during the winter. The evaluation of the whale's body condition provides an indicator of the whale?s health and reproductive condition and, by inference, is indirectly an indicator of the health of the environment. During the 2022 winter breeding season in Laguna San Ignacio (LSI), Baja California Sur, Mexico we photographed 788 gray whales, from which we were able to evaluate the body condition of 626 single whales (male or female without a calf) and 42 mothers with calves (Mc). Their condition was classified as ?good?, ?fair? or ?poor?, according to the methodology developed for gray whales of the Western North Pacific (WNP). In 2022, the proportion of single whales with ?good? body condition? was 43% (n=269), ?fair? 37.5% (n=235) and ?poor? 19.5% (n=122). For the body condition of mothers with calves in 2022, ?good?, ?fair?, and ?poor? was 90.5% (n=38), 9.5% (n=4) and 0%, respectively. The percentage of single whales with ?good? and ?fair? body conditions increased compared to 2021, meanwhile, the percentages of whales with ?poor? body condition decreased, being the lowest since the UME began in 2019. The percentage of Mc with ?good? body condition was as high as the previous 3 years, but the numbers of Mc observed in the lagoon from 2019-2022 were the lowest since 2010. It is possible that the body condition of the gray whales observed in 2022 was the result of similar environmental factors as those that affected gray whales during the previous 3 years, however, it is necessary to compare and correlate the environmental data for the feeding areas and other breeding zones to fully comprehend the factors that contribute to the body and reproductive condition of the whales.