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SC/69B/IA/02
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Resource ID
22119
Access
Open
Document Number
SC/69B/IA/02
Full Title
Differentiation and mixed-stock apportionment of humpback whales in the North Pacific based on mtDNA haplotypes and microsatellite genotypes
Author
Debbie Steel, Franca Eichenberger, Kelly Lizewski, Jorge Urb n R., John Calambokidis and C. Scott Baker
Authors Summary
As part of the IWC?s comprehensive assessment of North Pacific humpback whales, SC69b/IA/__ presents mixing matrices based on molecular markers. These matrices were generated for four stock scenarios: two for different stratifications of breeding grounds and two for different stratification of feeding grounds. The two breeding ground stratifications differed by grouping all three Mexico breeding stocks (B1) or treating MX-ML and MX-AR as separate breeding stocks (B2). The two feeding ground stratifications differed by grouping the WGOA with either NGOA (F1) or with BER and EAL (F2). Two sets of matrices were generated for each of the four scenarios. The first used mixed-stock analyses of maternally inherited mtDNA haplotypes combined with biparentally inherited microsatellite markers to estimate apportionment from feeding grounds to breeding stocks. The second used mixed-stock analyses of mtDNA haplotypes, only to estimate apportionment from breeding stocks to feeding grounds. The intent of the matrices derived from molecular markers was to evaluate the fit of the mixed-stock estimates to other model inputs, particularly the mixing matrices from photo-identification. All matrices were made available for population dynamic modeling during a recent workshop in Seattle, Washington, USA (March 2024).
Publisher
IWC
Publication Year
2024
Abstract
Previously (Lizewski et al. 2021; SC68c/IA/01rev01), we used mixed-stock analyses of mtDNA haplotypes to estimate the apportionment of humpback whales from feeding areas to breeding regions (i.e., source stocks). For this, we updated the frequencies of mtDNA haplotypes from regional samples collected during the program Structure of Populations, Levels of Abundance and Status of Humpback Whales (SPLASH) from 2004-2006, adding nearly 1,000 additional samples to the 1,800 published previously (Baker et al. 2013). Following review of initial modeling efforts after SC68c and subsequent discussion by the Working Group on the Comprehensive Assessment, we updated these mixed-stock analyses to include microsatellite genotypes and to focus on four scenarios, two for stratification of breeding regions and two for stratification of feeding areas. We also included a ?reverse? mixed-stock analysis with mtDNA, in which the feeding areas were considered to be the source stocks (Lizewski et al. 2022; SC68d/IA/05). The working group then chose to proceed with the forward analysis using both mtDNA and microsatellite loci and the reverse analysis with mtDNA only. The results are presented again here and have been made available for population dynamic modeling efforts intended for the Comprehensive Assessment.