| Summary: | This study utilized tissue and sperm reserve (i.e., spermathecae) samples taken from female snow, Tanner, and snow-Tanner hybrid crabs collected by Alaska Department of Fish and Game (ADF&G) during the annual NOAA eastern Bering Sea bottom trawl survey over a 10-year period (2007-2016) to examine spatiotemporal trends in snow crab mating dynamics. It additionally involved the collection and live holding of snow crab in 2017 and 2018 to determine the number of males that contributed to the paternity of brooded embryos. New shell females mating at the time of their first molt of maturity and old shell condition females mating subsequently were considered separately in the study. Two types of genetic markers were used in this work: nuclear and mitochondrial DNA (nDNA and mtDNA) single nucleotide polymorphisms (SNPs) and nDNA microsatellites. The SNP markers ITS (nDNA) and 16S (mtDNA) were used to determine species and maternal lineage, respectively. The five microsatellite markers Co17, Co34, Co36, Cop2 and EC0106 were selected for use in identifying individuals and determining male contributions to mating, though only Co17, Co36 and Cop2 were used in the analysis due to artifacts associated with the other two. Genotypes were generated for female crab, sperm reserves, and individual embryos in support of three objectives. Objective 1 validated the performance of known markers across the closely related snow, Tanner, and snow-Tanner hybrid crab complex in the EBS and examined the maternal lineage of hybrid crab to determine the mating combinations between snow and Tanner crabs. Objective 2 examined the mating history of snow crab using sperm reserve samples. Objective 3 examined the paternity of brooded embryos and the overlap between male genotypes present in the embryos and sperm reserves.
|
|---|