Mating strategies such as polyandry, where one female mates with multiple males, has the potential to influence the amount of genetic diversity of a population and increase the reproductive success of a given individual. This type of mating strategy may help species maintain genetic diversity during genetic bottleneck situations such as overharvesting, severe environmental fluctuations, disease, and founding events.
Multiple paternity thought to be inherent only in broadcast spawners has recently been observed in rockfish (Sebastes spp.) which are live bearers and reproduce by internal fertilization.
While recent studies of mating strategies in rockfish have focused on samples collected from aquarium populations and species caught off the coast of California and Oregon, scientists with Auke Bay Laboratories (ABL) recently had the opportunity to genetically test for multiple paternity in wild Alaskan quillback rockfish which are an inshore, demersal, non-schooling species.
Embryos and tissue samples from pregnant quillback rockfish were collected by members of ABL's Marine Ecology and Stock Assessment Program near NOAA's Little Port Walter (LPW) Marine Station, located on the southern tip of Baranof Island in Southeast Alaska.
Parentage analysis using 13 microsatellites was conducted on 25 embryos each from 25 females. Preliminary results indicate multiple paternity in wild quillback, with multiple males contributing to 8 of 25 broods tested. Further analysis will be conducted to test for correlations between female age/length/weight with multiple paternity practices.
We also observed a larva which carried mtDNA from the mother but was homozygous for the paternal alleles across 13 microsatellite loci. The sample was analyzed twice with the same conclusion. This indicates either a haploid individual carrying only one set of paternal chromosomes, which would not be a viable individual, or an incident of natural androgenesis, where the paternal chromosomes are doubled and produce a viable individual. Further study of this unusual individual will be ongoing.