Journal of Heredity Advance Access originally published online on December 7, 2006
Journal of Heredity 2006 97(6):603-606; doi:10.1093/jhered/esl042
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Brief Communications |
Estimation of Effective Population Size for the Long-Lived Darkblotched Rockfish Sebastes crameri
From the Department of Fisheries and Wildlife and Coastal Oregon Marine Experiment Station, Hatfield Marine Science Center, Oregon State University, 2030 SE Marine Science Drive, Newport, OR 97365 (Gomez-Uchida and Banks). Daniel Gomez-Uchida is now at Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, NS B3H 4JI, Canada
Address correspondence to Dr. D. Gomez-Uchida at the address above, or e-mail: daniel.gomez-uchida{at}lifetime.oregonstate.edu.
We report the variance effective population size (Ne) in darkblotched rockfish (Sebastes crameri) utilizing the temporal method for overlapping generations, which requires a combination of age-specific demography and genetic information from cohorts. Following calculations of age-specific survival and reproductive success from fishery data, we genotyped a sample (n = 1087) comprised by 6 cohorts (from 1995 to 2000) across 7 microsatellite loci. Our Ne estimate (
) plus 95% confidence interval was
= 9157 [649512 215], showing that the breeding population number could be 34 orders of magnitude smaller than the census population size (
= 24 376 210). Our estimates resemble closely those found for fishes with similar life history, suggesting that the small
ratio for S. crameri is most likely explained by a combination of high variance in reproductive success among individuals, genetic structure, and demographic perturbations such as historical fishing. Because small
ratios have been commonly associated with potential loss of genetic variation, our estimates need careful consideration in rockfish management and conservation.