Genetic diversity despite population collapse in a critically endangered marine fish: the smalltooth sawfish (Pristis pectinata)

Chapman, Demian S., Simpfendorfer, Colin A., Wiley, Tonya R., Poulakis, Gregg R., Curtis, Caitlin, Tringali, Michael, Carlson, John K., and Feldheim, Kevin A. (2011) Genetic diversity despite population collapse in a critically endangered marine fish: the smalltooth sawfish (Pristis pectinata). Journal of Heredity, 102 (6). pp. 643-652.

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Abstract

Sawfish (family Pristidae) are among the most critically endangered marine fish in the world, yet very little is known about how genetic bottlenecks, genetic drift, and inbreeding depression may be affecting these elasmobranchs. In the US Atlantic, the smalltooth sawfish (Pristis pectinata) has declined to 1–5% of its abundance in the 1900s, and its core distribution has contracted to southwest Florida. We used 8 polymorphic microsatellite markers to show that this remnant population still exhibits high genetic diversity in terms of average allelic richness (18.23), average alleles per locus (18.75, standard deviation [SD] 6.6) and observed heterozygosity (0.43–0.98). Inbreeding is rare (mean individual internal relatedness = −0.02, SD 0.14; FIS = −0.011, 95% confidence interval [CI] = −0.039 to 0.011), even though the estimated effective population size (Ne) is modest (250–350, 95% CI = 142–955). Simulations suggest that the remnant smalltooth sawfish population will probably retain >90% of its current genetic diversity over the next century even at the lower estimate of Ne. There is no evidence of a genetic bottleneck accompanying last century's demographic bottleneck, and we discuss hypotheses that could explain this. We also discuss features of elasmobranch life history and population biology that could make them less vulnerable than other large marine vertebrates to genetic change associated with reduced population size.

Item ID: 20886
Item Type: Article (Refereed Research - C1)
Keywords: elasmobranch, genetic bottleneck, genetic drift, inbreeding, K-selected species, microsatellites
ISSN: 1465-7333
Date Deposited: 15 Mar 2012 22:34
FoR Codes: 07 AGRICULTURAL AND VETERINARY SCIENCES > 0704 Fisheries Sciences > 070402 Aquatic Ecosystem Studies and Stock Assessment @ 100%
SEO Codes: 83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8302 Fisheries - Wild Caught > 830204 Wild Caught Fin Fish (excl. Tuna) @ 100%
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