Population structure, effective population size and adverse effects of stocking in the endangered Australian eastern freshwater cod Maccullochella ikei

Nock, C. J., Ovenden, J. R., Butler, G. L., Wooden, I., Moore, A. and Baverstock, P. R. (2011) Population structure, effective population size and adverse effects of stocking in the endangered Australian eastern freshwater cod Maccullochella ikei. Journal of Fish Biology, 78 1: 303-321. doi:10.1111/j.1095-8649.2010.02865.x


Author Nock, C. J.
Ovenden, J. R.
Butler, G. L.
Wooden, I.
Moore, A.
Baverstock, P. R.
Title Population structure, effective population size and adverse effects of stocking in the endangered Australian eastern freshwater cod Maccullochella ikei
Journal name Journal of Fish Biology   Check publisher's open access policy
ISSN 0022-1112
1095-8649
Publication date 2011-01
Sub-type Article (original research)
DOI 10.1111/j.1095-8649.2010.02865.x
Volume 78
Issue 1
Start page 303
End page 321
Total pages 19
Place of publication West Sussex, United Kingdom
Publisher Wiley-Blackwell
Language eng
Formatted abstract
Microsatellite markers were used to examine spatio-temporal genetic variation in the endangered eastern freshwater cod Maccullochella ikei in the Clarence River system, eastern Australia. High levels of population structure were detected. A model-based clustering analysis of multilocus genotypes identified four populations that were highly differentiated by F-statistics (FST = 0· 09 − 0· 49; P < 0· 05), suggesting fragmentation and restricted dispersal particularly among upstream sites. Hatchery breeding programmes were used to re-establish locally extirpated populations and to supplement remnant populations. Bayesian and frequency-based analyses of hatchery fingerling samples provided evidence for population admixture in the hatchery, with the majority of parental stock sourced from distinct upstream sites. Comparison between historical and contemporary wild-caught samples showed a significant loss of heterozygosity (21%) and allelic richness (24%) in the Mann and Nymboida Rivers since the commencement of stocking. Fragmentation may have been a causative factor; however, temporal shifts in allele frequencies suggest swamping with hatchery-produced M. ikei has contributed to the genetic decline in the largest wild population. This study demonstrates the importance of using information on genetic variation and population structure in the management of breeding and stocking programmes, particularly for threatened species.
Keyword Conservation
Genetic variation
Isolation by distance
Microsatellite
Stocking impact
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Biomedical Sciences Publications
 
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