Intra-annual genetic variation in the downstream larval drift of sutchi catfish (Pangasianodon hypophthalmus) in the Mekong river

So, Nam, Maes, Gregory E., and Volckaert, Filip A.M. (2006) Intra-annual genetic variation in the downstream larval drift of sutchi catfish (Pangasianodon hypophthalmus) in the Mekong river. Biological Journal of the Linnean Society, 89 (4). pp. 719-728.

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Abstract

Larvae of the sutchi catfish Pangasianodon hypophthalmus were collected during peak downstream drift in the Lower Mekong river on four occasions over an 8-week period during the 2003 spawning season, and genotyped using seven microsatellite loci. We provide evidence for several heterogeneous groups within and among the temporally discrete larval peak samples. Strong evidence for a significant deficit of heterozygotes was observed for each larval sample and the pooled sample, possibly due to population admixture. Although individual-based assignment tests suggested that each larval peak sample was admixed, significant but low genetic differentiation was observed among larval samples (FST = 0.0052, P < 0.01). The lack of significant relatedness confirms the multifamily composition of each larval group, excluding family bias to explain the observed genetic heterogeneity. Both the entire larval peak and each temporally separated larval peak originated from spawning groups with heterogeneous allelic composition involving several distinct spawning events. We propose three explanations to account for our findings: (1) the ecological match/mismatch hypothesis; (2) the genetic 'sweepstakes' selection hypothesis; and (3) life-history-specific characteristics of the spawning populations. Finally, an intra-annual shift in the contribution of the spawning populations to the larval drift was detected on successive occasions.

Item ID: 34304
Item Type: Article (Research - C1)
ISSN: 1095-8312
Funders: Belgian Technical Cooperation (BTC), Katholieke Universiteit Leuven, International Foundation for Science (IFS), Mekong River Commission (MRC)
Projects and Grants: MRC/DANIDA/DoF-Fisherhers projects
Date Deposited: 20 Aug 2014 04:16
FoR Codes: 07 AGRICULTURAL AND VETERINARY SCIENCES > 0704 Fisheries Sciences > 070402 Aquatic Ecosystem Studies and Stock Assessment @ 30%
06 BIOLOGICAL SCIENCES > 0604 Genetics > 060411 Population, Ecological and Evolutionary Genetics @ 50%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060204 Freshwater Ecology @ 20%
SEO Codes: 83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8302 Fisheries - Wild Caught > 830204 Wild Caught Fin Fish (excl. Tuna) @ 50%
96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960807 Fresh, Ground and Surface Water Flora, Fauna and Biodiversity @ 50%
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