ICES Journal of Marine Science: Journal du Conseil Advance Access published online on July 4, 2007
ICES Journal of Marine Science: Journal du Conseil, doi:10.1093/icesjms/fsm086
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Conservation aspects of natural populations and captive-bred stocks of turbot (Scophthalmus maximus) and Dover sole (Solea solea) using estimates of genetic diversity
1 Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Street, 384 46 Nea Ionia Magnesias, Hellas, Greece
2 Port Erin Marine Laboratory, School of Biological Sciences, University of Liverpool, Port Erin, Isle of Man IM9 6JA, UK
3 Department of Fisheries and Marine Biology, University of Bergen, 5020 Bergen, Norway
Correspondence to A. Exadactylos: tel: +30 24 210 93073; fax: +30 24 210 93071; e-mail: exadact{at}apae.uth.gr
Exadactylos, A., Rigby, M. J., Geffen, A. J., and Thorpe, J. P. 2007. Conservation aspects of natural populations and captive-bred stocks of turbot (Scophthalmus maximus) and Dover sole (Solea solea) using estimates of genetic diversity. ICES Journal of marine Science, 64: 000000.Population genetic analyses have been highly successful in predicting inter- and intraspecific evolutionary relationships, levels of gene flow, genetic divergence, and effective population sizes. Parameters estimated are evolutionary averages and are therefore relevant for addressing contemporary ecological or conservation issues. Changes in genetic variation within the range of a species may indicate patterns of population structure resulting from past ecological and demographic events that are otherwise difficult to infer, so may provide an insight into evolutionary development. Genetic data, drawn from 14 enzyme loci amplified from two populations of turbot (Scophthalmus maximus) and five populations of Dover sole (Solea solea) from the Irish Sea were used to examine population structure estimated from measures of genetic diversity. The aim was to provide an empirical assessment of whether artificial propagation poses a genetic threat to conservation of naturally spawning populations, and whether the fitness for natural spawning and rearing can be rapidly and substantially reduced or increased by artificial propagation. Because of prolonged overfishing, turbot and sole populations in the region are below natural levels, and survive in small local populations in fragmented habitats. Genetic data derived from allozymes have shown that populations are characterized by relatively low levels of genetic diversity. A hypothetical model supporting genetic population substructure, such as range expansion with founder-flush effects, and subsequent population decline with small effective population sizes was considered. Observations support our belief that conservation measures based on genetic diversity have to be developed to ensure the survival of this diverse gene pool.
Keywords: conservation genetics, flatfish, genetic diversity, hatchery stocks, natural populations
Received 16 October 2006; accepted 19 May 2007.