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The objectives of this study were (1) to develop novel genome-wide nuclear markers using a Reduced Representation Genotyping by Sequencing approach (RRGS) to evaluate the level of admixture between the sympatric populations of C. tilstoni and C. limbatus of the eastern coast of Australia; (2) to identify a minimum number of diagnostic single nucleotide polymorphisms (SNPs) with maximum power to delineate the hybrid classes present between the two blacktip species for application in fisheries enforcement and forensic cases; (3) to compare the power and resolution that diagnostic markers provide for hybrid class delineation with previous results that used mtDNA, microsatellite markers and pre-caudal vertebrae count discordance.

The objectives of this study were (1) to develop novel genome-wide nuclear markers using a Reduced Representation Genotyping by Sequencing approach (RRGS) to evaluate the level of admixture between the sympatric populations of C. tilstoni and C. limbatus of the eastern coast of Australia; (2) to identify a minimum number of diagnostic single nucleotide polymorphisms (SNPs) with maximum power to delineate the hybrid classes present between the two blacktip species for application in fisheries enforcement and forensic cases; (3) to compare the power and resolution that diagnostic markers provide for hybrid class delineation with previous results that used mtDNA, microsatellite markers and pre-caudal vertebrae count discordance.

The objectives of this study were (1) to develop novel genome-wide nuclear markers using a Reduced Representation Genotyping by Sequencing approach (RRGS) to evaluate the level of admixture between the sympatric populations of C. tilstoni and C. limbatus of the eastern coast of Australia; (2) to identify a minimum number of diagnostic single nucleotide polymorphisms (SNPs) with maximum power to delineate the hybrid classes present between the two blacktip species for application in fisheries enforcement and forensic cases; (3) to compare the power and resolution that diagnostic markers provide for hybrid class delineation with previous results that used mtDNA, microsatellite markers and pre-caudal vertebrae count discordance.

The objectives of this study were (1) to develop novel genome-wide nuclear markers using a Reduced Representation Genotyping by Sequencing approach (RRGS) to evaluate the level of admixture between the sympatric populations of C. tilstoni and C. limbatus of the eastern coast of Australia; (2) to identify a minimum number of diagnostic single nucleotide polymorphisms (SNPs) with maximum power to delineate the hybrid classes present between the two blacktip species for application in fisheries enforcement and forensic cases; (3) to compare the power and resolution that diagnostic markers provide for hybrid class delineation with previous results that used mtDNA, microsatellite markers and pre-caudal vertebrae count discordance.

The objectives of this study were (1) to develop novel genome-wide nuclear markers using a Reduced Representation Genotyping by Sequencing approach (RRGS) to evaluate the level of admixture between the sympatric populations of C. tilstoni and C. limbatus of the eastern coast of Australia; (2) to identify a minimum number of diagnostic single nucleotide polymorphisms (SNPs) with maximum power to delineate the hybrid classes present between the two blacktip species for application in fisheries enforcement and forensic cases; (3) to compare the power and resolution that diagnostic markers provide for hybrid class delineation with previous results that used mtDNA, microsatellite markers and pre-caudal vertebrae count discordance.

The objectives of this study were (1) to develop novel genome-wide nuclear markers using a Reduced Representation Genotyping by Sequencing approach (RRGS) to evaluate the level of admixture between the sympatric populations of C. tilstoni and C. limbatus of the eastern coast of Australia; (2) to identify a minimum number of diagnostic single nucleotide polymorphisms (SNPs) with maximum power to delineate the hybrid classes present between the two blacktip species for application in fisheries enforcement and forensic cases; (3) to compare the power and resolution that diagnostic markers provide for hybrid class delineation with previous results that used mtDNA, microsatellite markers and pre-caudal vertebrae count discordance.

The objectives of this study were (1) to develop novel genome-wide nuclear markers using a Reduced Representation Genotyping by Sequencing approach (RRGS) to evaluate the level of admixture between the sympatric populations of C. tilstoni and C. limbatus of the eastern coast of Australia; (2) to identify a minimum number of diagnostic single nucleotide polymorphisms (SNPs) with maximum power to delineate the hybrid classes present between the two blacktip species for application in fisheries enforcement and forensic cases; (3) to compare the power and resolution that diagnostic markers provide for hybrid class delineation with previous results that used mtDNA, microsatellite markers and pre-caudal vertebrae count discordance.

The objectives of this study were (1) to develop novel genome-wide nuclear markers using a Reduced Representation Genotyping by Sequencing approach (RRGS) to evaluate the level of admixture between the sympatric populations of C. tilstoni and C. limbatus of the eastern coast of Australia; (2) to identify a minimum number of diagnostic single nucleotide polymorphisms (SNPs) with maximum power to delineate the hybrid classes present between the two blacktip species for application in fisheries enforcement and forensic cases; (3) to compare the power and resolution that diagnostic markers provide for hybrid class delineation with previous results that used mtDNA, microsatellite markers and pre-caudal vertebrae count discordance.

The objectives of this study were (1) to develop novel genome-wide nuclear markers using a Reduced Representation Genotyping by Sequencing approach (RRGS) to evaluate the level of admixture between the sympatric populations of C. tilstoni and C. limbatus of the eastern coast of Australia; (2) to identify a minimum number of diagnostic single nucleotide polymorphisms (SNPs) with maximum power to delineate the hybrid classes present between the two blacktip species for application in fisheries enforcement and forensic cases; (3) to compare the power and resolution that diagnostic markers provide for hybrid class delineation with previous results that used mtDNA, microsatellite markers and pre-caudal vertebrae count discordance.

Linkage maps based on markers derived from genes are essential evolutionary tools for commercial marine fish to help identify genomic regions associated with complex traits and subject to selective forces at play during exploitation or selective breeding. Additionally, they allow the use of genomic information from other related species for which more detailed information is available. Sole (solea solea L.) is a commercially important flatfish species in the North Sea, subject to overexploitation and showing evidence of fisheries-induced evolutionary changes in growth- and maturation-related traits. Sole would definitely benefit from a linkage map to better understand how evolution has shaped its genome structure. This study presents a linkage map of sole based on 423 single nucleotide polymorphisms derived from expressed sequence tags and 8 neutral microsatellite markers. The total map length is 1233.8 cM and consists of 38 linkage groups with a size varying between 0 to 92.1 cM. Being derived from expressed sequence tags allowed us to align the map with the genome of four model fish species, namely medaka (Oryzias latipes), Nile tilapia (Oreochromis niloticus), three-spined stickleback (Gasterosteus aculeatus) and green spotted pufferfish (Tetraodon nigroviridis). This comparison revealed multiple conserved syntenic regions with all four species, and suggested that the linkage groups represent 21 putative sole chromosomes. The map was also compared to the linkage map of turbot (Scophthalmus maximus), another commercially important flatfish species and closely related to sole. For all putative sole chromosomes (except one) a turbot homolog was detected, confirming the even higher degree of synteny between these two flatfish species.

Reduced representation genome sequencing such as restriction-site-associated DNA (RAD) sequencing is finding increased use to identify and genotype large numbers of single-nucleotide polymorphisms (SNPs) in model and nonmodel species. We generated a unique resource of novel SNP markers for the European eel using the RAD sequencing approach that was simultaneously identified and scored in a genome-wide scan of 30 individuals. Whereas genomic resources are increasingly becoming available for this species, including the recent release of a draft genome, no genome-wide set of SNP markers was available until now. The generated SNPs were widely distributed across the eel genome, aligning to 4779 different contigs and 19 703 different scaffolds. Significant variation was identified, with an average nucleotide diversity of 0.00529 across individuals. Results varied widely across the genome, ranging from 0.00048 to 0.00737 per locus. Based on the average nucleotide diversity across all loci, long-term effective population size was estimated to range between 132 000 and 1 320 000, which is much higher than previous estimates based on microsatellite loci. The generated SNP resource consisting of 82 425 loci and 376 918 associated SNPs provides a valuable tool for future population genetics and genomics studies and allows for targeting specific genes and particularly interesting regions of the eel genome

Many marine pelagic fish species are characterized by subtle but complex genetic structures and dynamics, depending on the balance between current-mediated larval dispersal and adult active homing behavior. The circumantarctic continuous hydrodynamics of the Southern Ocean is a prime example of a system with a potentially great homogenizing effect among distant populations. We tested this hypothesis by analyzing the contemporary genetic relatedness among populations of a common and endemic mesopelagic fish of the Southern Ocean, Electrona antarctica. Seven newly developed species-specific microsatellite markers were used to investigate patterns of neutral genetic variation in 11 geographically widespread samples (n=400) collected between 2006 and 2007. We detected a very high level of genetic diversity, but a striking lack of genetic differentiation on a circumantarctic scale, indicating large effective population sizes complemented with high levels of admixture. These findings underscore the large scale homogenizing effect of the Southern Coastal Current, leading to a high level of connectivity of our model species in the Southern Ocean, which is congruent with its huge biomass and central role in marine food webs. As an important Antarctic marine living resource this species may as such be managed on a circumantarctic level, although the demographic stability of this stock should be estimated urgently.

Many marine pelagic fish species are characterized by subtle but complex genetic structures and dynamics, depending on the balance between current-mediated larval dispersal and adult active homing behavior. The circumantarctic continuous hydrodynamics of the Southern Ocean is a prime example of a system with a potentially great homogenizing effect among distant populations. We tested this hypothesis by analyzing the contemporary genetic relatedness among populations of a common and endemic mesopelagic fish of the Southern Ocean, Electrona antarctica. Seven newly developed species-specific microsatellite markers were used to investigate patterns of neutral genetic variation in 11 geographically widespread samples (n=400) collected between 2006 and 2007. We detected a very high level of genetic diversity, but a striking lack of genetic differentiation on a circumantarctic scale, indicating large effective population sizes complemented with high levels of admixture. These findings underscore the large scale homogenizing effect of the Southern Coastal Current, leading to a high level of connectivity of our model species in the Southern Ocean, which is congruent with its huge biomass and central role in marine food webs. As an important Antarctic marine living resource this species may as such be managed on a circumantarctic level, although the demographic stability of this stock should be estimated urgently.

Zoetwatermilieus zijn kwetsbare ecosystemen die door toedoen van de mens vaak aan natuurwaarde inboeten. De eerst opgemerkte slachtoffers zijn meestal vissen. Natuurherstelprogramma's richten zich op habitatherstel richten zich op habitatherstel en verbetering van de paai- en migratiemogelijkheden. Het kostenplaatje ligt echter hoog, en tegelijk moeten bekkenbeheerders rekening houden met andere aspecten van waterbeheer, zoals transport, watervoorziening en waterveiligheid. Voor een doeltreffend en verantwoord natuurbeheer is een goede kennis van de populatiegenetica van zoetwatervissen nodig. Deze kennis heeft inmiddels geleid tot een beter begrip van de structuur van zowel gezonde, kwetsbare, verdwenen, opnieuw geïntroduceerde als exotische vispopulaties, en daarmee tot het opstellen van doeltreffende beheermaatregelen. Op termijn verdient populatiegenetisch advies een vaste plaats in een duurzaam visstands- en waterlopenbeheer.