Abstracts (first author)
West vs East Mediterranean Sea: origin and genetic differentiation of the sea cucumber Holothuria poliiPDF
We studied the genetic structure of the sea cucumber Holothuria (Roweothuria) polii (Delle Chiaje 1823) by analyzing the mitochondrial DNA variation in a fragment of cytochrome oxidase I (COI) and 16S genes. Individuals were collected in 7 locations along the Mediterranean Sea, which cover a wide range of the species distribution. We found high haplotype diversity for COI and moderate for 16S and low nucleotide diversity for both genes. Our results for the COI gene showed many recent and exclusive haplotypes with few mutations between them, which suggests populations might be under expansion. The Western and Eastern Mediterranean populations exhibited slight but significant genetic differentiation showing the highest genetic diversity on the East. The most ancient haplotype was not present in the most western sampling location (Spain). Also, Kusadasi (Turkey) displayed the oldest expansion time, which corresponds to mid Pleistocene epoch, as well as the highest genetic diversity (number of exclusive haplotypes, polymorphisms, haplotype and nucleotide diversity). This suggests that individuals from Kusadasi could be the origin of the subsequent colonizations through the Mediterranean Sea. However, for future research, nuclear markers should be used to confirm this hypothesis. Keywords: Genetic structure, colonization, Holothuria polii, Mitochondrial DNA, Mediterranean Sea
Assessing the effects of human selection through fishery on sea cucumber genetic structure and population dynamicsPDF
Increased fishing pressure has resulted in widespread overexploitation of populations, with declines in overall abundance of stocks and average size; adverse genetic selection leading to loss of potential fecundity; reduced average spawning size; change of sex-ratio and interspecific equilibrium; and loss of genetic diversity. After the failure of traditional management measures, marine protected areas have been strongly advocated as an ideal tool for the management of coastal fisheries protecting critical spawning stock biomass, intraspecific genetic diversity, population age structure, recruitment supply and ecosystem balance. The sea cucumber fisheries have increased world wide and several species (Holothuria polii, H. tubulosa and H. mammata) are now targeted in Turkish waters reaching a total production around 600,000 kg in the last year. In this work, we assess the fishery effects on the genetic structure and population dynamics of three sea cucumbers species. We found significant differences in H. tubulosa and H. polii among protected (Kusadasi) and non-protected (Ayvalik) localities considering their length and weight, showing Kusadasi the largest and heaviest individuals. H. mammata did not shown significant differences. Also, we found higher genetic diversity for the three target species (number of total and exclusive haplotypes, haplotype and nucleotide diversity, polimorphic sites) in Kusadasi (marine protected area) than Ayvalik.