Population genetic structure of white teatfish, Holothuria fuscogilva in south-coast, Kenya

Abstract

Abstract The white teatfish, Holothuria fuscogilva, is widely distributed in coastal areas, including waters around coral reefs and seagrasses in the Indo-Pacific. In Kenya, the species is distributed in shallow reefs, with higher landings reported from the Vanga-Shimoni-Msambweni seascape on the Kenyan south coast. The present study investigated the genetic structure and effects of fishing pressure on genetic diversity of H. fuscogilva populations from three fish landing sites in south-coast Kenya, using an analysis of the mitochondrial cytochrome oxidase sub-unit I (COI) gene. Muscle tissues were obtained for a total of 60 individuals collected from three sites. Genomic DNA was extracted from the ethanol stored samples using commercial DNA extraction kit method. DNA samples for 47 samples were able to amplify using the polymerase chain reaction method (PCR). High-quality PCR products yielding high-quality sequences, producing 22 haplotypes with high haplotype diversity but low nucleotide diversity (h = 0.922, π = 0.008). The northernmost site, Gazi, reported higher genetic diversity (h = 0.933) than other populations. The genetic structure was analyzed using Analysis of Molecular Variance (AMOVA), a comparison of the genetic differentiation between populations using Fixation Indices (FST) based on Wright's F-statistics. AMOVA showed the highest proportion of variation within the populations than among the populations. The fixation index FST showed a lack of structure among H. fuscogilva (FST = 0.01186, p. value = 0.29069). The H. fuscogilva populations at the three study sites along Kenya's south coast appear to have genetic connectivity but no significant genetic structure. The genetic structure estimates and intra-population genetic diversity depict a robust population that can regenerate lost individuals after a fishing event. This study has generated information on genetic structure and the status of genetic diversity of H. fuscogilva under fishing pressure in south-coast Kenya. The study has provided genetic information to elucidate population genetic structure along the Kenya south-coast that is critical in guiding the formulation of sound harvest strategies and conservation management policies for the H. fuscogilva species.