Variabilidad genética y estructura poblacional del tunicado Pyura chilensis Molina, 1782, en la costa de Chile

Abstract

The ascidian Pyura chilensis is an ecologically important species due to its aggregates, providing habitat for other species. In addition, it is an economically important species being commercially exploited along the coast of Chile. Here, changes in distribution and abundance have been observed during the last decade that have been linked to overfishing. Patterns of genetic variation and population structure are important to understand biodiversity, management and conservation of species. Thus, the main objective of this study was to determine the genetic variability and population structure of Pyura chilensis in three localities along the Chilean coast (Antofagasta, Talcahuano, Puerto Montt). The polymorphic loci obtained were: Mdh-1 and Gpi-1 for P. chilensis. The Fst values showed slight population structure (Fst = 0.019), and the genetic differentiation showed statistically significant values (P = 0.031). The Puerto Montt locality was significantly different from the other two sites in the pairwise comparison in some loci. The genetic differentiation among localities of P. chilensis could be explained by a combination of different causes: (i) low larval dispersion capacity associated to the larval life time of this species (12 to 24 h), and (ii) differences in oceanographic conditions between localities and a closed circulation pattern that restrict dispersion. We conclude that monitoring of genetic diversity levels are essential to establish conservation and management plans of exploited marine resources. © 2007 Sociedad de Biología de Chile.