Distribución temporal de larvas de Mytilus chilensis (Hupé, 1954) (Mollusca: Mytilidae), en el mar interior de Chiloé, sur de Chile

Abstract

The larval presence of M. chilensis was determined monthly from September 2007 to March 2008, in Quillaipe, Metri, Sotomo, Canutillar, and Pichicolo (interior sea of Chiloe) using vertical plankton trawls through a water column from 0 to 7.5 m. At the same time, the reproductive stage of adult individuals was determined histologically. Larvae were detected continuously at the five study sites, with a significant increase from October to December, exceeding 49 thousand per m -3 at Canutillar where, along with Sotomo, the greatest densities were recorded during the study. Cohort analysis showed a similarity in the larval cohorts present at the different sites from September onwards; this was accentuated in November and December, as was the constant appearance of cohorts in the initial stages. In contrast with these results, the reproductive process of M. chilensis at these sites occurred from January to March. Whether or not the spawning recorded at these sites is responsible for the observed larvae is a matter of debate, as the sites may receive and retain larvae exported from other sites. These results suggest a need to compile further biological and ecological knowledge on the areas where this species is distributed and its larval and post-larval dynamics in order to identify exporting and retention areas and thereby contribute to efficient management and the optimization of spat collection.