Distribucion temporal de larvas de Mytilus chilensis (Hupe, 1954) (Mollusca: Mytilidae), en el mar interior de Chiloe, sur de Chile

Abstract

RESUMEN.Entre septiembre 2007 y marzo 2008, en Quillaipe, Metri, Sotomo, Canutillar y Pichicolo (mar interior de Chiloé), se determinó mensualmente la presencia larval de M. chilensis, mediante arrastres verticales de plancton, en una columna de 0-7,5 m y paralelamente se determinó histológicamente el estado reproductivo de ejemplares adultos. Se detectó permanentemente la presencia de larvas en los cinco sitios estudiados, con un significativo incremento entre octubre y diciembre, superando en Canutillar 49 mil larvas por m -3 , sitio que junto a Sotomo registraron las mayores densidades. El análisis de cohortes mostró una similitud de los grupos larvales presentes en los diferentes sitios a partir de septiembre, acentuándose durante noviembre y diciembre, así como una permanente aparición de cohortes en estadios iniciales. En contraste con estos resultados, el proceso reproductivo de M. chilensis en estos sitios, se manifestó de enero a marzo. Se discute que los desoves registrados en estos sitios, no serían responsables de la presencia de las larvas, actuando en consecuencia como áreas receptoras, y de retención de larvas provenientes de otros sitios. Estos resultados sugieren la necesidad de profundizar conocimientos biológicos y ecológicos en áreas de distribución de la especie, así como de dinámica larval y post-larval para identificar áreas exportadoras y de retención, para contribuir a un manejo eficiente y optimizar la captación de semilla. Palabras clave: larvas, Mytilus chilensis, distribución, bivalvo, aguas interiores, sur de Chile.Temporal distribution of larvae of Mytilus chilensis (Hupé, 1854) (Mollusca: Mytilidae), in the interior sea of Chiloé, southern 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 Chiloé) 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 ...

A biogeography‐based management forMytilus chilensis: The genetic hodgepodge of Los Lagos versus the pristine hybrid zone of the Magellanic ecotone

“…Such a consistent genetic hodgepodge scenario across studies likely results from the intense historical anthropogenic seed exchange around Los Lagos Region (41-44 S; Pantoja, Iriarte, & Daneri, 2011) that creates a population mosaicism by admixing larval cohorts of different ages and origins (e.g. Avendaño, Cantillánez, Le Pennec, Varela, & Garcias, 2011).…”

Evaluation of culture of the mussels Choromytilus chorus and Aulacomya ater (Molina) in northern coasts of Chile

“…The population size structure of the larvae of both mytilidae during both sampling surveys was later subjected to a discriminant cohort analysis (Avendaño et al . ) to identify the number of microcohorts, their mean sizes and their representativeness using the program MIX 3.1a (MacDonald & Pitcher ). Size frequency histograms were represented based on a normal distribution (significance level = 0.05).…”

“…Triplicate samples were obtained along an 18 m deep water column by vertically pulling a 53-lm plankton net. These samples were subsequently transported to the laboratory, where the larvae were identified, counted and measured following the methods of Avendaño, Cantill anez, Le Pennec, Varela and Garcia (2011).…”

Spatial distribution pattern of Mytilus chilensis beds in the Reloncaví fjord: hypothesis on associated processes

“…In coincidence with the growth in mussel culture activities, recruitment on the artificial substrates decreased in traditional collection areas (Avendaño et al 2011). From the 1990s onwards, these were replaced by other recruitment areas, towards the fjords of the Los Lagos region (Leiva et al 2007).…”

“…The only information available relates to a few isolated aspects regarding estimated abundance in some areas (Leiva, et al 2007;Lizama 2003) and some knowledge about larval stages present in the water column (Avendaño, et al 2011;Barría, et al 2012).…”