Resumen del producto

Marine bivalve reproduction is affected by environmental conditions, mainly by water temperature and food availability. In several species the gametogenesis is related to energy storage cycles (in several somatic tissues) during high food availability periods and its use when food is scarce. The reproductive process of N. subnodosus in Bahía de los Ángeles B.C. in relation with the biochemical composition, and the influence of temperature and food availability was analyzed in this study. From January 2006 through May 2007 30 organisms per month were collected, which were weighed and dissected alive, a portion of each tissue (gonad, muscle, mantle, and digestive gland) was stored at -80°C for biochemical analysis. To analyze the reproductive process the conventional histological process was used and the average ovocyte diameter and gonadosomatic index were calculated. To corroborate the energetic reserves storage and utilization, muscle, digestive gonad, and mantle indexes were calculated, biochemical analysis (Bradford protein assay, sulfofosfovainillina for lipids, and antrona for carbohydrates) for each tissue were also carried out. In situ temperature and from satellite images chlorophyll a values were obtained. Given the high food availability in Bahía de Los Ángeles, the indifferent phase (inactive reproduction) of N. subnodosus was not present, and then the gametic production is continuous. This is supported by the presence of partially spawning and mature orgnaisms which were in process of re-maturation. The reproductive activity of N. subnodosus in Bahía de Los Ángeles is affected by highest water temperature (26-30°C), which causes a massive lysis period (July-November) with minimal or no reproduction. The changes in biochemical component concentrations in each tissue indicates that the energetic reserves have a minimal participation during reproduction of N. subnodosus, which means that the main energetic expenditure falls mainly on the energy obtained from recently ingested food (opportunistic estrategy).

Palabras clave: Reproduction; Scallop; Nutrient transference; Food availability

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