Variación en los parámetros fisiológicos yvalores isotópicos en sangre del tiburón demersal Scyliorhinus canicula (Linnaeus, 1758) en relación a la estación del año, al sexo y al estado de madurez

Abstract

Trabajo final presentado por Elisenda Valls Mateus para el Máster en Biodiversidad, realizado bajo la dirección del Dr. Joan Josep Navarro Bernabé y de Claudio Barría Oyarzo del Institut de Ciències del Mar (ICM-CSIC).-- 26 pages, 7 figures, 3 tablesMarine predators such elasmobranchs exhibit variations in nutritional requirements related to reproductive traits or conditioned by variations in food availability in the marine environment throughout the year. In this study, the main objective was to examine how certain physiological parameters and stable isotope values in blood of demersal shark Scyliorhinus canicula in the wild change in relation to season, sex and maturity stage change. For this purpose, plasma lipid fractions (cholesterol, triglycerides, phospholipids), a ketone body metabolite (3-hydroxybutyrate) and isotopic values of N and C in blood of Scyliorhinus canicula individuals captured and released alive in the Western Mediterranean were analyzed. The results indicated that the isotopic values changed between summer and winter, males and females and mature and immature individuals. In relation to the physiological parameters we found that during summer triglycerides and phospholipids values were lower in mature individuals (especially in females, probably due to breeding season and laying eggs) and higher in immature specimens, indicating a higher physical activity than in winter. Cholesterol showed high values in summer, probably related to the reproduction. In the case of 3-hydroxybutyrate, the observed pattern was different from the other physiological parameters. Mature males showed higher values than other individuals during the winter season, indicating some physical activity, both mature and immature males showed higher values of this parameter in comparison to females during winter. During summer we found no differences by sex or maturity stage in the values of this metabolite. This study uses an innovative analysis of stable isotopes and plasma lipid fractions in the blood, without causing further damage to the target species. With this methodology new information regarding trophic ecology and physiological state of an abundant elasmobranch is providedEste trabajo de fin de máster es una contribución dentro del proyecto ECOTRANS (CTM2011-26333, Ministerio de Economía y Competitividad del Gobierno Español)Peer Reviewe