Evolució de les reserves energètiques de la sardina al llarg del període de posta

Abstract

The European sardine, Sardina pilchardus, is in the Mediterranean Sea, among other geographic areas. It receives strong fishing pressure because it is one of the most valued blue fish species, since it is a great fishing resource. In addition, it is considered a key species in the ecosystem, so it is important to know in what state it is. One of the parameters that indicates their state is the physical condition that we can know from indices that are related to the energy reserves or lipid content available to the individual. The reserves are used as energy during the spawning period, which relates these indices to the reproductive capacity of individuals. The indices used in the study are the condition factor of Le Cren (Kn), the mesenteric fat index (MFI) and the gonadosomatic index (GSI). On the other hand, the fat content of muscles and total fat has been estimated using the fatmeter, a device that provides many advantages over traditional methods. The objectives of the study were to determine the evolution of these parameters throughout the spawning period and according to the stage of gonadal development and analyse the characteristics to be taken into account in the use of the fatmeter. The study was carried out by analysing 369 specimens captured in different locations of the Costa Brava throughout the spawning period, later they have been frozen. The statistical analyses carried out were based on the realization of different ANOVA in order to determine if there were differences in the parameters throughout the spawning period and according to the stage of gonadal development. To determine the reliability of the use of fatmeter, a correlation test between S2 and S1 + MFI was performed, and finally to determine if the measurements of the device were consistent with each other, a paired data t test was performed. The results confirm the reliability of fatmeter given the strong correlation between S2 and S1 + MFI. The results show that there are statistically significant differences in the different rates throughout the spawning period as well as in the different stages of gonadal development. In this way, it has been determined that the energy expenditure associated with the reproduction of females (where the investment is greater) takes advantage of the mesenteric reserves during the development of gonads and, at the end of the vitellogenesis process, they use the musculature reserves