Dr. Urzua-Osorio, Angel

The fishery resource Concholepas concholepas is a key species in the benthic marine ecosystems of the Southeastern Pacific Ocean. In the present study, the spatio-temporal changes in the biochemical parameters were evaluated for adult individuals of C. concholepas. They were sampled in summer and winter under upwelling and Non-upwelling conditions in two Management and Exploitation Areas for Benthic Resources of Valparaíso, Chile. The results indicated that the variation in the biochemical parameters is explained to a greater extent by the season. For example, in both upwelling and Nonupwelling conditions, we found a higher content of total lipids, proteins, glucose, and energy in winter than summer. Temporal variations can be explained by the reproductive process after summer season, in which the egg spawning require a greater energy reserves to be perform. Nonetheless, differences in the nutritional status of preys along seasons of the year, can also influence on these results. In fact, these variations in the biochemical parameters of C. concholepas may be indicative of an adaptive seasonal physiological response to the environment for maintaining an optimal energy budget year-round. Altogether, this knowledge will contribute to the Management and Exploitation Areas for Benthic Resources, improving regulatory measures during the annual period of captures and landings of C. concholepas, favoring a more sustainable fishery in the Southeastern Pacific Ocean within an ecosystem approach.

The integrated biochemical condition (IBC) of gonads is closely related to the reproductive success of highly migratory marine species. The IBC of gonads can be influenced not only by size and/or age, but also by environmental conditions. Here, female swordfish, Xiphias gladius, that migrate to temperate regions with a marked seasonality (e.g., the Southeastern Pacific Ocean, SEPO) were compared in relation to the IBCs (lipids, proteins, glucose and, fatty acid profiles) of their gonads; individuals with two body size ranges and distinct degrees of sexual maturity were evaluated, and considered as: small and/or virginal (SV: <170 cm lower jaw fork-length (LJFL), oocyte size (OS) <0.08 mm) vs large and/or maturing females (LM: >190 cm LJFL, OS >0.133 mm). This comparison was conducted in two environmentally contrasting seasons (winter vs spring). Our results showed that the gonadosomatic index (GSI) was significantly higher in LM than SV. Lipid contents varied significantly between seasons and body sizes. The highest lipid concentrations were recorded in the spring in large females. No significant differences were found when comparing the protein and glucose contents of the two evaluated seasons or body size ranges of the studied females. In turn, the fatty acid (FA) profiles of female gonads significantly varied for both seasons and body size ranges. A high content of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and poly-unsaturated fatty acids (PUFAs) were recorded in female gonads in the spring. The SFAs C16:0 and C18:0, the MUFA C18:1n9, and the essential PUFA C22:6n3 were the main contributors to the observed differences between spring and winter. These results could be used as indicators of the nutritional condition and health status of swordfish individuals. Hence, the IBC of female swordfish gonads have great potential to aid in estimating survival rates and stock abundances of this species. The integration of this information constitutes an asset in fishery management models with an ecosystem approach.