Oceanographic upwelling conditions influence signaling pathways involved in muscle growth of intertidal fish

Few studies have addressed the impact of the upwelling oceanographical conditions on biological processes, such as growth, using a molecular and physiological approach. Upwelling conditions are characterized by low temperature seawater and high nutrient availability, which represents an ideal opportunity to understand how habitat modulates animal performance at different levels of biological complexity. We aimed to assess intraspecific variations in weight, oxygen consumption, protein content, and key signaling pathways involved in muscle-growth (protein kinase B (AKT) and extracellular signal-regulated kinase (ERK)) under experimental trials considering high/low seawater temperatures with full/restricted food rations. For this purpose, we studied Girella laevifrons, one of the most abundant fish species inhabiting rocky intertidal zones along the Eastern South Pacific coasts. Using fish obtained from upwelling (U) and non-upwelling (NU) zones, we reported that U animals displayed higher growth performance during both contrasting trials, with a weight gain (~3 g), lower oxygen consumption (~12%), and higher protein contents (~20%). Only ERK showed significant differences during the trials (~2-fold downregulation between NU and U fish). We also found that U fish increased protein ubiquitination in high water temperature and restricted food ration in contrast to NU fish. Our results help to elucidate how upwelling conditions may influence fish growth at physiological and molecular levels. Still, future analyses are necessary to improve the information regarding the impact of U and NU condition on animals, as well as the possible applications of this data in the aquaculture industry.