CONICET | Buscador de Institutos y Recursos Humanos

Cancer setosus is an important brachyuran crab for small-scale benthic fisheries, inhabiting shallow(5-10 m) bottoms of the upwelling ecosystem off Chile and Peru. Temperatures in these ecosystemchange dramatically during El Niño Southern Oscillation events. C. setosus is susceptible to thesesudden changes in temperatures. To understand the metabolic processes behind this adaptation westudied the effects of temperature on: standard metabolic rate, the change on the metabolic rate aftersudden increase in temperature and the enzymatic activity of animals acclimated over ~6 weeks tothree different temperatures.Animals were caught off Antofagasta (23ºS), Chile, by diving at 5 8 m. Oxygen consumption ofanimals acclimated to 12º, 16° and 20°C was measured. An intermittent flow system was used forrespiration measurement. Oxygen content was determined with microoptodes connected to a PresensOXY-4-array. After standard metabolism was measured, temperature was increased at a rate of2°C·day-1. Thereafter, and on a daily basis, the metabolic rate at the increased temperature wascalculated. This was repeated until animals surpassed their upper temperature threshold. Animalswere dissected after respiration experiments, and gills and muscles were frozen to determine theenzymatic activity of citrate synthase and pyruvate kinase.We show results from respiration experiments; the determination of the enzymatic activity isundergoing. We present and compare the standard metabolic rates at every temperature. We willshow the effects of sudden changes in temperature and we will address differences related toacclimated temperature.These results will be discussed in the context of the temperature tolerancewindow of the species along its wide latitudinal distribution range.