Temperature increment is one of the most visible aspects of climate change. Reservoirs in northern Patagonia are the main location for rainbow trout cage aquaculture activities in Argentina and here, surface water temperature shows an increment that despite leading towards better growth rates, also provokes lack of ovulation, atresia and a partial or total absence of spawning during the breeding season. During the early life history, low survival rates at hatching and first feeding are also observed. The increase in market size (>2 kg) has changed management practices, minimizing the difference between brood stock and individuals destined for consumption. Thus, the present situation differs deeply from carrying capacities forecasted few years ago and this analysis attempts to contribute to management policies including the idea of adaptation to climate change in the making of decisions.

Rainbow trout is a salmonid specie of commercial importance raised in hatcheries in many countries. Studies over mineral requirements have being perform to guarantee the fulfillment of the nutritional needs and therefore improving the fish farm productions. The aim of this work was to investigate the performance of the elements like Ag, As, Br, Ca, Cr, Cs, Fe, Hg, K, Na, Rb, Se, and Zn, in rainbow trout from a Patagonian fish farming. Body burden of each element in relation to weight were analyzed for identifying potential bioaccumulation or dilution processes. Our results indicated that water and food were the sources for most of the elements, except Se and Ag. Selenium showed the highest value in unfertilized eggs, and Ag was detected in larvae newly after feeding. Toxic elements as Ag, Cr, and Hg were below the regulation standards for human consumption but tend to bioconcentrate in the juvenile state, and the As was during all the growth studied. The macro and micro nutrients assemble the daily requirements for the humans consume, excepting the K.