Crescimento e fisiologia do tambaqui Colossoma macropomum (Cuvier, 1818) e do pirarucu Arapaima gigas (Schinz, 1822) em resposta ao aquecimento da água

Abstract

Humans progress has led to the uncontrolled exploitation of natural resources, resulting in elevated levels of gas emissions, which boost the greenhouse effect, causing global warming. Temperature is an essential factor for organisms within their tolerance ranges. But the rise in temperature has caused disruptions, contributing to high levels of stress. Fish are primarily ectothermic organisms that rely on environmental thermal fluctuations. The rise in temperature has forced them to increase their plasticity capacity to cope with warmer habitats. Fish inhabiting the Amazon live in close to their upper thermal limits, with significant implications for the conservation status and management/production strategy of this group. In this investigation, we analysed the effects of water temperature increase (beginning from an ambient temperature range of 27.0 ºC to 37 ºC) on the physiological and zootechnical responses of the tambaqui Colossoma macropomum and the pirarucu Arapaima gigas to determine optimal breeding conditions and establish conservation management approaches. Our primary outcomes demonstrated that these two species seem capable of coping with temperatures up to 34 ºC. Beyond this threshold, oxidative stress levels escalate, and the efficacy of the antioxidant response hinges upon the mode and duration animal exposure. Concurrently, liver damage markersrise, survival rates fall, and overall performance diminishes. Thus, the research findings outlined in this thesis demonstrate that Amazonian species are vulnerable to the negative effects of water warming. It is imperative that measures are implemented to protect their breeding systems and environments, ensuring their survival and reproductive success. These mechanisms and strategies should be developed in light of the significance of these species to protect their integrity and provide adequate conditions for their survival and good performance, given the importance of these species for fisheries and aquaculture, as well as for food security and food sovereignty.