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  • Anacleto, P.

Presentation at Aquaculture 2019, Berlin, Germany

Updated: Oct 7, 2019

On October 8, 2019, Patrícia Anacleto (Principal Investigator) will be presenting at the Aquaculture 2019 conference, held in Berlin (Germany), the most recent study performed under the framework of Project FISHBUDGET, entitled: "Fish energy budget of the zebra seabream (Diplodus cervinus) under ocean warming and acidification".


Here's the summary of the presentation:


Introduction

Climate change is one of the greatest environmental challenges that cause profound impacts on marine organisms and ecosystems (IPCC, 2014). According to the latest report of the Intergovernmental Panel on Climate Change (IPCC, 2014), it is predicted seawater pH decrease (0.2-0.6 units) and seawater surface temperature increase (0.3–4.8°C) in estuarine and coastal areas by the end of the 21st century with strong local variations. Indeed, ocean warming and acidification represent the major threats to many marine organisms, particularly fish, deeply affecting their physiological responses in ways that often compromise their energy budget, i.e. the energy intake and expenditure within the whole organism (Jobling, 1994; Yurista, 1999). The impacts of these environmental stressors on fish bioenergetics remain unclear and still require further understanding. In this context, the main goal of this work was to study, for the first time, the effects of ocean warming (+4°C, i.e. 23°C) and acidification (ΔpH=−0.4 units equivalent to ΔpCO2~1000 μatm) on the energy budget (i.e. growth, excretion, metabolism and food consumption) of juvenile zebra seabream (Diplodus cervinus). Energy proportion spent for growth dominated the mode of the energy allocation of juvenile zebra seabream under the combined effect of ocean warming and acidification. Acidification alone strongly decreased the ammonium excretion rate (AER), but increased fat and protein contents, as well as the viscerosomatic index, VSI. On the other hand, under warming conditions, an increase in metabolic rates (RMRs) was registered, likely since temperature directly affects the rate of all biological processes. Nevertheless, the combined effects of both stressors promoted an increase of fish growth, but a decrease of the hepatosomatic index (HSI). Overall, such extreme conditions of ocean warming and acidification, is expected to greatly affect the energy budget of marine fish, leading to impacts on fish communities and ecosystems. Such studies are extremely relevant to unravel the partitioning of energy in the different physiological processes of fish species. Further research combining other stressors (e.g. hypoxia or presence of contaminants) are needed to better understand and forecast fish ecological effects, in order to develop potencial mitigation measures.


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