Effects of extreme environmental variation on the physio-immunological response of euryhaline fish

Global warming results in increased climate variability and extreme weather conditions with abrupt environmental changes more likely to occur. Globally, temperature and precipitation patterns have changed markedly in recent decades and are predicted to change even more in the future as a result of anthropogenically driven climate change. Fluctuations in environmental variables affect many aspects of physiological responses in fish, including feed intake, survival, growth, physiology, reproduction, behavior, and distribution of fish.

The European sea bass (Dicentrarchus labrax L.) is a marine teleost, is widely distributed throughout the Mediterranean Europe and extensively used for aquaculture and is therefore of great commercial and ecological importance. Sea bass grows better at temperature ranges from 22 to 24 o C with 26 to 32 ppt salinity. This fish is sensitives to a temperature below 6o C and over 30o C, which leads to impairments of growth, physiology, and high mortality rate. In the southern part of the Mediterranean, the maximum water temperature in ponds are reported to periodically exceed 33–34oC during late spring to August, whereas, in autumn, the temperature of lagoons can decrease to 5–6 °C.

To date, researches about the effect of temperature and salinity of euryhaline fish have been conducted separately for a shorter period. To the best of our knowledge, very little work has been published on euryhaline fish exposed to extreme temperature and salinity stress for a prolonged period. To face the global and regional climate changes, a thorough study on the metabolic and molecular stress responses of euryhaline fish exposes to extreme environmental condition (temperature and salinity) is necessary. Besides, there is an impending necessity of remediation measures to the environmental stress of euryhaline fish through dietary manipulation.

This PhD study aims to investigate different metabolic and molecular stress responses indictors with temperature, salinity variations and both thereof. These will be studied to identify the critical threshold of biological indicators and conditions for which remediation actions should be taken to keep fish healthy and fighting climate changes.

 

Funded by a scholarship from the German Academic Exchange Service (DAAD)

In cooperation with Leibniz-Zentrum für Marine Tropenforschung (ZMT)