The influence of habitat characteristics on the energy reserves of female spawners of red mullet (Mullus barbatus) in the Mediterranean Sea

Abstract

This study aims to describe the effect of habitat characteristics on the energy reserves of red mullet (Mullus barbatus) in the north-western Mediterranean. We compare the energy reserves between individuals inhabiting different areas of the seabed (e.g. areas close to the Ebre and Rhône River mouths versus areas not influenced by river run-off; seabed areas strongly impacted by trawling activities versus areas less impacted). This study also attempts to establish a relationship between female adult condition (i.e. energy reserves in the muscle) and their reproductive potential (i.e. energy reserves in the gonad). To evaluate energy reserves, wet and dry weights of tissue were measured and concentrations of total lipid were estimated with the Soxhlet method for the muscle and gonad of female spawners from samples collected during spring 2004. Absolute lipid levels in each tissue were analysed to describe the distribution and storage of lipids during spawning. We also study the relationship between the total lipid content and the triacylglycerol levels (TAG), which is the most important lipid class for energy storage purposes in fish. Finally, we establish the relationships between total lipid content and simple indicators of condition such as Fulton’s K index