New bioenergetic perspective of European hake (Merluccius merluccius L.) reproductive ecology

In spite of the economic and ecological importance of hake and the depletion of the European stocks, studies about these species, especially about its reproductive potential, are almost nonexistent. In the present work the relationship between gonad development and female's physiological condition and energy reserves has been studied. Gonadosomatic index (GSI) was significantly but not strongly related to condition factor (K) and not significantly related to hepatosomatic index (HSI), whereas gonad energy content was positively related to liver and muscle energy content. On the other hand, it was observed that both, number of developing oocytes (NDOs) and batch fecundity (BF), were significantly related to length and gutted weight. Besides, NDO was related to HSI and total fish energy reserves, while BF was significantly related to liver energy density. Multiple regression models were constructed using maternal attributes as variables. 27% of NDO and 57% of BF variability was explained by these models. Results suggest that European hake egg production depends more on energy intake during spawning season and growth capacity than on energy reserves accumulated several months before spawning season begins.