Spawning pattern and batch fecundity of the European hake (&lt;i&gt;Merluccius merluccius&lt;/i&gt; (Linnaeus, 1758)) in the western Mediterranean

Velia Chiericoni,Paola Belcari,Laura Recasens

doi:10.3989/scimar.2008.72n4721

Abstract

The spawning cycle of the European hake (Merluccius merluccius, (Linnaeus, 1758)) was studied in two western Mediterranean areas, the Catalan Sea and the northern Tyrrhenian Sea, including observation of the monthly seasonal variation of the gonad maturity and the gonadosomatic index (GSI). The estimation of the maturity stages by GSI gave similar values in the two study areas: the spawning stage (IV) was easily distinguished from the other maturity stages and its range of variation showed a low overlap with stage III and no overlap with other stages. Although in both study areas active females were present during all the sampled months, the peak of reproductive activity was concentrated from February to May in the northern Tyrrhenian Sea but from August to December in the Catalan Sea, which was subjected to winter cascading events. Batch fecundity gave similar values in the Catalan and northern Tyrrhenian Seas: 204 and 202 eggs per gonad-free female gram, respectively. An asynchronous oocyte development is suggested for M. merluccius in the western Mediterranean.

Highlights

The European hake, Merluccius merluccius (Linnaeus, 1758), is widely distributed in the eastern North Atlantic Ocean and the Mediterranean Sea (Alheit and Pitcher, 1995)
The estimation of the maturity stages by gonadosomatic index (GSI) gave similar values in the two study areas: the spawning stage (IV) was distinguished from the other maturity stages and its range of variation showed a low overlap with stage III and no overlap with other stages
In both study areas active females were present during all the sampled months, the peak of reproductive activity was concentrated from February to May in the northern Tyrrhenian Sea but from August to December in the Catalan Sea, which was subjected to winter cascading events

Summary

Introduction

The European hake, Merluccius merluccius (Linnaeus, 1758), is widely distributed in the eastern North Atlantic Ocean and the Mediterranean Sea (Alheit and Pitcher, 1995). The species inhabits the shelf and shelf-break zones throughout the western Mediterranean (Oliver and Massutí, 1995). T), being at present similar to the level of the 1980s (FAO, 2005). It is still the second most important demersal fish species by landings (after blue whiting, Micromesistius poutassou) and one of the most important target species of the western Mediterranean trawl fleet (Sánchez et al, 2007). As in many zones of the Mediterranean, growth overfishing can be assumed (the hake stock shows signals of growth overexploitation) (Aldebert et al, 1993; Aldebert and Recasens, 1996; Lleonart et al, 2003; FAO, 2005)

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