An analysis of the population dynamics of &lt;i&gt;Nephrops norvegicus&lt;/i&gt; (L.) in the Mediterranean Sea

Francesc Sardá,Joan E Cartes,Jordi Lleonart

doi:10.3989/scimar.1998.62s1135

Abstract

SUMMARY: The state of exploitation of the Nephrops norvegicus fisheries in different areas in the Mediterranean Sea is examined for the first time. Length cohort analysis (LCA) by sex has been applied for each area, and Y/R curves are presented to show the current status of the stocks under the steady-state assumption. A simulation of short and long-term effects of changes in fishing effort levels is presented. Norway lobster populations in the Mediterranean share the same biological features, but different exploitation patterns have been observed in several areas. Considering current exploitation levels, certain of the stocks analysed appear to be slightly growth-overexploited, while others seem to be placed near the optimum level of exploitation. For comparison purposes, the study areas can be classified as follows: fully exploited: Catalan Sea (Spain), Adriatic Sea and Tyrrhenian Sea (Italy); moderately exploited: Ligurian Sea (Italy) and Euboikos Gulf (Greece); and lightly exploited: Atlantic (Portugal). The stock in the Alboran Sea (Spain) is a special case and is therefore discussed separately.

Highlights

Management of the Norway lobster (Nephrops norvegicus) fisheries in the North Atlantic has been common for many years (Anon. 1997), with varying levels of success
The objective of this paper is to present a comparative analysis of the exploitation pattern on the Norway lobster (Nephrops norvegicus) in a series of different study areas in the Mediterranean
Length frequency distributions have been obtained by means of monthly samples collected over a two-year period (1994-95) in seven areas (Fig. 1)

Summary

Introduction

Management of the Norway lobster (Nephrops norvegicus) fisheries in the North Atlantic has been common for many years (Anon. 1997), with varying levels of success. Management of the Norway lobster (Nephrops norvegicus) fisheries in the North Atlantic has been common for many years The objective of this paper is to present a comparative analysis of the exploitation pattern on the Norway lobster (Nephrops norvegicus) in a series of different study areas in the Mediterranean. Analytic methods have been employed in the present assessment. The strength of such methods lies in their robustness when biological data and size frequencies are accurate. One of the underpinnings of this study has been to put great care and effort into collecting accurate data on the biology of the species in each of the study areas considered

Objectives

Methods

Results

Conclusion