Effects of recreational fishing on three fish species from the &lt;i&gt;Posidonia oceanica&lt;/i&gt; meadows off Minorca (Balearic archipelago, western Mediterranean)

Ignasi Díez,David López,Marta Sales,Luis Cardona,Sònia De Caralt

doi:10.3989/scimar.2007.71n4811

Abstract

Experimental fishing and visual censuses were conducted at nine Posidonia oceanica sites off Minorca exposed to different levels of fishing intensity to assess the effects of recreational fishing on the species that dominate the catch. Total catch per unit effort (CPUE) was highly seasonal and a statistically significant interaction term existed between the season and the level of fishing intensity. CPUE decreased everywhere at the end of the fishing season (autumn), but such a reduction was more intense at those sites exposed to the highest level of fishing. Visual censuses confirmed that there was a lower abundance of vulnerable fish in autumn. Differences vanished in spring probably because fish reshuffled between the considered sites throughout the winter, when the level of fishing intensity was extremely low. Although the average total lengths of Serranus scriba and Diplodus annularis were unaffected by the level of fishing intensity, the average total length of Coris julis was smaller at the most heavily fished sites. In conclusion, recreational fishing has a relevant impact on most of the exploited species and some of the seasonality reported for the Posidonia oceanica fish assemblages might be caused by the seasonality of the fishery.

Highlights

Sport fishing of marine fish has been practiced for a long time (Bickerdyke, 1887; Ferrer, 1914), but fishery biologists have long neglected it as a relevant source of exploitation
SUMMARY: Experimental fishing and visual censuses were conducted at nine Posidonia oceanica sites off Minorca exposed to different levels of fishing intensity to assess the effects of recreational fishing on the species that dominate the catch
Total catch per unit effort (CPUE) was highly seasonal and a statistically significant interaction term existed between the season and the level of fishing intensity

Summary

Introduction

Sport fishing of marine fish has been practiced for a long time (Bickerdyke, 1887; Ferrer, 1914), but fishery biologists have long neglected it as a relevant source of exploitation. Pickett and Pawson (1994) assessed the relevance of recreational angling for a marine species in Europe for the first time and concluded that sport anglers generated half the total catch of sea bass (Dicentrarchus labrax) off the United Kingdom. Coll et al (2004) and Chavoin and Boudouresque (2004) demonstrated the role of recreational spearfishing in the depletion of large fish from Mediterranean rocky reefs and Morales-Nin et al (2005) pointed out that 31% of the annual fish production at trophic level 4 is removed from the coastal waters of Majorca Island (Balearic Archipelago, western Mediterranean) by sport fishing. Previous studies have demonstrated that recreational angling on rocky areas may change the reproductive biology of at least one of these species (Harmelin et al, 1995), but information about the impact of fishing on the meadow-dwelling populations is contradictory (Francour, 1994; Harmelin et al, 1995; Francour, 2000)

Objectives

Methods

Results

Discussion

Conclusion