Effects of Desertification Caused by Lithophaga lithophaga (Mollusca) Fishery on Littoral Fish Assemblages along Rocky Coasts of Southeastern Italy

Authors

  • PAOLO GUIDETTI,

    Corresponding author
    1. Laboratory of Zoology and Marine Biology, Department of Biological and Environmental Sciences and Technologies, University of Lecce, 73100 Lecce, Italy
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  • SIMONETTA FRASCHETTI,

    1. Laboratory of Zoology and Marine Biology, Department of Biological and Environmental Sciences and Technologies, University of Lecce, 73100 Lecce, Italy
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  • ANTONIO TERLIZZI,

    1. Laboratory of Zoology and Marine Biology, Department of Biological and Environmental Sciences and Technologies, University of Lecce, 73100 Lecce, Italy
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  • FERDINANDO BOERO

    1. Laboratory of Zoology and Marine Biology, Department of Biological and Environmental Sciences and Technologies, University of Lecce, 73100 Lecce, Italy
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*email paolo.guidetti@unile.it

Abstract

Abstract: We surveyed shallow, rocky reefs in southwestern Apulia (Mediterranean Sea) to assess the effects on coastal fish assemblages of the date mussel ( Lithophaga lithophaga) fishery, an illegal practice that strips the rocky reef bare. We visually sampled fish four times over 15 months at three locations, one affected by date-mussel fishery and two controls. The fish assemblage at the affected location differed significantly from those at the control locations over all sampling times. Herbivorous fishes, sparids, and labrids (genus Symphodus) contributed most to the differences between the affected location and controls. Lower densities of Symphodus spp. were observed at the affected location, whereas detritivorous fishes were recorded exclusively at control sites. Small serranids and sparids showed temporal trends that differed between the affected location and the control locations. Our results suggest that the date-mussel fishery affects fish assemblages chiefly through reduction of arborescent macroalgae (contributing to habitat complexity and primary production) and emphasize the need for more effective policing against this destructive practice.

Abstract

Resumen: Muestreamos arrecifes rocosos someros en Apulia sudoccidental (Mar Mediterráneo) para evaluar los efectos de la pesquería de Lithophaga lithophaga, una práctica ilegal que desnuda al arrecife rocoso, sobre ensambles de peces costeros. Visualmente muestreamos peces cuatro veces a lo largo de 15 meses en tres localidades diferentes, una afectada por la pesquería y dos controles. El ensamble de peces en la localidad afectada difirió significativamente de los sitios control en todos lo tiempos de muestreo. Los peces que más contribuyeron a las diferencias entre la localidad afectada y los controles fueron herbívoros, espáridos y lábridos (género Symphodus). En la localidad afectada se observaron densidades menores de Symphodus spp., mientras que en los sitios control se registraron peces detritívoros exclusivamente. Serránidos pequeños y espáridos mostraron tendencias temporales que difirieron entre la localidad afectada y los controles. Nuestros resultados sugieren que la pesquería de mejillón afecta principalmente a los ensambles de peces por la reducción de microalgas arborescentes (que contribuyen a la complejidad del hábitat y a la producción primaria) y enfatizan la necesidad de políticas más efectivas contra esta práctica destructiva.

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