Spatial and temporal trend in the abundance and distribution of gurnards (Pisces: Triglidae) in the northern Mediterranean Sea

Francesco Colloca,Giacomo Milisenda,Stefano Montanini,Francesc Ordines,Francesca Capezzuto,Angélique Jadaud,Alessandro Cau,Nedo Vrgoc,Sotiris Kiparissis,Maria Vallisneri,Germana Garofalo,Alessandro Voliani,Ioannis Thasitis,Reno Micallef,Walter Zupa

doi:10.3989/scimar.04856.30a

Abstract

In this study we investigated the spatio-temporal distribution of gurnards (8 species of Triglidae and one species of Peristediidae) in the northern Mediterranean Sea using 22 years of MEDITS bottom trawl survey data (1994-2015). Gurnards showed significant differences in terms of abundance, dominance and composition among geographical sub-areas and ecoregions, with the highest relative biomass (BIy) being found in Malta, eastern Corsica, the Balearic Islands and the eastern Ionian Sea. The lowest gurnards BIy were observed in the highly exploited areas of the western Mediterranean and the Adriatic Sea, where the largest number of species with a negative linear trend in BIy was also found. The temporal trends in species abundances highlighted a general decrease for the coastal species (C. lucerna, C. lastoviza, C. obscurus) as compared with the species inhabiting the deep continental shelf and slope (T. lyra, P. cataphractum). The results provide for the first time an overview of the spatiotemporal trend in the abundance of gurnards over the wide spatial scale of the northern Mediterranean Sea, also suggesting the possible use of these species as indicators for monitoring the impact of fishing pressure on demersal fish assemblages.

Highlights

The Triglidae is a large family of fish of the order Scorpaeniformes, which comprises 8 genera and 125 species dwelling in tropical and temperate marine areas (Richards and Jones 2002)
Summary: In this study we investigated the spatio-temporal distribution of gurnards (8 species of Triglidae and one species of Peristediidae) in the northern Mediterranean Sea using 22 years of Mediterranean bottom trawl survey (MEDITS) bottom trawl survey data (1994-2015)
The temporal trends in species abundances highlighted a general decrease for the coastal species (C. lucerna, C. lastoviza, C. obscurus) as compared with the species inhabiting the deep continental shelf and slope (T. lyra, P. cataphractum)

Summary

Introduction

The Triglidae (or gurnards) is a large family of fish of the order Scorpaeniformes, which comprises 8 genera and 125 species dwelling in tropical and temperate marine areas (Richards and Jones 2002). In the Mediterranean Sea, the family is represented by 4 genera (Eutrigla, Trigla, Chelidonichthys and Lepidotrigla) and 8 species (E. gurnardus, T. lyra, C. lucerna, C. cuculus, C. obscurus, C. lastoviza, L. cavillone and L. dieuzeidei). These fish are an important component of demersal assemblages in terms of biomass in both the eastern and western Mediterranean basins (Jukic-Peladic et al 2001, Labropoulou and Papaconstantinou 2004, Massuti and Reñones 2005). The 8 gurnard species, along with the closely related African armoured searobin, Peristedion cataphractum, play similar roles in the trophic web, feeding mainly on epibenthic crustaceans (Colloca et al 1994). Interspecific competition for food is reduced by species segregation across gradients of prey size and habitat type (Morte et al 1997, Colloca et al 2010, Montanini et al 2017)

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