Comparison of Elasmobranch Catches from Research Trawl Surveys and Commercial Landings at Port of Viareggio, Italy, in the Last Decade

A. J. Abella and F. Serena

Agenzia Regionale per la Protezione Ambientale della Toscana
Via Marradi 114, 57100 – Livorno Italy

Publication (Upload) date: 14 February 2005

ABELLA, A. J., and F. SERENA. 2005. Comparison of Elasmobranch Catches from Research Trawl Surveys and Commercial Landings at Port of Viareggio, Italy, in the Last Decade. J. Northw. Atl. Fish. Sci., 35: 345-356. https://doi.org/10.2960/J.v35.m526

Abstract

A program to monitor commercial elasmobranchs was put into effect at Viareggio, the most important fishing port of the Tyrrhenian and Ligurian seas. Size structure of the catches and spatial information on fishing effort distribution were collected monthly by species and gear over the period 1990–2001. Data on catch rates and geographical distribution were also obtained from annual research trawl surveys during 1985–2001 in the same area that the fish landed at Viareggio were caught. The distribution of the fishing effort for every major fishery was compared with catch rates of research trawl surveys for the more important elasmobranch species; two batoids, Raja asterias and Raja clavata and two sharks, Scyliorhinus canicula and Galeus melastomus. Trends in catch rates derived from fishery independent and fishery dependent sources appear inconsistent. This is probably due to spatial shifts in the effort allocation of the fisheries as a consequence of changes in target species that occurred during the analysed period. The current level of fishing pressure and fishing pattern, that remained almost unchanged for the last 10 years, seems sustainable for each one of the four species studied. This may be related to a relatively low fishing pressure on some grounds where certain species are concentrated, to the discarding of a portion of the individuals caught as well as to life history characteristics of some species that make them less sensitive to increased fishing mortality.

Key words: catch, distribution, effort, landings, rays, research surveys, shark