Long-term trajectory of some elasmobranch species off the Tuscany coasts (NW Mediterranean) from 50 years of catch data


  • Alessandro Ligas Centro Interuniversitario di Biologia Marina ed Ecologia Applicata “G. Bacci” (CIBM)
  • Giacomo C. Osio EC Joint Research Centre (JRC), Institute for Protection and Security of the Citizen (IPSC)
  • Paolo Sartor Centro Interuniversitario di Biologia Marina ed Ecologia Applicata “G. Bacci” (CIBM)
  • Mario Sbrana Centro Interuniversitario di Biologia Marina ed Ecologia Applicata “G. Bacci” (CIBM)
  • Stefano De Ranieri Centro Interuniversitario di Biologia Marina ed Ecologia Applicata “G. Bacci” (CIBM)




historic data, trawling, auto-correlation factor analysis, cartilaginous fish, Mediterranean Sea


The time series of elasmobranch catch rates off the Tuscany coasts (NW Mediterranean) were investigated by means of min/max auto-correlation factor analysis in order to estimate variations in population abundance and evaluate the influence of environmental and anthropogenic factors. The analyses highlighted a general decreasing trend in the catch rates of sharks and skates from 1961 to the mid-1990s, mainly influenced by the increase in fishing effort. Since the 1990s, the EU Common Fishery Policy for the Mediterranean has promoted the reduction of fishing fleets through incentives to vessel demolition. The Porto S. Stefano trawl fleet has decreased by about 50%, leading to a decrease in fishing effort which seemed to be the most relevant factor affecting the increasing trend shown by the catch rates of Galeus melastomus, Scyliorhinus canicula and skates from 1991 to 2009. The elasmobranch assemblage did not undergo major shifts but the weighted frequency of occurrence shows that elasmobranchs were more frequent in the past. Particular caution should be paid in interpreting the recent rebound of some species as an early sign of recovery: trawl survey data and landing data show that over the last 50 years elasmobranch fauna have undergone a drastic decline and that recent rebounds are still far from a recovery to historical levels.


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How to Cite

Ligas A, Osio GC, Sartor P, Sbrana M, De Ranieri S. Long-term trajectory of some elasmobranch species off the Tuscany coasts (NW Mediterranean) from 50 years of catch data. Sci. mar. [Internet]. 2013Mar.30 [cited 2024May21];77(1):119-27. Available from: https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/1430




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