Large pelagic fish, swordfish, bluefin and small tunas, in the Ligurian Sea: biological characteristics and fishery trends.

This article presents a review and summary of the data on large pelagic fish, collected over the period 1990–2007, thanks to national and European Community research programmes. Swordfish are present in the Ligurian Sea at all life history stages. Time series of longline fishing catch per unit effort (CPUE) values showa good exploitation status, possibly related to the dismission of past questionable fishing technics (e.g. ‘spadare’ nets). CPUE values were also negatively related to North Atlantic oscillation: climatic factors probably had synergic effects. Bluefin is present in the Ligurian Sea with mainly schools of young fish aged 1–4 years, which feed on small pelagic fish and on the Ligurian krill Meganyctiphanes norvegica. Recent limitations on catches have severely reduced local fishing activities. Following the dismission of purse seiners, artisanal hook-based fisheries should be maintained, regardless of the length of fish caught, as a way of monitoring stock status. The two most abundant species of small tuna, Sarda sarda and Auxis rochei rochei, are present in the Ligurian Sea at all life stages. In particular, Auxis rochei rochei is a commercially neglected species which, in terms of larval occurrence, is the most abundant in the Mediterranean. Physiomorphological and genetic studies have been recently carried out in order to improve forthcoming exploitation.