Identification and characterization of trammel net métiers: A case study from the southwestern Sicily (Central Mediterranean)

The high variability of trammel fisheries, due to a marked seasonality in target species and fishing activities needs to be investigated with high spatial and temporal resolution. The present study focuses on trammel net fishery in southwestern Sicily (central Mediterranean Sea) identifying and characterizing the main métiers in relation to some key aspects of the fishery such as the target species, composition of landings, main fishing grounds and time of the year. For this purpose, a multivariate statistical approach based on landings and effort data of the Mazara del Vallo southwestern Sicily, Italy) trammel fleet in the period 2009-2013 was applied. A total of 153 different landed species and four different trammel net métiers were identified. These métiers showed differences in target species (i.e. Sepia officinalis, Palinurus elephas, Mullus surmuletus and a mix of species), fishing season, fishing grounds and dimension of fishing vessels. The métiers identified were significantly different in terms of total average landing per unit of effort (LPUE) with métier 1 targeting M. surmuletus, showing the highest average LPUE (2047 (192 s.e.) g*(h)*10 m net) and métier 2 targeting S. officinalis, exhibiting the lowest value (1175 (119 s.e.) g*(h)*10 m net). The study provides new knowledge on the dynamics of trammel fisheries in southwestern Sicily also showing that the complex nature of this peculiar fishery should be taken into account in any future sampling program aimed at the monitoring and management of artisanal fisheries in this area and more in general in the Mediterranean Sea.