Collection and validation of self-sampled e-logbook data in a Mediterranean demersal trawl fishery

Over the last several years, a great deal of emphasis has been given to the use of participatory research to enhance knowledge co-production between fisheries stakeholders, involving fishers in the sampling of their catches both for scientific and control purposes. Indeed, this approach could complement data collection through trawl surveys and onboard observers, which is usually expensive and thus, does not allow much spatio-temporal coverage. Within the EU participatory research project, GAP2, electronic logbooks were installed on board otter-trawlers to collect haul-by-haul geo-referenced catch data in the Adriatic Sea (NW Mediterranean Sea). Between September 2012 and December 2013, catches of some of the most important otter-trawl target species (8 species including teleosts, cephalopods, and crustaceans) were recorded in 3588 self-sampled hauls. Because a major concern for the use of these data is related to their quality, self-sampling was run concurrently with a scientific observers’ program, which allowed the detailed monitoring of catches from 249 hauls. The latter dataset was used to test the reliability of fishers’ self-sampled data and for their validation. In all species, no significant disagreement between the two datasets was observed. The full self-sampled dataset was thus used to describe the spatio-temporal changes in catches, as derived by observers’ data, allowing important insights into species’ life cycles. Results agreed with available literature information and fishers’ experience-based knowledge, which was thus embedded in the process of data validation and results interpretation. The collaboration between scientists and fishermen was demonstrated to be a valuable approach for generating reliable fisheries data, allowing a better understanding and quantitative descriptions of species’ life cycles and the attainment of a common base of knowledge for the enforcement of spatially explicit fisheries management.