History of the IATTC Bycatch Data Collection and Description of the ‘Bycatch Database’ for use in Ecosystem and Bycatch Research

Since its inception, the primary responsibility of the Inter-American Tropical Tuna Commission (IATTC) has been to ensure the sustainable exploitation of principal species of tuna and tuna-like fishes. When the Antigua Convention entered into force in 2010, the IATTC extended its responsibilities to include the ecological sustainability of its tuna fisheries. Observers onboard purse-seine vessels targeting tropical tunas in the eastern Pacific Ocean (EPO) have collected data on the incidental catch of non-target species (i.e., “bycatch”) associated with tuna fishing operations for over four decades. The scope of this data collection effort has evolved over time. Bycatch data on marine mammals have been collected since the late 1970s. In the late 1980s, bycatch data collection for sets on floating objects was initiated, and in the early 1990s bycatch data collection began for all species in all set types, with a view for these data to support ecosystem approaches to fisheries management. This wealth of information allows IATTC scientists to conduct various analyses on bycatch species to guide managers and policy makers on potential conservation and management issues. However, not only has the scope of the data collection changed over time, but so have the methods of collection, storage and reporting of bycatch data, in response to changes in financial and staff resourcing, as well as political drivers such as increased scientific and public awareness of potential ecological impacts of tuna fishing. Therefore, in an attempt to maintain transparency in data collection and processing methods, this paper describes the history of bycatch data collection, the bycatch database, methods used to generate summary data tables from the database, and efforts made to improve bycatch data collection and management. Such efforts are aimed at optimizing the quality of data for the purposes of estimating bycatch mortality by tuna fisheries in the EPO, which in turn will enhance the quality of the various analyses that these data may be used for to guide conservation and management efforts for individual bycatch species and the supporting ecosystem more broadly.