8 years of best practices onboard French and associated flags tropical tuna purse seiners: An overview in the Atlantic and Indian oceans

In 2012, the first manual for the safe handling of sensitive species onboard tropical tuna purse seiners was released. This Code of Best Practices, developed in collaboration between French associated flags tropical purse seiners and French scientistsof IRD and Ifremer, provides a set of recommendations and techniques to improve the survival of sensitive species incidentally caught by tropical tuna purse seiners, while taking into consideration crew safety. Following the release of the Guideof Best Practices, purse seinecrews have been trained to Best Practices, vessels have been equipped with adequate Best Practices handling gear, and the methodology for the monitoring of Best and UnsuitablePractices has gradually improved. This document presents the evolution of the methodology used for this monitoringsince 2015,describes the data collectedby onboard and electronic observers in the frame of the OCUP program and proposes further improvements in the monitoring methodology. Theanalysis of the data collected fromApril 2016to March 2020 indicatesthat Best Practices are more easily applied for sea turtles and whale sharks than for undetectable small sharks and rays, dangerous sharks, or large sharks and mobulid rays that cannot be easily handled with Best Practices. Our results also suggest differences in the exhaustivity and objectivity of the data collected by onboard and electronic observers. The results we obtain are used to draw recommendations for future work, such as a better consideration of the effect of vessel configuration or individualized training of crews and observers to Best Practices.