Phase IV – By Catch Assessment and Mitigation in Western Indian Ocean Fisheries

While there are considerable industrial marine fisheries in the southwestern Indian Ocean (SWIO), notably for tunas and crustaceans, regional Scale Fisheries (SFF) are of greater social importance, employing > 0.5 million fishers and contributing > 70% of regional marine fisheries’ catches. Despite often being overlooked, SSF may impact marine ecosystems, thus, they reflect the global challenge of balancing conservation goals with communities’ dependence on marine resources. Marine megafauna (elasmobranchs, marine mammals, and sea turtles) are vulnerable to fisheries and play important roles in marine ecosystems. Yet, little is known of the interactions between SWIO SSF and these species. This lack of information was the main driver for the WIOMSA/MASMA-funded BYCAM project. The overall aim of BYCAM was to provide for future sustainable fisheries by creating a baseline estimate of current marine megafauna exploitation and subsequently developing and testing methods for the mitigation of vulnerable megafauna catches and to provide recommendations for future governance and management. BYCAM focussed on three fisheries with known bycatch problems: semi-industrial prawn trawls, small-scale coastal longlines, and gillnets.

BYCAM provides a much-needed first independent quantitative assessment of SFF catch in the SWIO region and demonstrates that current FAO data for elasmobranch catches are seriously underreported, whilst catches of both marine mammals and sea turtles are ongoing. The implication of catch underestimates in official data is that vulnerable elasmobranch species may be overexploited and, further, that the livelihood strategies of those relying on this catch are under threat. The project also demonstrates the need for a multi-method approach towards assessing marine megafauna interactions with SSF in the SWIO and other data-poor areas. The low-cost mitigation methods developed and trialled in the project to reduce bycatch of vulnerable megafauna are promising. Funding has been secured, and new trials with the bottle alarm and acoustic reflectors are underway. Further, there is considerable scope for more widespread use and implementation of TEDs in SWIO prawn trawls. The project has taken the first steps towards building governance frameworks to promote sustainable fisheries management within the WIO.