A blueprint for collaborative, pan-regional cetacean surveys in the Indian Ocean - a necessary baseline for assessing threats
The Indian Ocean is home to a high diversity of cetacean species. It is also a region where human activities and subsequent impacts on cetaceans and other marine megafauna species are increasing. Bycatch of cetaceans in gillnet fishing gear has been particularly recognised as a significant threat across the region. The lack of baseline knowledge on cetacean species and populations (population units, abundance, and distribution), is limiting conservation efforts to assess and address bycatch and other threats. Despite past international initiatives which have attempted to fill these knowledge gaps, the Indian Ocean has not been systematically surveyed across its entire region, and visual survey coverage remains very low in some regions. This paper aims to prompt discussions on the need for coordinated pan-regional survey initiative for cetaceans - to acquire baseline information on species and populations and to adequately monitor and address the impact of threats. We propose that such an initiative could be formed of four distinct elements: 1) the compilation, review and analysis of historical survey data and other relevant datasets; 2) national surveys, acoustic and visual, in EEZs led by individual governments; 3) international collaborative surveys in the ABNJ coordinated by lead countries; 4) the coordinated use of platforms of opportunity to maximise survey coverage. The paper suggests some next steps for the IWC Scientific Committee, contracting governments and the IWC Secretariat in exploring this proposed initiative further. The paper includes a non-exhaustive list of previous visual surveys, available in published and unpublished sources, and survey initiatives which are underway or planned in the near future. Major spatial gaps are identified. This paper was developed by the IWC Secretariat in close collaboration with individual Scientific Committee members, and their contribution will be formally acknowledged in future iterations of this paper.