Tuna and Transshipment - A global Analysis to Explore the Links between Tuna Diversity and Transshipment Vessel Location

Transshipment at sea is a practice where refrigerated cargo vessels, also known as reefers, meet with fishing boats to exchange catch, fresh water, food and crew. Transshipment can greatly extend the time a vessel can spend at sea fishing. However, it compromises the transparency pertaining to environmental and social sustainability within the seafood industry as catch, both legal and illegal, from several fishing vessels are mixed onboard the reefer. Satellite-based AIS data and published data on the distribution of tuna was used to map tuna presence, spawning areas, and diversity. This study aims to connect transshipment vessels and distribution patterns of seven tuna species by correlating tuna distribution and spawning grounds with reefer activity.