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Open Access Publications from the University of California

Tracking refrigerated transshipment vessels to inform the Food and Agriculture Organization's Agreement on Port State Measures


Concern is increasing over declining fisheries and safeguarding global ocean resources. Protecting fisheries requires numerous conservation and management approaches. At the same time, fishing vessels are able to maximize harvest because fleets of cargo-sized refrigerated vessels ‘transship’ at sea. Transshipment occurs when a fishing vessel transports its catch on to a refrigerated transshipment vessel at sea. During transshipment, illegally caught fish can be ‘laundered’ with legal fish before entering the port. Transshipment can allow fishing vessels to stay at sea for years at a time and has been linked to transnational crime and human rights violations. This paper uses collision avoidance transceivers, Automatic Identification Systems (AIS), that transmit the vessel’s information to inform the Agreement on Port State Measures to Prevent, Deter and Eliminate Illegal, Unreported and Unregulated Fishing (PSMA). PSMA is a binding international treaty of the United Nations Food and Agriculture Organization. PSMA addresses illegal fishing by denying port entry, and consequently markets, to foreign vessels suspected of illegal fishing activity. Employing novel methods, AIS data can be used to gather information and support decision-makers from the perspective of the State, an individual port, a specific vessel, or a State’s fleet of vessels. This paper used AIS data from 784 individual refrigerated transshipment vessels from 2015-2018. These transshipment vessels made 67,308 port visits from voyages greater than 24 hours in duration; of these, 67.5% were from foreign refrigerated transshipment vessels. PSMA participation is growing and AIS data on refrigerated transshipment vessels can strengthen PSMA leverage and address the key conditions requisite in illegal fishing and human rights violations in seafood. The methodology and application of AIS outlined here offers reliable and accessible information regarding transshipment port visits that has previously been difficult to obtain.

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