UC Santa Barbara

Fish move through the ocean unaware of the socially-constructed spatial boundaries imposed on them by legal and administrative systems. The vast majority of marine species move beyond a single national jurisdiction and these species play a pivotal role in global food security. However, movement across boundaries increases competitive incentives among nations, leading to overfishing. One way to slow this ‘race to fish’ is by forming agreements, where countries come together to manage how marine resources are shared. Because agreements are self-enforcing, agreement success depends on the strategic manipulation of incentives. Here I measure how effective an existing agreement has been at preventing overfishing, how a different agreement that has failed to curb illegal fishing can use competition from aquaculture to reduce poaching, and how fish movement can incentivize a marine reserve agreement. First, I use an econometric approach to measure how effective a tuna agreement management measure has been at reducing fishing mortality for highly mobile, boundary-spanning tuna and billfishes. Next, I use a bioeconomic model to find new solutions for an international wildlife trade agreement, specifically examining how competitive responses to aquaculture can disrupt a lucrative illegal trade in Mexico. Finally, I create a dynamic and spatial game to examine how fish movement can incentivize the development of a bilateral transboundary marine reserve agreement, which can help countries meet their commitment to protect 30% of the ocean by 2030. These results demonstrate how successful agreements can resolve externalities generated from the movement of fish and fish products across boundaries, and how effective agreements can be measured and designed.