Sea turtle interactions with Hawaii's longline fishery: an extended multi-objective programming model incorporating spatial and seasonal dimensions

Endangered and protected sea turtle interactions with the pelagic longline fishery have become an important fishery policy concern recently. A multi-objective programming model for Hawaii's longline fishery that incorporated sea turtle interactions (Pradhan and Leung, 2006a) has been extended with spatial and seasonal dimensions. The synergetic effect of these added features indicate that there exists better economic and environmental efficiency gains in terms of higher profit and reduced turtle interactions, compared to the base case without these added dimensions, by reconfiguring fishing efforts across space and seasons. There also exists a trade-off between fleet-wide profit and turtle interactions. The current fishery policy related to sea turtle interactions disallows capturing all the potential efficiency gain, as the number of turtles allowed to get interacted severely limits swordfish-targeted longline fishing that uses conventional technologies. Restricting longline fishery to operate sub-optimally would result in average shadow value of $15 957 and $60 908 per turtle in terms of lost profit and revenue, respectively. These shadow values are higher than those estimated from earlier model without the spatial and seasonal dimensions. Adaptation to 'turtle-friendly' fishing technologies is among the many strategies that would allow for higher optimal fishing efforts and also leading to higher overall welfare and towards more responsible fishery.