Movement Patterns, Spatially Explicit Stock Assessment and Bioeconomic Model for Two Alaskan Skate Species

Skates are in growing demand worldwide. In 2008, the U.S. landings of skates, mainly from the Atlantic Ocean, totaled 65 million pounds, worth US$11 million. Because skates are long-lived, mature late in life and possess slow intrinsic growth rates, they are vulnerable to overfishing. As such, many Atlantic Ocean skate stocks are depleted. In contrast, Alaska has relatively healthy skate stocks and there is increasing economic pressure to develop fisheries for them. Big (Raja binoculata) and longnose (R. rhina) skates are the most commonly landed skates in Alaska and a directed fishery is being developed in Prince William Sound (PWS). To sustainably manage this marine resource more information is needed. Our objectives are to 1) use satellite telemetry and conventional tags to understand habitat use, movement and transfer of skate biomass among management areas, 2) use the information from the first objective to develop a mark-recapture-based stock assessment for PWS skates, and 3) develop a bioeconomic model of the skate fishery in PWS. In this poster, we present preliminary results from tagging experiments and a framework for developing a spatially explicit stock assessment and a bioeconomic model for PWS skates. This interdisciplinary information is important for managing existing and proposed future skate fisheries.