Updating of Seapodym Swordfish Population Model Underway

A data-access agreement with the Western and Central Pacific Fisheries Commission (WCPFC) is enabling Melanie Abecassis, a scientist with the University of Hawaii Joint Institute for Marine and Atmospheric Research, to access fine-resolution international longline fishery data provided by WCPFC member countries to the Commission. Abecassis is on the staff of the PIFSC Ecosystems and Oceanography Division. She will use the latest information on fishing effort, swordfish catch, and swordfish length composition to revise the Seapodym (Spatial Ecosystem and Population Dynamics) model for Pacific swordfish. The new data have finer spatial resolution than data previously available and should result in an improved model.

In the accompanying graphs produced by the previous Seapodym swordfish model, model-generated spatial distributions of swordfish (expressed as number of fish per km2), are shown along with average swordfish catch per unit of effort (CPUE) derived from longline data. The top pair of graphs shows results for young and adult swordfish. The bottom graphs show model predictions and CPUE data for El Niño and La Niña periods.

Mean distributions (in Nb/sq.km) of young (left) and adults (right) from 1992-2001 overlaid with Korean (L5) and Japanese (L4) CPUEs 
        (circles) resepectively.
Mean distributions (in Nb/sq.km) of young (left) and adults (right) from 1992-2001 overlaid with Korean (L5) and Japanese (L4) CPUEs (circles) resepectively.
Mean distributions of young swordfish biomass (N/sq.km) overlaid with Korean CPUEs (L5) during the 1998 El Niño event 
        (left, Oct. 1997 - Feb 1998) and during La Niña (right, Jul. 1998 - Jan. 1999).
Mean distributions of young swordfish biomass (N/sq.km) overlaid with Korean CPUEs (L5) during the 1998 El Niño event (left, Oct. 1997 - Feb 1998) and during La Niña (right, Jul. 1998 - Jan. 1999).