Updated stock status indicators for silky sharks in the eastern Pacific Ocean (1994-2015)

Purse-seine indices for the silky shark have been updated with data from 2015. The index for all silky sharks in the northern area shows an increase in 2015 relative to 2014, but the index for all silky sharks in the southern area remains at the 2014 level. This increase in the index in the northern area may be in part the result of changes in availability, rather than abundance, due to strong El Niño conditions. Differences among trends computed for sub-areas in the north suggest that the overall recent increasing trend in the north may reflect an integration of spatially-distinct processes, including the effect of fishing pressure closer to the coast, and environmentally-mediated movement of individuals into the tropical eastern Pacific Ocean (EPO) from the west. The IATTC staff does not consider the more optimistic recent trends to be strong enough to offset the urgent need for precautionary management actions, and reiterates its previous recommendations. It is critical that improvements are made in shark fishery data collection in the EPO so that conventional stock assessments and/or other indicators of stock status can be developed and the results made available to better inform the management of silky and other shark species.