A summary of blue shark (Prionace glauca) and shortfin mako shark (Isurus oxyrinchus) tagging data available from the North and Southwest Pacific Ocean

The ISC Shark Working Group has identified tagging data as potentially useful data to examine stock structure hypotheses and provide information on movements for stock-assessments in support of population management. Shark tagging programs in the Pacific have been in operation since the 1960’s but there is still limited information on the stock structure of highly migratory pelagic sharks, and movement data from these programs generally have not been included in stock assessments. The tagging data presented here do not support a hypothesis of panmixia of blue shark or shortfin mako stocks in the Pacific Ocean. Rather this evidence suggests at least northern and southern sub-populations of both species, demarked by the equator.