Shark Working Group

The ISC Shark Working Group (SHARKWG) is made up of scientists from ISC Member nations and observers. The SHARKWG meets regularly to assess and analyze fishery data and other information, including trends in population abundance and developments in fisheries; to determine the status of the stocks of key shark species captured in the North Pacific; and to develop scientific advice concerning conservation needs. The SHARKWG also promotes cooperative and collaborative research among members by developing proposals for international research programs and coordinating, to the extent possible, national programs addressing research needs for these shark species.

The two species of greatest priority to the SHARKWG based on their distribution with respect to North Pacific fisheries and high relative encounter rates are the blue (Prionace glauca) and shortfin mako (Isurus oxyrinchus) sharks. The SHARKWG had completed a North Pacific blue shark stock assessment in July 2017, and has been conducting a North Pacific shortfin mako shark assessment to be completed by July 2018. The SHARKWG monitors ongoing research and fishery activities related to other shark species of interest to the ISC, including bigeye thresher (Alopias superciliosus), pelagic thresher (A. pelagicus), common thresher (A. vulpinus), oceanic whitetip shark (Carcharhinus longimanus), silky shark (C. falciformis), hammerhead sharks (Sphyrna spp.), longfin mako (I. paucus), salmon shark (Lamna ditropis), and crocodile shark (Pseudocarcharias kamoharai).

• Blue Shark (Prionace glauca)
• Shortfin Mako Shark (Isurus oxyrinchus)

• The SHARKWG has developed a matrix of life history information from several North Pacific regions for blue and shortfin mako sharks. This matrix will be reviewed periodically and revised as necessary to facilitate identification of data gaps and set research plans and priorities.
• The SHARKWG has prioritized genetics studies of blue and shortfin mako sharks, including efforts to increase sample collection and sharing. Ongoing studies are addressing whether North and South Pacific stocks can and should be treated separately. Other studies aim to clarify stock structure within the North Pacific for the stock assessments and to contribute to global studies.
• The SHARKWG will examine the distributions of blue sharks and shortfin mako by size and sex using the available tagging data. In addition, member nations are conducting collaborative conventional and electronic tagging studies in order to fill existing data gaps.
• The SHARKWG has initiated international collaborations on age and growth of blue and shortfin mako sharks.
• The SHARKWG has identified the issue of discards as an important factor to consider in shark assessments. As such, compilation of information on the number of discards, the ratio of live release to dead discards, and post-release mortality has begun. The SHARKWG is also evaluating various methods to enhance live release of captured sharks.

• Keelung, Chinese Taipei (April 2011)
• La Jolla, USA (November 2011)
• Shizuoka, Japan (May 2012)
• La Jolla, USA (January 2013)
• Shizuoka, Japan (April 2013)
• Busan, Korea (July 2013)
• La Jolla, USA (January 2014)
• Keelung, Chinese Taipei (June 2014)
• Puerto Vallarta, Mexico (November 2014)
• Shizuoka, Japan (March 2015)
• Busan, Korea (November 2016)
• La Jolla, USA (March 2017)
• Shizuoka, Japan (October 2017)
• Shizuoka, Japan (November 2017)
• La Jolla, USA (April 2018)