International Science Meetings Focus on Seamount Bottomfish Stocks, Tuna and Billfish

PIFSC has continued to be actively engaged in international research programs to improve the scientific basis for fisheries management and ecosystem-based resource conservation in the Pacific Ocean.

During August, the Scientific Working Group of the Multilateral Meeting on Management of High Seas Bottom Fisheries in the North Pacific Ocean met in Bellevue, Washington. PIFSC scientists were active participants. The main topic of discussion was updates to the recent (2000-2008) data for bottom fisheries on the Emperor-Northern Hawaiian Ridge Seamounts by the three states participating in the fisheries: Japan, Russia, and Republic of Korea. Data on the number of fishing vessels, type of fishery, fishing effort, catch by species, and seamount location were updated. The working group reviewed the coverage of fisheries observer data collected by participating states, including observer data collected by the U.S. during the 1978-1984 foreign bottom trawl permit fishery at the Hancock Seamounts.

After completing their 2+ year pelagic phase armorhead recruit to the seamounts. There they reproduce annually for the next 4-5 years, gradually becoming emaciated with age (bottom to top).

Workshop participants agreed to develop a collaborative stock assessment of armorhead (Pseudopentaceros wheeleri), a species targeted by trawl fisheries that operated on the seamounts historically. The study would incorporate data from all historic seamount fishing grounds up through the present, ranging from Koko Seamount at the north end of the chain to the Hancock Seamounts at the south end, which were fished up to 1984. Prior to this meeting of the working group there had been some reluctance to developing an assessment and differing ideas as to whether stocks should be assessed separately on each individual seamount or as a single biological unit. The preponderance of biological evidence indicates that armorhead caught on the Koko-Hancock trawl grounds represent a single stock and this will be the approach taken as the new assessment is developed. As a first step in the process, data templates were developed with the objective of identifying the extent and quality of commercial and scientific catch data. An integrated research plan in support of an armorhead stock assessment was presented by the U.S. and discussed by the working group.

During August, PIFSC staff also participated in the 9th Meeting of the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean (ISC), chaired by Dr. Gary Sakagawa of the NOAA Southwest Fisheries Science Center. Held in Kaohsiung, Taiwan, the plenary meeting brought together scientists from Japan, Republic of Korea, Taiwan, China, Canada, U.S., and other ISC members and participating entities. The committee reviewed information and recommendations from its scientific working groups on the status of albacore, bluefin tuna, striped marlin, and swordfish in the North Pacific. The committee endorsed a new stock assessment for North Pacific swordfish which found the stock to be healthy and well above the level required to sustain recent catches. A special seminar was held on reference points for fisheries management, and a proposal for multi-national, multi-species biological research was completed and endorsed.

The ISC considered several requests from the Western and Central Pacific Fisheries Commission, and a Memorandum of Understanding with the Inter-American Tropical Tuna Commission was advanced. The ISC agreed to organize a World Blue Marlin Symposium to convene experts on this species and gather information for an upcoming blue marlin stock assessment.

The ISC's work priorities for the coming year will focus on improving the group's Web site and database by retaining services of a professional Database Administrator and Web Designer. The ISC's scientific workplan for 2009-2010 includes revisiting the 2009 swordfish assessment and preparing for new assessments of albacore, Pacific bluefin tuna, and blue marlin. The next ISC Plenary meeting will be held in July 2010 in Canada.

Finally, during August, staff of the PIFSC Fishery Biology and Stock Assessment Division were active participants in the two-week long 5th meeting of the Scientific Committee (SC5) of the Western and Central Pacific Fisheries Commission (WCPFC) held in Port Villa, Vanuatu. The committee reviewed updates of catch statistics and information on the status of tuna stocks. The tuna catch for the WCPFC Convention Area during 2008 was estimated provisionally at 2,426,195 mt, the highest annual catch ever recorded. The SC5 concluded that the 2009 stock assessment of bigeye tuna in the Western Central Pacific Ocean (WCPO) indicates a continuing decline of the bigeye resource, as noted in previous assessments. Bigeye tuna fishing mortality in relation to the MSY (maximum sustainable yield) level, or Fcurrent/FMSY, is considerably greater than 1, ranging from 1.51 to 2.01 for a variety of assumptions with similar steepness (~0.98) in the stock recruitment relationship. An evaluation of the WCPFC management measure addressing bigeye tuna overfishing indicated that the objective of achieving a 30% reduction in bigeye tuna fishing mortality by 2011 will not be achieved. The lack of effectiveness of the conservation measure is broadly related to: 1) reductions in longline catch that do not result in the required reduction in fishing mortality on bigeye; 2) increases in both purse seine effort allowed under the measure and purse seine efficiency since 2001–2004; and 3) exclusion of catches in archipelagic waters from catch limits. Opinions on what should be recommended regarding the measure varied considerably amongst committee members.

SC5 also addressed other matters, including sea turtles. The body recommended adoption of the draft WCPFC Guidelines on the Handling of Sea Turtles to reduce injuries and risk of mortality for turtles caught incidentally in fishing gear and released alive.