September 20, 2021 — The following was released by the Western Pacific Regional Fishery Management Council:
The Scientific and Statistical Committee (SSC) of the Western Pacific Regional Fishery Management Council adopted recommendations to improve the management of impacts to false killer whales (FKWs) in the Hawai‘i deep-set longline fishery. The issues paper from an SSC working group reviewed cetacean avoidance research and interaction reduction measures, and risk assessment methods used to evaluate the population-level impacts of fishery interactions.
The paper, endorsed by the SSC, raises concerns about the serious lack of fundamental population demographic information needed to support evidence-based policy guidance on the issue. The current risk assessment framework used to evaluate the potential impacts of FKW bycatch in the U.S.-based pelagic longline fishery is based on a concept called the potential biological removal (PBR), which is required under the Marine Mammal Protection Act (MMPA). At its June 2021 meeting, the SSC acknowledged the PBR approach does not account explicitly for the present assumption that long-term consequences exist for FKW populations exposed to anthropogenic hazards such as pelagic longline gear. The working group found that available scientific data do not strongly support this assumption.
The SSC’s recommendations highlighted several approaches to address the current deficiencies in the risk assessments. This includes implementing a conceptual framework called “population consequences of disturbance” comprised of a four-level sequence, ranging from observed changes in individual behavior to population-level effects like impaired reproductive, survival or population growth rates. Another recommendation noted the need for a risk assessment model based on population dynamics to assess the applicability of PBR for bycatch management.
Also, the group recommended that a post-release study on FKWs should be conducted using satellite tags or other technology to assess mortality rates and sublethal effects of capture and release. Currently, there is not enough demographic information, such as survival rates at different ages and reproductive rates, to do a population assessment or diagnose trends for FKWs. Additionally, the lack of post-release survival data has led to the assumption that most FKWs observed in the Hawai‘i deep-set longline fishery are not likely to survive, even though most individuals are released alive.
“The underlying theme to all of these recommendations is that fishery impacts on FKWs to date have been seemingly small and infrequent,” said SSC Chair Jim Lynch, who presented the report. “Take reduction measures imposed should balance the biological and economic impacts.”
FKWs are incidentally hooked in the Hawai‘i deep-set longline fishery, which primarily targets bigeye tuna. Under the FKW Take Reduction Plan, fishermen are required to use hooks of a certain diameter intended to straighten and release the animals. However, this “weak hook” measure, among other requirements, has not been successful in achieving the conservation goals required under the MMPA. The Take Reduction Team, which includes members from academia, conservation groups, fishing industry, government and fishery management organizations, was not able to reach consensus on measures to revise the existing Plan after nearly three years of deliberations. In light of this situation, the SSC formed the working group to inform the future direction of this issue for the Council, which holds a seat on the Team.
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Regarding seabird conservation in the Hawai‘i longline fishery, the SSC recommended that tori lines should replace blue-dyed fish bait as a required bycatch mitigation measure. Scientists endorsed the findings from the tori line experimental fishing permit study that showed the streamers are significantly more effective than colored bait at reducing fishery interactions with seabirds like Laysan and black-footed albatross.
The Hawai‘i Division of Aquatic Resources (HDAR) summarized data for the SSC from four reopened bottomfish restricted fishing areas, or BRFAs. Data quality and quantity were concerns, creating challenges to interpreting effort and landings in evaluating the effects of BRFA opening. The SSC reiterated its recommendation since 2013 to eliminate all BRFAs in federal waters, due to the change in stock status since their establishment and because their management utility has been superseded by annual catch limits. The SSC also recommends HDAR continue to improve fishery-dependent data collection through better fisher engagement to effectively manage the bottomfish fishery.
Recommendations made by the SSC on these and other matters will be considered by the Council when it meets Sept. 21-23, 2021, virtually with host sites at Tedi of Samoa Building, Suite 208B, Fagatogo Village, American Samoa; BRI Building, Suite 205, Kopa Di Oru St., Garapan, Saipan, Commonwealth of the Northern Mariana Islands (CNMI); and Cliff Pointe, 304 W. O’Brien Dr., Hagatña, Guam.
Instructions on connecting to the web conference, agendas and briefing documents are posted at www.wpcouncil.org/meetings-calendars. Host sites are subject to local and federal safety and health guidelines regarding COVID-19; check the Council website for updates.