Background Information
Stock condition
North Pacific swordfish is in good condition. The 2021 spawning biomass (SSB) is estimated at ~35,778 t, roughly 2.2× SSBₘₛᵧ (~16,388 t). Recent fishing mortality (F ≈ 0.09 for ages 1–10, averaged over 2019–2021) is about half of Fₘₛᵧ (~0.18). The Kobe status plot places recent years firmly in the “not overfished” and “no overfishing” quadrant with >99% probability.
Current fishery status
Catches are taken mainly by longline fleets across the Western/Central and Eastern North Pacific. Annual catch peaked near 19,230 t (1998) and has since stabilized at ~10–12 thousand t (2019–2021 mean ~10,653 t). Biomass (age 1+) in 2021 is ~88,800 t; CPUE has generally improved in the last decade, consistent with a stable to slowly increasing stock.
Importance of the Fishery
This is a multi‑national, basin‑wide fishery prosecuted by at least 19 fleets in areas managed by both WCPFC and IATTC. The assessment area spans the WCPFC north of the equator and the IATTC north of 10° N. The WCPFC Northern Committee has requested catch/effort summaries north and south of 20° N to support decision‑making; recent increases south of 20° N include longline catches in 0–10° N (EPO) and gillnet catches around Vietnam (Catch Distribution).
Science
Stock status – latest assessment
The ISC Billfish Working Group used Stock Synthesis (SS3) with data for 1975–2021. Base‑case reference points: Fₘₛᵧ ≈ 0.18, SSBₘₛᵧ ≈ 16,388 t, MSY (CMSY) ≈ 14,924 t, SPRₘₛᵧ ≈ 19%. Current conditions correspond to SPR ≈ 43–44% and F ≈ 0.09. Overall, the probability of not overfished and no overfishing is >99%.
Scientific advice to managers
Since 2016, the fishery has produced ~11,500 t/yr (about two‑thirds of MSY), indicating room for somewhat higher yields if managers’ risk tolerance allows. Projections to 2031 show SSB remains above SSBₘₛᵧ under status‑quo F and even at Fₘₛᵧ; modeled catches converge toward ~15,000 t as F increases. A projection using the 2008–2010 fishing intensity (the CMM baseline) stabilizes catches around ~13–14 kt by 2031. Diagnostics highlight uncertainties, especially with a lack of sex‑specific size data, simplified spatial structure, and a retrospective signal that may underestimate recent spawning potential, so any increase in pressure should be paced and risk‑aware.
How does the WCPFC manage the North Pacific swordfish fishery?
Current management framework
WCPFC’s CMM 2023‑03 applies to high seas and EEZs north of 20° N in the Convention Area. For fisheries taking >200 t/yr in the Area, fishing effort must not exceed the 2008–2010 average (with fishery‑specific footnotes—for example, U.S. limited‑entry permits and Chinese Taipei coastal artisanal longline vessel numbers). Annual catch and effort reporting is required for the Area and across the North Pacific for fisheries subject to the cap, by gear, using Annex 1 (which allows multiple effort metrics where “fishing days” are not suitable). WCPFC has also adopted a Harvest Strategy that sets an exploitation‑rate limit reference point at Fₘₛᵧ. The preamble notes EPO swordfish was not likely overfished but likely experienced overfishing in some recent years and that stock boundaries are under review, emphasizing cross‑RFMO coordination.
Management issues
First, biomass‑based reference points for swordfish are not yet formalized at WCPFC (status is evaluated against MSY‑based metrics via ISC), which complicates translation of science into explicit harvest rules. Second, because swordfish spans WCPFC and IATTC areas, coordination is essential to keep objectives and monitoring aligned. Third, data and assessment gaps (sex‑specific size data; spatial structure; some CPUE conflicts) should be addressed to strengthen future advice.
Improving Future Management
Priorities include: (1) adopt biomass‑based targets/limits for swordfish to complement the F‑limit (Fₘₛᵧ) and underpin clear harvest control rules; (2) coordinate WCPFC–IATTC approaches for this shared stock; (3) tighten key data streams, such as sex‑specific length sampling, spatial stratification, and CPUE standardizations; and (4) use the assessment’s 2008–2010 effort projection as a policy benchmark to test whether the current cap remains fit‑for‑purpose.
Summary
North Pacific swordfish is healthy and stable: SSB ≈ 2.2× SSBₘₛᵧ, F ≈ 0.5× Fₘₛᵧ, and a >99% probability of not overfished and no overfishing. Projections keep SSB above SSBₘₛᵧ to 2031 under status‑quo and even Fₘₛᵧ. Immediate policy wins are to formalize biomass‑based reference points, maintain transparent reporting, and coordinate with IATTC while continuing to improve sex‑specific and spatial data to keep advice robust as management evolves.