Albacore tuna (Thunnus alalunga) comprise a discrete stock in the South Pacific (Murray 1994, Hoyle 2012, Jordán et al. 2021). This highly migratory species, when mature, spawn in tropical and sub-tropical waters between latitudes 10◦S and 30◦S during the austral summer (Muhling et al. 2017) and appear to disperse north from the southern latitudes as they grow gradually (Langley n.d., Nikolic et al. 2017, Nikolic et al. 2020). The south-north mixing and the prevalence of smaller albacore in the southern region of the WCPO suggest a southern juvenile feeding/nursery area, south of 30°S, with increased northerly movements and residency with age (Nikolic et al. 2017). The level of mixing between the WCPFC and IATTC convention areas is poorly known (Jordán et al. 2021). 

For the South Pacific Albacore fishery, distant-water longline fleets and distinct domestic longline fleets catch adult albacore over a broad geographic range in the South Pacific region (see map). This fishery presents an overlapping area between the Western and Central Pacific Fisheries Commission (WCPFC) and the Inter-American Tropical Tuna Commission (IATTC). However, management and compliance monitoring is attributed only to the WCPFC. The stock assessments for the South Pacific albacore are currently conducted by the Oceanic Fisheries Program of the Secretariat of the Pacific Community (SPC) (WCPFC 2022).

The Parties to the Nauru Agreement (PNA) is a regional binding treaty-level instrument to facilitate cooperation in the management of fisheries resources of common interest. The agreement requires the management of straddling/highly migratory fish stocks on a subregion basis through Regional Fisheries Management Organizations (RFMOs), and the WCPFC Convention (the regional fisheries agreement covering the WCPFC convention area). PNA members are simultaneously members of the WCPFC and so, a single management unit is set for PNA-related profiles.