Figure 3 - uploaded by Peter Williams
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5.1 Skipjack tuna CPUE (mt per day-left) and yellowfin tuna CPUE (mt per day-right) by settype, and all set types combined, for selected purse seine fleets fishing in the tropical WCP-CA.
Source publication
This paper provides a broad description of the major fisheries in the WCPFC Statistical Area (WCP-CA) highlighting activities during the most recent calendar year (2021) and covering the most recent summary of catch estimates by gear and species. The provisional total WCP-CA tuna catch for 2021 was estimated at 2,493,571 mt, around 210,000 mt lower...
Citations
... As in other oceans, ensuring genetic sample integrity is increasingly important to fisheries research in the Western and Central Pacific Ocean (WCPO). The WCPO is home to the world's largest tuna fishery, valued at US$4.9 billion in 2020 (Williams and Ruaia, 2021). Work is afoot to employ genetics to answer long-standing management questions on WCPO tuna population connectivity, stock structure, movement, and abundance (Grewe et al., 2015;Bravington et al., 2021;Vaux et al., 2021). ...
Sample cross-contamination remains a pervasive issue in genetics and genomics. With growing reliance on molecular methods for managing marine resources, the need to ensure the integrity of tissue samples that underpin these methods has never been more pressing. We conducted an experiment on wild-caught bigeye tuna (Thunnus obesus) to assess cross-contamination risk under seven at-sea and laboratory-based tissue sampling treatments. The six at-sea treatments (T1–T6) differ in sampling equipment, cleaning, and storage procedures. Combining observed heterozygosity (Ho) and relatedness coefficients (r) to flag cross-contamination, treatments T2–T6 proved effective at mitigating contamination risk. Each exhibited significantly smaller mean Ho and less Ho variability compared with intentionally contaminated samples in the T1 treatment. In T2-T6, no samples flagged as contaminated based on Ho outlier thresholds and elevated r were traced to the point of sampling at sea. Laboratory-based subsampling of T1 tissue (T7) also led to significantly smaller, less variable Ho values compared to T1, suggesting that recovery of samples contaminated onboard, or those of unknown provenance, is possible. We show that simple adjustments to current tissue sampling protocols dramatically reduce cross-contamination risk for downstream genetic analyses on tunas and potentially on other species and fisheries.
Changes in climate factors affect the distribution of various tuna species differently due to their unique physiological adaptations and preferred habitats. As the resulting spatial distributions of tunas alter in response to climate change and climate variability, the distribution of fishing effort will, in turn, be affected. This study uses a quantitative model to estimate the impacts of SST and ENSO events on trip distance of the Hawaii deep-set longline fleet between 1991 and 2020. The results show that the higher the SST of the fishing grounds of the Hawaii longline fleet, the longer trip distance; whereas ENSO events could result in shorter trip distance, possibly due to changes in catch rates of different tuna species through spatial redistribution during El Niño and La Niña events.
The tuna fisheries assessment report (commonly referred to as the "TFAR") provides current information on the tuna fisheries of the western and central Pacific Ocean and the fish stocks (mainly tuna) that are impacted by them. The information provided in this report is summary in nature, but a list of references (mostly accessible via the internet) is included for those seeking further details. This report focuses on the primary tuna stocks targeted by the main Western and Central Pacific Ocean industrial fisheries - skipjack tuna (Katsuwonus pelamis), yellowfin tuna (Thunnus albacares), bigeye tuna (T. obesus) and South Pacific albacore tuna (T. alalunga).
The report is divided into three parts: the first section provides an overview of the fishery, with emphasis on developments over the past few years; the second summarises the most recent information on the status of the stocks; and the third summarises information concerning the interaction between the tuna fisheries, other associated and dependent species and their environment.
The data used in compiling the report are those which were available to the Oceanic Fisheries Programme (OFP) at the time of publication, and are subject to change as improvements continue to be made to recent and historical catch statistics from the region. The fisheries statistics presented will usually be complete to the end of the year prior to publication. However, some minor revisions to statistics may be made for recent years from time to time. The stock assessment information presented is the most recent available at the time of publication.
