GBYP

Phase 14 started in February 2024, running for 23 months. Following budget adjustments, the Secretariat requested an amendment to the EU Grant Agreement in July 2025 to adapt activities and funding.

Highlights from September 2024 – August 2025:

• Data Systems: Strengthened information systems at the ICCAT Secretariat to better manage biological and electronic tagging data.
• Aerial Surveys: 2024 survey results improved stock abundance indices; updates were made for the Balearic Sea, and a new Western Mediterranean survey was completed in June 2025.
• Tagging: Over 140 tags deployed through new partnerships, supporting electronic pop-up and internal archival tagging, as well as acoustic tagging. In 2025 (until 15 October) a total of 29 pop-up, 4 internal archival and 10 acoustic tags have been recovered. Most campaigns were very successful, including tracking of a bluefin tuna that showed a one-year journey without leaving the Eastern Mediterranean Sea.

TUNIPEX staff isolating a shoal of bluefin tuna specimens at a tuna trap off Southern Portugal, during an ICCAT acoustic tagging campaign (Source: ICCAT).

• Biological Studies: Genetic research advanced, which improved our understanding of population structure, mixing, and interbreeding. Nearly 4,000 new larvae samples were added to the Tissue Bank, which is being expanded and digitized.
• Modelling: Two new contracts were launched to test the impact of new genetic and survey data on management strategy evaluations (MSE).

These activities are critical to refining stock assessments and strengthening science-based management of Atlantic bluefin tuna..

Additional information can be found here.

ALBYP

Significant progress has been made regarding biology, movement, and management strategy evaluations.

Reproduction:

• North Atlantic: 649 gonad samples and 460 spine samples (2019–2025) showed all maturity stages, with peak spawning April–September between 15°–25°N. Size and age at first maturity seems to be lower than previous estimates (females: 72.6 cm/3.8 years; males: 80 cm/4.7 years).
• South Atlantic: 441 histological samples confirmed spawning in the tropical SW Atlantic during spring–summer. Size at maturity was ~95 cm, with rapid growth in the first two years.

Movements & Habitat Use:

• North Atlantic: 33 MiniPATs and 225 internal archival tags deployed; 50 tag recoveries produced >9,000 tracking days. For the first time, albacore were tracked for over a year, revealing seasonal migrations and unexpected winter residency in the Bay of Biscay.
• South Atlantic: New MiniPAT deployments planned for late 2025–early 2026.

AZTI (EU-Spain) staff deploying Lotek internal archival tags (on the right panel) off the Bay of Biscay, within the ICCAT Atlantic Albacore Tuna Tagging Program (Source: AZTI)

Management Strategy Evaluation (MSE):

• Contractors developed new Operating Models and Observation Error Models, refining the framework for future stock management.
• These updates ensure continued testing of the Management Procedure (MP) adopted in 2021 and alignment with ICCAT’s harvest control objectives.

Additional information can be found here.

SMTYP

Since 2018, this programme has coordinated biological sampling of small tunas — little tunny (LTA), Atlantic bonito (BON), and wahoo (WAH), among others. Initial contracts (2018–2023) engaged a consortium of 12 institutions from 11 CPCs, followed by new agreements in 2024–2025 involving 13 entities from 10 CPCs.

Objectives:

• Fill size gaps for growth and maturity estimates.
• Determine growth and reproduction parameters for BON, LTA, WAH, frigate tuna (FRI), and bullet tuna (BLT).
• Refine stock structure analyses for these species.
• Investigate genetic differentiation between FRI and BLT.

Results and updates have been presented during intersessional meetings. Priorities for 2026–2029 include:

• Updating the biological meta-database.
• Estimating length–weight relationships at stock/regional levels.
• Calibrating and adopting common maturity scales.
• Developing data-limited methods for management advice.

Additional information can be found here.

EPBR

This programme continued in 2025 under the coordination of Dr. Rui Coelho (EU-Portugal, East Atlantic) and Ms. Karina Ramírez López (Mexico, West Atlantic). Originally designed to collect catch/effort data and support tagging and ageing studies, the programme has since expanded to include habitat use, spawning, and genetics research.

Key highlights:

• Sample collection: Since 2019, 735 biological samples of BUM, WHM, and SAI have been collected in the Eastern Atlantic, by teams from West Africa and Portugal, focusing on age and growth studies. A bomb-radiocarbon validation study for blue marlin otoliths began in 2025.
• Reproduction studies: Ongoing research in the Gulf of Mexico (led by Mexico) is investigating blue marlin reproduction.
• Tagging: Since 2023, satellite and conventional tagging has been carried out in the eastern Atlantic, with 11 white marlins and 2 blue marlins tagged with pop-up tags, plus 31 conventional tags deployed on white marlines. Early satellite tag performance was limited, but improved devices are in use in 2025. Expansion to other Atlantic regions is planned for 2026, pending funding.

EPBR activities are now financed through ICCAT’s general science envelope and supported by the U.S. Data Fund.

Additional information can be found here .

SRDCP

The Shark Species Group (SSG) advanced several key studies in 2025:

• Age & Growth: A collaborative study on South Atlantic shortfin mako confirmed a new ageing method, now applied to both Atlantic stocks. Age and growth research also progressed for longfin mako, oceanic whitetip, and silky shark, with vertebrae sampling and collection of images underway.

Shark vertebra cut used for age readings (left). Distribution of samples by species and fleet used on the ICCAT collaborative study on shark aging (right) (Source: IPMA, Portugal).

• Genetics: Porbeagle studies confirmed two sibling species (North Atlantic vs. Southern Hemisphere), but no differentiation within each hemisphere. New genome-wide analyses of 106 juveniles revealed kinship links, offering insights into connectivity.
  
  
• Tagging & Movements:

• Shortfin mako: Updated post-release mortality analysis (29.4%) from 128 tags; 52 satellite tags deployed, including in the SW Indian Ocean.
• Porbeagle: 9 electronic tags deployed in the North Atlantic, showing migrations up to 5,000 km; joint regional analyses planned.
• Other sharks: 86 tags deployed across silky, oceanic whitetip, hammerheads, blue shark, bigeye thresher, and longfin mako, with new campaigns in 2024/2025. Additional tagging of blue sharks began in 2025 to study connectivity between the Mediterranean and NE Atlantic.

• Reproduction: A hormone-based study on North Atlantic shortfin mako confirmed the potential of muscle tissue for reproductive assessments. A campaign to collect gravid female samples has been rescheduled for October 2025.

These efforts are refining knowledge on shark biology, stock boundaries, habitat use, and mortality, directly supporting more robust conservation and management measures.

Additional information can be found here.

SWOYP

Progress 2018–2025

Launched in 2018, the SWOYP brings together 23 institutions from 15 CPCs to reduce key uncertainties in swordfish biology and improve stock assessments. The programme focuses on ageing and growth, reproductive biology, genetics, and tagging, with over 4,700 swordfish samples collected across all three ICCAT-managed stocks.

Key Highlights:

• Age & Growth: 3,582 fin spines, 1,392 otoliths, and 783 gonads analysed; new protocols developed; bomb radiocarbon validation underway; preliminary estimates support maximum ages of 10–12 years.
• Reproduction: 3,185 individuals staged for maturity, including 776 through histology; further sampling needed in spawning hotspots such as the Sargasso Sea and Gulf of Guinea.

Preliminary results swordfish sexual maturity (sex combined) for the North Atlantic (SWO-N), South Atlantic (SWO-S) and Mediterranean (SWO-M) stocks (Borrego-Santos et al., 2025).

• Genetics: Genome sequenced; SNPs identified for stock differentiation; epigenetic ageing shows promise with 57 CpG sites identified as age predictors.
• Tagging: 54 satellite tags deployed since 2018 across the Atlantic and Mediterranean; recent campaigns in the NE Atlantic and off Newfoundland have expanded knowledge of migration, stock mixing, and vertical habitat use.

Looking Ahead:

From 2026, work will continue with further ageing calibration, gonad histology, genetic analyses, and targeted tagging to fill geographic and size-class sampling gaps. These efforts are essential to refine growth, reproduction, and movement models, ultimately strengthening management advice for swordfish stocks.

Additional information can be found here.

TTRaD

This programme, which was launched in 2024, supports ICCAT tropical tuna management through data collection, tagging, age and growth studies, and Management Strategy Evaluation (MSE) developments. In 2025, TTRaD focused on improving scientific advice, updating spatio-temporal models, and maintaining the Atlantic Ocean Tropical Tuna Tagging Programme (AOTTP) database.

Key Achievements:

• MSE & Stock Assessment: Western skipjack models reconditioned with updated data, including climate change robustness scenarios; multi-stock MSEs advanced using hybrid harvest control rules to simulate TAC and fleet effort adjustments.

• Age & Growth Studies: Extensive specimen collection in the Gulf of Guinea and Central/Southern Atlantic; processing of otoliths, spines, and vertebrae is nearly complete, with preliminary age data already presented.

• Mortality Estimates: Using conventional tagging data, preliminary estimates of total (Z), natural (M), and fishing (F) mortality were made; uncertainties and reporting biases are being addressed for integration into stock assessments.

• Spatio-Temporal Modelling: The agent-based POSEIDON-EAO model tested fleet behaviour, FAD use, and management measures; results suggest moderate FAD limits could reduce juvenile bigeye risk while maintaining catch levels.

These activities enhance understanding of tropical tuna stocks, informing robust management measures and decision-making for ICCAT.

Additional information can be found here.

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