The Atlantic Ocean tropical Tuna Tagging Programme (AOTTP) Final Symposium
Experience, Results and Lessons Learnt from Oceanic Tuna Tagging Campaigns: the AOTTP in Context.

ONLINE. From 12th to 14th JANUARY 2021 12:00 to 16:30 (MADRID TIME)

The AOTTP Final Symposium will bring together students, scientists, managers, NGOs and other stakeholders to present and discuss AOTTP results. This will be an opportunity for dialogue and collaboration among stakeholders with special focus on reinforcing local capacity and ensuring better conservation and management of tropical tunas. Lessons learnt from the AOTTP will provide valuable reflection points for developing a path forward.

Opening Session

Title  Video Youtube  PDF File
EU Keynote (Delivering fisheries sustainability and economic development through better science) video pdf
Industry Keynote (AOTTP: A view from the purse seine industry) video
Scientist Keynote (AOTTP: an example of actionable science) pdf
AOTTP Video video

Theme Session 1- Age and Growth

Ageing tropical tunas is notoriously difficult and limited information on age and growth exists, particularly for the Atlantic Ocean. Knowledge of age, longevity and growth are particularly important in stock status evaluations and much of the current uncertainty in the assessments is related to basic biological information. The AOTTP has now provided an important dataset on the age and growth of tropical tuna derived from traditional tag-recapture data, electronic internal/archival tagging, chemical tagging and direct ageing of otoliths and spines. The objective for this session will be to describe and discuss the contribution in general of tag-recapture data and specifically the update of the growth models for tropical tunas, aiming to improve the accuracy of stock assessments and the overall management in these fisheries resources in the Atlantic Ocean

Title  Video Youtube  PDF File
Age determination of tropical tunas in the Atlantic Ocean from ololith microstructures Video pdf
Final AOTTP Report of Côte d'ivoire video pdf
Relationship between number of days after tagging and number of increments deposited video pdf
Results on AOTTP validation of otolith increment deposition rates in yellowfin and bigeye tuna in the Atlantic video pdf
Comparative study of age determination of fish from otolith, spine and vertebra of Thunnus albacares landed at the port of Abidjan video
Improving Age Composition Estimates: Evaluating a Bayesian Method for Estimating Ages from Spines with Vascularized Cores video pdf
Updated Growth Curves for Atlantic Ocean Tropical Tuna Species (Skipjack, Yellowfin, and Bigeye) video
Methods of counting daily and annual increments of transversal and longitudinal cross-sections of otoliths marked with oxytetracycline (OTC) video pdf
Trophic relationships revealed by dart tags found in the stomachs of large pelagic fishes in the Atlantic Ocean. video pdf
Cookie-cutter shark Isistius sp. parasitism at different ontogenetic stages of the yellowfin tuna Thunnus albacares from the southwestern Atlantic Ocean video pdf

Theme Session 2- Tagging and Spatial Dynamics

AOTTP and partners have tagged ca 120,000 fish with conventional tags and nearly 600 with electronic tags (both pop-ups and internal/archival tags). Electronic tags collect information on light-intensity, temperature and depth, from which the location of the fish can be inferred and habitat preferences gauged. This session will, therefore, focus on how the information on fish movement gleaned from both conventional and electronic tags can be used to update our knowledge of mixing rates and stock structures, important for stock assessments and management

Title  Video Youtube  PDF File
Characterization of the thermic habitat of yellowfin and bigeye tunas in the Atlantic Ocean video pdf
Migration patterns and residence of bigeye tuna (Thunnus obesus) in North Atlantic Ocean, based on recent tagging, recapture data and historical data from Canary Islands, Madeira y Azores video pdf
Final dissertation/Study on the migration and size structure of the little tunny (Euthynnus alletteratus) stock in the Eastern Central Atlantic from tagging and recapture data video pdf
Methods for estimating geographic movements using conventional tags (population migration rates) and electronic tags (tracks) video pdf
Migration patterns of skipjack tunas in the tropical Atlantic, described through tag attrition models based on historical and recent tag and recapture data video pdf
AOTTP has died, long live AOTTP! video
Tuna tagging surveys on fishing vessels, effects and consequences of the handling process video pdf
Site fidelity of yellowfin tuna in the central South Atlantic Ocean video pdf
Studying the displacements and the size structure of the tropical tuna species (bigeye, skipjack and yellowfin) between the Senegalese EEZ and adjacent waters video pdf
On the dialogue between knowledge backgrounds involved in tagging programs video pdf

Theme Session 3- Mortality and abundance

Natural mortality (M) is one of the most influential quantities in fisheries stock assessment as it relates directly to the productivity of the stock and the estimation of sustainable yields. Typically, M is estimated through indirect means, but it can, be estimated with greater precision using tag-recapture data. AOTTP is providing a new source of information from which to derive direct estimates of natural mortality and abundance for the three main tropical tuna species, which will improve stock assessments and management advice. Auxiliary quantities tightly linked to the estimation of mortality and abundance (i.e., tag reporting, tag shedding, tag mixing, tag induced mortality) will also be discussed

Title  Video Youtube  PDF File
Estimating Mortality from Mean Length Data of the little tunny, Euthynnus alletteratus, exploited in the Senegalese waters, 1981-2017 video pdf
Tag-shedding estimates for tropical tuna species in the Atlantic Ocean from AOTTP data video
Effects of release conditions on recovery rates of tagged tropical tunas during the AOTTP video pdf

Theme Session 4- Stock assessment and Management

Stock Assessment and Management. A main objective of the AOTTP is that it will provide information capable of reducing uncertainty in population assessments that will lead to improved management advice and decisions towards a more sustainable exploitation of the fisheries resources. In the case of Atlantic tropical tunas, the main fishery for these species is a truly multispecies fisheries with major catches on FADs. This feature has important consequences for management, the SCRS has started a Management Strategy Evaluation (MSE) process for Atlantic Tropical tunas that will address the multispecies issue. This session will explore the AOTTP data that can provide basic information and stock/fisheries interactions for the development of the operating models for the MSE. The session will also provide an opportunity to examine the role of tag-recapture data in assessing the general impact of FADs on tropical tuna fisheries and whether the FAD related measures originally intended to protect juveniles of yellow fin and bigeye tunas, has been effective

Title  Video Youtube  PDF File
From Science to Compliance pdf
Modeling the small-scale spatial distribution and movement of tropical tuna in the central eastern Atlantic video pdf
Past and current dFADs fishing moratoria in Eastern Atlantic ocean: what can aottp data tell about the current dFAD moratorium efficiency for the conservation of juvenile tunas and about alternate protected time-areas video
Animal Telemetry and Ecosystem Based Fisheries Management video pdf
Movement patterns shown by the recoveries of tunas tagged with dart tags in various areas of the Atlantic video pdf
Transition Matrices from AOTTP Bigeye Tuna video pdf
Determining an appropriate tag mixing period for fish tagged during the AOTTP video
A proposal for correcting the misreporting of seamount associated schools in the schooltype variable of the AOTTP database video
Yellowfin tuna vertical behaviour and catchability in the South Atlantic video pdf
Detailed overview of apparent movements of tunas tagged in 15 tagging areas in the Atlantic video pdf
Estimation of tag-reporting rates for yellowfin, bigeye and skipjack tunas from tag-seeding experiments conducted during the AOTTP video pdf
Analysis of the impact of the tagging platform on the recapture rate of tropical tuna species tagged in the Exclusive Economic Zone of Côte d’Ivoire video pdf