Bluefin Tuna Research Program (BTRP) Selected Projects
The tables below, organized by fiscal year, list the recipients of BTRP projects, project title, synopsis, principal investigator, award number, and funding amount awarded. For copies of the final report please contact the Fisheries Grants Program Officer.
2024
| Recipient | Project | Federal Funding |
|---|---|---|
| SOCIAL AND ENVIRONMENTAL ENTREPRENEURS (SEE), INC. | Title: Directed longline sampling of the Slope Sea to resolve reproductive dynamics and population structure of Atlantic bluefin tuna. Synopsis: We propose to plan and conduct a research longline cruise via charter of a commercial pelagic longline vessel, to the Slope Sea area adjacent to the NW Atlantic canyons. The purpose is to target and land an estimated 55 adult Atlantic bluefin tuna (ABFT) in order to conduct biological sampling: gonads, otoliths, tissues for DNA sampling, and oceanographic features at that location. Directed sampling will help establish 1) reproductive status, population connectivity, and potential familial relationship to ABFT larvae found in the same general location and elsewhere. PI: Molly Lutcavage (NA24NMFX472C0004-T1-01) | $200,502 |
| The Ocean Foundation | Title: Using electronic tags and genomics to model mixing rates and natural mortality of Atlantic Bluefin Tuna. Synopsis: The proposed work is to continue a multi-decadal satellite, archival and acoustic E-tag deployment time series on ABT as part of the “TAG-A-Giant” program run by The Ocean Foundation and Stanford University. Our E-tag campaign combines US-based efforts with international partners we have trained (Ireland, UK, Norway, Spain and Israel), who together are generating a rich dataset that enables NOAA and ICCAT modelers to examine where fish of different populations go to spawn and forage. In addition, we will continue to utilize advanced WGS techniques to identify stock-of-origin for each track and expand upon our previously developed multi-state Bayesian mark-recapture model which estimates rates of natural mortality using E-tag, age and stock data. PI: Barbara Block (NA24NMFX472C0007-T1-01) | $223,002 |
| The Ocean Foundation | Title: Implementing the Next-Generation, Multi-Stock Assessment for Atlantic Bluefin tuna Synopsis: This project aims to implement a next-generation stock assessment model (MARS: Multistock Assessment with Regional Spatiotemporal dynamics)for Atlantic Bluefin tuna that may also be used as an operating model for future Management Strategy Evaluation (MSE) frameworks. Current stock assessments for the East and West Atlantic management areas do not appropriately model the western and eastern bluefin tuna stocks, which display complex spatial dynamics that violate assumptions of closed populations. This key criticism was a major reason why recent assessments of the western and eastern stocks failed to pass peer-review. A variety of data are available to inform movement and spatial distribution of a more complex multi-stock model. An assessment that simultaneously models eastern and western stocks is being fitted to electronic tagging and stock of origin data to account for seasonal availability and movement. Learning from the experience of designing a mixed stock model for the operating models of the MSE process, such an assessment could be configured to be sufficiently fast and robust to pass peer review and be used in the provision of management advice. In this project, we propose to process up-to-date data streams and fit a base case MARS model to those data, including typical analyses and diagnostics that support the peer-review of a conventional stock assessment such as sensitivity tests, retrospective analyses, likelihood profiles and management projections. PI: Eddie Love (NA24NMFX472C0008-T1-01) | $84,678 |
| UNIVERSITY OF MASSACHUSETTS DARTMOUTH | Title: Otolith Isotopic Signatures from Atlantic Bluefin Tuna Larvae Sampled in the Slope Sea, Gulf of Mexico, and Mediterranean Sea Synopsis: The proposed work is to compare the isotopic signatures in otoliths between Atlantic bluefin tuna larvae spawned in the Slope Sea, Gulf of Mexico, and the Mediterranean Sea. Recent sampling in the Slope Sea has suggested that some Atlantic bluefin tuna spawning occurs there, in contrast to the assumption that the Gulf of Mexico is the only spawning location for the western stock. We propose to test for differences in otolith chemistries found in Atlantic bluefin tuna larvae collected from the Slope Sea, Gulf of Mexico, and Balearic region of the Mediterranean Sea. If differences are found, we can determine a baseline isotopic signature for each spawning ground, as influenced by unique seawater chemistry. These baselines can support future research to determine the relative contributions of each spawning location to the western population of Atlantic bluefin tuna. PI: Steven X. Cadrin (NA24NMFX472C0006-T1-01) | $47,497 |
| UNIVERSITY OF MAINE ORONO | Title: Evaluating age, growth and stock structure of Atlantic bluefin tuna in the northwest Atlantic. Synopsis: Utilizing commercial dealers, commercial and recreational fishermen, the PIs will collect hard and soft tissues across size-classes and gear categories for ABFT from 10-330 cm in length. Otoliths will be used to age fish, improve existing age length keys and growth parameters and for stock composition analysis using established and new stable isotope stock assignment methodology, paired with genetic based stock discrimination to analyze differences in stock mixing proportions by method. In this study, we propose to continue our biological sampling program, age, growth and stock composition analysis. This includes new aging techniques and methods for stock of origin assignment. PI: Walt Golet (NA24NMFX472C0005-T1-01 ) | $315,783 |
2023
| Recipient | Project | Federal Funding |
|---|---|---|
| University of Maine System, acting through the University of Maine | Title: Age and Stock Composition of Atlantic Bluefin Tuna in the Northwest AtlanticSynopsis: Updated age, growth and stock composition information has been identified as a major priority for reducing uncertainties in the assessment and management of the western Atlantic bluefin tuna (ABFT) stock. The ICCAT GBPY program and the US BTRP have made considerable contributions toward furthering understanding of life history for ABFT over the past years. This has led to extensive analyses of age and stock composition using standardized techniques, routine estimates of stock mixing utilizing conventional otolith chemistry and the development of new genetic analysis for stock composition and ultimately estimates of absolute population abundance using close kin mark and recapture; all of which are possible by the routine collection of biological samples collected from previous BTRP support in PI Golet’s lab and other Atlantic-wide programs. Utilizing a network of dealers, commercial and recreational fishermen from Maine to North Carolina, and via direct sampling, the PIs will collect hard and soft tissues across size-classes from 10-330 cm in length for age, growth, stock composition and population abundance studies (genetics). Otoliths will be used to age fish, improve existing age length keys and growth parameters. Otoliths will be used for stock composition analysis using established stable isotope methodology, paired with genetic based stock discrimination to analyze differences in stock mixing proportions by method. Growth and stock composition data will be provided to the NMFS and ICCAT’s Standing Committee on Research and Statistics for incorporation into upcoming Atlantic bluefin tuna assessments including bulk mixing and individual assignment (random forest) estimates by region, gear, and age at length for combined US commercial and recreational fisheries. Sex specific growth curves and stock specific growth rates will be updated, and soft tissues will be shipped to the Southeast Fisheries Science Center (SEFSC) and Department of Fisheries and Oceans (DFO) in Canada for genetic stock identification and suitability for close kin mark recapture analysis given the positive results from the pilot program. In this study, we propose to continue our biological sampling program and use those samples to estimate age, growth, and stock mixing of ABFT to improve the assessment and management process for this important fishery resource which may include the adoption of a new management strategy evaluation structure for this species. PI: Dr. Walter Golet (NA23NMF4720183) | $251,613 |
| The Ocean Foundation | Title: Designing a next-generation, multi-stock assessment for Atlantic Bluefin tuna. Synopsis: This project aims to develop a next-generation stock assessment model for Atlantic bluefin tuna that may also be used as an operating model for future Management Strategy Evaluation (MSE) frameworks. Current stock assessments for the East and West Atlantic management areas do not appropriately model the western and eastern bluefin tuna stocks, which display complex spatial dynamics that violate assumptions of closed populations. This key criticism was a major reason why recent assessments of the western and eastern stocks failed to pass peer-review (Maunder 2021, Ianelli 2022). A variety of data are available to inform the movement and spatial distribution of a more complex multi-stock model. An assessment that simultaneously models eastern and western stocks could be fitted to electronic tagging and stock of origin data to account for seasonal availability and movement. Learning from the experience of designing a mixed stock model for the operating models of the MSE process, such an assessment could be configured to be sufficiently fast and robust to pass peer review and be used in the provision of management advice. With project oversight and coordination provided by The Ocean Foundation (Shana Miller, Co-principal Investigator), the Blue Matter analytical team, led by Drs. Tom Carruthers (Co-Principal Investigator) and Quang Huynh (Lead Analyst) will develop the multi-stock assessment model for bluefin tuna. There are four milestones associated with the project: (i) Review and identify the data available to inform bluefin tuna stock dynamics; (ii) Design and develop the model code for the multi-stock assessment; (iii) Conduct simulation testing of the assessment model to identify scenarios with good and poor estimation performance; and (iv) Design an R package with supporting code for model diagnostics and performance evaluation. PI: Eddie Love (NA23NMF4720184) | $84,215 |
| The Ocean Foundation | Title: Using electronic tags and genomics to model mixing rates and natural mortality of Atlantic Bluefin Tuna.Synopsis: Electronic tagging has emerged as a powerful tool for reducing scientific uncertainty regarding Atlantic bluefin tuna (ABT) population structure, life history traits and seasonal distributions. Despite rapid advances in knowledge of ABT, key questions remain about the number of populations, the degree of mixing, recruitment dynamics, and natural and fisheries mortality. Electronic tags (e-tags) can reduce this uncertainty and, when combined with genomics, the data they provide have the potential to improve stock assessments and inform quota allocations in the lucrative ABT fishery. We propose to continue deploying e-tags on ABT as part of the “TAG-A-Giant” program run by The Ocean Foundation (TOF) and Stanford University. The TAG campaign has deployed 1900 e-tags in the west and east Atlantic. Our results will directly advance our multistate Bayesian mark-recapture model for estimating rates of natural mortality by population, and provide results that improve the ICCAT multi-stock Management Strategy Evaluation framework. BTRP funding will ensure the continuation of a multi-decadal time series of e-tags, ensure genetic origin is assigned to tracks with modern genomic techniques, and provide funding for Stanford to work with ICCAT on international tag collaborations, where international deployments and processing of valuable data is essential. We propose to continue our e-tag research program by conducting acoustic, archival and satellite tagging, movement ecology, genetic stock identification and fisheries modeling. PI: Barbara Block (NA23NMF4720185) | $232,213 |
2022
| Recipient | Project | Federal Funding |
|---|---|---|
| University of Maine System, acting through the University of Maine | Title: Age, Growth and Stock of Origin For Western Atlantic Bluefin Tuna Synopsis: Updated age, growth and stock composition information has been identified as a major priority for reducing uncertainties in stock assessment models for the western Atlantic bluefin tuna (ABFT) stock (ANON 2018). The ICCAT GBPY program and the US BTRP have made considerable contributions toward furthering understanding of life history for ABFT over the past years (ANON 2018). This has led to extensive analyses of age and stock composition using standardized techniques, routine estimates of stock mixing utilizing conventional otolith chemistry and the development of new genetic analysis for stock composition and ultimately estimates of absolute population abundance using close kin mark and recapture; all of which are possible by the routine collection of biological samples collected from previous BTRP support in PI Golet’s lab and other Atlantic wide programs. Utilizing a network of dealers, commercial and recreational fishermen from Maine to North Carolina, and via direct sampling, the PIs will collect hard and soft tissues across size classes from 10-330 cm in length for age, growth, stock composition and population abundance studies (genetics). Otoliths will be used to age fish, improve existing age length keys and growth parameters. Otoliths will be used for stock composition analysis using established stable isotope methodology, paired with genetic-based stock discrimination to analyze differences in stock mixing proportions by method (co-PI Kerr/NMFS). Growth and stock composition data will be provided to the NMFS and ICCAT’s Standing Committee on Research and Statistics for incorporation into upcoming Atlantic bluefin tuna assessments including bulk mixing and individual assignment (random forest) estimates by region, gear, and age at length for combined US commercial and recreational fisheries. Sex specific growth curves and stock specific growth rates will be updated, and soft tissues will be shipped to the Southeast Fisheries Science Center (SEFSC) and Department of Fisheries and Oceans (DFO) in Canada for genetic stock identification and suitability for close kin mark recapture analysis given the positive results from the pilot program. In this study, we propose to continue our biological sampling program and use those samples to estimate age, growth, and stock mixing of ABFT to improve the assessment and management process for this important fishery resource. PI: Dr. Walter Golet (NA22NMF4720113) | $198,884 |
| Gulf of Maine Research Institute | Title: Incorporating the influence of climate into the western Atlantic bluefin tuna stock assessment Synopsis: Evidence of changing ocean conditions is increasingly apparent with regions such as the northwest Atlantic experiencing rapid increases in sea surface temperature. Ocean climate is known to be an important determinant of the spatial-temporal distribution and dynamics of Atlantic bluefin tuna (BFT). Shifts in abundance indices have been documented in the western stock area that suggests a northward shift in the distribution of BFT from U.S. to Canadian waters associated with ocean warming. Recent ICCAT stock assessments of western BFT have been challenged with the need to resolve conflicting trends in U.S. and Canadian catch-per-unit-effort (CPUE) indices. In the last two years, the stock assessment for western BFT has integrated a climate indicator, the Atlantic Multi-decadal Oscillation (AMO) to account for the impact of warming on BFT catchability. The integration of the AMO to modulate catchability marks a significant advance in the recognition of changing ocean conditions on stock dynamics; however, many questions remain regarding the influence of ocean climate on BFT and the best approach for accounting for shifts in distribution. The goal of this study is to develop improved indices of abundance for western BFT that account for the effects of changing ocean conditions on BFT spatial distribution. We propose to work collaboratively with fishery stakeholders to develop spatio-temporal models of BFT CPUE and evaluate its influence on the stock assessment. Specific objectives include 1) engaging with fishery stakeholders on approaches to improve indices of abundance for the western BFT stock, 2) applying spatial-temporal modeling to develop improved indices of abundance for the western BFT stock, and 3) evaluating the influence of CPUE indices derived from spatial-temporal modeling on the stock assessment compared to conventional CPUE indices and the inclusion of environmental covariates within the stock assessment model. PI: Lisa Kerr (NA22NMF4720115) | $160,064 |
| University of Massachusetts Dartmouth | Title: Development of Age Structured Assessment Program Applications for Atlantic Bluefin Tuna Synopsis: The International Commission for the Conservation of Atlantic Tunas (ICCAT) is considering a transition to an empirical management procedure for determining total allowable catch (Carruthers 2021), but occasional stock assessments will continue to be applied for status determination and evaluating performance of the management procedure for avoiding overfishing and rebuilding (ICCAT 2021). Eastern and western stocks of Atlantic bluefin tuna are assessed by the using virtual population analysis and stock synthesis applications (ICCAT 2020, 2021). In response to uncertainties in the 2020 updated assessment of the eastern Atlantic stock, previously developed Age Structured Assessment Program (ASAP) applications were updated (Maguire & Cadrin 2020), and further development of ASAP applications was recommended. Similar problems were encountered in the 2021 updated assessment of the western Atlantic stock (Lauretta et al. 2021, Tsukahara et al. 2021). This proposal is intended to collaborate with SEFSC scientists and other ICCAT scientists to advance ASAP applications to eastern and western Atlantic bluefin tuna assessments by applying best practices in iterative model building. For example, the fleet structure that was initially included in the ASAP application to western Atlantic bluefin tuna by Legault and Restrepo (1998) will be reconsidered with the updated time series developed for the 2020 ICCAT assessments. ICCAT fleets are spatially defined, so fleet-based ASAP applications involve an ‘areas-as-fleets’ approach to spatial patterns (e.g., Hurtado-Ferro et al. 2014, Waterhouse et al. 2014), which may be a viable model of intermediate complexity for routine application by ICCAT. Model developments will be initially reviewed by collaborators, and the performance of selected applications will be evaluated using previously developed simulation frameworks (Morse et al. 2020). Model performance of ASAP applications will be compared to those from previous simulation-estimation analyses for ICCAT virtual population analyses. Ancillary analyses that are necessary for meeting the requirements of the ICCAT management system will also be developed to interface with ASAP applications. Results will be presented to the ICCAT Bluefin Tuna Species Group for consideration as a method to determine stock status and catch advice. PI: Steven X. Cadrin (NA22NMF4720114) | $101,407 |
| The Ocean Foundation | Title: Electronic Tags and Genomics Inform Stock Distributions, Mixing Models, and Mortality Estimates of Atlantic Bluefin Tuna Synopsis: Advances in electronic tagging (e-tags) and genomics offer new insights into understanding the life history of Atlantic bluefin tuna (ABT) populations in the North Atlantic and adjacent seas. Despite the rapid advances in research in this field, key questions remain. Knowing the number of populations, their biological parameters, and the spatial boundaries over which ABT fishery populations interact has far-reaching implications for species management and conservation. Current ABT fisheries models are hindered by the lack of consensus on the number of ABT populations, their migratory patterns, and the level of mixing on foraging and spawning grounds. Management models are highly sensitive to assumptions about the spatial mixing of populations, and estimations of survivorship and recruitment. Here, we propose to use acoustic and satellite tagging of ABT to assign stock specific mortality estimates, map stock-specific spatial-temporal movements at high resolution in the North Atlantic, and improve our capacity to quantify areas of population overlap in relationship to population assignments, age and environmental parameters. Our work will provide new inputs for Virtual Population Assessments and ICCAT mixing models that support more effective and sustainable ABT management. Our proposal specifically addresses BTRP priority areas #2 “Large scale electronic tagging to estimate movements, mortality of the western and eastern stock”, and #6, “Developing novel fishery-independent techniques to estimate abundance or mortality”. Our specific objectives are: 1) to deploy 80 electronic tags (50 acoustic and 30 satellite) to generate stock specific detection probabilities along the Canadian Maritimes and North American shelf waters; 2) to advance our multistate Bayesian mark-recapture framework for estimating rates of survival and seasonal movements for the e-tagged ABT including population of origin information, and to operationalize a fishery-independent acoustic ABT survivorship index. This includes establishment of time-varying M estimation, generating population-specific estimates of movement rates and M, and evaluating the possibility of estimating M by year class; 3) to expand our e-tag efforts in the eastern Atlantic to garner tracks on mature ABT for comparative spatial analyses with western tagged ABT, 4) to further define the behavior of Slope Sea spawners and assess differing hypotheses regarding their role in ABT population dynamics, to analyze habitat differentiation by stock and age-class to better understand ontogenetic shifts in GOM vs. MED movements, and to use spatio-temporal catch composition analysis, alternate stock structures, and age-specific movement scenarios to determine how these dynamics affect ICCAT model outcomes; 5) test the viability of a new cutting-edge approach for stock assignment using the whole ABT genome and compare to earlier genetic techniques; and 6) to process all incoming tag data from 2022-2023 deployments and recovered tags, acquire the acoustic data from all receivers in the Ocean Tracking Network (OTN), and to provide access to tagging data, metadata and genetic data sets by adding them to national and international (ICCAT) databases. This will improve access to data for parameterizing models at ICCAT. PI: Barbara Block (NA22NMF4720116) | $90,429 |
2021
| Recipient | Project | Federal Funding |
|---|---|---|
| University of Maine System, acting through the University of Maine | Title: Age, Growth and Stock of Origin For Western Atlantic Bluefin Tuna Synopsis: Updated age, growth and stock composition information has been identified as a major priority for reducing uncertainties in stock assessment models for the western Atlantic Bluefin tuna (ABFT) stock (ANON 2018). The ICCAT GBPY program and the US BTRP have made considerable contributions toward furthering understanding of life history for ABFT over the past years (ANON 2018). This has led to extensive analyses of age and stock composition using standardized techniques, routine estimates of stock mixing utilizing conventional otolith chemistry and the development of new genetic analysis for stock composition and ultimately estimates of absolute population abundance using parent offspring pair analysis all of which are made possible by the routine collection of biological samples collected from previous BTRP support in PI Golet’s lab and other Atlantic wide programs. Utilizing a network of dealers, commercial and recreational fishermen from Maine to North Carolina, and via direct sampling, the PIs will collect hard and soft tissues across size-classes from 10-330 cm in length for age, growth, stock composition and population abundance studies (genetics). Otoliths will be used to age fish, improve existing age length keys and growth parameters. Otoliths will be used for stock composition analysis using established stable isotope methodology, paired with genetic based stock discrimination to analyze differences in stock mixing proportions by method (co-PI Kerr/NMFS). Growth and stock composition data will be provided to the NMFS and ICCAT’s Standing Committee on Research and Statistics for incorporation into upcoming Atlantic Bluefin tuna assessments including bulk mixing and individual assignment (random forest) estimates by region, gear and age at length for combined US commercial and recreational fisheries. Sex specific growth curves and stock specific growth rates will be updated and soft tissues will be shipped to the Southeast Fisheries Science Center (SEFSC) and Department of Fisheries and Oceans (DFO) in Canada for genetic stock identification and suitability for parent offspring pair analysis given genetic markers for discrimination between East and West stocks are near completion. In this study, we propose to continue our biological sampling program and use those samples to estimate age, growth and stock mixing of ABFT to improve the assessment and management process for this important fishery resource. PI: Dr. Walter Golet (NA21NMF4720305) | $276,721 |
| The Ocean Foundation | Title: Evaluating Bluefin Harvest Strategies That Use Genetic Mark-Recapture Data Synopsis:This project aims to leverage the existing ICCAT Management Strategy Evaluation framework for Atlantic bluefin tunas to conduct rigorous simulation testing of novel and potentially powerful harvest strategies that use conventional gene tagging. With project oversight and coordination provided by The Ocean Foundation, the Blue Matter analytical team, led by Dr. Tom Carruthers will conduct a detailed literature review to establish credible gene tagging dynamics and code these into the existing MSE framework for Atlantic bluefin tuna. Using these simulation models as a testbed, a range of novel harvest strategies that use conventional gene tagging will be developed. A set of unique management systems will be defined that combine harvest strategies with varying release and recapture programs spanning a range of implementation costs. MSE closed-loop simulation will be then used to evaluate management performance and trade-offs, identify key system uncertainties and identify cost-effective management solutions. All methods and results will be summarized in a draft peer-reviewed paper. This project is aimed at three key program priorities listed in Section 1.B of the funding notice: (#2) Large-scale conventional, electronic and genetic tagging experiments specifically designed to estimate movement rates, abundance, and mortality of the eastern or western stocks; (#4) Simulation modeling to evaluate the performance of assessment models and management strategies in light of uncertainties related to stock mixing, reproductive potential and other life history traits; and (#5) Improving the quality of fishery data for stock assessments. PI: Shana Miller (NA21NMF4720304) | $84,238 |
2020
| Recipient | Project | Federal Funding |
|---|---|---|
| University of Maine System, acting through the University of Maine | Title: Age Structure, Mixed Stock Composition and Evaluation of Mixed Stock Composition Methods and Analysis for Bluefin Tuna in the Northwest Atlantic Synopsis: Updated age, growth, and stock composition information have been identified as major priorities for reducing uncertainties in stock assessment models for the western Atlantic bluefin tuna (ABFT) stock. The ICCAT GBPY program and the US BTRP have made considerable contributions toward furthering understanding of life history for Atlantic bluefin tuna over the past years. This has led to extensive analysis of age and stock composition using standardized techniques and the development of new genetic analysis for stock composition and ultimately stimates of absolute population abundance using parent-offspring pair analysis supported to a large degree through biological sampling from previous BTRP supported research in PI Golet’s lab. Utilizing an extensive network of dealers, commercial and recreational fishermen from Maine to North Carolina, and via direct sampling, the PIs will collect hard and soft tissues across size-classes from 10-330 cm in length for age, growth, reproductive status, stock composition and population abundance studies (genetics). Otoliths will be the primary structure used to age fish, establish age length keys and growth parameters. Otoliths will be used for stock composition analysis using established stable isotope methodology, paired with genetic-based stock discrimination to analyze differences in stock mixing proportions by method and utilizing larval and young-of-the-year samples update the baselines for otolith microchemistry analysis. Growth and stock composition data will be provided to the NMFS and ICCAT’s Standing Committee on Research and Statistics for incorporation into upcoming Atlantic bluefin tuna assessments including bulk mixing and individual assignment (random forest) estimates by region, gear, and establishment of age length keys for combined US commercial and recreational fisheries. Sex-specific growth curves and stock-specific growth rates are currently in development and soft tissues have been shipped to the Southeast Fisheries Science Center (SEFSC) and Department of Fisheries and Oceans (DFO) in Canada for genetic stock identification and suitability for parent-offspring pair analysis given genetic markers for discrimination between East and West stocks are near completion. In this study, we propose to continue our extensive biological sampling program and use those samples to estimate age, growth, and stock mixing of ABFT tuna to improve the assessment and management process for this important fishery resource.PI: Dr. Walter Golet (NA20NMF4720045) | $285,057 |
| The Ocean Foundation | Title: Using Electronic Tagging Data, Genetic Stock of Origin and Modeling to Improve ICCAT Management of Atlantic Bluefin Tuna Synopsis: This grant will enable the continuation of a two-decade US time series of electronic tagging of ABT in the western North Atlantic (1996-2020) as part of the Tag-A-Giant program of The Ocean Foundation and Stanford University, and advance our capacity to assign genetic stock-of-origin to current and past tracks. Electronic tag data reveal the complex migratory patterns of ABT. Tag data enhances ICCAT mixed modeling efforts as well as our multistate Bayesian mark-recapture models that estimates rates of survival and seasonal movements of ABT. Our specific objectives are to 1) deploy 55 electronic tags (acoustic and satellite) for generating detection probabilities along the Canadian Maritimes and North American shelf waters; 2) to assign genetic stock-of-origin to 300 prior tracks (1996-2019) that are in the TAG and ICCAT data sets; 3) to advance our multistate Bayesian mark-recapture framework for estimating rates of survival and seasonal movements for the electronically tagged ABT inclusive of the population of origin information. Also to establish time-varying M estimation, generate population-specific estimates of movement rates and M, and evaluate the possibility of estimating M by year class; 4) to conduct new modeling analyses that examine how genetic stock assignments of electronic tag tracks will influence mixing model simulations, and 5) to process all incoming tag data from 2020-2021 deployments or recovered tags, acquire the acoustic data from all receivers in the Ocean Tracking Network, and to provide access to tagging data, metadata and genetic data sets by adding them to national and international (ICCAT) data bases. This will improve access to unique data critical for parameterizing models at ICCAT. | $195,216 |
| University of South Florida | Title: Proof of Concept: Use of Eye-Lens Isotopes to Identify Spawning Origin and Lifetime Trophic Geographies of Bluefin Tuna Synopsis: This project proposes a pilot study to evaluate the feasibility of determining the spawning origin and recreating the migratory and trophic history of BFT from stable isotope analysis of eye lenses. They provide a precise and biologically static record of the trophic history and location of a fish throughout its lifetime. We propose to obtain 40 BFT eyes, with 20 coming from commercial landings in the western Atlantic and 10 each originating from Balearic Sea (Spain) and Adriatic Sea (Croatia) farms. We will conduct stable isotope profiles of the eye lens to re-create individuals’ migratory and trophic histories. The successful lifetime profiles of two BFT eye lenses and the unique inferences provided by them demonstrate proof of concept, warranting further exploration of the efficacy of eye lenses to re-create the migratory histories of individual BFT. Further, coupling Western fish with fish obtained from Mediterranean farms provides a unique control set (particularly fish from Croatian farms that are held for several years) as well as potentially providing records of ingress and egress through the Straights of Gibraltar. PI: Dr. Chris Stallings (NA20NMF4720044) | $41,993 |
2019
| Recipient | Project | Federal Funding |
|---|---|---|
| University of Southern Mississippi | Title: Modeling Abundance and Dispersal of Larval Atlantic Bluefin Tuna Thunnus Thynnus in the Gulf of Mexico - Synopsis: The proposed project will address two key uncertainties highlighted in the recent stock assessment. First, we will improve estimations of spawning stock biomass by integrating environmental data into a zero-inflated generalized additive model of larval abundance. Second, we will improve understanding of environmental drivers of recruitment by initializing three-dimensional hydrodynamic larval backtracking models, including vertical migration behaviors, with existing larval age measurements. This will allow the estimation of larval dispersal from spawning locations and show how growth and survival vary along these trajectories. The aim of the proposed work is to provide usable and relevant information to aid fishery managers in making informed management decisions for Atlantic bluefin tuna. Specifically, under BTRP Priority 7, the project will integrate satellite remote sensing and oceanographic modeling products to consider the effect of environmental conditions on recruitment by estimating larval bluefin tuna abundance, dispersal, and mortality. Additionally, the project proposes to improve the quality of fishery data for stock assessments (BTRP Priority 5) by improving current indices of spawning stock biomass. PI: James S. Franks (NA19NMF4720093) | $71,747 |
| University of Maine System, acting through the University of Maine | Title: Evaluating Age Structure, Aging Bias and Mixed Stock Composition of Atlantic Bluefin Tuna in the Northwest Atlantic - Synopsis: In this study, we aim to collect biological samples and use those samples to estimate age, growth and stock mixing of ABFT tuna to improve the assessment and management process for this important fishery resource. This research will enhance research collaborations with Robert Allman (Panama City Lab) and the SCRS stock assessment group at the Southeast Fisheries Science Center (Dr. Matt Lauretta), NMFS, Alex Hanke at DFO in Canada and support SEDAR objectives. This proposal addresses Research Priority Number One: Representative sampling of hard and soft tissues and associated analytical techniques for studies of population genetics, stock composition, age composition, growth and fecundity. PI: Dr. Walter Golet (NA19NMF4720094) | $229,383 |
| The Ocean Foundation | Title: Electronic Tagging of Bluefin Tuna: Improving Life History Estimates Utilized in ICCAT Models - Synopsis: Our proposal specifically addresses BTRP priority area #2, “Large scale electronic tagging to estimate movements, mortality of the western and eastern stock,” and area #6, “Developing novel fishery-independent techniques to estimate abundance or mortality (e.g., using advanced technology or enhancing coverage through effective multi-institution partnership).” BTRP funding will additionally ensure the continuation of an eleven-year, internationally collaborative time series of electronic tagging and modeling efforts for the northern foraging regions of western Atlantic bluefin tuna. We propose to accomplish 5 objectives during the one-year duration of the BTRP project: 1) We will deploy electronic tags on bluefin tuna in the GSL foraging ground. 2) We propose to update our Bayesian analyses of fisheries and natural mortality, and 3) We propose to incorporate the new telemetry data into ICCAT mixing models. 4) We will process new fin clips from tagged ABT for potential genetic population assignment. 5) We will recover and process all electronic tagging data sets and transfer these data to open source data systems (ICCAT and NOAA) to permit access by all international modeling teams. This will improve access to these unique data types for the parameterization of models at ICCAT. PI: Dr. Barbara Block (NA19NMF4720095) | $173,192 |
| Gulf of Maine Research Institute | Title: Spatio-temporal associations of western bluefin tuna indices of abundance with ocean climate conditions - Synopsis: The goal of this study is to investigate the spatio-temporal distribution of Atlantic bluefin catches in U.S. and Canadian waters and to understand the effects of changing ocean conditions on catch rates of bluefin tuna. We intend to apply this knowledge to inform the most appropriate methods for integrating environmental influence on catch rate indices into western bluefin stock assessment models. This proposal directly addresses BTRP Research Priority 3: Data mining to sharpen estimates of catch, catch composition, fishing effort, and spatial aspects of catch and BTRP Research Priority 7: Integration of satellite remote sensing, oceanographic modeling and other multidisciplinary scientific products to consider environmental effects upon biology, fishery operations or to resolve the uncertainties in historical recruitment patterns. PI: Dr. Lisa Kerr (NA19NMF4720096) | $155,258 |
2018
| Agency | Project | Federal Funding |
|---|---|---|
| University of Maine System, acting through the University of Maine | Title: Evaluating Age of Structure, Aging Bias and Mixed Stock Composition of Atlantic Bluefin Tuna in the Northwest Atlantic - Synopsis: Updated age, growth and stock composition information have been identified as major priorities for reducing uncertainties in stock assessment models for the western Atlantic bluefin tuna (ABFT) stock (ANON 2014). Utilizing an extensive network of dealers, commercial and recreational fishermen from Maine to North Carolina, and via direct sampling, the PIs will collect hard and soft tissues across size classes from 71-300+ cm in length for age, growth, reproductive status, stock composition and potential population abundance studies (genetics). Otoliths will be the primary structure used to age fish, establish new age length keys, growth parameters and in conjunction with dorsal spines used to assess aging bias between structures. Otoliths will also be used for stock composition analysis using established otolith chemistry methods, as well as additional otolith-based stock identification techniques (i.e. collaborative otolith shape and structure analysis Dr. Deirdre Brophy). Growth and stock composition data will be provided to the NMFS and ICCAT’s Standing Committee on Research and Statistics for incorporation into upcoming bluefin tuna assessments including bulk mixing and individual assignment (random forest) estimates by region, gear and establishment of age length keys for US commercial and recreational fisheries. Sex specific growth curves and stock specific growth rates are currently in development and soft tissues will continue to be archived in anticipation of genetic tagging studies for estimating ABFT tuna absolute population size (similar to methods used in southern bluefin tuna) once genetic markers suitable for discrimination between East and West stocks are established. In this study, we aim to collect biological samples and use those samples to estimate age, growth and stock mixing of ABFT tuna to improve the assessment and management process for this important fishery resource. This research will enhance research collaborations with Robert Allman (Panama City Lab) and the SCRS stock assessment group at the Southeast Fisheries science Center (Dr. Matt Lauretta), NMFS and support SEDAR objectives. This proposal addresses Research Priority Number One: Representative sampling of hard and soft tissues and associated analytical techniques for studies of population genetics, stock composition, age composition, growth and fecundity. PI: Dr. Walter Golet (NA18NMF4720044) | $234,627 |
| University of Massachusetts Dartmouth | Title: Facilitating Stakeholder Engagement in Management Strategy Evaluation of Atlantic Bluefin Tuna Fisheries - Synopsis: We propose to conduct stakeholder engagement in management strategy evaluation (MSE) of Atlantic bluefin tuna fisheries in response to the NOAA Bluefin Tuna Research Program’s Priority #4: Simulation modeling to evaluate the performance of assessment models and management strategies in light of uncertainties related to stock mixing, reproductive potential, and other life-history traits. The International Commission for the Conservation of Atlantic Tunas (ICCAT) is developing an MSE for providing Total Allowable Catch (TAC) recommendations for North Atlantic bluefin tuna fisheries that meet the objectives of fisheries management. Alternative management procedures are being simulation tested for their robustness to uncertainties. Despite progress in the development of operating models and estimation models, optimal implementation of MSE should involve stakeholder participation and acceptance. We propose to conduct a series of workshops with U.S. stakeholders in Atlantic bluefin tuna fisheries to explain MSE and the ICCAT implementation of MSE, and to get stakeholder perspectives on aspects of operating models, management objectives, performance indicators, and alternative management procedures. We will engage stakeholders from commercial and recreational fisheries as well as conservation groups. Previously developed operating models and estimation models will be revised to address stakeholder perspectives and to evaluate alternative management procedures for meeting stakeholders’ objectives. PI: Dr. Steven X. Cadrin (NA18NMF4720045) | $141,143 |
| The Ocean Foundation | Title: Improving Estimates of Natural Mortality of Atlantic Bluefin Tuna with Electric Tags - Synopsis: We propose to continue electronic tagging of bluefin tuna in the western North Atlantic as part of the Stanford University and The Ocean Foundation TAG-A-Giant program, and advance our multistate Bayesian mark-recapture framework for estimating rates of survival and seasonal movements in electronically tagged tuna. Our proposal specifically addresses BTRP priority area #2 “Large scale electronic tagging to estimate movements, the mortality of the western and eastern stock.” And area #6, Developing novel fishery-independent techniques to estimate abundance or mortality (e.g., using advanced technology or enhancing coverage through effective multi-institution partnership). BTRP funding will additionally ensure a decade time series of tagging, genetics and modeling in the northern regions of western Atlantic bluefin tuna foraging grounds, continues with international collaborations. We propose to continue our electronic tagging research program by conducting acoustic and satellite tagging, genetic stock identification, modeling and data processing recovered tags. Management stock assessment models of the Atlantic bluefin tuna depend upon knowing more about the aggregated populations we are fishing on foraging grounds in the western Atlantic. All biological data indicate that fisheries are mixed along the eastern seaboard of North America. In the northern areas such as the Canadian Gulf of St. Lawrence, the fishery tends to be derived more from the Gulf of Mexico (GOM) population, but Mediterranean (MED) fish are also more recently mixing at this location too. Our objectives are to: 1) deploy 40 acoustic tags for generating detection probabilities along the Canadian Maritimes and North American shelf waters that can be used to further develop mark-recapture models, and 2 ) to deploy 10 pop - up satellite - archival tags to generate an annual geolocation track with visitation to a spawning ground (GOM or Med). These tags will validate the stock of origin with visitation data to a spawning ground, that can be incorporated in the models; 3) Improve and update our current Bayesian mark-recapture models to include age structure, population of origin, and more recent tagging data from 2007-2018; 4) Use microsatellite genetic techniques to identify stock of origin for new electronic tagged fish entering the electronic tag data set, and to 5) process all incoming new tag data from 2017-2018 deployments, process the archival tag rewards and data from any recovered and returned tags in 2018, acquire the acoustic data from all receivers in the Ocean Tracking Network, and then to provide access to tagging data, metadata and genetic data sets by adding them to the ICCAT database and by pulsating the NOAA IOOS Animal Telemetry Network data assembly center. This will improve access to these unique data types for parameterizing models at ICCAT. PI: Dr. Barabara Block (NA18NMF4720046) | $165,240 |
| Monterey Bay Aquarium Foundation | Title: Historical Data Mining to Inform Bluefin Tuna Stock Assessments - Synopsis: The primary goal of stock assessment is to estimate stock productivity. However, estimates of stock productivity (e.g., stock-recruitment relationships) can be biased when the assessment model time series begins in a fished condition. Integrated assessment models allow for estimation of unfished productivity benchmarks when some historical information is available (e.g., estimates of landings, size composition of catches, aging data, or fishing effort). Stock productivity estimates of western Atlantic bluefin tuna provide contrasting perceptions of stock status and sustainable harvest levels. The last assessment model started in 1970, a fished condition, and estimated high recruitment levels during the early time series. The current assessment was conducted using age-structured models starting in 1974 when the size composition information is first available. However, the perception of stock productivity and status during a heavily fished condition may not be representative of potential stock productivity. PI: Dr. Andre Boustany (NA18NMF4720047) | $46,012 |
2017
| Agency | Project | Federal Funding |
|---|---|---|
| Gulf of Maine Research Institute | Title: Evaluating the performance of alternative assessment and management procedures of mixed Atlantic bluefin tuna stocks - Synopsis: Simulation testing of alternative assessment and management procedures is needed to understand the implications of stock mixing and uncertainty in the life history of Atlantic bluefin tuna. Our proposed research will address this need through Management Strategy Evaluation (MSE). MSE is considered state-of-the-art for developing and testing the performance and robustness of fisheries policy and strategic management advice. The approach involves building a model to simulate the population dynamics and movement of Atlantic bluefin tuna, as well as harvest by the fishery, wherein the simulated status of the resource triggers action based on management strategies, and subsequent management decisions in-turn affect fishing activities and feedback on the resource. The proposed objectives are to: 1) use a previously developed operating model framework to generate a simulated dataset with the typical quantity and quality of data available for stock assessment of Atlantic bluefin tuna, 2) apply alternative estimation models to the simulated data for Atlantic bluefin tuna stock assessment and compare model performance for accuracy and precision of stock status determination, 3) develop biological reference points for bluefin tuna that incorporate the influence of mixing, as well as different productivity regimes, and maturity assumptions, and 4) test alternative management strategies against the goal of sustainability of eastern and western spawning populations and consider the impact exploitation of each stock has on the other. This proposal directly addresses BTRP Research Priority 4: Simulation modeling to evaluate the performance of assessment models and management strategies in light of uncertainties related to stock mixing, reproductive potential and other life-history traits. PI: Dr. Lisa Kerr (NA17NMF4720151) | $142,425 |
| University of Maryland Center for Environment Science | Title: Sub-annual cohort representation in young-of-the-year juvenile recruits of the US Atlantic bluefin tuna population - Synopsis: This project addresses the BTRP priority, “improving the understanding of factors affecting recruitment success” through analysis of hatch-date distributions for a small but unique sample of young-of-the-year juveniles bluefin tuna collected in US waters. The project will also sample YOY Atlantic bluefin tuna to support population genetics, age and stock composition, and growth studies. The proposal develops and applies otolith microstructural analysis, addressing the question of natal origins of Western Stock recruits. Discovery of a new spawning area in the Slope Sea (Richardson et al. 2016) calls into question whether there is only a single location and period of spawning – that associated with Gulf of Mexico spawning – contributing to the Western Stock. Indeed, this is a key uncertainty, identified by the recent SCRS Intersessional Atlantic Bluefin Tuna Data Preparatory Meeting (ICCAT, Madrid; July 2016). Analysis of hatch date analysis for archived and newly collected YOY otoliths will test for the presence of two periods of spawning and also support development of an age-length key that can be used to translate existing and future YOY length distribution data into spawning periods and regions. PI Secor has expertise in otolith microstructural analysis, fish recruitment, age and growth, and migration. He has contributed this expertise and scientific advice to Atlantic bluefin tuna science assessment issues during the past 20 years. PI: Dr. David H. Secor (NA17NMF4720152) | $45,966 |
| University of Maine System acting through University of Maine | Title: Evaluating Age Structure and Mixed Stock Composition of Atlantic Bluefin Tuna in the Northwest Atlantic - Synopsis: In this study we aim to conduct biological sampling and conduct age and growth and stock mixing analysis of Atlantic bluefin tuna that contributes to the improvement of the assessment and management process for this important fishery resource. This research will enhance research collaborations with Robert Allman (Panama City Lab) and the SCRS stock assessment group at the Southeast Fisheries science Center (Dr. Matt Lauretta), NMFS and support SEDAR objectives. This proposal addresses Research Priority Number One: Representative sampling of hard and soft tissues and associated analytical techniques for studies of population genetics, stock composition, age composition, growth and fecundity. PI: Dr. Walter Golet (NA17NMF4720153) | $229,469 |
| The Ocean Foundation | Title: Tracking the Migrations, Spawning Locations, and Genetic Origin of Bluefin Tuna in the west Atlantic Fishery - Synopsis: Electronic tagging of Atlantic bluefin tuna has emerged as a powerful tool to reduce uncertainty in scientific knowledge about their population structure and seasonal distributions. Despite the rapid advances in knowledge on Atlantic bluefin tuna, key questions remain about the level of population mixing, recruitment dynamics, and the number of independent populations. Data obtained from electronic tags have the potential to improve modeling of key parameters of life-history traits related to maturation, fisheries, and natural mortality as well as movement probabilities valuable for evaluating mixing between stocks. Current Atlantic bluefin tuna fisheries models rely on biological assumptions, and reducing the uncertainty with an electronic tag and genetic data is vital to improving stock assessments. We propose to use electronic tagging and genetic techniques to study the Atlantic bluefin tuna populations that forage in the waters of the Gulf of St. Lawrence, Canada and spawn in the Gulf of Mexico (GOM) and the Mediterranean Sea. This GOM population may represent the most threatened bluefin tuna in our oceans today, and new information is required to ensure maximal protection of the remaining spawning biomass. Our proposal specifically addresses priority area #1 (we will be collecting genetic material from the Gulf of St. Lawrence fishery (GSL) and when possible otoliths), #2 (we will be conducting electronic tagging to examine movements and distribution of both eastern and western stocks), supports priority area #5 by (improving the quality of fisheries data), and we will contribute to priority area #6 (developing novel fisheries independent techniques for estimating mortality using advanced technology). BTRP funding is one of the only ways we can ensure a decade time series of tagging, genetics and modeling, from the most accessible of the northern regions of GOM foraging grounds, the GSL, can continue. Management of the western fishery of Atlantic bluefin tuna depends upon knowing more about the populations we are fishing on foraging grounds in the western Atlantic. All biological data indicate that fisheries are mixed along the eastern seaboard of North America. In the northern areas such as the Canadian GSL, the fishery tends to be derived primarily from the GOM population. This makes the region an ideal spot for accessing mature GOM fish to study. Our objectives are to: a) deploy 20 satellite archival tags on Atlantic bluefin tuna in the GSL fishery, to obtain long-term data sets critical for modeling mature fish, of western origin, to examine how they utilize spawning grounds, and North Atlantic foraging grounds. To obtain long-term data sets critical for modeling life-history traits and fisheries mortality we will: b) deploy 30, ten-year duration acoustic tags to incorporate long term mark-recapture data into population models; c) develop a Bayesian mark-recapture model that uses acoustic detections in combination with data from the first year satellite tag data sets to estimate survival rates of GOM and Med spawners using the GSL foraging grounds, d) use microsatellite genetic techniques to identify stock of origin for 200 electronic tagged fish from the GSL electronic tag data set, and e) provide access to tagging and genetic data sets by adding them to the ICCAT database and by populating the NOAA IOOS Animal Telemetry Network data assembly center. This will improve access to these unique data types for parameterizing models at NOAA and ICCAT. PI: Dr. Barbara Block (NA17NMF4720154) | $165,400 |
2016
| Agency | Project | Federal Funding |
|---|---|---|
| University of Maine System acting through the University of Maine | Title: The Use of Biological Samples to Refine Estimates of Age, Growth, and Stock Mixing for Atlantic Bluefin Tuna in the NW Atlantic - Synopsis: The need to conduct routine biological sampling to determine age, growth, reproductive status, stock composition and absolute population abundance for sound, basic fisheries information on tunas, determined to be “of critical importance to stock assessment and management” is prominently noted in the KOBE2 document (June, 2010), the Atlantic Highly Migratory Research Plan (2011) and by the Atlantic Bluefin Tuna Status Review Team (2011). The University of Maine, along with its collaborators at the Gulf of Maine Research Institute (GMRI) has established long-term capacity to conduct integrated fisheries research on Atlantic bluefin tuna (ABFT), particularly through the establishment of a large biological sampling network in commercial and recreational fisheries. This proposal addresses Research Priority Number One: Sampling of tissues and otoliths for studies of population genetics, age, growth, fecundity, and micro-constituent or other analysis in order to characterize the stock compositions of catches. PI: Dr. Walter Golet (NA16NMF4720097) | $208,578 |
| Commonwealth of Massachusetts | Title: Evaluation of natal origin and migratory pathways of Atlantic bluefin tuna (Thunnus thynus) using chemical tracers - Synopsis: Atlantic bluefin tuna (ABFT; Thunnus thynnus) are currently managed as two separate eastern and western stocks divided by the 45ºW meridian with spawning presumed to be spatially segregated between stocks. The only identified spawning grounds are the Mediterranean Sea and Gulf of Mexico (GOM) for the eastern and western stocks, respectively. ABFT is known to migrate widely across feeding grounds throughout the North Atlantic including trans-Atlantic migrations across the management divide. ABFT is one of the most valued fish species globally, and are directly targeted by fisheries throughout their range. Current management regulations strictly prohibit directed fishing towards ABFT in the GOM. However, with the exception of a two month gear-restricted time period (i.e., April and May), ABFT is allowable as by-catch from the pelagic longline commercial fishery. Because of the lack of a directed ABFT fishery in the GOM, many data gaps still exist regarding this spawning assemblage. For example, the first evidence of ABFT feeding in the GOM during the spawning season was documented in 2015. While commercial landings and electronic tagging data have provided valuable information about seasonal movements and regional “hot spots,” surprisingly few fish tagged on northern feeding grounds have been observed traveling into the GOM and information on the natal origin of these fish and their connectivity to feeding grounds is scarce. This paucity of tag-based movement information combined with the lack of a directed ABFT fishery in the GOM has resulted in persistent data gaps regarding the connectivity between seasonal feeding grounds and this western spawning ground. Understanding connectivity between feeding and spawning grounds is important for management since fishing effort and quotas vary widely across Atlantic feeding grounds. Such data are critical to understanding the relative pressure on this spawning assemblage from fishing activity in eastern and western management areas. Understanding the extent to which ABFT return to their natal spawning ground (i.e., natal homing) is also critical to management for similar reasons. Novel chemical tracers have been developed in recent decades to better characterize the movements and stock structure of many large pelagic predators and can be used to resolve outstanding questions about ABFT. Spatial differences in otolith oxygen isotope ratios have been used to infer ABFT natal origin, while differences in diet-derived stable isotope and organochlorine ratios have been used to infer long-distance movements. Preliminary application of these techniques has suggested a high degree of natal homing and recent connectivity to western shelf feeding grounds, but these results are based on small sample sizes and single tracer approaches. To better characterize the natal origin and feeding ground connectivity of the GOM ABFT spawning aggregation, we propose a combined analysis of otolith oxygen isotopes, muscle carbon and nitrogen stable isotopes, and muscle organochlorine ratios from a large dataset of archived samples (n=259) collected in the GOM over multiple years (2007 to 2014). This combined approach will identify 1) the prevalence of natal homing to the GOM and 2) the connectivity between the GOM spawning grounds and regional feeding grounds where commercial harvest occurs. By making use of a large, multi-year dataset, this approach will provide a robust analysis of these questions, accounting for both inter- and interannual variability as well as potential size class and sex-based variation in ABFT migratory histories. PI: Dr. John Logan (NA16NMF4720098 | $123,025 |
| Virginia Institute of Marine Science | Title: Building the statistical and experimental framework for parentage-based abundance estimation of Western Atlantic bluefin tuna - Synopsis: Stock assessment via parentage analysis (also referred to as close-kin mark-recapture) has been successfully implemented for southern bluefin tuna (SBT), and scoping projects are in progress to develop genetic markers and parentage-based assessment strategies for Atlantic bluefin tuna (ABFT). Nevertheless, implementing this approach for ABFT requires confronting a number of complications and sources of uncertainty. First, ABFT differs from SBT in that there are at least two known spawning stocks, Western (Gulf of Mexico) and Eastern (Mediterranean), that mix on large parts of the Western foraging grounds. Though a number of techniques are being developed to distinguish individuals of the two stocks, these will likely have error rates on the order of 10-30%. In addition, large differences between fishery- estimated stock sizes and effective population sizes based on genetic diversity suggest significant ABFT spawning irregularity and/or “sweepstake spawning”, potentially impacting bias and variability in parentage-based stock assessments. Among the technical challenges, several sampling protocols with different advantages and disadvantages are being considered, including plankton surveys for larvae, and destructive and non-destructive adult sampling. Finally, the robustness of available ABFT genetic markers to sample quality is unknown, but is potentially a major issue as sample handling procedures are likely to vary significantly between fisheries and ABFT class sizes. We propose to address these issues through experimental genetics work to assess sample handling errors and integrative model development as a basis for sensitivity and cost-benefit analyses of the various assessment strategies. Genotyping errors related to the sample collection process will be assessed by repeatedly collecting and genotyping tissue samples from individuals subjected to a series of degradative processes designed to mimic potential operational sample collection protocols. These error estimates will form part of the basis for sensitivity analyses of a statistical model of the parentage-based abundance assessment process applied to the Western ABFT stock. In addition to uncertainty due to sample handling errors, the model will integrate uncertainty due to stock separation (e.g., via otolith micro-chemistry), sweepstake spawning, reproductive capacity as a function of size and other fishery-derived parameters required for parentage-based abundance estimation. Given this model sensitivity analysis, we will be able to estimate the amount of sampling effort required for each of the potential sampling protocols (e.g., source fisheries) and types of genetic markers to achieve a target level of certainty in the stock size estimate, and thereby do a cost-benefit analysis for potential assessment strategies. This project most strongly addresses Priority 6. Developing novel fishery-independent techniques to estimate abundance of the BTRP call for proposals, though it also has relevance for Priorities 4, 2 and 1. PI: Dr. David M. Kaplan (NA16NMF4720099) | $62,408 |
| The Ocean Foundation | Title: Electronic Tagging of Atlantic Bluefin Tuna that Spawn in the Gulf of Mexico - Synopsis: Electronic tagging of Atlantic bluefin tuna has emerged as a powerful tool to reduce uncertainty in scientific knowledge about their population structure and seasonal distributions. Data obtained from electronic tags have the potential to improve modeling of key parameters of life history traits related to maturation, fisheries, and natural mortality as well as movement probabilities valuable for evaluating mixing between stocks. Population models rely on biological assumptions, and reducing the uncertainty in these assumptions with electronic tag data is vital to improving stock assessment models. Despite the rapid advances in knowledge on Atlantic bluefin tuna, key questions remain about the level of population mixing, recruitment dynamics, and the number of independent populations. Furthermore, spatial movements and mixing vary with ontogeny of each bluefin tuna population. We propose to use electronic tagging techniques to study the western bluefin tuna population that spawns in the Gulf of Mexico (GOM). This mature group of fish may represent the most threatened population of bluefin tuna in our oceans, and new information is required to ensure maximal protection of the remaining spawning biomass. Our proposal specifically addresses priority area #5 (‘archival tagging to track individual movement in the eastern and western stocks), supports priority area #4 (‘modeling efforts to simulate the effects of stock mixing and efficacy of alternative management regimes’), and will contribute to priority area #6 (developing novel fisheries independent techniques for estimating mortality using advanced technology). Future management of the western fishery of Atlantic bluefin tuna depends upon knowing more about the unique biology of the Gulf of Mexico population. This GOM population gets to the largest body size, matures the latest for all Atlantic bluefin tuna populations, and spawns in the warm waters of the GOM. Retaining the genomic specializations of this genetically unique population for large size, and increased cardiac tolerances to warmer spawning temperatures, are vital in warming world. We propose to continue electronic tagging of adult bluefin tuna (fish of 15 to 30 years of age) assembled in the Gulf of St. Lawrence in Canada. Our objectives are to: a) deploy 25 satellite archival tags on Atlantic bluefin tuna in the GSL fishery, to obtain long-term data sets critical for modeling how mature fish, of western origin, utilize GOM spawning grounds and North Atlantic foraging grounds; b) deploy 30 five-year acoustic tags to incorporate long term mark recapture data into population models for estimates of natural and fisheries mortality; c) evaluate the habitat use of mature fish visiting the GOM in relationship to the new federal mandated closure areas and oceanographic variables, to better forecast specific locations they use in the GOM, and to provide predictive suitable spawning habitat forecasts that could eliminate bycatch mortality on pelagic longliners, d) we will develop a Bayesian mark-recapture model that uses acoustic detections in combination with data from the first year satellite tag data sets to estimate survival rates of GOM origin spawners, and e) provide access to tagging data sets by populating the NOAA IOOS Animal Telemetry Network data assembly center with the Atlantic bluefin electronic tagging data set. This will improve access to these unique data t y p e s for parametrizing movements in future ICCAT assessment models. PI: Dr. Barbara Block (NA16NMF4720100) | $128,724 |
| University of Massachusetts Darthmouth | Title: Comparative evaluation of stock assessment models for mixed Atlantic Bluefin tuna stocks - Synopsis: Eastern and western stocks of Atlantic bluefin tuna exhibit high fidelity to distinct spawning areas in the Mediterranean Sea and the Gulf of Mexico, respectively. However, distributions of these stocks overlap in the North Atlantic Ocean, leading to considerable mixed-stock composition that varies across space time and demographic groups. Current assessments by the International Commission for the Conservation of Atlantic Tunas (ICCAT) do not incorporate these spatial dynamics (ICCAT 2014). However, ICCAT plans to develop new modeling approaches in the next stock assessment of Atlantic Bluefin tuna to account for more complex stock structure (ICCAT 2013b) , and ICCAT has recommended “to test the effects of such a structure on the scientific advice” (ICCAT 2013a). We propose to evaluate the performance of a series of stock assessment models for Atlantic bluefin tuna that incorporate stock mixing, including the current virtual population analyses (VPAs) of eastern and western fisheries (ICCAT 2014) as a baseline for comparison. We will apply several scenarios of our previously developed 7-box, seasonal operating model to simulate pseudodata that reflect the typical quantity and quality of data available for Atlantic bluefin tuna stock assessments. Each estimation model will be applied to the pseudodata to evaluate performance of each approach for estimating the status of both stocks. The simulation framework can be generalized to facilitate the application of alternative models and compilation of model estimates so that any collaborating model developer can test their model in a way that is entirely consistent and comparable with others (e.g., Deroba et al. 2015). This proposal addresses Research Priority 4 of the Bluefin Tuna Research Program: “Simulation modeling to evaluate the performance of assessment models and management strategies in light of uncertainties related to stock mixing, reproductive potential and other life history traits” and has direct relevance to other priorities involving sampling for stock composition, tagging experiments, and data mining. PI: Dr. Steven X. Cadrin (NA16NMF4720101) | $123,352 |
2015
| Agency | Project | Federal Funding |
|---|---|---|
| Virginia Institute of Maine Science | Title: Improving the Atlantic Bluefin Tuna Assessments by Providing Better Information on Age Composition - Synopsis: The goal of this project is to improve the Bluefin tuna stock assessment by addressing Priority 3 of the request for proposals, specifically improving estimates of age composition of the catch and of historical recruitment. The current procedure, cohort slicing, defines length bins corresponding to age groups and counts the fish in each bin. This proposal seeks to improve the growth curve used to define the length bins, evaluate cohort slicing and alternative methods for estimating age composition, quantify biases induced in the estimates of age composition (especially of year-class strength), study propagation of aging errors through the entire stock assessment process, and examine the stock-recruitment relationship in light of these improvements. There are 8 objectives. 1) Determine the best growth curve for establishing the length bins for estimating age composition. The growth curve for western Atlantic Bluefin tuna was revised recently, but the large body of information available in the ICCAT tagging database was not considered. Recent work strongly suggests the tagging data should be evaluated and incorporated in the growth estimation scheme. 2) Determine the implications of using alternative growth curves for cohort slicing and thus for estimating spawning stock biomass benchmarks and recruitment time series. 3) Quantify the errors induced in the estimated age composition arising from the use of cohort slicing. Because the magnitude of the errors depends on variability in size at age, estimates of this quantity will be obtained. 4) Evaluate the propagation of errors induced by cohort slicing through the catch-at-age analysis. 5) Evaluate the implications of different definitions of the plus group when age composition is estimated by cohort slicing. Currently, the plus group consists of animals estimated to be age 16 or older. The effects of using different definitions of the plus group will be investigated with respect to minimizing error, being able to estimate spawning biomass from the results, and determining the implications of changing selectivity in the plus group. 6) Evaluate whether the cohort slicing might be modified to reduce bias by adjusting the bounds of the bins according to information on variability in size at age. 7) Investigate two alternatives to cohort slicing: the Kimura and Chikuni (1987) and Hoenig et al. (2002) methods. 8) Extend the catch at age information and reconstructed cohort histories back to before 1970 using a variety of techniques and data sources to be discussed below; this will allow for a reconsideration of the stock-recruit relationship. The tagging data will be subjected to strict quality control measures and subsetting criteria, and then used to fit a growth curve. After the fit is evaluated, a new growth relationship will be estimated from all sources of data using maximum likelihood. Monte Carlo simulation will be used to evaluate methods for estimating age composition under conditions matching the biology of Bluefin tuna; propagation of errors through the stock assessment procedure will then be noted. Sensitivity analysis will be used to determine how changes in methodology affect the assessment results. We will work closely with NMFS and ICCAT scientists and participate in ICCAT meetings so that any issues that arise from the work can be resolved quickly. PI: Dr. John Hoenig (NA15NMF4720106) | $88,413 |
| Texas A&M University Galveston | Title: Development and Application of Mixed-Stock Models for Determining the Origin of Bluefin Tuna Using Natural Geochemical Tags - Synopsis: Recovery of Atlantic bluefin tuna (Thunnus thynnus) populations is confounded by our lack of knowledge regarding trans-Atlantic movement and mixing of individuals from eastern and western stocks. Recent research using natural geochemical tags has demonstrated that emigration of bluefin tuna from both eastern and western spawning areas is well developed, with individuals from each region commonly “crossing the line” (45oW management boundary) in the Central North Atlantic Ocean and mixing with the other population. Moreover, migrants from the smaller western population commonly enter regions of the eastern management zone with intense fishing pressure, albeit straying into the eastern spawning area (Mediterranean Sea) appears to be negligible. Geochemical tags show considerable promise for the understanding of the nature and magnitude of connectivity between eastern and western stocks; however, uncertainty remains regarding the actual proportion of expatriates on either side of the management boundary. While this is due in part the quality of the baseline (reference) sample, estimates appear to vary considerably depending upon the mixed-stock approach being used. Given that yields and rebuilding plans are highly sensitive to the movement and mixing of eastern and western stocks, predictions from commonly used mixed stock estimators (i.e., maximum likelihood) are increasingly questioned. In response, a detailed evaluation of mixed-stock procedures used with geochemical data is needed to confirm currently accepted values and fine-tune the mixed-stock framework for future investigations. Here, we propose to apply and compare several methods for classification and mixed-stock analysis, including maximum likelihood and Bayesian methods within the framework of a multinomial logistic regression (MLR). In addition, we will use the most desirable method(s) to re-examine the origin of bluefin tuna in three critical mixing zones in the Central North Atlantic Ocean (CNAO) and Northeast Atlantic Ocean (NEAO) using both recently published data (Rooker et al. 2014) and new data collected in part under the Atlantic Wide Research Program by the European Consortium. The proposed study addresses 2 of the 6 “Research Priorities” on the Funding Opportunity Description (Number: NOAA-NMFS-SE-2015-2004138), including “micro- constituent” analyses in order to characterize the stock composition of catches (Pt.1), and modeling studies to better understand the degree and effects of stock mixing (Pt. 4). Data from the project will also address specific research recommendations from NOAA’s PI: Dr. Jay Rooker (NA15NMF4720107) | $116,909 |
| Gulf of Maine Research Institute | Title: Operational Use of Otolith Chemistry to Inform Stock Assessment and Forward Projection of Atlantic Bluefin Tuna Populations - Synopsis: Characterizing stock composition and the effects of stock mixing is a key priority for improving assessment and management of Atlantic bluefin tuna. The aim of our research is to demonstrate the operational use of otolith chemistry techniques to characterize the stock composition of bluefin tuna caught in the Gulf of Maine and integrate this information into the stock assessment and management process. A bluefin tuna sampling program in the Gulf of Maine has accumulated over 1,700 sets of sagittal otoliths from juvenile and adult bluefin tuna. Identifying the stock composition of landings from the Gulf of Maine is of primary importance since approximately 70% of the entire U.S. western Atlantic total allowable catch is removed from this region annually. Prior research has established otolith chemistry as an effective and reliable stock identification tool and we will apply this approach to determine the population of origin of bluefin tuna collected in the Gulf of Maine. This stock composition information will be used to parse data inputs to stock assessment (catch, CPUE, age composition), which will be incorporated into revised stock assessments and inform stock projections that account for stock mixing. This proposal addresses Research Priority 1: Sampling of tissues and otoliths for studies of population genetics, age, growth, fecundity, and micro-constituent or other analysis in order to characterize the stock compositions of catches and Research Priority 4: Modeling to simulate the effects of stock mixing and efficacy of alternative management regimes. PI: Dr. Lisa Kerr (NA15NMF4720108) | $154,268 |
| University of Maine acting through the University of Maine | Title: Biological Sampling to Determine Age, Growth and Sex of Atlantic Bluefin Tuna in the NW Atlantic - Synopsis: The need to conduct routine biological sampling to determine age, growth, reproductive status, stock structure and absolute population abundance for sound, basic fisheries information on tunas, determined to be “of critical importance to stock assessment and management” is prominently noted in the KOBE2 document (June, 2010), the Atlantic Highly Migratory Research Plan (2011) and the Atlantic Bluefin Tuna Status Review Team (2011). The University of Maine, along with its collaborators, the Large Pelagics Research Center (LPRC) and the Gulf of Maine Research Institute (GMRI) has established a long-term capacity to conduct integrated fisheries research on Atlantic bluefin tuna (ABFT). This proposal addresses Research Priority Number One: Sampling of tissues and otoliths for studies of population genetics, age, growth, fecundity, and micro-constituent or other analysis in order to characterize the stock compositions of catches. Updated age and growth information has been identified as one of three major priorities for reducing uncertainties in stock assessment models for the western ABFT stock. Utilizing an extensive network of dealers, commercial and recreational fishermen from Maine to New Jersey, and via direct sampling, the PIs will collect hard and soft tissues across size classes from 71-300+ cm in length for age, growth, reproductive status, stock structure and potential population abundance studies (genetics). PI: Dr. Walter Golet (NA15NMF4720109) | $181,642 |
| University of Miami, RSMAS | Title: Measuring larval bluefin tuna growth to improve a fishery-independent index, and help resolve uncertainty with the stock-recruitment relationship - Synopsis: Atlantic bluefin tuna are distributed throughout the North Atlantic and are exploited with a variety of fishing gears throughout their range. Despite various management efforts, stocks have declined precipitously in the last 30 years. Most indices developed for stock assessment of bluefin tuna are fishery-dependent, but the Southeast Fisheries Science Center developed a fishery-independent index for the western bluefin stock from ichthyoplankton surveys carried out in the northern Gulf of Mexico (GOM) since the early 1980s (Scott et al., 1993, Ingram et al. 2010). This index is used to corroborate trends in estimates of stock size, and to tune the modeled population analysis. The larval index relies on estimates of age at length developed by Brothers et al., (1983) from specimens collected off South Florida. This estimate was used because survey catches were too small to support annual estimates of mortality, and it has been applied to all larval index mortality estimates since. Recent advances in sampling methods have increased larval catches, which will allow the development of annual growth estimates. We propose to address current knowledge gaps by focusing on environmental drivers of growth and mortality of larval bluefin tuna in the GOM. This project will address research priority 1 of the Bluefin Tuna Research Program by sampling otoliths for studies of age and growth, and will contribute to priority 6 by improving an existing fishery-independent index of abundance (the larval index). In addition, the July 2014 NMFS Atlantic HMS Management-Based Research Needs And Priorities report (NMFS, 2014) lists determination of the western Atlantic bluefin tuna stock-recruitment relationship as the highest priority for future research. The proposed project will directly address this issue, by quantifying the importance of environmental conditions to larval growth and survival, and thus the strength of the link between spawning biomass and recruitment. Despite 30 years of larval surveys in the GOM there is little understanding of fluctuations in recruitment, and little is known about early growth and survival. Recent work by Garcia et al. (2013) suggests anomalously warm conditions in Balearic Sea spawning areas increase growth rates in larval bluefin tuna and may correlate with stronger year classes. The oceanographic regime in the GOM is complex, and larvae may be exposed to a range of temperatures and oceanographic features throughout the first 14 days of life. It is not clear how these oceanographic process impact growth rates, and ultimate survival. This proposal will address this critical need. Growth rates will be examined from larvae collected across a wide variety of oceanographic features from both the eastern and western GOM, from multiple years. Understanding these drivers is essential for improving the larval index and developing a predictive recruitment model. In addition, results will inform and improve the larval index by adding regional and oceanographic feature-specific growth curves. The Principal Investigators will be Barbara Muhling and Estrella Malca. Dr. Muhling has been studying bluefin tuna spawning grounds in collaboration with NMFS since 2007. Estrella Malca has extensive expertise with studies of larval fish growth. The NOAA Collaborator will be Dr. Walter Ingram, who is responsible for developing the annual larval bluefin tuna index. PI: Dr. Barbara Muhling (NA15NMF4720110) | $118,760 |