April 25, 2008, Santander, Spain

Workshop on the reproduction biology of Atlantic bluefin tuna in the West Atlantic

workshop participants: Molly Lutcavage, Jessie Knapp, Gilad Heinisch, Chris Bridges, Gregorio De Metrio, Michele Delflorio, David Macias, Jean Marc Fromentin, Victor Restrepo, Guillermo Aranda, Lourdes Aragon, Antonio Medina, Francisco J. Abascal, Hillel Gordin, Victoria Ortiz de Zorate, Ziro Suzuki , Enrique Rodríguez-Marín

On April 25, the Large Pelagics Research Center (LPRC) hosted a scientific workshop on the reproduction biology of Atlantic bluefin tuna (ABFT) in the West Atlantic. The workshop was co-chaired by Dr. Molly Lutcavage, LPRC, UNH, and Dr. Hillel Gordin, Israel Oceanographic & Limnological Research, National Center for Mariculture (IOLR-NCM), Israel.

Research on ABFT reproduction physiology in the western Atlantic has lagged since the work published by Raymond Baglin in 1982, and has fallen behind the research achievements on the eastern spawning stock in the Mediterranean Sea . In the last ten years, advances in the field of endocrinology and reproductive physiology offer new research opportunities, and could significantly broaden our understanding of this unique, long-lived species.

The workshop brought together tuna experts specializing in the fields of stock assessment and migration, physiology of reproduction, age and growth, aquaculture, sampling and tagging. The scientists came from different countries around the world: USA, Spain, France, Italy, Japan, and Israel.

The two main issues addressed in the workshop were sexual maturation and spawning grounds of ABFT in the West Atlantic. The current assumptions are that western Atlantic bluefin tuna mature only when reaching the age of 10-12 years old, and spawn only in the Gulf of Mexico and Florida Straits. This scenario is quite different than reproductive patterns of the eastern stock, on which comprehensive research has been accomplished. ABFT of the eastern stock mature at 3-5 years old and show a spawning behavior that varies with space and time across the Mediterranean Sea . In addition, the assembled bluefin experts discussed the possible existence of a discrete/semi-discrete population in the eastern Mediterranean , which is currently under investigation.

The general agreement in the workshop was that the differences might represent a sampling bias, and not a physiological discrepancy in ABFT life history. Participants identified specific scientific goals concerning sample collection and physiological analyses during the workshop. These goals will serve as benchmarks for the physiological research to be conducted in the LPRC during the coming year.

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workshop participants, from left to right A. Rosenberg (UNH), T. Miller (UNH), R. Brill (VIMS), H. Arrizabalaga (AZTI Tecnalia, Spain), J. Powers (NOAA-NMFS, LSU), D. Butterworth (UCT, S. Africa), M. Lutcavage (UNH ), J. Sibert (U Hawai'i, PFRP), A. Cooper (UNH), S. Martell (UBC, Canada), F. Royer (UNH)

April 17-19, 2006, University of New Hampshire

Workshop on Initial Specifications for Atlantic Bluefin Tuna Operating and Management Procedure Models

The Standing Committee on Research and Statistics (SCRS) of the International Commission for the Conservation of Atlantic Tunas (ICCAT) has proposed a research plan (Report of the 2005 ICCAT Planning Meeting For Bluefin Tuna Research Madrid, Spain, June 27-30, 2005, SCI-030 / 2005) for the integration of accumulated knowledge on movement of Atlantic bluefin tuna into assessment models and an evaluation of the effectiveness of alternative spatial boundaries and management strategies. The research plan also proposed a schedule for development of the required operating model(s) and management procedures.

In order to facilitate the development of these models, a workshop was hosted at the University of New Hampshire April 17-19, 2006 by the Large Pelagics Research Center. At this workshop we 1) suggested alternative structures for mixing models, 2) developed broad ideas of how model parameters describing movement can be estimated from available data, 3) agreed on data (such as catch, effort, CPUE) that we may use, 4) clarified what resource monitoring data can confidently be assumed to be regularly available in the future and 5) clarified the nature of management decision rules that we will investigate (catch limits, area closures, etc.).

A detailed report of the results of the workshop discussions and activities was provided to the Atlantic bluefin tuna Working Group at the stock assessment meeting in June of 2006 and to the SCRS as a whole in the fall of 2006 for further discussion and suggestions for modification. A report of the finding was published in the document SCRS/2006/013.

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March 21-22, 2005, University of New Hampshire

Workshop on Juvenile Atlantic Bluefin Tuna: New Approaches for Assessment

workshop participants: John Annala (GMRI), Jean-Marc Fromentin (IFREMER), Haritz Arrizabalaga (AZTI), Steven Martell (UBC), Rich Brill (VIMS), Jon Lucy (VIMS), Joseph Powers (Louisiana State University), Greg Skomal (Mass. Div. of Marine Fisheries), Andy Cooper (UNH), Molly Lutcavage (UNH), Andy Rosenberg (UNH), Nancy Thompson (NOAA), Gerry Scott (NOAA), Michael Genovese and George Purmont, Solange Brault (UMASS), and Jennifer Goldstein (UMASS)

The Large Pelagics Research Center hosted a workshop on the assessment of juvenile bluefin tuna stocks and migration patterns, a noted gap in the current data, with several experts from the US, Canada, and Europe. The group was comprised of physiologists, stock assessment and movement modelers and reproductive biologists. The workshop began with a background on juvenile bluefin, including biological information, movements, physiological ecology, current indices of abundance, and current assessment approaches. Existing data was assessed, as well as the gaps in data for these fish.

After determining all of the obejctives, various forms of assessment were discussed. Of particular interest were aerial surveys, (which were successful in the past) and tagging programs.The group weighed the pros and cons of satellite tags, pit tags, even DNA tags, as well as modeling-based approaches, sonar and acoustic surveys, and stable isotope work (and combinations of all!).

After deliberation, it was the final recommendation of the workshop committe for there to be a pilot program over the summer of 2005 up and down the eastern seaboard to determine where the fish go during this critical time in their development, and when. Archival tags, which determine location, depth, sea surface temperature store information until a fish is (hopefully) recaptured are implanted into juvenile bluefin. This program became known to the Large Pelagics Research Lab as the Tag-a-Tiny program. It has been a successful program of the lab for the past two years. We hope to continue this program in the future.

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