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An Assessment of Atlantic Bluefin Tuna
these research recommendations. The following recommendations are not listed in order of importance or priority.
Tagging data show that there is movement of bluefin tuna between the eastern and western Atlantic fishing grounds, but the degree of gene flow between spawning areas is not known. Such knowledge is essential in defining population genetic structure and useful for refining stock assessments. The committee recommends that the one-stock hypothesis be tested rigorously, using the most appropriate technologies capable of detecting contemporary population genetic structure.
Estimates of spawning fidelity to a particular area are essential for stock assessments. The committee recommends that microconstituent analysis and archival tags be used to provide information on spawning fidelity.
Stock assessments can be refined by better estimates of life history characteristics such as spawning biomass, larval abundance, sex ratio, age at maturity, fecundity, and recruitment. The committee recommends that spawning biomass, sex ratio, age at maturity, and fecundity in the spawning grounds be estimated and that larval performance, as affected by environmental conditions, be studied.
The committee recognizes that knowledge of movement patterns is essential for estimating abundance and distribution and that movement rates and patterns may change over time. The committee recommends that a tagging program be undertaken, with an appropriate combination of conventional, PIT, acoustic, and archival tags to provide improved estimates of the magnitude and patterns of movement. This program should be designed to answer scientific questions pertinent to stock assessment and should be coordinated among all nations involved in the bluefin tuna fishery.
Estimates of abundance are confounded by the interaction between fishing and changes in distribution caused by interdecadal climatic and oceanic variability. The committee recommends a synthesizing analysis of existing data on distributions of bluefin tuna in relation to spatial and temporal dynamics of major oceanographic features.
The committee notes that a greater use of peer review would have improved the quality of some of the research reviewed during the preparation of this report. The committee recommends that review of all research proposals and resulting manuscripts include a process of external peer review.
The committee believes that the analyses and results in this report present a challenge to government and to conservation and industrial organizations for the conservation and management of bluefin tuna in the Atlantic Ocean. Responding to this challenge will require a new view, better science, and a commitment to international cooperation. The committee hopes that this report will serve as a catalyst for obtaining better scientific information to improve the status of Atlantic bluefin tuna.