areas, additional studies of age and size at spawning should be carried out. In particular, the committee suggests that all fish caught as by-catch in the Gulf of Mexico be sampled: the gonads should be taken for histological analysis, and body length should be measured to estimate age. It is more important to sample males than females because females have a higher rate of resorption than males, making their data a less reliable indicator of recent spawning history.

Bluefin tuna larvae grow rapidly (about 1 mm per day), and larval abundance in spawning locations ranges from 0.1 to 1.0 per square meter (Clay, 1990). Little information exists regarding food requirements, food availability, and potential predators of larvae, and it is not known whether larval growth is limited by food availability. There is little information about the movements of bluefin tuna larvae.

Numerous reports and papers on bluefin tuna describe the species as highly migratory. Figure 2-1 shows the distribution of bluefin tuna in the Atlantic

Front Matter (R1-R18)

Summary (1-4)

1 Background (5-8)

2 Historical Evidence for Stock Structure (9-38)

3 Transatlantic Movement of Atlantic Bluefin Tuna (39-78)

4 Fish Stock Assessment (79-108)

5 Conclusions and Recommendations (109-112)

References (113-118)

Appendix A: Biographical Sketches of Committee Members (119-122)

Appendix B: Bibliography (123-126)

Appendix C: Genetic Variation in Other Tunas and Related Fish (127-134)

Appendix D: Archival Tag Technology (135-138)

Appendix E: Evidence for Mixing Based on Parasites (139-146)

Appendix F: Microconstituent Analysis (147-148)