Summary

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.407.9886; http://www.cites.org/eng/cop/15/prop/E-15-Prop-19.pdf

1. The Atlantic bluefin tuna is found in throughout the North Atlantic Ocean and its adjacent seas, particularly the Mediterranean Sea. It usually occupies the surface and subsurface waters of coastal and open-sea areas, between the surface and 200m in depth. 2. The species is managed by the International Commission for the Conservation of Atlantic Tunas (ICCAT) as two stocks (eastern and western), based on separate spawning grounds, genetic differentiation, differing ages for reaching sexual maturity, and the apparent absence of spawning in the middle of the North Atlantic. However, the migratory ranges of both stocks overlap considerably. 3. Maturity is reached at a mean age of 4-6 years of age in the East Atlantic and Mediterranean, and at 8-12 years of age in the West Atlantic. Spawning commences in March in the Gulf of Mexico. In the Mediterranean, it occurs during May-June in the east, and in June-July in the centre and west. 4. A recent genetic study by Riccioni et al. (2009) shows strong spatial genetic structuring in the Mediterranean, suggesting the existence of various reproductively isolated subpopulations. These subpopulations would be characterized by a low genetically effective population size (Ne = 400-700), with associated risk in terms of maintaining genetic diversity and evolutionary potential in the long-term. 5. A virtual population analysis of the East Atlantic and the Mediterranean stock conducted in 2008 by ICCAT