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Social-Ecological Systems Meta-Analysis Database: Component

SummaryEastern Atlantic Bluefin Tuna are a subpopulation of Atlantic Bluefin Tuna that spawn in the Mediterranean
SubtypeNatural Resource Unit
SectorFisheries (Stock-specific)
Commons AggregationPopulation
ExplanationEastern Atlantic Bluefin Tuna are a meta population or stock of Atlantic Bluefin Tuna that spawn in the East Atlantic and Mediterranean. It is generally accepted that they do not interbreed with the Western stock.
Commons BoundariesVery unclear boundaries (1)
ExplanationAlthough the Eastern Atlantic Bluefin Tuna is most commonly found on the Eastern side of the Atlantic Ocean and Mediterranean Sea, they also migrate across the 45th parallel which marks the official boundary between Eastern and Western stocks. The extent of this migration is generally unknown.
Commons Unit SizeMedium (3)
ExplanationEastern Atlantic Bluefin can weigh up to 900 kg, although mature adults typically weigh 250kg with a length of approximately 2.5m.
Environmental MediumOceanic
ExplanationLocated throughout much of the Atlantic Ocean and Mediterranean Sea.
Inter Annual PredictabilityModerate (2)
ExplanationStocks of Eastern Atlantic Bluefin Tuna are moderately predictable, but scientific assessments are highly contested and it is generally acknowledged that there are important uncertainties regarding the size of stocks, and the methodologies used to estimate spawning stock biomass. However, given the use of consistent methodologies the relative magnitude of stocks can be ascertained.
Intra Annual PredictabilityHigh (3)
ExplanationVery little variation in resource numbers within a given year.
Commons RenewabilityRenewable (1)
ProductivityModerately Productive (2)
ExplanationEastern Atlantic Bluefin Tuna support a fairly large-scale fishery. However, the rate of regeneration is insufficient to cope with modern extraction technologies that have started to lead to declines in resource stocks.
Commons AccessibilityVery accessible (3)
ExplanationAlthough Eastern ABFT are located throughout much of the Atlantic Ocean, they are easily accessible to the ocean-going fleets that target them.
Commons HeterogeneityHigh (3)
ExplanationDuring the spawning season, sexually mature adults congregate in the Mediterranean Sea. There is some debate whether individual adults spawn annually over every 2-3 years. During the rest of the year, however, tuna are distributed widely over feeding grounds.
Commons MobilityHigh (3)
ExplanationEastern Atlantic Bluefin Tuna migrate extensively throughout the Eastern-Mid Atlantic and Mediterranean Sea and can travel at speed up to 60 km/h.
Commons Spatial Extent108000000
ExplanationApproximate size of Atlantic Ocean and Mediterranean Sea. Although the Eastern Stock is more concentrated in the Mediterranean and Eastern Atlantic Ocean, Trans-Atlantic migration is known to occur at least in small numbers
Technical SubstituteNo