DO SOME ATLANTIC BLUEFIN TUNA SKIP SPAWNING?

During the spawning season for Atlantic bluefin tuna, some adults occur outside known spawning centers, suggesting either unknown spawning regions, or fundamental errors in our current understanding of bluefin tuna reproductive schedules. Based upon recent scientific perspectives, skipped spawning (delayed maturation and non-annual spawning) is possibly prevalent in moderately long-lived marine species like bluefin tuna. In principle, skipped spawning represents a trade-off between current and future reproduction. By foregoing reproduction, an individual can incur survival and growth benefits that accrue in deferred reproduction. Across a range of species, skipped reproduction was positively correlated with longevity, but for non-sturgeon species, adults spawned at intervals at least once every two years. A range of types of skipped spawning (constant, younger, older, event skipping; and delays in first maturation) was modeled for the western Atlantic bluefin tuna population to test for their effects on the egg-production-per-recruit biological reference point (stipulated at 20% and 40%). With the exception of extreme delays in maturation, skipped spawning had relatively small effect in depressing fishing mortality (F) threshold values. This was particularly true in comparison to scenarios of a juvenile fishery (ages 4-7), which substantially depresse