Publication Detail

Movements and oceanographic associations of bigeye tuna (Thunnus obesus) in the Northwest Atlantic

Chi H Lam, Benjamin Galuardi, Molly E Lutcavage
14 pp.
MITSG 14-31

To address the lack of fisheries-independent information for Atlantic bigeye tuna (Thunnus obesus), we released 21 adults (131 ± 12 cm curved fork length) between 2008 and 2010 in the Sargasso Sea and Northwest Atlantic. Data from nine tags (range: 1–292 days; mean: 89 days) revealed (i) pronounced north–south movements in pelagic waters between areas including Georges Bank, Mid- and South Atlantic Bight, Caribbean Sea, and Brazilian shelf, (ii) a lack of east–west exchange, and (iii) a high-use area in the Hatteras Plain, centered southwest of Bermuda. Bigeye tuna occupied water masses of 2.7–28.2 °C and depths of 0–1280 m, with deeper depths in the daytime (daily mean ± standard deviation: 196 ± 92 m) than at nighttime (45 ± 29 m). Even though bigeye tuna are assumed to forage on the deep scattered layer during the day, generalized additive mixed models did not identify the deep scattered layer as an important predictor of daytime swimming depth. Model results highlight the importance of geographic location in influencing habitat utilization, and thus suggest the need for fisheries-independent monitoring in high-catch areas, such as the central and equatorial Atlantic.

type: Journal, book, proceeding reprints

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Parent Project

Project No.: 2011-E/E-66-NSI
Title: Benjamin Galuardi - MIT Sea Grant - NMFS Population Dynamics Fellowship: Integrating electronic tag information into stock assessment of large pelagic animals