Growth, Mortality, and Movement of Cobia (Rachycentron canadum)

Document Type

Article

Publication Date

1-1-2017

Department

Coastal Sciences, Gulf Coast Research Laboratory

School

Ocean Science and Engineering

Abstract

© 2017, National Marine Fisheries Service. All rights reserved. We describe the length-at-age relationship of cobia (>Rachycentron canadum) with the use of 3 nonlinear models, and examine both the movement patterns of cobia in the Gulf of Mexico and South Atlantic Ocean and the instantaneous total mortality rate (Z, per year) from tag-recovery models with data from the Sport Fish Tag and Release Program of the Universityof Southern Mississippi Gulf Coast Research Laboratory. The estimated mean asymptotic length (L∞) in this study (1172 mm in fork length [95% confidence interval (CI): 1151–1192]) was in the range of values reported for this species in the Gulf of Mexico and Atlantic Ocean, and the annual growth coefficient (k: 0.57 [95% CI: 0.52–0.61]) was greater than that reported for cobia elsewhere. Movements were reported between the 7Gulf of Mexico and the South Atantic Ocean and a statistically significant seasonal trend in recaptures was observed, both of which suggest that cobia inhabit the Florida Keys during the winter and the north central Gulf of Mexico during the summer. The most supported tag-recovery model included time-invariant survivorship and time-dependent recovery probability and the estimated Z was 0.59/year (95% CI: 0.55–0.63). This study provides a summary of a long-term cobia tagging program and information for future management of this species. We describe the lengthat-age relationship of cobia (Rachycentron canadum) with the use of 3 nonlinear models, and examine both the movement patterns of cobia in the Gulf of Mexico and South Atlantic Ocean and the instantaneous total mortality rate (Z, per year) from tag-recovery models with data from the Sport Fish Tag and Release Program of the University of Southern Mississippi Gulf Coast Research Laboratory. The estimated mean asymptotic length (L∞) in this study (1172 mm in fork length [95% confidence interval (CI): 1151-1192]) was in the range of values reported for this species in the Gulf of Mexico and Atlantic Ocean, and the annual growth coefficient (k: 0.57 [95% CI: 0.52-0.61]) was greater than that reported for cobia elsewhere. Movements were reported between the Gulf of Mexico and the South Atlantic Ocean and a statistically significant seasonal trend in recaptures was observed, both of which suggest that cobia inhabit the Florida Keys during the winter and the northcentral Gulf of Mexico during the summer. The most supported tag-recovery model included time-invariant survivorship and time-dependent recovery probability and the estimated Z was 0.59/year (95% CI: 0.55-0.63). This study provides a summary of a long-term cobia tagging program and information for future management of this species.

Publication Title

Fishery Bulletin

Volume

115

Issue

4

First Page

460

Last Page

472

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