Ontogeny of swimming ability in the European Sea Bass, Dicentrarchus labrax (L.) (Teleostei: Moronidae)

Abstract

Development of critical speed (U_crit) of reared young Sea Bass [6–63 days after hatch (DAH), 4–30 mm body length (BL)] at 18.5–21°C was measured using a swimming chamber. Critical speed increased from a mean of 2 cm s⁻¹ at 6 DAH to 41 cm s⁻¹ at 63 DAH at a rate of 0.6±0.03 cm s⁻¹ day⁻¹. When based on size (BL), U_crit increased at a rate of 2.0±0.1 cm s⁻¹ mm⁻¹. Relative speed increased from 4.7 BL s⁻¹ at 6 DAH to 13.1 BL s⁻¹ at 33 DAH, and was thereafter 13.5–15.7 BL s⁻¹. Sea Bass larger than about 11 mm (when the caudal fin forms) swam at Reynolds numbers > 1000, and were thus swimming in an inertial hydrodynamic environment. Sea Bass young swim fast enough from about 15 mm (approx. 27 DAH) to influence dispersal outcomes.

Keywords:

• Behaviour
• larva
• juvenile
• critical speed
• dispersal
• connectivity

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

This research was carried out while JML was Visiting Professor at EPHE, Université de Perpignan, and was supported by a grant to JML from the Australian Academy of Science. Alicia Estevez and Philippe Lenfant were very helpful in arranging logistics. The authors especially thank Suzanne Bullock for invaluable assistance in all phases of the research, and the staff at Les Poissons du Soleil for help in many aspects. This research was carried out under permits issued by CNRS to the USR 3278 CNRS/EPHE team to conduct research experiments in field and laboratory at all locations (under chapter Hygiène et Sécurité).

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark