Performances of individual Sea Bass (Dicentrarchus labrax):
Can they be used to predict success in the field?

The focus of this work is to discover physiological characteristics that are predictive of sea bass success in the wild. The method is to establish links between individual variance in several different types of locomotor performance, hypoxia tolerance, ability to increase oxygen consumption in support of exercise (metabolic scope) and survival/growth in a mesocosm setting. Scientists often measure locomotor capacities as an indicator of animal health or fitness, yet, the relationships between locomotor capacity, natural selection, and physiology are poorly known for fishes. Likewise, individual sea bass show massive variance in tolerance to hypoxia, yet there is little information on what factors account for individual variance to hypoxia. Most of this work has taken place in the various labs of Dr. Guy Claireaux. Here you see his lab at the Centre de Recherche en Écologie Marine et Aquaculture (CREMA), in L'Houmeau, France, site of the 2001-2006 experiments. The lab is carved out of an abandoned abbey; the fish holding room is the old chapel.

 

 CNRS-IFREMER Centre de Recherche en Écologie Marine et Aquaculture (CREMA) lab at L'Houmeau, France

I've also done some work at the Institut des Sciences de l'Evolution de Montpellier, Université de Montpellier 2, Station Méditerranéenne de l'Environnement Littoral, Sète, France in 2007. Here you see colleagues Stefano Marras and Guy Claireaux in front of our beautiful lab on the shores of the E'tang de Thau.

There are many reasons that we know little about the ecological relevance of locomotor performance in fishes. Not the least among these are the technical challenges faced when measuring locomotor capacities in aquatic species and problems associated with recapturing marked fish. Along with various key colleagues throughout the years (Dale Webber, Shannon Reidy and Jeff Klupt have been key) I've developed a unique computer driven, laser light/ photocell beam timing technique that redresses some of the problems associated with measuring burst locomotion in large number of fishes. This apparatus has already been used to reproducibly measure sprint velocity of fishes in several different studies. See:

    Nelson, J.A. and G. Claireaux. 2005. Inter-individual variance of sprint swimming performance, swimming metabolism and endurance in a cohort of European sea bass (Dicentrarchus labrax). Transactions of the American Fisheries Society. 134:1274-1284.

    Claireaux, G. C. Handelsman, E. Standen and J. A. Nelson.  2007. Thermal and temporal stability of swimming performances in the European sea bass. Physiological and Biochemical Zoology. 80(2):186-196.

    Handelsman, C. A. ,  J. A. Nelson and G. Claireaux. 2010. Sprint capacity and ecological performance of cultured and wild European sea bass in coastal tidal ponds. Physiological and Biochemical Zoology. 83(3): 435-445.

    Marras,S., G. Claireaux, D. J. McKenzie and J.A. Nelson. 2010. Individual variation and repeatability in aerobic and anaerobic swimming performance of European sea bass, Dicentrarchus labrax. Journal of Experimental Biology. 213: 28-32.

for examples of this sprint chamber in action.

 

Fish being chased in the sprint chamber at

(CREMA) lab at L'Houmeau, France

 

 

This international collaboration will hopefully lead to a more comprehensive understanding of how locomotor abilities and metabolic capacities of fish relate to success in the field.

Close up of a sea bass breaking the laser beams as it traverses the sprint chamber

 

This will allow the investigators to also establish the relationship between traditional measures of fast-start performance and other tests of locomotor performance. Endurance performance, metabolic rate and cardiovascular performance will also be assessed during swim tests in a swim tunnel respirometer. Altogether, these experiments will clarify the role of locomotor capacity in determining animal success in the field and help partition that success between anaerobic and aerobic capabilities. The results of this work will hopefully improve the use of physiological considerations in making management and aquaculture decisions concerning sea bass, an emerging food fish in Europe.

Finally, me spending endless hours in the basement of the CREMA lab sprinting seabass, anxiously awaiting that prochain verre du vignt rouge avec fromage Francais & grad student Corey Handelsmann, now working on his Ph.D. at Colorado State University, doing a side study on the proper geometry container out of which to drink Guinness.