International eel symposium, 2003 - Quebec August 11, 2003
Oral Presentation

American Eel Anguilla rostrata Movements, Growth and Sex Ratio Following Glass Eel Introduction

Verreault, G.* Société de la faune et des parcs du Québec, Direction de l'aménagement de la faune du Bas-Saint-Laurent, 506 rue Lafontaine, Rivière-du-Loup, QC,Canada G5R 3C4, guy.verreault@fapaq.gouv.qc.ca
Dargere, W. Université de Tours, Centre Universitaire de Chinon, 11 Quai Danton, 37500 Chinon, France
Tardif, R. Société de la faune et des parcs du Québec, Direction de l'aménagement de la faune du Bas-Saint-Laurent, 506 rue Lafontaine, Rivière-du-Loup, QC,Canada G5R 3C4

Presenter email address: guy.verreault AT fapaq.gouv.qc.ca

Abstract Text: Introduction is not a common practice for American eel Anguilla rostrata. The species decline in the St. Lawrence-Lake Ontario system urges for the need of new management tools to tentatively reverse this downward trend. Among them, introduction arises as an interesting alternative for managers and fishermen. To evaluate the impact of this management, 40 000 glass eels were marked with tetracycline and introduced in an unexploited 400-ha freshwater lake located in an eel-free watershed. Tetracycline mark on the otolith enable us to perform precise age determination and annual sampling were conducted to evaluate movements within the catchment area, growth and sex-ratio. Four years afterwards, eels were well established in the lake and rivers at short distance from introduction site (< 5 km). Mean annual growth differs among eels from different habitat. Eels sampled in lacustrine habitat showed rapid growth with a mean increment of 84.8 mm/year, 2.5 time more than those in rivers (34.7 mm/year). Sex determination was performed on specimens >200mm and males occurrence was 33%, which is different from all nearby watershed where no males are found. The dynamics and potential impacts of introduction are discussed in a management perspective for the northern part of the distribution range.