title: How does salinity influence habitat selection and growth in juvenile American eels Anguilla rostrata?
abstract: The influence of salinity on habitat selection and growth in juvenile American eels Anguilla rostrata captured in four rivers across eastern Canada was assessed in controlled experiments in 2011 and 2012. Glass eels were first categorized according to their salinity preferences towards fresh (FW), salt (SW) or brackish water (BW) and the growth rate of each group of elvers was subsequently monitored in controlled FW and BW environments for 7 months. Most glass eels (78-89%) did not make a choice, i.e. they remained in BW. Salinity preferences were not influenced by body condition, although a possible role of pigmentation could not be ruled out. Glass eels that did make a choice displayed a similar preference for FW (60-75%) regardless of their geographic origin but glass eels from the St Lawrence Estuary displayed a significantly higher locomotor activity than those from other regions. Neither the salinity preferences showed by glass eels in the first experiment nor the rearing salinities appeared to have much influence on growth during the experiments. Elvers from Nova Scotia, however, reached a significantly higher mass than those from the St Lawrence Estuary thus supporting the hypothesis of genetically (or epigenetically) based differences for growth between A. rostrata from different origins. These results provide important ecological knowledge for the sustained exploitation and conservation of this threatened species.
authors.affiliation: Université du Québec à Rimouski, 310 Allée des Ursulines, Rimouski, QC, G5L 3A1, Canada.
authors.forename: B
authors.initials: B
authors.lastname: Boivin
authors.affiliation: Institut Maurice-Lamontagne, Pêches et Océans Canada, 850 Route de la Mer, Mont-Joli, QC, G5H 3Z4, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Castonguay
authors.affiliation: Université du Québec à Rimouski, 310 Allée des Ursulines, Rimouski, QC, G5L 3A1, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Audet
authors.affiliation: Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, QC, G1V 0A6, Canada.
authors.forename: S A
authors.initials: SA
authors.lastname: Pavey
authors.affiliation: Ministère des Forêts, de la Faune et des Parcs, 880 chemin Sainte-Foy, Québec, QC, G1S 4X4, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Dionne
authors.affiliation: Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, QC, G1V 0A6, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Bernatchez
keywords: St. Lawrence salinity preferences; geographic differences; glass eels; locomotor activity; pigmentation