Spawning Dynamics of American Shad (Alosa Sapidissima) in the St. Lawrence River, Canadausa
Ecology of Freshwater Fish 2010: 19: 586–594 Ó 2010 John Wiley & Sons A/S Printed in Malaysia Æ All rights reserved ECOLOGY OF FRESHWATER FISH Spawning dynamics of American shad (Alosa sapidissima) in the St. Lawrence River, Canada–USA Maltais E, Daigle G, Colbeck G, Dodson JJ. Spawning dynamics of E. Maltais1,*, G. Daigle2, American shad (Alosa sapidissima) in the St. Lawrence River, G. Colbeck1, J. J. Dodson1 Canada–USA. 1De´partement de Biologie, Universite´ Laval, Ecology of Freshwater Fish 2010: 19: 586–594. Ó 2010 John Wiley & Que´bec, QC, Canada, 2De´partement de Sons A ⁄ S Mathe´matique et de Statistique, Universite´ Laval, Que´bec, QC, Canada Abstract – The most northerly population of American shad (Alosa sapidissima), located in the St. Lawrence River, is considered vulnerable because of low population abundance and limited spawning habitat located at the upstream extent of the population’s anadromous migration. Here, we aimed to establish the temporal and spatial extent of spawning based on a novel hatch-date analysis of juveniles. Spawning activity Key words: alosine clupeid; hatch-date analysis; lasted from early May to early July. We found that juveniles captured multiple spawning events downstream during the summer hatched later in the year than those captured further upstream. As a result, younger juveniles were distributed Julian J. Dodson, De´partement de Biologie, 1045 Avenue de la Me´decine, Universite´ Laval, Que´bec, somewhat further downstream. In addition, we found significant QC, Canada G1V 0A6; e-mail: julian.dodson@ multimodality in hatch-date distributions at midstream and downstream bio.ulaval.ca sampling stations.
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