SS1.05 How Will Aquatic Ecosystems Respond to Climate Change?
Date: Tuesday, June 11, 2002
Time: 10:30:00 AM
Location: Oak Bay
 
DionneM, Laval University, Québec, Canada, melanie.dionne@giroq.ulaval.ca
Sainte-Marie, B, , Maurice-Lamontagne Institute, Mont-Joli, Canada, Sainte-MarieB@dfo-mpo.gc.ca
Bourget, E, , Laval University, Québec, Canada, edwin.bourget@rectorat.usherb.ca
Gilbert, D, , Maurice-Lamontagne Institute, Mont-Joli, CANADA, GilbertD@dfo-mpo.gc.ca
 
DISTRIBUTION AND HABITAT SELECTION OF EARLY BENTHIC STAGE SNOW CRABS, CHIONOECETES OPILIO, IN A CLIMATE CHANGE PERSPECTIVE
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The snow crab is one of the most valuable marine invertebrate fisheries in North America. The early benthic stages (EBS) of snow crab are considered to be cold stenotherms and therefore may be quite sensitive to climate change. We tested the hypothesis that EBS select for the coldest water available through investigation of distribution patterns in the Gulf of St. Lawrence and controlled laboratory experiments. Field sampling was carried out with a beam trawl equipped with temperature probes and grab samples were taken to characterize sediment. Laboratory choice experiments were conducted in aquaria with a temperature gradient and a choice of three sediments (mud, sand and gravel). Field and laboratory data indicate that EBS have sharp size-dependent temperature and substrate preferences. In the field, all EBS seemed to avoid the coldest water (<0ºC) and concentrated in temperatures between 0-2ºC. In the laboratory, instar III crabs were associated with fine sediment and colder water than instars IV and V. By comparison, pre-adult and adult crabs occurred over a much broader range of temperatures and sediment types. Our results suggest that EBS would be the first population component affected by climate change.