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dc.contributor.supervisor Blanchfield, Paul (Biological Sciences) en_US
dc.contributor.author Callaghan, David
dc.date.accessioned 2016-02-01T21:39:49Z
dc.date.available 2016-02-01T21:39:49Z
dc.date.issued 2015-07-29 en_US
dc.identifier.citation David T. Callaghan, Paul J. Blanchfield, Peter A. Cott, Lake trout (Salvelinus namaycush) spawning habitat in a northern lake: The role of wind and physical characteristics on habitat quality, Journal of Great Lakes Research, Available online 29 July 2015, ISSN 0380-1330, http://dx.doi.org/10.1016/j.jglr.2015.07.001. en_US
dc.identifier.uri http://hdl.handle.net/1993/31123
dc.description.abstract Lake trout (Salvelinus namaycush) have a broad distribution across Canada’s north, yet most studies that describe reproductive habitat and behaviour have been conducted in the southern extent of their range. Northern regions are experiencing unprecedented changes from climate and industrial development, and thus there is a pressing need to understand the reproductive habitat and behaviour of this species. I examined a dozen sites around Alexie Lake, Northwest Territories, to test if physical habitat and wind exposure were important determinants of spawning site use and embryonic survival. Spawning was found to occur in ~2 m water depth, on 3–15 cm diameter clean substrate on the leading edge of shoals that ended in a rock crib rising abruptly in nearshore regions around the lake. Wind direction was predominantly from the west, although it was highly variable within and among spawning seasons. I found evidence of lake trout spawning at each site examined, which was not limited to shoals facing a predominant wind direction. High variation in embryonic survival (2–83%) from incubation trays was observed among spawning sites, demonstrating a large gradient in habitat quality exists within a given lake. However, modelled wind exposure did not predict embryonic survival, nor did physical characteristics - including shoal depth and slope, as well as cobble size and shape - that may influence interstitial water flow on spawning shoals. Using an acoustic telemetry monitoring system and novel spatial temporal clustering analysis, I was able to quantify lake trout spawning movements and behaviours over the course of an entire spawning season. Lake trout formed clusters on spawning shoals around the entire nearshore region, as well as around several islands, confirming that suitable spawning habitat is abundant in Alexie Lake. Males arrived on spawning shoals earlier than females and remained longer for a maximum of 25 consecutive days; females occupied spawning shoals for a maximum of 8 consecutive days over the course of the spawning season. Males formed over four times as many spawning clusters and visited twice as many sites than females. Spawning clusters were predominantly formed at night but were also observed during daylight hours, especially during the peak spawning season (September 9–19). I found males had higher activity rates, and spent longer periods on spawning shoals, than females, in spite of similar daily travel distances between sexes. Overall, my findings challenge the conventional role of wind as a predominant predictor of lake trout spawning site quality. I propose that the unpredictable nature of wind and abundance of suitable habitat may favour lake-wide spawning by lake trout as a bet-hedging strategy in northern lakes with limited fetch. en_US
dc.publisher Journal of Great Lakes Research en_US
dc.rights info:eu-repo/semantics/openAccess
dc.subject Lake trout en_US
dc.subject Reproductive strategies en_US
dc.subject Habitat quality en_US
dc.subject Spatial temporal clustering en_US
dc.subject Behaviour en_US
dc.subject Telemetry en_US
dc.subject Spawning en_US
dc.title Spawning habitat and reproductive strategies of lake trout (Salvelinus namaycush) in a northern boreal lake en_US
dc.type info:eu-repo/semantics/masterThesis
dc.type master thesis en_US
dc.degree.discipline Biological Sciences en_US
dc.contributor.examiningcommittee Hare, James (Biological Sciences) Manseau, Micheline (Natural Resource Institute) Cott, Peter (Government of the Northwest Territories) en_US
dc.degree.level Master of Science (M.Sc.) en_US
dc.description.note May 2016 en_US


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