Spatial and trophic niches through ontogeny and the influence on native species restoration: Using Lake Ontario Atlantic salmon (Salmo salar) as a model species
Species reintroductions are an important aspect of conservation biology to prevent biodiversity loss, and post-release monitoring can help in understanding and improving restoration success. Generally, population sizes are monitored to determine if reintroductions are successful, however, it does no...
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| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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University of Windsor
2021
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| Online Access: | https://scholar.uwindsor.ca/etd/8564 https://scholar.uwindsor.ca/context/etd/article/9569/viewcontent/uc.pdf |
| Summary: | Species reintroductions are an important aspect of conservation biology to prevent biodiversity loss, and post-release monitoring can help in understanding and improving restoration success. Generally, population sizes are monitored to determine if reintroductions are successful, however, it does not reveal why it is a success or failure. This thesis proposes that by understanding a species ecological niche within the introduced abiotic and biotic habitat throughout its life history, the mechanisms behind restoration success or failure can be better determined, as well as assist management with improving the potential for species restoration. Once extirpated, Atlantic salmon (Salmo salar) have been reintroduced into Lake Ontario, however, numbers of returning adults remain low. Thus, focusing on Lake Ontario Atlantic salmon provided an opportunity to assess restoration potential and improve restoration success. The spatial and trophic niches of Lake Ontario Atlantic salmon were assessed at various life stages. This thesis begins with understanding the seasonal trophic niche of juvenile Atlantic salmon stocked into streams with different fish communities, and specifically to determine if trophic interactions and other species abundances limit restoration success. Stream resident fish communities appeared to partition resources across seasons such that abundant species had low trophic niche overlap with young-of-year Atlantic salmon minimizing overall competition given available resources. The next chapter followed the migration success of Atlantic salmon smolts coming from different rearing environments. Acoustic telemetry revealed that there was similar migratory performance and no impacts from weirs, yet survival was greater in naturally-reared smolts than hatchery-reared smolts. Survival was lowest at the release site indicating pre-migration mortality, and specifically high stocking-related mortality of hatchery-reared smolts. Overall, when either stocked as parrs or smolts there was low mortality during the ... |
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