Consequences of Environmental Manipulation on Behavioural and Neuromorphological Plasticity as It Relates to the Reintroduction of Atlantic Salmon (Salmo salar) to Lake Ontario
The reintroduction of imperilled species has become an important tool in conservation biology and relies on the captive-rearing of remaining individuals, or a subset thereof, as a lifeline to prevent extinction. The success of reintroduction efforts has generally been low, mainly due to poor post-re...
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| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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University of Windsor
2023
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| Online Access: | https://scholar.uwindsor.ca/etd/9039 https://scholar.uwindsor.ca/context/etd/article/10045/viewcontent/Consequences_of_Environmental_.pdf |
| Summary: | The reintroduction of imperilled species has become an important tool in conservation biology and relies on the captive-rearing of remaining individuals, or a subset thereof, as a lifeline to prevent extinction. The success of reintroduction efforts has generally been low, mainly due to poor post-release performance of captive-reared animals. Captive-breeding programs tend to produce behaviourally and neurologically compromised animals that deviate from wild phenotypes and are less fit in natural settings. While genetic adaptation can account for some of the behavioural deficiencies expressed by captive-reared animals, phenotypic plasticity has been shown to play a large role. Phenotypic plasticity is generally defined as the ability of an individual to produce different phenotypes, or change the trajectory of phenotypic development, when exposed to different environmental conditions. This thesis proposes that by understanding the environmental factors and mechanisms that shape the phenotype, conservation biologists and managers alike can alter the rearing conditions and release protocols of captive-bred animals destined for stocking to increase the success of reintroduction efforts. Throughout this thesis I examine the effects conditioning tactics – methods aimed at manipulating the rearing environment and release protocol to counteract the negative effects of captive-rearing on fitness-related behaviours in Atlantic Salmon (Salmo salar). Specifically, I investigated the effects of manipulating the early developmental rearing via enrichment (sensory enrichment via alarm cue exposure and physical enrichment via increased structure in the rearing environment) on anti-predator related behaviours. Alarm cue exposure during early development had no significant effect on anti-predator related behaviour but fish exposed to alarm cue showed significant plastic changes to regional brain volumes (smaller olfactory bulbs), suggesting the potential for alarm cue to affect post-release behaviour. Physical enrichment during ... |
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