Date of Award

9-12-2024

Publication Type

Thesis

Degree Name

M.Sc.

Department

Biological Sciences

Keywords

cortisol;reintroduction;salmon;stress;transport

Supervisor

Trevor Pitcher

Supervisor

Christine Madliger

Abstract

Transport is a necessary tool when moving animals for reintroduction efforts. During these events, organisms are often subjected to several different stressors. It is particularly important to minimize the effects of stress to improve the likelihood of survival upon release. I am evaluating the effectiveness of pre-transport enrichment and post-transport release strategy on the mitigation of transport-induced stress in reintroduced juvenile Atlantic salmon (Salmo salar). I first compared dietary and structural enrichment as pre-transport rearing strategies that may reduce the stress response of fish to transport. The stress physiology (using cortisol, glucose and lactate as measures) of enriched fish was compared to that of non-enriched (control) fish following a standard two hour transport reintroduction event. I found that compared to non- enriched control fish, enrichment in rearing had no effect on the stress physiology of fish throughout transport. For post-transport stress mitigation, I compared the stress physiology of fish that experienced a standard hard-release strategy following transport (immediate release and no acclimation period), to fish that experienced a soft-release strategy following transport, in which they were given an extended period to safely acclimatize in their new environment prior to release. I found that soft-release procedures had a significant mitigative effect on the stress physiology of transported fish compared to those that were hard-released. Collectively, my thesis aimed to monitor stress levels in fish throughout necessary transport reintroduction events, as well as evaluate strategies that could be used to mitigate excessive transport-induced physiological stress in juvenile Atlantic salmon. This project provides valuable information for the Ontario Atlantic salmon reintroduction program as a whole, as well as for other fish stocking, supplementation or conservation programs that rely on transport.

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