Escape-related behaviour of Atlantic cod (Gadus morhua): motivation to escape from sea cages and spatiotemporal dispersal post-escape

• Main Author: Zimmermann, Emily W.
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2012
• Subjects: atlantic cod; Gadus morhua
• Online Access: https://research.library.mun.ca/10041/; https://research.library.mun.ca/10041/1/Zimmermann_EmilyW.pdf

This study addresses the potential for interaction between escapee farmed and wild cod following escape from aquaculture sea cages. The first chapter introduces the topic of fish escapes from a behavioural perspective. The second chapter investigates the role of suboptimal conditions and individual temperament on net biting behaviour. The data suggest that appropriate feeding levels combined with cage enrichment, as well as good net maintenance, may lead to reduced net interactions and thus fewer holes, reducing the potential for fish to escape. In the third chapter, I used acoustic telemetry to determine the spatiotemporal distribution of local wild cod and escapee farmed cod following a simulated escape. Farmed cod dispersed from the cage site rapidly and mixed with local wild cod, suggesting a high potential for interactions and highlighting the importance of reducing escapes before they occur. These results can be applied to reduce the number of escapes, streamlining the development of the industry before mitigation becomes too difficult and costly to implement.