AQUA 2012: Help Prevent Cod Escapes with Enriched Cages

5 September 2012, at 1:00am

CZECH REPUBLIC - According to Emily Zimmermann, Memorial University of Newfoundland, access to feed and providing an enriched cage can help to prevent cod escapes from farm cages, writes Lucy Towers, TheFishSite Editor, Live from AQUA 2012, Prague, Czech Republic.

Ms Zimmermann stated how cod are much more prone to net biting and escapes than salmon due to their behavioural differences.

Cod are much more curious and tend to swim by the edge of nets. Bering this in mind, Ms Zimmermann looked at how net biting could be reduced in order to prevent escapes and to enhance the welfare of the fish.

Cod are often motivated to bite due to sub-optimal conditions.

Ms Zimmermann therefore created a study looking at the affects that huger/food deprivation and cage enrichment, using tunnels and ropes, had on net biting.

The results of the project showed that more net biting took place in the plain cage than enriched. Fish with access to feed also showed less biting.

The project highlighted that there were 7.5 fewer interactions per fish/ per hour with the net when food was present and 12.6 when the cage was enriched.

Cod were also seen to interact with the net at damaged areas than undamaged.

In conclusion, Ms Zimmermann noted that hunger, boredom and net damage all lead to increased interactions with the cage wall/net.