Behaviour of growth hormone transgenic coho salmon Oncorhynchus kisutch in marine mesocosms assessed by acoustic tag telemetry.

Underwater acoustic tag telemetry was used to assess behavioural differences between juvenile wild-type (i.e. non-transgenic, NT) and growth hormone (GH) transgenic (T) coho salmon Oncorhynchus kisutch in a contained simulated ocean environment. T O. kisutch were found across days to maintain higher baseline swimming speeds than NT O. kisutch and differences in response to feeding were detected between T and NT genotypes. This is the first study to assess behaviour of GH transgenic salmonids in a marine environment and has relevance for assessing whether behavioural effects of GH overexpression seen in freshwater environments can be extrapolated to oceanic phases of the life cycle.