The Manchester-based fish farming consultant with Callander McDowal was responding to the government’s consultation on its aquaculture and fisheries bill. Dr Jaffa said the weakness in the salmon gene pool – “genetic drift” – identified by scientists was not the result of escaped farmed salmon and the wild fish interbreeding. He said: “Genetic drift is caused by random events that occur by chance. As a result, some individuals have a greater impact on the population than might be expected.