Almost impossible that farmed fish infect wild fish with sea lice
The recently published report "Lice and escaped farmed salmon should not restrict the production of farmed salmon in Hardanger" caused big doubts about the current management of salmon farming. Jan Arve Gjøvik, who has compiled the report, believes a lot more research is needed.
"Based on the models currently used in the management, one would expect that sea lice attack wild fish at the same time as fish kept in pens. But important observations from real data shows the opposite. Currently there are not enough adequate and corresponding data available for the rest of the country, but I suspect that the situation in the Hardanger Fjord is the same as all along the Norwegian coast," he says.
"Sea trout find feed in the coastal zone where it comes into contact with many fish species. These might be temporarily hosts for lice. For example, one has documented that lice can survive on cod and produce lice eggs, so similar can be expected in other species. Researchers should pay more attention toward the shoreline," he concludes.
Genetic interference
When it comes to genetic interference from escaped farmed salmon to wild salmon, Gjøvik is clear in his speech.
"For decades sign of genetic interference has been monitored and registerd without finding prove that the wild stock has suffered from it. I question the whole concept that each wild strain has unique genetic resources," he says.
He thinks it is sensational that farmed salmon is constantly being suspected of reproducing better in rivers, than wild salmon itself.
"It is very unlikley that farmed fish will survive and reproduce outside the net pens.
"Possible interference with wild fish, does not necessarily mean that it is negative. In nature it is often beneficial for the survival of the fittest. There is much logical thinking in genetics, but in several areas in the debate on genetic interference, it's a lack of logical thinking," he says.
