Sterilisation pilot to protect wild stocks

SCIENTISTS are conducting a study to find out whether genetically sterilising farmed salmon would prevent them from breeding with their wild counterparts.
The team of researchers, from the University of East Anglia, have received £300,000 funding from the Biotechnology and Biological Sciences Research Council (BBSRC) and the Natural Environment Research Council (NERC), reported FIS.
They hope that inducing the genetic condition known as triploidy will help dwindling wild salmon stocks.
Lead researcher Prof Matt Gage, from UEA’s School of Biological Sciences, said: ‘Around 95 per cent of all Atlantic salmon on earth are farmed, and domestication has made them very different to wild populations.
‘Farmed salmon have been selected over nearly 50 years for fast growth in dense rearing cages, and they have become more naïve at dealing with predators.
‘These domestic traits are good for producing fish for the table, but not for the stability of wild populations, each of which is shaped to be perfect for their own natural river system.’
Farmed salmon that escape can enter wild spawning populations, where they reproduce and erode wild gene pools, introducing these negative traits.
Gage said triploid salmon could be produced by exposing just-fertilised salmon eggs to high pressure, which stops the normal shedding of the second set of maternal chromosomes. The resulting offspring develops with the usual set of chromosomes from its father, but instead has two sets from its mother, which can induce sterility.
‘This method is routinely applied for farming rainbow trout, and its implementation is now being considered for salmon,’ he said.
‘However, the reproductive effects can vary between individual species, so we will verify whether triploidy completely sterilises Atlantic salmon.
‘If sterility is complete, this will provide an excellent biosecurity solution for wild populations when farm salmon escape into them.’