The problem of sea lice which infest salmon may be solved by researchers in Aberdeen who have found a way of tricking the lice.
Lice are attracted to salmon by the strong smells that the fish release into the water. By manipulating the chemicals that produce these very smells, it is possible to trick lice into believing they are on their way to a tasty lunch, when in fact they are being lured into a trap – a far cry from tasty salmon nibbles.
“What we have found so far is that lice actively respond to water in which salmon are kept, as opposed to other fish, so we know for sure that it is the chemicals released by salmon that attract the lice”, explains Dr Jenny Mordue, project leader at the University of Aberdeen.
“We are now trying to establish a simple push/pull strategy in which lice would be both distracted away from their natural target, salmon, whilst being drawn towards traps containing salmon smells,” she added.
The theory is that the push part of the process can be achieved by disrupting the salmon smells which are currently released from salmon cages and are obviously attractive to lice. The pull part of the strategy would be created through the release of salmon smells elsewhere, creating the potential for lice to be drawn into a trap, removing them from the farm site.
Modifying or changing sea lice behaviour is not only a short term solution to lice infestation of salmon. Long-term control can also be achieved through similar methods. Many parasites use chemical cues such as smells to identify and
find mates, therefore it should be possible to disrupt mating by causing confusion in mate location by a simple adaptation of the push-pull strategy.
Other traditional methods of controlling lice involve the use of sea lice treatments to which lice can easily develop resistance. The proposed behavioural method for controlling sea lice could form part of an integrated pest management strategy which could be commercially viable and environmentally sustainable.