Scottish salmon farming has had a welcome boost in its drive to control sea lice challenges with the confirmation that two producers have completed the lifecycle of farmed wrasse.
Marine Harvest Scotland and Scottish Sea Farms have been working with the Institute of Aquaculture at the University of Stirling to produce farm-reared cleaner fish, which consume naturally-occurring parasites such as sea lice.
Over six years, the project team has bred wild-caught Ballan wrasse (Labrus bergylta) and raised the offspring from egg to adults of reproductive age. In what is believed to be a world first, those offspring have now produced their own eggs, which have successfully hatched, thus completing the lifecycle of farming wrasse in a controlled environment.
The team has also successfully weaned the wrasse larvae and fry from live food to a dry diet, which will give salmon farmers more control over the health and nutrition of these fish.
Longer term, it is hoped the breakthrough will help meet the growing demand for cleaner fish as Scotland’s salmon farmers increasingly seek to control sea lice through non-medicinal, environmentally-friendly approaches.
Currently, the majority of wrasse used as cleaner fish is wild-caught in accordance with guidelines specified by Marine Scotland, RSPCA Assured and local fishery boards to ensure it is done sustainably. However, it is the sector’s ambition to become self-sustaining and use only farmed stocks of cleaner fish.
“Ballan wrasse provides highly effective, highly natural sea lice control and as such is in huge demand. With this breakthrough, we now have proven procedures for breeding, weaning and rearing wrasse, which will both help ensure farmers have a more secure, controllable supply and reduce reliance on wild stocks,” said Paul Featherstone, hatchery manager at Marine Harvest Scotland.
Marine Harvest Scotland and Scottish Sea Farms entered into the multi-million pound collaboration in 2011 with support from Innovate UK (formerly the Technology Strategy Board), then more recently the Scottish Aquaculture Innovation Centre and feed specialist BioMar.
Under the terms of the arrangement, all insights gleaned will be shared with the wider sector for the common good, the organizations said.
