This article appears as part of the Winds of Change newsletter.

The results from a new study on sea lice movement and distribution are a reminder that current stalling, with new lice regulations caught up in legal appeal by the salmon farming industry, is not helping wild fish.

The parasites, the modelling by Dr Tom Scanlon and Dr Mark Sticland, found, from Scottish salmon farms are “accumulating” in vast numbers in vital migration routes used by wild fish.

The study looked at an area in the north west of Scotland, from south Skye to Torridon, creating visual modelling maps that show how sea lice larvae released from salmon farms can disperse tens of kilometres across Scotland’s west coast.

For migrating wild salmon, this means that as they swim from their home rivers to the open ocean, they are likely to encounter lice from not just one farm, but the combined pressure of multiple farms.

Once the lice attach, they feed on the mucus, skin, and blood of fish. Young migrating wild salmon are particularly vulnerable to sea lice, with even low infestations capable of causing significant mortality.

Meanwhile, a new sea lice regulatory system, launched by SEPA, has been stuck in the legal system for over a year as a result of an appeal led by Salmon Scotland and its producer members.

As a result, the conservation charity Wildfish points out, 210 salmon farms are currently operating “without an adequate system in place” to prevent the accumulating sea lice parasites and new salmon farms are still being approved by local authorities with no effective controls on sea lice.

Their stalling means, says Nick Underdown Scotland Director of Wildfish, that “councillors are still being asked to approve new farms........

© Herald Scotland