Published on Sunday 23 October 2011 20:00

WHEN the Norwegian salmon farming industry starts spending £22 million on sea lice research, you can reckon the industry has more of a problem on its hands than anyone realised

The lice not only eat caged salmon but, far worse, eat endangered wild salmon and sea trout as they swim past the fish farm cages into their home rivers on the west of Scotland.

In Loch Broom this year one fish was found to have 500 lice on it. Almost in tandem with the Norwegian “initiative” the UK industry announced research grants of £2.1million to see if the tiny lice-eating wrasse can be persuaded to eat lice, which it does to a certain extent, but in insufficient quantities to save the expense of having to drench the cages in “medication” which no longer works. The Scottish industry pretty well refuses to admit there is a problem, but has a neat arrangement with the Government that allows it not to disclose just how bad things are with lice on grounds of commercial confidentiality.

The Norwegians, who are entirely responsible for the mess in the first place as they own most of the world’s salmon industry, are rather more open about things.

So this month they reported an “alarmingly high level of sea lice infestation in wild salmon smolts and salmon trout”. And just to show that their “delousing” chemicals aren’t working they are now having to “medicate” fish cages three times a year.

The report goes on: “Resistance to seven of the nine delousing products has been documented. We are running out of measures to employ against sea lice.” The position is the same here and in Canada. But in the great traditions of open government and vested interest, no one here will say so for fear the EU environment people wake up and start being difficult about endangered wild species and filling the seas with chemicals. So what has the UK come up with? Wrasse – the “sustainable option”. Well better something than nothing. They have been banging on about wrasse for 15 years at least.

There have been trials in Shetland and early fish farmer and musician Ian Anderson, he of Jethro Tull, got terribly excited about wrasse. But you need a continuous and huge quantity of these lice-eating fish.

If wrasse can be made to work to the extent they can keep up with the mega expansion of salmon farming required to service the Chinese market then we must not carp. It would be the answer to everyone’s prayers. But why are we only now returning to wrasse? The reason, simply, is that everyone thought they would find a quick, and cheap, chemical fix – and they haven’t. So wrasse are back on the menu.