WHY THE PRICE OF SALMON IS SOARING
And beware — the reason may put you off this wonderful fish for life
by pumping the fish through a large tube containing heated water. Because the sea lice have a low tolerance to temperature change, the higher water temperature kills the lice.
But its deployment in Scotland has not been without problems. In a single incident at a Marine Harvest farm in Loch Greshornish, on Skye, some 115,000 salmon died following a Thermolicer treatment last summer.
The company put the deaths down to a ‘lack of experience’ and rebutted newspaper claims at the time that the fish had been ‘poached alive’.
It all cuts little ice with Mr Lymbery: ‘The Thermolicer procedure involves crowding the fish used to the cold coastal waters of Scotland, pumping them into heated water and then dumping them back into their seawater cages. Salmon would never normally experience such sudden temperature changes.’
Despite these issues and the rising cost of salmon, demand remains strong. Current NHS advice is that we should eat two portions of fish a week, one of which should be a so-called ‘oily’ fish.
But while farmed salmon is undoubtedly a good source of omega-3 it is a less good source than it used to be.
A recent study by Stirling University found that the amount of omega-3 in salmon had halved in the past decade.
This is because of the changing diet of farmed salmon. The more oily fish that goes into the feed of the salmon, the more omega-3 the salmon contains. Not long ago, 80per cent of the feed was made up of oily fish — but today it is more like 20 per cent.
This is because of the fact that it became unsustainable to harvest the amounts of oily fish — mainly anchovies and sardines — needed to supply the booming farmed salmon industry.
Fish oils have been replaced with vegetable oils. As a result, from having far more omega-3 than wild salmon, today they have much the same.
According to the Marine Harvest report its salmon feed is made up of 24 per cent vegetable oils, 17 per cent wheat, 14 per cent corn, 12 per cent fish-meals, 11 per cent soy proteins, 10 per cent beans, eight per cent fish oils and four per cent supplements.
It should also be noted that farmed salmon is not naturally pink in colour. The pink of the salmon flesh, wild or farmed, is caused by the presence of carotenoid pigments.
Wild salmon get these from eating krill, zooplankton, small fish and crustaceans. Farmed salmon are given these pigments, either synthetically manufactured or harvested from natural sources, as additives in their feed.
Faced with these myriad challenges, the industry insists that it is doing all it can to put a difficult period behind it.
‘Environmental challenges come and go, be it in terrestrial or marine farming, but we are coming out of the other end of that,’ says Scott Landsburgh, chief executive of industry body the Scottish Salmon Producers’ Organisation.
‘We have invested huge amounts of money, about £60million, in fish health management, and our lice numbers have improved dramatically in the past four to six months.’
He believes that Scottish salmon production will increase this year and that in the future there will be further ‘sustainable growth’.
As for damaging the environment, Mr Landsburgh denies that the industry is to blame.
‘We are portrayed as these bad guys, but the last thing we want is to be damaging the pristine environment and therefore our fish — no one wins in that,’ he says.
He believes that salmon farming has a minimal impact on wild salmon, adding that stocks are declining on the east coast of Scotland, where there are no fish farms, at a similar rate to the west coast.
A spokesman for Marine Harvest Scotland echoed those sentiments, saying: ‘We have worked hard to address the sea lice and gill health challenges, and a year on the picture is much improved.’
One initiative which is having some success against lice is the use of so-called ‘cleaner fish’. The idea is that instead of using chemicals, fish such as wrasse and lumpfish live side by side with the farmed salmon in their cages.
One wrasse for every 25 salmon is used, their natural instinct being to eat the lice from the salmon’s flanks.
The main drawback is the amount of cleaner fish needed. Environmentalists claim that wrasse stocks in England and elsewhere are being plundered for transportation north.
OTHER plans being pursued include moving fish farms into deeper, off-shore waters, where stronger currents mean that lice are less likely to take a stranglehold. These structures, however, will need to be able to withstand extreme weather conditions.
Escaping farmed fish can breed with wild salmon, eroding genetic traits necessary for survival in the wild.
Salmon are born in fresh water, then migrate to the ocean, before returning to the same spot they were born to spawn — often travelling hundreds of miles.
But studies have found that hybrid fish have poor survival rates at sea and may also struggle to find their way back to freshwater to spawn. Farmed salmon are also selected to put on weight quickly and may be less able to evade predators or to time their return to local rivers.
Another option is to seal off the entire process in giant tanks, controlling everything that goes in and goes out. These pods could either be placed in the ocean or inland.
While some believe such drastic measures are the only way that rivers such as the Doon will be able to recapture their former glories, they do not come cheap.
But, given the costs currently incurred in trying to produce healthy fish for the nation’s dinner tables, it may one day be the only option.