The ‘numbers game’ leads to over optimistic forecasts
Dr Ted Needham: an independent view
RECENTLY I was with a friend, sharing reminiscences of the Unilever salmon farming days of nearly 20 years ago, when he rather surprised me. ‘The old excitement has gone,’ he claimed. ‘It is now all about numbers.’ Certainly salmon farming has become a numbers game. We are told - tains that we will have more than trebled output in Scotland by the end of the be wrong. Furthermore, it is an error to raise people’s hopes by making them in
- blooded and totally at the mercy of the weather. How many smolt producers
business expansion plans in Scotland which, compounded with other factors, will
farmers, at least in Scotland. But looking at the last 20 years on the land it is the contrast could not be greater, for every year the weather has a major impact on some or all of us.
Some thought needs to be given to making us less reliant on the vagaries
The engine of farmed salmon output is the smolt producer and he more than anything else will act as the brake on output. This is not because we wants to
It takes some four years from planning a large smolt unit to achieving maximum output. Every site has its wrinkles. These are primarily environmental fea years to learn to work a site properly. Eventual guaranteed output is usually well below original targets which seemed quite sensible when they were set.
Region planners are threatening to slow things down a bit and many of the privilege will be denied to Orkney and Shetland unless there are big changes in the way we raise our smolts.
One factor, freshwater cage culture, could alter all this. The techniques were Isles. Raising smolts in lochs is now the primary means Marine Harvest employs
Freshwater cage culture has much to commend it. The technology is not quickly, though great care must be taken to provide suitable access. Fry are being transferred earlier than ever- it is now acceptable to stock cages with more predictable.
Freshwater lochs are more stable than burns or rivers supplying many con- temperatures vary less widely and pH and other water quality changes striking, it is adequate in most lochs tested.
Two important problems remain; these are environmental impact.
should get together to tell us how we should monitor a freshwater loch for parasites to asses the risk to cage culture.
Most of the monitoring has been conducted using rainbows in Scotland and
increased phosphorous imput to the water body. This can give rise to plankton blooms.
It is prudent, nevertheless, to follow a few guidelines, like using slowly salmon’s requirements for phosphorus is supplied in most commercial diets. In extreme cases underwater pumps or propellors could be used to promote
Environmental change brought about by farming salmon parr in freshwater experience of salmon farmers. Somebody should prepare a statement for stated guidelines are followed.
In conclusion, I have two further comments. First, John Burn of the Marine -