Salmon farming poses as big an environmental threat as scallop dredging

Sandy Mccall Smith highlighted the damage to the seabed by scallop dredging (Scotsman, 19 September). But what about the damage to the seabed and marine creatures done by the poison poured in by salmon farms?

Of course it is done to kill off the sea lice which damage the salmon in their cages floating in the sea water. But it is so preventable.

Over the years we have seen different methods of killing off these scurrilous pests, sea lice, which multiply by feeding off the caged fish and then spread towards the river fish on their way up to their spawning grounds up stream.

How do you prevent sea lice from damaging caged salmon in these off-shore cages? Simple! Put the cages into translucent tanks on the off-shore base; pump the sea water in and microfilter that water with chambers to catch the sea lice and to remove them and destroy them.

The water may have to be oxygenated to prevent the possibility of algae bloom and other diseases, but the growing salmon can even be hand fed in a sheltered environment and the product at the end of the day should be as close to 100% as possible in such a marketable crop! No poison required to kill sea lice, so the fish should be completely healthy.

Last week we saw the horrifying spectacle on the BBC of tons of unfit for consumption salmon being buried in a huge pit because of damage by sea lice.

The practice at present is to attempt to kill the sea lice with poison and it is difficult to ensure that all sea lice are killed. And the bottom of the sea beneath the cages is unfit for other creatures so the cages are shifted at regular intervals.

Is SEPA content to let this poison be regularly poured into our seas in which the lobsters and other valuable marine species live?

If fish farmers stop carrying on the way they were running their fish farms over 50 years ago and use the methods suggested, they could make it a much more profitable industry and less damaging to the environment.

There is also a bonus in that they would not have to pay rental to the Crown Estate Commissioners.

There will be a capital cost in getting the tanks and adjacent equipment, but its all allowable for tax! The detritus which will collect in the tank bottom can be sold for manure.

I am not a fish farmer, I am just a lawyer who has had dealings with many fish farms over the years.

The concept I have outlined is one that a fish farmer client outlined to me just as he was selling off his interest in a project. And he was the chap with a degree in aquaculture who knew what he was talking about!

How many more tons of unfit salmon will be destroyed before the industry changes? And if they do change their habits the criticisms of the rod fishermen can change as well, in addition to the practice of having to throw back the salmon they catch and even then be able to put wild salmon on the tables of the nation again!