Fish farm catches a whopper
SALMON farmers off Colonsay had an unexpected visitor when a three-metre, 47-stone Pacific blue fin tuna appeared in one of their pens.
After some initial head scratching, the salmon farmers worked out a way to safely move the fish back into open waters.
The Marine Harvest salmon farm at Colonsay opened in August 2015 and the team has become used to seeing a lot of marine wildlife, but as farm manager Ali Geddes explained, this was unusual.
‘We’d noticed a lot of activity around the southern part of the farm. There seemed to be a real feeding frenzy going on with the dolphins and porpoises. It’s now clear they were chasing a tuna.
‘These things can move at real speed – up to 50mph – and it seems to have burst through the foot of the pen like a torpedo.
‘Thankfully, the tuna seems to be unhurt and none of our own fish has escaped.
‘They are very small at this stage – the site has only recently been stocked with smolts which tend to swim towards the top of the pens away from the base.
‘The hole the tuna made was more like a slash than a round hole and we called in divers who repaired it within a few hours.’
Atlantic blue fin tuna are common in Scottish waters, but Pacific blue fin tuna are incredibly rare as they prefer the warmer waters of the Pacific ocean.
The Colonsay team finally used a panel net to capture the tuna.
This type of net is normally used during harvesting as it allows smaller fish to swim through the gaps.
The landing craft crane was then used to lift the tuna into a large basket for transfer to the open sea, where it swam away.
Ben Hadfield, managing director of Marine Harvest Scotland, praised the team for releasing the tuna unscathed. He said: ‘We believe it was a whacking 300 kilos, which is more than 47 stone.
‘They’re certainly skilled in handling fish but our salmon grow to about five kilos in size, so this was well beyond the norm.’