Salmon survival scheme ahead of schedule

Mowi's fish health team assess wild caught smolts at the Drimsallie hatchery yesterday (photo: Jon Gibb)

A NEW wild salmon restoration trial pioneered by the River Lochy fishery and Mowi Scotland took a step forward yesterday – two months ahead of schedule.

As part of the indigenous Lochy smolt to adult supplementation programme, the fish health team at Mowi visited the Drimsallie hatchery, near Glenfinnan, to test the seawater readiness of wild caught smolts prior to transfer to sea pens.

Jon Gibb, fishery manager of the Lochy, launched the project earlier this year, taking around 500 wild migrating smolts and growing them in the hatchery.

The smolts will be transferred to a dedicated pen at Mowi’s Ardnish site at Lochailort and raised alongside the farmed fish there.

The intention had been to transfer the fish at 500g in September, but Gibb said they will be moved in the next fortnight, to get the maximum benefit of the sea growth.

The 500 salmon – there have been no losses – are currently between 60-100g, which is big for wild smolts, so they are getting a ‘head start’, he said.

Once they are in the pen, and have reached an appropriate size, wrasse will be added. The salmon will then be released as adults in autumn 2020 to procreate naturally in the wild.

The salmon farmers carried out ATPAse tests to assess the stock’s readiness for transfer to Lochailort, with samples sent to Norway, using the new Pharmaq SmoltVision tool.

‘The professionalism of the Mowi fish health team is unbelievable,’ said Gibb. ‘The meticulous nature they’re treating this project, I’m really impressed.’

Lochy fishery manager Jon Gibb at Drimsallie

 

Gibb, who has managed restoration schemes for nearly 20 years, said this new programme is a first for Scotland.

Up to 99 per cent of wild smolts are not returning to rivers to spawn, and Gibb said using fish that will die anyway and putting them back in the river is ‘a very natural way’ of restocking.

Using Mowi’s sea pens will get faster growth than Gibb can achieve in Drimsallie, a freshwater hatchery.

Past schemes have involved fry production, using indigenous broodstock and releasing their fry at first feeding.

Another project, currently underway at Drimsallie, takes smolt from several rivers and grows them into adult salmon in tanks. These are then stripped and when the eggs are eyed ova they are placed into artificial redds in the river tributaries.

The latest approach, however, stocks the river with adult salmon.

‘We’re still treating this very much as a trial, we don’t know what the fish are going to do,’ said Gibb.

‘We have plenty of reason to believe they will cut redds and do what fish are supposed to do at that time of year but of course we don’t know. But it’s all going to plan.’