16th August 2018
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ISA back to haunt fish farmers

, by , in Fishing & Sea

By JOHN ROBERTSON

THE THREE salmon farm sites caught up in an infectious salmon anaemia (ISA) scare off Scalloway have been cleared of fish, raising hopes the disease will not wreak the havoc suffered in Shetland 10 years ago. However, there are 10 more sites off the south-west Mainland with fish in them which may have been vulnerable to the virus.

There has been some concern about the length of time taken to react to a potential disaster for the industry, given that inspectors were first alerted in November to an unusually high number of fish deaths at the Scottish Sea Farms site east of Hildasay. Testing started on 9th December yet it took until Friday, 2nd January for action to begin after confirmation of ISA on the site, owned by the Norwegian company Scottish Sea Farms.

Two more of the company’s sites to the north, at Fore Holm and Brei Geo in the entrance to Sandsound Voe, have been placed under suspicion of harbouring the virus, although one had already been empty of salmon for six weeks.

According to Shetland Aquaculture general manager David Sandison the only reason the two were made suspects was because they contained fish from the same source as those in the Hildasay cages. The last of the fish from the sites was harvested on Tuesday. Six more sites in the control zone still contain fish and four within the wider surveillance zone also have stock.

Government scientists from Fisheries Research Services (FRS) have been busy sending away fish samples from a number of the neighbouring farms and may have some results by the end of next week to show whether the virus has spread in an area which has the most densely located salmon farm sites in Shetland. A full set of results could take up to six weeks due to the processes they have to go through in the lab. In the meantime investigations will focus on how the virus got to the Hildasay site.

Mr Sandison said it was disappointing that ISA had popped up again after 10 years but there was a good opportunity to control the outbreak and he would have been much more worried if there had already been a clinical outbreak of disease.

“This is a situation which we shouldn’t over-exaggerate,” he said on Wednesday. “Already, because the fish are out, we’ve significantly lessened any risks that remain.

“It’s now about making sure the inspectors get on with the job and get the sampling done that they need to really satisfy us that there is not a problem. The fact that only one site has been confirmed is very good indeed. But it is early and I’m not going to be complacent about it.”

The government clampdown which swung into place has banned unauthorised movement of fish or fish farm traffic within a control zone which, along with Sea Farms, affects two other companies – the other Shetland salmon farming giant, Hjaltland Seafarms, and independent Shetland fish farmer Skelda Salmon, which has one site in the zone at Spoose Holm, between the Cheynies and Papa.

The farms in the wider surveillance zone are being monitored. Between the two zones there are more than 40 licensed farm sites, most of them disused or lying fallow.

The fish from the site at Hildasay had already been harvested and packed at Sea Farms’ factory in Scalloway before confirma­tion of the virus surfaced. The last fish came out on 21st December. In fact, according to Mr Sandison, it was during harvesting in late November that company workers first noticed increased numbers of dead or dying fish, prompting a request to the FRS lab in Aberdeen to investigate.

Inspectors arrived to conduct tests and take samples on 9th December, which appar­ently showed a suspicion that the virus could be present. Follow-up samples were taken on 15th December, leading to the declaration on 2nd January, which was the first time other farmers were made aware of the concerns.

The director of aquaculture and aquatic animal health at FRS, Rob Raynard, told a different version of events, saying that one of his inspectors spotted signs of disease and took tests while in Shetland carrying out farm audits relating to the control of sea lice – a new compulsory test required by the government since November.

Dr Raynard said on local radio his team was “optimistic” the outbreak would be contained. A spokeswoman for FRS said yesterday she could not comment regarding the response time to the crisis but said she was sure action had been taken as quickly as possible.

Robert Nicolson of Skelda Salmon was annoyed to learn of the outbreak from the media. He heard a radio bulletin which inaccurately stated that his farm was suspected of having ISA. He has since received a full apology from the Scottish government, which had given out the duff information.

He said his company had been planning to harvest fish today but the ISA restrictions meant it could not get permission to use Scottish Sea Farms’ well-boat. However, he hopes to push ahead early next week.

Grieg Seafood Hjaltland is also suffering. Managing director Michael Stark said he had two sites in the control zone containing fish which he wanted to harvest but production was currently affected “drastically” by the restrictions although it had not yet come to the stage of having to lay off any workers from his factory in Lerwick.

Affected by movement restrictions to a lesser degree are the NAFC Marine Centre’s experimental salmon farm and Shetland Halibut’s halibut farm. The sea trout hatchery at Kergord and the trout site in Strom Loch are subject to fish movement restrictions too. The number of affected companies is far fewer than would have been the case 10 years ago before a lot of the small independent farmers went out of business and were bought out by the Norwegians.

If the outbreak cannot be snuffed out it could lead to a repeat of the mass culling required 10 years ago, for which there was no insurance cover or government compensation, although grants were later provided by the government and the SIC to help companies recover.

Mr Sandison said no approach had yet been made about possible compensation. But the Scottish government has already taken the step of announcing that it would give “very careful consideration” to any claim resulting from stock having to be destroyed.

The government, its scientists and the industry have been keen to stress that the salmon flesh poses no risk to humans and that while fish from Hildasay had the ISA virus they did not show clinical signs of the disease. If fish are still present on a site once a diagnosis of ISA is confirmed they may have to be culled under EU rules, as happened in 1998 and 1999 on some sites around Shetland including the same Hildasay one, then owned by another Norwegian company, Nordvik.

Mr Sandison said there were no public health issues in this case and the presence of the virus did not mean the fish from Hildasay would be worth less.

“This was a normal harvesting procedure. You put the fish through the factory and if they are fit for the market they can proceed to market as per normal and that’s what has happened. People need to realise it’s not a clinical disease outbreak and that is why you can continue to harvest the fish.”

In its information release, FRS stated: “In the particular case under investigation from fish sampled in Shetland, no characteristic visual symptoms (particularly darkening of the liver, severe anaemia and visceral haemorrhage) have been observed.”

There are various theories about how the disease spreads. During the last outbreak the virus was found to be present in wild sea trout in Laxo Voe but no case has been recorded of a wild fish being found with the clinical disease, according to FRS. The biggest risk of transmission comes from movement of live fish, discharge of untreated blood and waste and contact with infected vehicles and equipment.

There have been suggestions that the Scottish salmon industry has dropped its guard against ISA in recent years, failing to adhere to the disinfection and environmental control regimes encouraged during and after the first outbreak. Mr Sandison did not accept that charge although he admitted that people needed to be reminded from time to time why the procedures were crucial to avoiding diseases.

ISA was first discovered in Norway in 1984 and is currently raging in Chile, costing about 6,000 jobs so far on fish farms and factories. It almost destroyed the Faroese salmon industry in 2000 and has also hit Canada, the US and Ireland. Vaccines are still being trialled but are not yet commercially available.

The disease first appeared in Scotland in May 1998 and was found in Shetland in August that year at Millburn Salmon in Mangaster Voe, Northmavine, which was then owned by the Johnson family. They were growing smolts for Marine Harvest McConnell, having received them four months before from a well-boat which had been in contact with a Scottish farm which was found to be infected a few days later. The infection went unnoticed for four months, allowing it to spread to other farms.

Eventually by the all-clear in November 1999 a total of 11 farms in Shetland and Scotland had been confirmed with ISA and 25 had been placed under suspicion. The cost to the industry was put at £30 million. There was a suspected case again in 2004 in South Uist but it was never confirmed and Marine Harvest culled and buried the fish voluntarily.

About John Robertson

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