Sleeping with the fishes

1st May 2020

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  • Biodiversity


Jo Gillen

David Burrows explores the environmental record of Scotland's salmon-farming industry, and what aggressive expansion could mean for nutrition and local ecosystems

Last year, Scotland exported record amounts of its farmed salmon; some 94,000 tonnes were sold to 54 different countries. The product's “good environmental story, with its small carbon footprint and low water use, plus global recognition of its taste, quality and provenance, is clearly understood in almost every corner of the globe,“ says Julie Hesketh-Laird, chief executive at the Scottish Salmon Producers Organisation (SSPO).

Scotland has done a brilliant job of marketing its salmon as both “climate friendly“ and healthy. However, look beneath the surface and there are secrets lurking in the dark of the vast open-net cages used to produce the fish. “By wreaking havoc on the environment, the salmon industry is in the process of destroying its own marketing strategy, along with Scotland's image as a quality food producer,“ wrote Lynn Schweisfurth, a member of the Salmon Aquaculture Reform Network Scotland, in 2018.

Rising controversy

During the past two years, the sector has been the subject of a damning BBC Panorama investigation – in some farms salmon were being “eaten alive“ due to severe infestations of sea lice – plus two inquiries by MSPs that questioned the sector's plan to double production by 2030. “There's not many places I've regulated where we've had such controversy around a whole sector,“ Terry A'Hearn, chief executive of the Scottish Environment Protection Agency (Sepa), told me recently.

He was speaking prior to the publication of Sepa's latest compliance assessment scores. These show whether the thousands of sites being monitored by the regulator are complying with specific environmental licences. Aquaculture has traditionally been a laggard – and continues to be. The 2018 scores, released in February, showed that 85.5% of the 372 sites were compliant: an improvement on 2017 (81.14%), but below 2016 (85.75%). Compare this with whisky, distilling and brewing – another Scottish economy powerhouse – which managed 95.5% compliance, and fish farms clearly have a long journey ahead.

Farms tend to fail because they don't adequately protect the seabed from the organic waste that floats down onto it. This is largely faeces and uneaten feed, and there are 40,000 tonnes of it every year, according to campaigners. The waste leaves a 'footprint', smothering the seabed and the creatures that live in this benthic zone. Given that most of the farms use open-net cages, some of waste also disperses far and wide.

Farmers have long found it tricky to tackle this issue. The government flagged it all the way back in 2002, and MSPs who looked afresh (and in great detail) more recently found the same old problems – but the scale and impact had increased. “The sector continues to grow and expand with little meaningful thought given to the impact this will have on the environment,“ noted the Environment, Climate Change and Land Reform Committee. It also stated that “if the current environmental impact issues are not addressed, the expansion will be unsustainable and may cause irrecoverable damage.“

This was a blow: the sector had plans to double production to 350,000 tonnes of salmon by 2030 (against 2016 levels), but now MSPs were pushing for a “precautionary approach“. Sepa changed its approach and updated its modelling to better predict how waste will be distributed as it reaches the seabed. Cathy Tilbrook, head of sustainable seas and coasts at Scottish Natural Heritage, another organisation involved in overseeing the salmon sector, says the previous model wasn't giving the correct answers in some cases, but the new one is “more sophisticated“.

“I think we need to not kid ourselves about the new modelling and what this is designed to do for benthic pollution“

Trouble ahead

Others are not convinced. “I think we need to not kid ourselves about the new modelling and what this is designed to do for benthic pollution,“ says Guy Linley-Adams, a solicitor who works for Salmon and Trout Conservation Scotland (S&TCS). “Sorry to be cynical, but one senior Sepa person once told me that his view was that there is an awful lot of sea bed out there, so 'so what' if the fish farmers trash a little?“

What's more, the new model could permit even bigger farms – the previous limit was 2,500 tonnes, but plans have been submitted for a 20-cage, 5,000-tonne farm off the coast of Arran. Local campaigners say this will produce faecal waste equal to a town of 66,000 people, not the 14,000 claimed by the owners, Scottish Salmon Company.

The size of the farm has made it national news. However, there are a number of other new plans in the system, amounting to another 14,000 tonnes of salmon production. The likes of the SSPO has complained that these are stuck in a regulatory system that is “tangling companies up“, but environmental groups argue there shouldn't be any expansion until the sector improves on its environmental record and get to grips with the issue of sea lice.

These parasites have hit production volumes hard and are proving pesky to control. Data compiled by the S&TCS showed that the average adult female sea lice count per fish almost doubled between April 2018 and April 2019. The government recognises that farming salmon can result in elevated numbers of sea lice in open water, and increase infestations in wild fish – but the extent of the impact on wild populations and mortality isn't well understood.

Better to be safe than sorry, then, because the treatment options aren't ideal either. Chemicals have traditionally been used, but their residues are hanging around for longer and spreading much further than previously thought. There are also issues with so-called 'cleaner fish' – demand for these to help address sea lice infestations has soared, putting some wild stocks at risk. The welfare of these fish from capture to deployment is “also a concern“, the Marine Conservation Society has warned.

“If nothing is done, the level of beneficial omega-3 can only really go down“

Declining nutrients

The capture of wild fish to feed the salmon is another worry. “We catch fish in various parts of the world, process them into salmon food, and then feed them to salmon. That is highly inefficient,“ professor Ian Boyd, then chief scientific adviser for Defra, told MPs in 2018. Double production of salmon and the demand for these resources will inevitably increase.

The hunt is on for alternatives, with algae and genetically modified crops the subject of attention. This is because vegetable oils and protein are proving inadequate replacements for oily fish in the salmon's diets. As Corin Smith, founder of the campaign group Inside Scottish Salmon Feedlots, explains, it's a bit like feeding a lion corn on the cob: it's not going to go down as well.

Greater use of vegetables and plants in the feed has also had a knock-on impact on levels of long-chain omega-3 fatty acids in Scottish salmon. Research of 3,000 farmed fish between 2006 and 2015 by the University of Stirling showed a dramatic fall – so dramatic, in fact, that people have to eat “double portion sizes“ to meet the weekly recommended intake of these health-promoting fatty acids. “Farmed salmon is just about the best way of getting omega-3 in our diet,“ lead researcher Professor Douglas Tocher told the BBC. However, “if nothing is done, the level of beneficial omega-3 can only really go down“.

Despite all the scandals and criticisms, salmon companies still have plans for production to go up. “We can do better and we are determined to do better,“ says SSPO's Hesketh-Laird, adding that the target to double growth is not under review. Campaigners will keep pushing for a moratorium on expansion, though. “Scottish ministers need to act now and stop kicking the necessary decisions into the long grass,“ said Linley-Adams.

Politicians are not as worried as they once were. In January, SSPO published a survey of MSPs showing that 43% now viewed the sector favourably, compared to 34% in 2018. Only 20% had a poor impression. Whether this is because the sector has leaped into action and is tackling its challenges head on, or because it has spun a good story, is a moot point. “The industry hasn't reacted as well as it could have done,“ admits a senior source in the industry. However, it is “the healthiest, most sustainable source of protein you can grow.“ Proving this remains a challenge.

Sizing up Scottish salmon

94,000 tonnes of farmed salmon were exported from Scotland to 54 different countries in 2019 – a record amount

Double portion sizes of farmed salmon are now required to meet the weekly recommended intake of omega-3

40,000 tonnes of organic waste floats down onto the seabed each year. This is largely faeces and uneaten feed

David Burrows is a freelance writer and researcher.

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