Sepa gave 400 Scottish lochs 'good' environmental status but only checked 54 of them

The monitoring of marine pollution by the Scottish Government’s green watchdog has been dubbed a “scandal” following the discovery that it rates 400 of Scotland’s coastal waters as being environmentally fine based on wildlife samples from just 54 of them.

The Scottish Environment Protection Agency (Sepa) samples insects, crabs and worms from single sea lochs to classify as many as 20-40 other lochs as having a “good” or “high” environmental status. They can be up to 58 miles apart. 

In one case, a loch known to be polluted by the salmon farming industry has been rated as good based on ten-year-old samples from another loch 12 miles away.

Campaigners accuse Sepa of “flying blind”, and describe the monitoring regime as “not fit for purpose”. More resources need to be devoted to ensuring the health of Scotland’s seas and encouraging nature recovery, they say.

Sepa is planning to “comprehensively review” its monitoring of the marine environment, with the aim of implementing new arrangements in 2027. It defended using samples from “representative” sea lochs to classify other lochs as “an established scientific approach”. 

In response to a freedom of information request, Sepa released a large spreadsheet listing the coastal waters and firths which are “classified as part of a group”. It reveals that 87 per cent gain their good ratings from samples of wildlife taken from elsewhere.

Samples from Loch Ewe by Poolewe in Wester Ross are used to classify 40 other sea lochs and straits as environmentally acceptable. These include Loch Broom, which is 12 miles east as the crow flies, Loch Alsh, which is 37 miles to the south, and the Kyle of Tongue which is 58 miles to the north.

Samples from Loch Erisort on the Isle of Lewis are used to rate 35 other lochs on islands as far away as North Uist, Benbecula and South Uist. Samples from Olna Firth on the Shetland mainland help classify 33 other voes and firths, including Burra Firth over 31 miles to the north in Unst.

According to Sepa, Loch Sunart, south of the Ardnamurchan peninsula, was last tested for wildlife in 2016. Those samples have helped classify 21 other sea lochs as environmentally fine.

One of them is Loch Creran, which is 12 miles to the south on the other side of Loch Linnhe. It is rated as “good” despite having a known pollution problem. 

The Ferret reported in July 2025 that Sepa had banned a salmon farming company from dumping pesticides in Loch Creran following 273 environmental breaches over six months. According to the Scottish Government’s wildlife agency, NatureScot, rare reefs in the loch were in an “unfavourable declining” condition.

Ban on salmon farm polluting loch after 273 breaches

A ban on a Norwegian salmon farming company dumping toxic pesticides in a Highland loch following 273 environmental breaches over six months has been strongly defended by the Scottish Government’s green watchdog. The Scottish Environment Protection Agency (Sepa) insisted that it was “proportionate and reasonable” to suspend a licence

The FerretRob Edwards

But Sepa argued that there was a “strong evidence base for a robust decision” on the loch’s classification as good. "There is no evidence that the water body’s status is likely to have changed since 2016,” it said.

According to Sepa, the last time wildlife samples had been taken in Loch Creran itself was 2005. 

The state of all Scotland’ waters are published on Sepa’s online water classification hub. The vast majority of coastal waters and firths are rated as “good” or “high”, with only eight having a “moderate” or “poor” environmental status, including parts of the Clyde, Forth, Solway and Ythan estuaries.

The Coastal Communities Network, which brings together 30 groups around Scotland concerned about the marine environment, described Sepa’s water classification system as a “scandal”. It obtained the spreadsheet on sampling locations from Sepa under freedom of information law.

It was a “very odd and misleading” way of assessing how polluted the seas were, said the network’s John Aitchison. “Sepa's admission that it is going to review how it samples water bodies, starting next year, seems to show that it knows the system is not fit for purpose.”

He added: “There seems to be far too little money put into monitoring the health of the sea, even though so many people’s jobs and communities depend on it.

There seems to be far too little money put into monitoring the health of the sea, even though so many people’s jobs and communities depend on it. — John Aitchison, Coastal Communities Network

"Sepa gives the impression that it knows what is happening in the sea but in most places it is actually flying blind. Nature recovery is not going to happen unless we can trust regulators to properly check how it is doing at the moment, and to report on that clearly, especially when they do not know.”

The Scottish Greens urged Sepa to explain the rationale behind its sampling regime, and address concerns. “Many people would be surprised to know that such clear and far-reaching conclusions about the quality of our lochs and waters are being drawn from such limited samples that come from totally different sources,” said the party’s rural affairs spokesperson, Ariane Burgess.

“This raises fundamental questions about the quality of the analysis that is underpinning these classifications and the conclusions that are being drawn from it.”

In its freedom of information responses, Sepa said its monitoring was "prioritised based on risk” and that it intended “to comprehensively review our approach to evidence gathering for the marine environment by March 2027, and implement thereafter.”

Sepa told The Ferret that it drew on a wide range of evidence to inform its understanding of Scotland’s water environment, which was “kept under review”. This included monitoring polluters, computer models and environmental samples.

“Using data from representative water bodies to inform the classification of similar waters is an established scientific approach. Water bodies are grouped based on shared characteristics, allowing monitoring to be targeted where it provides the most value while still supporting a robust national picture,” a spokesperson said.

“This work is complemented by wider marine monitoring and evidence from partners including the Scottish Government’s Marine Directorate and NatureScot, ensuring a more complete understanding of Scotland’s coastal waters.”

Sepa would be consulting on its planned review of water monitoring “later this year” with the aim of developing a plan to cover 2028 to 2034. 

“Regular review of our monitoring priorities and programmes is essential to ensure our approach keeps pace with advances in science and technology and responds to emerging risks to the environment,” the spokesperson added.

Sepa was working closely with NatureScot to understand the condition of the rare reefs in Loch Creran. Where breaches of environmental regulations were identified, it promised to take “appropriate enforcement action”.