The Decline of the Firth of Clyde

The Firth of Clyde is a semi-enclosed expanse of water located on the west coast of Scotland. There is considerable debate over the exact dividing lines between the Firth of Clyde and the River Clyde. The Firth of Clyde is around thirty miles across at its widest point and much of the area contains very deep water and a number of lochs open into the Firth.

Firth of Clyde

There are also around forty islands in the Clyde, although only a handful are inhabited, with the largest being the Isle of Arran. The area has become very important for both shipping and ship building, with large amounts of industry being built up around this area over the last several centuries. Today the Clyde remains an important deep-water port and sees large amounts of commercial shipping and cruise liners every year. There is also a significant Royal Navy presence in the Clyde, with Britain’s nuclear armed Vanguard-class submarines based at HMNB Clyde.

The Abundance of the Clyde

Fishing has been one of the most important parts of the Clyde economy for hundreds of years. Prior to industrial fishing the area saw an abundance of fish species. Huge shoals of herring entered the Firth, in turn attracting cod, ling, plaice, turbot, monkfish, rays and skate (1). Blue sharks and basking sharks were also present, while large spurdog were so numerous they reached pest portions – becoming tangled in the primitive nets set out by fishermen (1). This abundance of marine life saw the fishing industry around the Firth of Clyde grow throughout the 1800s, with the combination of abundant fish stocks and the relatively sheltered waters of the Firth creating the prefect environment for the fishing industry to expand. This provided employment for hundreds of people in the fishing industry and thousands more in the related industries and supply chains, causing towns and villages around the Firth of Clyde area to grow and expand. However, even in the 1800s there was concern that there were too many fishing vessels operating in the area, and a range of restrictions were brought in to protect fish stocks, most significantly the Firth of Clyde was closed to all large bottom trawling vessels in the late 1800s (2).

A Booming Fishing Industry

Commercially Caught Cod
Commercially valuable species – such as cod – were once abundant in the Firth of Clyde.

From the post-World War Two years until the 1970s the Firth of Clyde was a booming fishery continuing to provide employment and prosperity for the people of the surrounding area. The pelagic (mid-water) herring fishery was central to the Firth of Clyde. There had been around over 40,000 tons of herring caught per year in the late 1940s (3), and in the 1960s the Clyde was still producing around 14,000 tons of herring every year (4). In addition to the commercial fishing operations there were also thousands of recreational sea anglers attracted to the area every year, putting even more money into aspects of the local economy which were not directly related to fishing, such as pubs, restaurants, hotels and guest houses. However, in the 1960s the ban on bottom trawling which had been firmly in place since the late 1800s was lifted with bottom trawling now allowed in the Firth of Clyde, although there was a ban on trawling within three nautical miles of the shore (5).

The Decline Begins

The combination of trawling close to the shore, along with the increasing efficiency of fishing vessels due to increased engine power, electronic fish finders and seabed mapping and advances in net technology, meant that the area could be fished like never before. Bottom dwelling demersal fish such as cod, hake, turbot, haddock, whiting and flatfish were now all being caught along with the pelagic (mid-water) species such as herring. However, such fishing intensity could not last and by the 1980s stocks of demersal fish were showing serious signs of depletion, while the herring fishery was also producing much less than it had in previous years (5). This should have sparked both the Firth of Clyde fishing industry and politicians into action to protect the remaining fish stocks and allow both the fish numbers and marine environment to recover. Instead the absolute opposite happened. The ban on trawling within three miles of the shore was lifted (6) allowing the entire Firth of Clyde to be intensively trawled. While this provided a short term boost to the now-struggling fishing industry it was a short-term measure which caused the remaining stocks to be effectively fished out. By the year 2000 the entire Firth of Clyde fishery was producing a fraction of the fish it had just a few decades previously. The Community of Arran Seabed Trust (COAST) quotes official government figures which illustrate the decline. The Lamlash Fishing Festival used to attract hundreds of anglers to the Isle of Arran, with seven tonnes of fish caught in 1967. This had dropped to under a ton by 1975, and by the 1990s the festival was producing under a quarter of a ton of fish (7). The festival no longer takes place.

The Switch from Big Fish to Small Crustaceans

With the main commercially valuable fish species now absent from the entire Firth of Clyde the fishing industry shrank dramatically with jobs being lost and boats decommissioned. With the stocks of herring and whitefish fish too low to support commercial fishing the fishermen who remained were forced begin ‘fishing down the food chain’ by turning their attention to fishing for prawns, scallops and nephrops (a crustacean species which is also known as Norway lobster, Dublin Bay prawn and scampi).

Nephrops now make up the majority of commercial catches in the Firth of Clyde.

With their predators removed these species had been rapidly increasing in number and the market for this type of species had also been growing rapidly. However, this new type of fishing came at a price. Very fine mesh nets needed to be dredged across the seabed to catch these species. This caused further damage to the already ravaged ecosystem and effectively stopped any form of recovery from taking place. Along with the nephrops fishery has a horrific level of bycatch – for every kilogram of target species caught nine kilograms of bycatch is discarded. This means that effectively 25,000 tons of fish and other species are discarded in the Firth of Clyde every year by the nephrops fishery alone (6). With such damage being done to both the marine environment any chance of the Firth of Clyde fishery recovering to even a fraction of its former productivity looks very remote.

Indeed, by the early 2000s the Firth of Clyde was described as being on the verge of becoming a “marine desert” and the entire ecosystem of the area was described as being in “meltdown” (8). The herring are now so reduced in the area that stocks are classed as too low to merit economic assessment (3), and the cod and haddock fisheries, having declined from over 90% of their peak catch rates, are now classed as collapsed in the Firth of Clyde (3).

Advocates of commercial fishing point to the fact that there is still some fish in the area, but often neglect to mention that it is immature whiting which dominate, and the vast majority are well below the legal landing size (4). Sea angling still takes place in the Firth of Clyde but it is a shadow of former times, with dogfish and small whiting making up the majority of catches. Only the summer mackerel still arrive in anything approaching decent numbers.

As of 2008 nephrops made up the vast majority of commercial catches from the Firth of Clyde as the table below shows:

The Clyde’s over-reliance on nephrops is seen as a major cause of concern. Parasites, disease and climate change could all seriously reduce nephrops numbers in the future, with the several world-renowned experts stating that the fishery is already living on “borrowed time” (9), as an ecosystem dominated by just a few species cannot be healthy and is itself unsustainable in the long term. The Community of Arran Seabed Trust (COAST) state that the following species are now so reduced in number that they are – in commercial terms – absent from the Clyde: Herring, Turbot, Cod, Whiting, Plaice, Saithe (Coalfish), Ling, Hake, Halibut, Dab, Angler Fish (Monkfish), Flounder, Skate and Rays (10).

The Future of the Clyde

There are now some limited measures to attempt to rebuild fish stocks in the Firth of Clyde. Commercial fishing for herring is banned at certain times of the year and fishing is not allowed to take place across certain spawning grounds at other times. There is also a No Take Zone (NTZ) in Lamlash Bay, Isle of Arran where all forms of fishing are banned, including recreational sea angling. These NTZ was set up in 2008 and is approximately one and a half square miles in size. There are also plans for Marine Protected Areas (MPAs) in the Firth of Clyde (11). The inshore fishery authorities have taken action to attempt to reverse the decline by appointing staff specifically to take action to restore the fishery, while there have also been petitions and public action to draw politicians attention to the plight of the Firth of Clyde (12). Indeed, the lack of political interest in the decline of the Firth of Clyde has been remarkable, with many blaming politicians for taking action only to support the short term interests of the fishing industry and ignoring the medium to long term sustainability of the whole fishery (10).

In 2015 an application was made to establish a Regulated Fishery in the Firth of Clyde (13). This would create some zones where fishing would be banned to allow the marine ecosystem to recover and a more varied range of marine life to re-establish itself in the Firth of Clyde. In other areas commercial fishing would be limited to methods which have less impact on the environment such as diving and setting creels and traps for shellfish, while dredging and other forms of damaging fishing would still be allowed in the remainder of the Firth of Clyde (13).

Fergus Ewing
Fergus Ewing

In 2016 the Scottish Government announced that after careful consideration they would not be able to support the application to create a Regulated Fishery in the Firth of Clyde (14). The Scottish Rural Environment Secretary Fergus Ewing said that the reasons for declining the order were because of “practical difficulties in managing quota,” [issues with] “fleet flexibility,” and “a low level of support from those who would be directly managed by the Regulating Order” (14). The Scottish Fishermen’s Federation (SFF) welcomed the decision to reject the order with Bertie Armstrong, the Chief Executive of the SFF stating:

“The imposition of a Regulating Order and the consequent restrictions on legitimate and sustainable fishing would have devastated Clyde fishing communities. “The Clyde fishery is already very carefully managed … We are pleased that the Cabinet Secretary has listened to the compelling case put forward by the fishing industry and has moved to protect our fishing communities and ensure a sustainable future for the Clyde fishery (15).”

If the Scottish government is not prepared to act now to restore the marine environment of the Firth of Clyde it is difficult to see when they will finally take action. The Scottish fishing industry clearly do not believe that there is a problem with the current state of the Clyde fishery, and until they face facts and get on board with conservation efforts (even if that means a reduction in commercial fishing) it is difficult to see anything changing.

Lamlash Bay No Take Zone
The No Take Zone (NTZ) at the northern end of Lamlash Bay, Isle of Arran. This NTZ came into force in 2008 and is the first one in Scotland. No marine life can be removed from the zone by any methods, commercial or recreational.

The tale of the Firth of Clyde is a sorry story and one we have seen repeated around the world. Although less famous than the collapse of Canada’s Grand Banks fishery the decline of the Clyde has been just as depressing, and avoidable. While the actions being taken to restore fish stocks in the Clyde are welcome they are only a tiny step in the right direction, and while the Clyde is being intensively fished for prawn, crustacean and shellfish species by a commercial fishing industry resistant to change it is unlikely that any meaningful recovery will take place.

Update: In October 2021 an article in the Guardian looked at the recovery of the Clyde. It found that while fish stocks had recovered due to a reduction in fishing it was sprat which had become the dominant species. The reason for this is not currently known, but could be down to warming seas due to climate change or that conditions favour sprat reproducing more than other species. There was also controversy over plans to protect cod by limiting commercial fishing.

Revive the Clyde is a campaign ran by SIFT (Sustainable Inshore Fisheries Trust) which aims to work to restore the Clyde and help make the changes which will once again lead to the Clyde becoming a diverse and healthy fishery. You can pledge your support by signing the Clyde Charter by clicking here, and follow the campaign on Twitter and Facebook.


  1. Ecological Meltdown in the Firth of Clyde, Scotland – Two Centuries of Change in a Coastal Marine Ecosystem – Environment Department, The University of York
  2. The Firth of Clyde –
  3. Fisheries Manager Appointed to Restore Clyde Fishery – SIFT (Sustainable Inshore Fisheries Trust)
  4. Recovering the Clyde – Scottish Environment Link
  5. The Parable of the Clyde – The Economist
  6. Human Impacts: Fisheries –
  7. Arran Community Imposes No Fishing Zone – The Guardian
  8. Clyde Cleaned Out to Become Marine Desert – The Sunday Times 11/7/2010.
  9. Clyde Prawn Fishery on Borrowed Time, Says Study – The Scotsman
  10. Firth of Clyde – CoastMS
  11. Arran’s Community Marine Reserve No Take Zone –
  12. Save Fishing on the Clyde (SOS) – Petition |
  13. Firth of  Clyde Regulating Order Application – SIFT (Sustainable Inshore Fisheries Trust)
  14. Fishing Order in Firth Denied –
  15. SFF welcomes rejection of Regulating Order proposal for Firth of Clyde –
  16. Clyde’s Fish Stocks Start to Recover – With a Different Fish Than Before – The Guardian