
This in-depth piece about the history of the “three mile limit” comes from John McIntyre, courtesy of the Sea Change blog.
The Scottish Creel Fishermen’s Federation submitted a report to Cabinet Secretary Fergus Ewing in May 2017, which outlines the case for better spatial management and a modernised return of the 3 Mile Limit. It can be downloaded here.
The aim of all fisheries management is to maintain a rich fishery (and ecosystem) and hence wealth and jobs. If we fail to do so we become poor and hungry – at least for fish.
The goal of wealth and jobs was why the three mile limit was set in place and then later removed. It was created to protect spawning grounds and maintain the fishery. It was then removed in 1984 after a decade of debate following the recommendation of the Cameron report.
“As we have already noted, most of the commercially exploited fish stocks move freely to and fro across the limits and any relief afforded the stocks in inshore waters by such prohibitions is offset by the additional effort imposed on the same stocks in offshore waters. Such regulations may affect the distribution of fishing effort but they do not restrict the total intensity of effort—and it is the intensity of fishing which matters.”
The report was right in the sense that it is the total intensity of effort that matters. Since this was not controlled we sieved the fish out of the sea, and in doing so put the common skate on the IUCN red list. It was wrong in that the damage done by unrestricted bottom trawling was not in fact well understood then.
That is not to say that all trawling is bad, just that where it is allowed needs to be based on knowledge of local conditions.
The Cameron Report
In 1970 The Cameron Report looked at the existing law governing inshore fishing with a view to remove it and replace it with something simpler. (The report is worth reading if you want a concise review of the pre-existing legislation without having to search for and read through several hundred years of law.)
Its main conclusion was the prohibition on the use of mobile gear within the three mile limit should be removed. This was because fisheries scientists advised that it was not needed for conservation. They did however advise that plaice spawning grounds should be protected. And that an efficient monitoring system should be set up, so that limits on effort could be imposed if stocks declined.
Before the internet made searching relatively easy the only way to find out what was known about a fishery, for example herring spawning grounds, was to spend many days systematically reading through decades of old journals to construct a picture of the state of knowledge that could be looked up if it was needed.
It was known in 1959, (21 years before The Cameron Report was published), that herring spawned in the Firth of Clyde on the Ballantrae Bank and in shallow water on the South West corner of Arran. This fact did not make it into the Cameron report and no protection was recommended.
The Firth of Clyde
Callum Roberts & Ruth Thurstan describe the results in “Ecological Meltdown in the Firth of Clyde, Scotland: Two Centuries of Change in a Coastal Marine Ecosystem.”
“The trawl closure within three nautical miles of the coast was repealed in 1984 under pressure from the industry. Thereafter, bottom fish landings went into terminal decline, with all species collapsing to zero or near zero landings by the early 21st century.”
“Herring fisheries collapsed in the 1970s as more efficient mid-water trawls and fish finders were introduced, while a fishery for mid-water saithe underwent a boom and bust shortly after discovery in the late 1960s. The only commercial fisheries that remain today are for Nephrops and scallops.”
Many other things of ecological importance were not known in detail or at all. For instance, little was known about distribution and abundance of seaweeds. This led David Bellamy to set up a baseline kelp survey with the help of the BSAC in 1967/8. It is to be noted that Maerl, a corraline pink seaweed, which is now highly protected was dredged to replace lime as an agricultural soil conditioner.
And yet a thread of knowledge from the observation of fishermen and early fisheries science ran through the laws that banned beam trawling and caused the three mile limit to be set in law. Time and again fishermen had reported seaweed and spawn brought up in trawls and were concerned.
In 1376, English fishers wrote to King Edward III to request his intervention in the use of the “wondyrechaun,”a weighted net dragged along the seafloor to snatch up anything in its path.
The Inshore Fishing (Scotland) Act
The UK joined the EU in 1972, with the UK’s entry into the common fisheries policy not negotiated butsimply imposed by the EU as a condition of membership of the EU.
Following a period of adaptation and further consultation with the fishing industry, the Inshore Fishing (Scotland) Act 1984, removed all previous legislation and replaced it with new legislation which gave ministers power to regulate fishing in inshore waters.
It is very important to note that nursery andspawning areas were not explicitly defined or protected in law by the act, as recommended by Cameron, because the act was written to allow such restrictions to be made and removed as conditions and knowledge changed. Sadly this appears to have been forgotten.
What happened?
My first recommendation is to read Callum Robert’s Ocean of Life and take into account the quote from his research on what happened in the Clyde.
In 2014 Wester Ross Marine Protected Area was only a possible MPA yet to be designated and the management measures for it were being hotly debated. In 2014, during the early stage of the debate I was asked if I could plot a graph showing what happened when the three mile limit was removed. “Sure” I said, “Give me the data.”
But it turned out no one I knew had any. I sat down for several months of evenings, often late into the night, and typed the landing statistics from the annual reports of thefishery board for Scotland from 1882 onwards into spreadsheets to see what they showed. It is an imperfect way to work out what happened, so it must be used with caution, but it’s all I had.

The following graph shows the landed by-catch in the Scottish prawn trawl. It has been corrected for effort. © John McIntyre
I am not sure how much the decline is due to unintended damage to habitat and spawning grounds and how much is due to over fishing. Or to the cascade of change that happen when part of an ecosystem is removed.
I have tried to look at other factors too: agricultural run-off, the effect of detergent, TBT antifouling, plastic pollution and rising water temperatures etc. But there has been so much technological and environmental change in a hundred years that it’s hard to know how the complexity of all these factors fit together to produce the changes we see.
What should we do?
It seems to me the real goal is to negotiate a transition to an inshore fisheries management that:
- Provides a good living with job security in the long term for the maximum no. of people;
- Provides a living for fishermen during the transition;
- Does the above based on joined up ecological thinking, which builds an economy of businesses that create wealth but have a low or minimal impact on the environment.
The factors that must be considered in planning this are how to limit effort and the need for large no take zones to help reseed areas. Counter intuitively these have been shown by science to actually benefit fisheries.
Should we limit effort by fishing with a few large boats or a larger number of smaller boats? Which of these choices has the least energy cost in materials and fuel and which produces the greatest benefit for fishing communities?
The Cameron Report suggested boats up to 80 feet should be allowed to trawl inside of the three mile limit. The assumption being that bigger boats would produce a higher catch and profit for a few ‘efficient’ hard working crews. While this may well be the case I am not sure it is the best solution if one of the aims of management is job creation and security.
But bear in mind that the report was written in 1970 when energy was cheap and efficiency with little regard for the social costs was considered to be desirable. That is a political and social choice. A better choice would be to ensure stability in order to provide food and job security while avoiding repeating another marine tragedy of the commons.
Read the full blog post The Three Mile Limit at the Sea Change blog.