Arran seabed restoration championed by Sir David Attenborough

Don MacNeish and Howard Wood have almost a century of recreational diving experience between them so when they saw the seabed off the Isle of Arran being destroyed they took action.

The pair spent years convincing the Scottish government to create Scotland's first "no take zone" in Lamlash Bay which halted all forms of fishing.

As world leaders gather in the south of for the UN Oceans Conference, their story is being showcased as a prime example of how the seas can be protected.

Don has featured in the latest David Attenborough film, Ocean, which was released to coincide with the summit.

The destruction the pair witnessed was being caused by bottom trawling and dredging which involves dragging heavy equipment or nets along the seabed to scoop up the catch.

The "no take zone" - introduced in 2008 - banned all forms of fishing within an area of one square mile.

Seventeen years on and the zone, along with the Marine Protected Area (MPA) surrounding it, has naturally restored to create a nursery ground for young fish and marine life.

Lobster populations have quadrupled while the number of king scallops has increased six fold.

But it could take two centuries for it to become the complex, balanced ecosystem it once was.

A focus of the UN Oceans Conference is expected to be the environmental damage caused by bottom trawling and dredging.

• UK proposes wider ban on destructive bottom trawling

"Because we were part of the first divers that went down to the sea bed round about Arran, we started to see the damage that was being caused and realised that unless we can bring up these images, people wouldn't understand," Don said.

Howard added: "There was the odd star fish left but basically the whole sea bed was just raked away."

The pair said they originally gathered together local fishermen in a pub and asked them which area of the sea would inconvenience them the least if it were to be closed off.

They pointed to Lamlash Bay between Arran and Holy Isle.

There followed a years' long battle with politicians and civil servants before the protected area was finally created.

A Marine Protected Area was later added, covering the waters around south Arran which restricted some, but not all, forms of fishing.

Don, who is 78, has an engineering background and first began diving in the early 1980s while Howard, a 70-year-old horticulturalist, first dived in 1974.

In the film Ocean with David Attenborough, Don delivers powerful testimony of how he had witnessed alarming changes to the seabed since the three-mile limit was scrapped in 1984.

The limit banned inshore dredging and trawling and many creel fishermen would like to see it return.

Creel fishing involves baited traps being left on the seabed which are usually collected a few days later.

It is considered to be a "low impact" method compared with bottom trawling and dredging.

The Scottish Fishermen's Federation has said these methods are only damaging if they are carried out "in the wrong place" and that Scotland's waters are already heavily managed.

It added that dredging and trawling were "really efficient methods of producing food" and that the right balance needed to be struck between food production and protection of the seas.

But conservationists have long argued that many MPAs do not offer any protection at all against damaging fishing.

Don says David Attenborough's film is "absolutely crucial" in highlighting the damage caused to the seabed by some forms of fishing.

He wants people to start taking personal responsibility for what they eat and says small pockets of nature need to be allowed to reproduce to seed wider areas.

Howard added that there needed to be "proper" protection of the seas - banning damaging fishing methods.

The men are backing a call from the Our Seas coalition to ban bottom trawling and dredging in 30% of Scotland's inshore water.

Although the pair don't dive as much as they used to, both revisited the "no take zone" together a couple of years ago to see what progress was being made.

Don said: "I just couldn't believe the regeneration that had happened and I was just swimming along with a demand valve in my mouth and a huge smile on my face. This is what it was all about.

"I'm all for fishing, but not necessarily everywhere. We just need small pockets of protection to be able to reseed the entire area."