At current rates of decline, scientists predict our seas could be empty of fish within 40 years. With a billion people eating fish as their primary source of animal protein and 200 million people depending on fishing as their only source of livelihood, that would mean a humanitarian disaster.

In 2008, Scotland established its first fully-protected marine reserve off the coast of the island of Arran. This followed a decade of campaigning by a community-led organisation called COAST - the Community of Arran Seabed Trust.

The Clyde once had a thriving fishing industry employing well over a thousand people, with the area known for its plentiful cod and herring. However, after years of overfishing, including destructive dredging and trawling which rake up the sea bed and destroy fish habitats, the industry had significantly declined.

The goal of the 'no take zone' is to help regenerate the local marine environment, and enhance commercial shellfish and fish populations. Already there are signs of life returning - seaweeds, macro algae, sponges and corals, which provide habitats for a huge array of fish and shellfish.

Following these encouraging early results, COAST are proposing a marine protected area a hundred times bigger, which will contain two important spawning areas. If these breeding grounds are protected, fish stocks are likely to recover - good news for fisherman in surrounding areas.

Oliver Steeds dives to the sea bed, to find out how the marine ecosystem is recovering.

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