FOR generations their annual arrival off Scotland’s shores sparked a fishing frenzy that kept thousands in work.

Herring was the lifeblood of coastal communities right up until the Second World War until the fatty fish was almost killed off.

Now, for the first time ever, huge shoals of spring spawning herring off the north-west of the country, sparking feint hopes that stocks might one day recover.

The images were captured close to Gairloch for the BBC’s ground-breaking Blue Planet UK series broadcast on Friday.

Local fishermen have been watching the fish throughout the month of March, suggesting they were were likely to spawn in the area.

These Atlantic herring, which once underpinned a thriving west coast industry, have remained at historically low levels for years.

Populations of the fish across Scotland collapsed in the 1970s and 1980s, and although there has been a gradual increase in North Sea herring, west coast stocks are still recovering from decades of over-exploitation.

Nick Underdown of the campaign group Open Seas said: “Shoals of fish returning to spawn in Gairloch is hugely exciting. Given the boom and bust history of the herring fishery, these fish need all the help they can get.

“Herring are one of the foundations of healthy seas. If the stock was to recover on the west coast it could underpin the future of our fishing industry and rural communities for decades to come. Spawning grounds are precious and we are urging the Scottish Government to protect the full, known extent of the herring spawning ground in Gairloch”.

Every year herring swim from deep offshore seas towards our coasts where each female fish lays tens of thousands of eggs.

The eggs stick to the seabed and after a few weeks develop into fish larvae - the next generation.

Herring spawning used to take place in such huge numbers that there are tales of the waters turning white with fish eggs.

Such massive spawning events give food to seals, seabirds, dolphins and other fish, and where stocks are healthy, such as in Canada, these events still bring in huge numbers of other marine wildlife. A famous spawning ground in Gairloch has been closed to bottom-towed fishing, such as prawn-trawling and scallop dredging, for over 150 years.

West coast herring stocks continue to decline and the International Council for the Exploration of the Sea (ICES) says that all measures should be taken to protect the places where herring spawn to improve their chances for the future.