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Join the most recognised certification programme and benefit from trading ASC certified seafood.

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Mussel farming for the 21st century

The rope mussel farms of Offshore Shellfish Ltd are situated in open water in Lyme Bay in the English Channel between 3 and 6 miles off the South Devon coast. The ASC-certified farms produce a sustainable and delicious crop of molluscs (Mytilus edulis) each season. Once fully built, they will be the largest in Europe and produce around 10,000 tonnes of mussels per year.

To take a deeper look into the world of offshore mussel farming, we spoke to Sarah Holmyard, head of sales and marketing for the family-run company. She shared insights into the way they work with nature and study the ecology in and around the farm, to ensure they can harvest the most sustainable crop of mussels each season.

As with many family companies, ‘it’s in the blood’, according to Sarah. Both of her parents were pioneers in the seafood industry – her mother Nicki is a seafood writer and communications specialist, and her father John is a marine biologist and oceanographer. He is the brains behind the mussel farms and has spent a lifetime researching, trialling and adapting equipment to find the best method to grow a top-quality commercial crop of mussels. Oceanographer brother George also works in the business and heads up the offshore operations.

Commitment to sustainability

As with many of our ASC certified farms, sustainability is at the forefront of this business, which works closely with its stakeholders and the community.

Sarah explained that her father went into mussel farming because it is one of the purest forms of food production and ticks all of the boxes in terms of sustainability, responsible production and ecosystem benefits.

The farming process starts with custom-made ropes hung in continuous loops from suspended buoyed longlines, which are attached to the seabed with screw anchors. These collect naturally occurring wild mussel larvae, which settle as microscopic ‘spat’ during late spring. After the spat has grown for a few months, it is stripped from the ropes, then washed, graded and seeded onto new ropes at the ideal density, using a wrapping of biodegradable cotton. The reseeded ropes are hung back in the water, where the mussels are left to grow to market size. From seed settlement to harvest takes just over one year.

“We wanted to be able to produce sustainable food in large quantities to feed a growing global population, and mussels deliver on these goals. They require no external inputs, no food, no fertiliser, no medications and no fresh water. Nothing is added – we just give them a place to grow,” she said.

A day in the life…

Sarah tells us a bit about a typical day at Offshore Shellfish: “We start with a crew meeting in the harbour at 7am each day, where we go through the roles and responsibilities for each person and discuss the tasks for the day. The work is always different, depending on the weather, and whether we are harvesting, carrying out site or boat maintenance, drilling anchors, diving, putting out new floats to keep the lines buoyant, laying new spat ropes, or reseeding the crop… The list is long, as farming at sea, just as on land, is a dynamic process and we have to adapt to the conditions we face on any given day. We also have a shore crew tasked with refurbishing our used rope and keeping equipment maintained.”

While life at sea involves long days and often inclement weather, Sarah reflects on her favourite parts of the job: “The main part of my job is sales, marketing and logistics. I handle all of the exports and the ever-increasing amount of paperwork involved. I also liaise with our external stakeholders and government bodies. I’m mainly shore based, but I do love being out at sea, and regularly join the crew for a hard day’s work. For me there is no better place than being out on the farm, monitoring the crop, looking at the different sea life that lives in and around it, and bringing in a harvest. An added bonus is having dolphins swim alongside our boats most days.”

Economies of scale

On a harvest day, both of the purpose-built boats go to the farms. The smaller boat, named after Sarah’s daughter Alysée, has a crew of 3-4 and is used for line maintenance, and the larger one, with a crew of 5-6, does the harvesting.

On a full harvest day, Offshore Shellfish will harvest around 44 tonnes of mussels, packed into 1 tonne bags, which takes 4-5 hours. Once the mussels are onboard, the boat carries out work on the farm, usually redistributing floats, before heading back to shore to load the crop into two refrigerated lorries. The mussels head straight to a partner’s processing unit in the Netherlands, where they are processed within 24 hours of harvest. Mussels are packed live for European restaurants and retailers, or turned into award-winning ready-to-cook packs which contain fresh sauces. They can be found in retailers in Austria, Belgium, Germany, France, Netherlands, Slovakia, Romania and the Czech Republic.

The mussels are seasonal, and there is a break in harvesting when they are spawning, to give them time to recover. This is something Offshore Shellfish takes very seriously, to ensure they only deliver a top quality product.

 “For us, ASC certification was the obvious choice as it enables us to demonstrate our commitment to our customers”.

Commitment to the environment

The Offshore Shellfish farms give back to nature and are a haven for the diverse range of species found in and around the farm sites.

The company made a commitment, before putting any ropes in the water, to involve Plymouth University Marine Biologists to study the seabed, surrounding waters and the farm itself. The aim was to closely monitor any changes in the ecology of the area.

Sarah remarked that:

“What we’ve seen, recorded, and proven beyond any doubt, is that the mussel farm is hugely beneficial to the area. It has created a diverse ecosystem for hundreds of different species to breed and live, including many commercially important species such as seabass, seabream, crab and lobster.”

Remember to look for ASC’s sea green label whenever you buy seafood, to know you’re getting the most responsibly raised seafood in the world.

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