7/5/2017 10:14:45 AM News

New suspended rope mussel farm within the Cromarty Firth.

Cromarty Mussels

News from the Cromarty Firth on a new mussel farm in the process of being established by Association of Scottish Shellfish Growers member Andrew Jones. The Firth has produced farmed salmon, mussels and oysters in the past but there has been no activity for some years. The Firth has a 15 metre deep channel with bays on either side, a narrow mouth and a tidal range of 4.5 metres.

Andrew reported, "I set out to incorporate the latest developments and technology from around the world into the farm infrastructure, aiming to maximise yield with low operational costs and minimal environmental impact. The anchor, mooring and buoyancy equipment has now been installed for the first phase of 12 longtubes.

Cromarty Mussels Ltd has received funding from the Scottish Government and the EU through the European Maritime and Fisheries Fund (EMFF) towards the capital cost of this equipment and the installation work was carried out in March by two companies, AquaMoor and Fusion Marine based near Oban.

I decided to use helical screw anchors which may be the first such installation in Scotland. Helical screw anchors were first used as lighthouse piles in the mid 19th century and are regularly used in the land based construction sector. Their aquaculture application has been developed and used in New Zealand and Australia for over twenty years and recently they have been installed on the UK's largest off shore farm on the south coast.

The buoyancy is provided by 315mm diameter PE pipe, welded together onshore to form 263 metre 'longtubes'. It took two weeks to fabricate the twelve longtubes utilising three automatic butt fusion welding machines.

Longtubes are not widely used yet but are in the sea off Galicia and in the Mediterranean. The use of PE pipe has long been proven in the manufacture of salmon pens located in harsh conditions around the world. The next stage will be to develop a method for putting out the spat rope in the strong, two-knot current for the mussel spawn to attach itself to.