I recently had the chance to spend a day out on the water with our Marine Officer, Lara, carrying out BRUV surveys in the Western Irish Sea Mud Belt. BRUV stands for Baited Remote Underwater Video. A camera is positioned facing a container of bait, which attracts marine life into view. We can then leave the equipment on the seabed for an hour, collect it, and see who stopped by by checking through the camera footage. It gives us a window into life beneath the surface without disturbing the seabed or the animals living there.
The BRUV units are dropped at locations, both inside the Western Irish Sea Mud Belt temporary closed areas and in the open areas outside it, this closure is temporary for mobile fishing gear. Each unit is attached to a buoy by a rope, so once it has been recording long enough, we can find it and bring it back up. After around an hour, we retrieve the unit, change the batteries and replace the bait, ready for its next drop. The footage then has to be watched back, and the species appearing on camera are recorded and counted. These surveys are particularly useful because they are efficient, standardised and non-destructive, and are generally less selective towards particular species or sizes of fish.
The Irish Sea has two large muddy areas. One lies to the east of the Isle of Man, towards Morecambe Bay, while the other is to the west; this is the Western Irish Sea Mud Belt (WISMB). This stretches from around five miles off the coast of Peel and extends almost as far as the Irish coast. This muddy seabed plays an important role in storing carbon.
We often hear about forests and peatlands when we talk about carbon storage, but the sea plays an important role too. Blue carbon is carbon captured and stored by marine and coastal ecosystems. This includes habitats such as seagrass meadows, saltmarshes and seabed sediments. Research estimates that the WISMB is the largest blue carbon store within Manx territorial waters, with around 510,312 tonnes of carbon held in its surface sediments. It is also estimated to bury around 11,319 tonnes of carbon each year, equivalent to roughly 7% of the Island's annual greenhouse gas emissions.
The WISMB has been an important fishing area for decades. At the same time, research has shown that areas experiencing higher levels of trawling can have significantly depleted organic carbon. Scientists are continuing to investigate exactly how fishing activity affects carbon storage and burial within the mud belt. By collecting information about the species living in and around these habitats, we can build up a better picture of what is actually happening beneath the waves.
The Manx Blue Carbon Project has also been looking at a whole range of marine and coastal habitats around the Island. These include seagrass meadows, saltmarshes, kelp and other large brown algae, horse mussel reefs and maerl beds, as well as offshore sediments. Each habitat has its own characteristics and benefits. Seagrass, for example, provides nursery habitat for young fish and supports a variety of marine life. Saltmarshes help protect our coastlines by absorbing wave energy and reducing erosion, while also providing valuable habitat for wildlife.
The Manx Blue Carbon Project is a collaboration between the Isle of Man Government's Department of Environment, Food and Agriculture, the National Oceanography Centre, Swansea University and Bangor University. The first phase of the project focused on understanding our blue carbon habitats, assessing their carbon storage, examining biodiversity, and identifying ways they could be better protected and managed. There is still plenty to learn, particularly about how human activities affect carbon storage in the Western Irish Sea Mud Belt. Further research is underway, with important results expected in 2026. The recommendations include continuing research, monitoring the mud belt over the long term and using the findings to inform future marine planning, fisheries management and conservation.