ROV Protecting seagrass, one mooring at a time blog

Saving the Seagrass: How two clever mooring tricks - and an ROV are bringing Strangford Lough back to life

Seagrass Matters More Than Most People Realise

Strangford Lough is the largest sea lough in the United Kingdom, and it’s one of Europe's most biodiverse marine areas. The Zostera marina seagrass meadows that grow across its shallower sections are one of the reasons why. These meadows act as nurseries for juvenile fish, feeding grounds for wildfowl and waders - including over 80% of the global population of brent geese that overwinter in the region - and critical habitat for dozens of invertebrate species that underpin the entire food chain.

Then there’s the carbon angle. Seagrass is a blue carbon habitat, and its capacity to absorb and lock away atmospheric carbon is thought to exceed that of equivalent areas of terrestrial forest. In a marine environment that covers tens of thousands of square metres, the climate mathematics start to look significant.

The Lough has been a protected area - designated under the EC Habitats and Species Directive and monitored through the Environment Order (Northern Ireland) 2009 - for decades. It became the first Marine Conservation Zone in Northern Ireland in 2013. But protection on paper doesn’t stop boat chains from dragging across the seabed.

The Mooring Problem Nobody Has Solved

Traditional boat moorings work by dropping a heavy block or anchor to the seafloor and attaching a chain that runs up to a surface buoy. The boat ties off the buoy. Simple, cheap, reliable - and profoundly destructive to whatever happens to be growing on the seabed beneath.

The problem is the chain, as tides change and boats swing, the chain drags continuously across the seabed in a circle - scouring away sediment, uprooting seagrass rhizomes, and leaving a bare scraped disc around every mooring point. Multiply that across the many sailing clubs, private moorings, and recreational anchorages throughout Strangford Lough and you have a systematic, relentless, decades-long assault on the very habitat the area is supposed to protect.

As Darren Rice of Newry, Mourne and Down Council’s geopark team put it plainly: the traditional mooring system scars the bottom of the seabed and gets rid of the seagrass. The trial sites for the Advanced Mooring Systems (AMS) project were deliberately located in Ballyhenry Bay, just north of Portaferry on the Strangford Narrows - a well-established seagrass bed that dive surveys had already identified as patchy and damaged, particularly around existing mooring positions.

Two Fixes, Beautifully Simple

The DAERA-funded trial - run since 2022 through a partnership between Ulster Wildlife, Newry, Mourne and Down District Council, and Strangford and Lecale AONB - set out to test two distinct approaches to the chain drag problem. The design philosophy was deliberately minimal: change nothing above the water line, fix everything below it.

Method One: Floating the Chain

A series of small subsurface buoys - mini buoys - attached at intervals along the mooring chain, lifting it off the seabed entirely. The chain still hangs from the surface buoy to the anchor below, but it no longer touches the bottom. Instead, it curves through the water column in a gentle catenary arc, with each mini buoy providing just enough buoyancy to keep the chain suspended clear of the sediment. The seabed beneath is untouched. The mooring above functions exactly as before. The boat owner doesn’t notice any difference.

Method Two: Absorbing the Movement

An elasticated band system that replaces or augments the rigid chain with a length of elastic mooring line. As tides rise and fall, as wind and waves push the boat around, the elastic stretches and contracts - absorbing the dynamic loads that would otherwise translate directly into chain movement across the seabed. No rigid chain drag. No scouring arc. The Strangford Lough trail used Seaflex® and Stirling® system designs, both established Advanced Mooring System technologies now being evaluated for their effectiveness in this specific habitat and tidal environment.

Where the ROV Comes In

Checking whether any of this is actually working requires getting underwater and looking. In tidal environments like the Strangford Narrows - with some of the fastest tidal streams anywhere in the world - sending divers down for every monitoring visit is expensive, weather-dependent, and genuinely risky. It also limits when and how often you can check, because you need qualified dive teams, appropriate conditions, and significant logistical overhead every time.

CHASING INNOVATION TECH ROVs change that calculation entirely. A compact underwater ROV can go where divers go - and in many cases, where divers can’t. Nicholas Baker-Horne and the Ulster Wildlife team deployed CHASING ROVs to inspect the trial mooring sites directly: checking the chain configurations, examining the seabed around each mooring type, and capturing clear underwater footage of what was happening at the sediment level.

The CHASING M2 and M2 Pro series - the platforms most likely in use for this type of coastal conservation survey work - are built for exactly this kind of deployment. Eight vectored thrusters give omnidirectional control for navigating around mooring hardware and seabed structures. The 4K Sony CMOS camera with electronic image stabilisation captures sharp footage even in the low-visibility, particulate-heavy conditions typical of shallow tidal channels. Powerful LED lighting - up to 4,000 lumens on the M2 Pro - illuminates the seabed clearly without causing the scattering and washout that often plagues underwater imaging in turbid water.

Single-person operation and a three-minute deployment time mean that the team can get eyes on the trial sites repeatedly, quickly, and without the logistical overhead of a dive operation. The ROV goes in, records what it sees, comes back out. The footage provides the evidence base. The trial progresses.

What CHASING ROVs Bring to Environmental Survey Work

CHASING INNOVATION TECH is probably best known in the professional underwater space for their M2 series - a family of compact, modular, highly capable ROVs that have found roles in hull inspection, search and rescue, aquaculture monitoring, and offshore infrastructure survey worldwide. What makes them particularly well-suited to environmental work like the Strangford seagrass project is the combination of portability, image quality, and accessory flexibility.

The M2 Pro weights under 6kg - light enough for single-person transport to remote foreshore locations, deployable from a small inflatable or directly from a jetty. It runs on a hybrid battery/AC power system, so a long monitoring session doesn’t require multiple battery swaps. The accessory ecosystem is extensive: laser scalers for accurate size reference on footage, grabber claws for minor intervention work, multibeam sonar for navigation in zero-visibility conditions, and USBL positioning for accurate geo-tagging of exactly where in the water column was captured.

Key CHASING M2 Pro specifications:

8 vectored thrusters - omnidirectional control in any posture
4K / 1080p camera with 12MP Sony CMOS sensor and EIS image stabilisation
4,000-lumen LED lighting with stepless brightness control
150m depth rating / 400m horizontal range
Hybrid battery + AC power: up to 5 hours on 700Wh battery, unlimited on shore power
3-minute deployment, sub-6kg total weight
Compatible with sonar, USBL positioning, laser scaler, grabber, and 20+ accessories
Single-operator

For conservation teams working on limited budgets and with small field crews, that spec sheet translates directly into more monitoring visits, better evidence, and faster feedback loops between what’s happening on the seabed and what decisions get made on land.

The Result: Seagrass Is Growing Back

The BBC Countryfile feature - broadcast nationally and available from the 16:27 mark - showed the tram reviewing what the ROV footage had revealed. The verdict was clear and genuinely encouraging: both mooring approaches are working. The chain-lifting mini buoys are keeping the mooring chain off the seabed. The elasticated system is absorbing tidal movement without scouring. And - most importantly - seagrass is clearly and visibly regrowing in areas where it had previously been damaged or absent.

The DAERA Advanced Moorings report, which covers the trial in detail across its 2022 setup and subsequent 2023 and 2024 annual reviews, confirms that the ecological response is real. Conservation Officer Dr David Smyth, on inspecting the trial moorings, found that beyond the chain - where scouring had been prevented – the seagrass was in good shape with a solid root system intact into the substrate. The substrate tells you what the canopy above it will eventually become.

That’s not a small thing. Seagrass restoration is notoriously difficult. Active replanting campaigns are expensive, labour-intensive, and unpredictable. Simply removing the source of damage and letting the meadow recover on its own - with healthy substrate, intact root systems, and the right tidal conditions – is far more reliable when it works. At Strangford, it’s working.

What Comes Next

The results from Ballyhenry Bay have already fed into broader planning. Strangford and Lecale AONB is now actively monitoring the two AMS trial sites as part of its formal environmental action plan, collaborating with DAERA to develop proposals for an eco-sensitive benthic habitat. The Mourne Gullion Strangford UNESCO Global Geopark’s CMAP project (a €9.6 million coastal monitoring and adaptation programme running through 2029) has included the AMS findings in its evidence base for future habitat recovery planning.

There are mooring sites across dozens of locations in the Lough. If the trial results justify a wider rollout – and the early evidence suggests they do – the scale of potential seagrass recovery could be significant. That’s more blue carbon sequestration, more juvenile fish that’s been slowly losing it for decades.