Planting in Plymouth

02 June 2021  /  By Emma Nolan, Seagrass Cultivation Officer

It is 7am and I’m standing outside the National Marine Aquarium (NMA) in Plymouth, Britain’s Ocean City, looking out to Plymouth Sound on what is a beautifully calm and clear day.

It’s the perfect day for the task at hand – deploying 4000 seagrass seed bags into the ocean. This is the first day of seagrass restoration efforts for the Life Recreation ReMEDIES project.

Plymouth and Sound Estuaries SAC. Photo credit Ocean Conservation Trust

Plymouth and Sound Estuaries SAC. Photo credit Ocean Conservation Trust

I joined the ReMEDIES project as Seagrass Cultivation Officer, based within the Ocean Conservation Trust (OCT) – the charity that runs the NMA. Much of the work I have undertaken in the past year has been leading up to this moment, from the collection of 800,000 seagrass Zostera marina seeds last summer, maintenance and care of seed and seedling in the cultivation facility at the NMA over winter, and the preparation of thousands of seed bags through a massive volunteer effort. It all culminates today, when we finally get the seed and seedling back into the ocean from which they originated.

I am joined by Loveday Trinick and Mark Parry, my colleagues at the OCT who also work on the ReMEDIES project. Yesterday, Loveday and I hosted 20 volunteers at the NMA who helped us to pack the precious seeds into bags. This is quite a simple task of filling small hessian bags with a small amount of sand and seed, carefully measured, and then tying the bags at the top.

Seedling restoration. Photo credit Ocean Conservation Trust.

Seagrass seedling. Photo credit Ocean Conservation Trust.

A simple task but a large one as we want to restore four hectares of seagrass bed in Plymouth sound, that’s 40,000 square metres, and we need to make two bags for every square metre, that’s 80,000 bags over the course of the project. Many hands make light work though, and thanks to the work of a group of enthusiastic volunteers we could make 4000 bags ready for our first deployment.

Volunteering. Photo credit Ocean Conservation Trust.

Volunteers packing seed bags. Photo credit Ocean Conservation Trust.

Having packed the bags into fishing crates (thanks to Plymouth Trawler Agents), lifted them onto pallets and transported them to the dockside, we are now awaiting our vessel to transport them to our restoration site in Plymouth Sound. Each fishing crate contains 100 seagrass seed bags, so we have 40 fishing crates today to take with us. Luckily, the vessel we are waiting on is the Plym catte, the Cattewater Harbour Commissioners barge, with its own crane, so we can at least reduce some of the heavy lifting. The barge comes alongside and Cameron, one of the crew, immediately jumps ashore, fixing straps to the pallets to lift them, while Dave controls the crane. This is a tense moment for me, seeing the bags being hoisted into the air, dangling over the water, but I need not worry, this is an easy job for these guys.

Restoration. Photo credit Ocean Conservation Trust

Seagrass restoration. Photo credit Ocean Conservation Trust

We then hop on the barge and make our way to the restoration site at Jennycliff bay. The plan is for the barge to follow a set heading for 200m, along which we deploy the bags at a rate of 1 every 0.5m by dropping from the back of the barge. The barge will then turn around and follow the opposite heading for 200m, creating parallel straight lines along which the bags will be deployed, exactly like sowing a terrestrial crop in a field. The reality of doing this on the water is slightly trickier. The barge is being handled by Dave, who has pre-loaded latitudes and longitudes uploaded to his GPS, we try a dry run to see how the barge handles in maintaining a fixed heading, it is possible despite the wind picking up slightly, but we can only maintain the heading if we also maintain a speed of 1.5 to 2 knots, or ~1 m/s, this means we have to deploy 2 bags every second to get the coverage needed. We anticipated this. We have a plan.

Restoration. Photo credit Ocean Conservation Trust

Seagrass restoration. Photo credit Ocean Conservation Trust

We have brought with us 4 x 4m long drainage pipes and attach two pipes to each back corner of the barge, we will deploy the bags down these tubes to avoid the propeller wash, helping the bags to fall more uniformly to the seabed. We get set up and see how the pipes fair when traveling at a speed of two knots. They hold. We then transfer two fishing crates to each tube and take our stations. Each person will be required to deploy 200 bags down each tube over the 200m stretch, making a drop of 1 bag per second approximately. We are ready but not yet in position, the barge needs to manoeuvre, we wait for the signal.

Seagrass restoration bag down tube. Photo credit Ocean Conservation Trust

Seagrass restoration bag down tube. Photo credit Ocean Conservation Trust

We have gloves on to protect us from the sharp corners of the drainage pipes, the sun is in our eyes but there is a cool wind at our back and I’m grateful for the salopettes I’m wearing. We wait with a seagrass seed bag in each hand. I think about all the effort that has gone in to getting us to this moment: the work of the past year, all the support we have received, the volunteers who helped us, the local organisations who loaned us equipment, my colleagues on the ReMEDIES project and within the NMA. We hear Dave shout “GO” and we drop the first bags into the sea. In that second, I imagine the bags falling through the pipe and through the water column, landing with a thud on the sea floor. All that’s left now is for the seed to grow.

Seed bag on seabed. Photo credit Ocean Conservation Trust

Seed bag on seabed. Photo credit Ocean Conservation Trust