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Oyster Reefs – not just a home for oysters

Wilder Humber Native Oyster Restoration Officer, Laura, dives deeper into the underwater world of oyster reefs and the diverse marine life they provide a habitat for.

In April 2023, Yorkshire Wildlife Trust, Lincolnshire Wildlife Trust, and Orsted launched Wilder Humber, an ambitious five-year pilot programme aimed at restoring marine habitats and species across the Humber estuary.

Wilder Humber focuses on the connection between habitats, understanding that each different habitat offers an important contribution to broader ecosystems. The programme is implementing a seascape-scale model that combines sand dune, saltmarsh, seagrass, and native oyster restoration efforts to benefit both conservation and biodiversity. By focusing on the restoration of multiple habitats, we hope to see significant benefits to ecosystem services, including increasing biodiversity

As part of the seascape restoration efforts, Wilder Humber is focused on supporting the restoration of native oysters in the estuary, building upon the successful trial of oyster deployment onto trestles at Spurn Point, which began in 2019.

Woman standing at the oyster trestles on the sandy seashorecredit Simon Welton

Laura Welton, Wilder Humber Native Oyster Restoration Officer at the oyster trestles (c) Simon Welton

Oysters are known as a keystone species, meaning they have a significant impact on ecosystems relative to their limited abundance. One of their key features is building and providing vital habitat for other species.

Over many years, individual oysters fuse together to form a biogenic reef for species to attach to and/or take shelter in—including young bass, crabs, and anemones—thereby enhancing local biodiversity. But what does this mean?

Fused oysters being displayed to the camera on the palm of a gloved hand of someone stood on the seashore.

Fused oysters (c) Laura Welton

We've already spotted an increasing number of marine species living in and on the Wilder Humber oyster boxes. These mini habitats serve as ideal shelter, allowing us to observe a diverse range of marine life. Some of the species we have identified include:

Dahlias anemone being held in a gloved hand and shown to the camera

Dahlias anemone (c) Laura Welton

Anemones

These soft-bodied invertebrates seek out hard surfaces to settle on and are able to ensnare passing prey with their stinging tentacles.

Dahlias anemones are named after dahlia flowers, although their striking striped tentacles are hidden whilst they are out of the water. Interestingly, this species sticks fragments of sand, shell, and gravel to their bodies to help them camouflage.

nudibranch oyster from a birds eye view being looked at in a clear dish.

Nudibranch (c) Laura Welton

Nudibranch

Also known as sea slugs—these animals typically are associated with having two horn-like tentacles or feathery gills. This is where they get the name ‘nudibranch’ which means ‘naked gill’.

However, nudibranchs can be hard to identify to a species level due to their wide-ranging shapes and colours—which also contribute to their popularity amongst divers and rock-pooling enthusiasts.

Underwater shot of oaten pipes hydroid. There are three long stems and each have long tenticles on the end in a flower head shape.

Oaten pipes hydroid (c) Linda Pitkin

Oaten Pipe Hydroid

Perhaps a less familiar species, the oaten pipe hydroid belongs to the phylum Cnidaria alongside the more familiar jellyfish, corals, and sea anemones.

As such, they are also armed with stinging tentacles to catch tiny prey from the water.

Blue Mussel being helf in a gloved hand next to the oyster trestles being shown to the camera.

Blue mussel (c) Laura Welton

Blue mussels

Another habitat forming bivalve and a familiar species found on the dinner plate. Mussels use sticky fibres called ‘byssus threads’ to hold themselves in place.

Dog whelk

Dog whelk (c) Laura Welton

They can also use these threads to immobilise predators, such as the dog whelk—a species also found amongst our oysters. Mussels and oysters are commonly found next to each other in the wild.

At Spurn Point, we want to grow resilient oysters that can withstand the challenges of their natural habitat. Between December 2022 and November 2023, we've been closely monitoring the growth of our native oysters, and we're excited to share some great news!

Our oysters have been hard at work, and the results are in, the mean growing edge of our oysters reached an impressive 17mm, leading to an average shell length of 42mm. Why is this significant? Because it means our oysters are now surpassing the crucial 40mm mark, making them more robust and ready for release into the wild.

It's really encouraging to observe numerous species thriving alongside the oysters currently on the farm. These species likely wouldn't be present here without something to anchor onto.
Laura Welton, Wilder Humber Native Oyster Restoration Officer

The oysters are providing a vital habitat for a variety of marine life, turning our farm into a bustling underwater community. Laura and the team are eagerly looking forward to the next step: releasing the oysters into the estuary. The team will continue to monitor which new marine species will make their home in this restored habitat.

shore crab hiding in an empty oyster shell being shown to the camera in a red and black gloved hand. The person is standing over the oyster trestles on the sea shore.

shore crab hiding in empty oyster shell (c) Laura Welton

To follow Wilder Humber’s progress and our native oysters’ journey, and to find out about upcoming engagement events, visit www.wilderhumber.org.uk

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