5 reasons we love native oysters

As it’s National Oyster Day on 5th August, we wanted to show these amazing shellfish a bit of love.

Native oysters are some of our sea’s unsung heroes. But sadly their numbers around the UK’s coast were decimated by pollution, overfishing and disease. In Scotland’s waters, oyster numbers are less than five per cent of what they used to be. 

But all is not lost because people like Ailsa Mclellan are helping oyster populations recover. She currently works for the charity Seawilding, restoring native oysters to Loch Broom. Here are five reasons why we think everyone should show a bit of love for our native oysters.

1. They’re clean freaks

Individual native oysters can filter a bathtub’s worth of water every day! They filter out nitrates and phosphates, as well as helping to keep the water clear of sediment. The sediment stabilises around the oyster beds, which means it’s not as mobile and that leads to clearer water for all of us. 

2. They build reefs

When oysters settle in large enough numbers, the oyster beds create what’s known as a biogenic reef. This is a habitat that attracts a host of other creatures. “There are so many species associated with growing on the oysters themselves and amongst them in the reef, because of this incredible three-dimensional habitat they create,” Ailsa explained. 

3. They attract a host of other creatures

On their shells, you’ll find tube worms, barnacles, anemones and even sea squirts. Among the oysters you can find pipefish, gobies and juvenile fish from a range of species.

4. They can be carbon sinks

If they’re left to build up to a big enough scale, oyster reefs can become a carbon sink. Oysters spawn prolifically when left to their own devices. For the first couple of weeks of their lives, oysters float around in the ocean until they find a place to settle. 

Their preference is to stick their shells to those of larger oysters. Over the course of decades, they build huge structures that can eventually act as carbon sinks. 

5. They support other priority habitats and species

By filtering the water and keeping it clean, oysters allow other habitats to thrive, like seagrass and maerl beds. These habitats are particularly badly affected by the nitrates and phosphates that wash into the sea from land – and so by helping remove these from the water, oysters are supporting other types of marine environment to thrive too. 

You can find out more about how to get involved in the oyster restoration project run by Seawilding on their website – and you can listen to Cal’s full conversation with Ailsa on the Our Ocean Podcast.