London Mayor Sadiq Khan made a commitment this week to “explore the role” that oysters could have in cleaning the Thames.
This was following a visit to the Billion Oyster Project in New York, an initiative restoring oyster reefs to New York Harbour.
There have been longstanding concerns about the river Thames’ water quality and this potential solution has left some people confused about how oysters could help.
Professor of Marine Zoology at the University of Portsmouth, Gordon Watson explained: “Oysters are filter feeders; they open their shell which is in two parts, inside there is a kind of pump system.
“Water is brought in on the inhaling side from the surrounding water and they have a filter system, where water filters out using really tiny hairs called cilia.
“All the organic material, all the particles, those are then transferred to the stomach, digestive, and the water which has been cleaned is then sent out through the exhaling side.
“They filter a huge amount of water per day, certainly tens of litres depending on the size of the oyster.”
Professor Watson is working on the Solent Seascape Project, one of the biggest restoration projects in Europe, which recently utilised its $5m funding to restore the oyster reefs in the River Hamble.
In Hampshire, the project reintroduced over 14,000 oysters into the River Hamble to restore the habitat which provides a home for hundreds of other species and provides a natural defence against coastal erosion.
Professor Watson said: “If we are successful in the Solent then absolutely, we can do it in places like the Thames.”
There is a history of oyster beds in the Thames.
Professor of Marine Biology Joanne Preston said: “Like its USA counterpart, the Thames estuary, prior to the industrial oyster fishing that occurred during the 1800s, was the home of native oyster reefs stretching for many kilometres.”
The Mayor of London also hopes other species like otters, water voles, eels and mayflies can help to cleanse the Thames.
Khan recently released a list of safe swimming spots in London, at the same time citing places that he hopes will be swimmable in future including Teddington in southwest London.
Professor Watson explained that Europe’s native oysters live in saltwater, so oyster beds would not likely spread up the Thames to South West London but would be nearer the estuary.
The Billion Oyster Project uses oyster shells from restaurants they partner with.
Chef Patron Gianluca di Monaco of La Salon Privé said: “We would do it but there are issues.
“We would need to sanitise and sterilise the shells or they will stink, also how would we give them, would they be collected?”
La Salon Privé is an award winning restaurant that serves classic French cuisine including oysters in St Margarets.
Image credit: Isabella Harris
