The Marine Diaries

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Shellfish reefs need us!

Megan Hayes

Shellfish reef restoration efforts around the world need your help. Over the past two centuries we have lost 85% of the world’s historic shellfish reefs and the natural water filtration they provide. Conservation projects around the world are working to reverse this trend by addressing two of the main limiting factors preventing shellfish reefs from bouncing back: the lack of habitat for juvenile oysters to settle on and the reduced numbers of shellfish unable to support a robust population. There are things we can do to help though. You can help shellfish reefs bounce back by donating your time or money to these restoration efforts, eating farmed or caught by hand shellfish, and demanding higher water quality from your government.

Over the past two centuries 85% of the world’s historic shellfish reefs have been lost. Photo: Unsplash

Many shellfish reef restoration efforts around the world rely partially on the efforts of volunteers. In these projects, habitats for juvenile oysters to settle on are created and the health of the restored reef is monitored. Juvenile oysters require a hard surface to settle on for their adult lives and other oysters or oyster shells are the ideal surface to do so. Restaurants and conservation projects around the world have partnered together to use the empty shells from diners for restoration. Volunteers bag shells, place them in cement blocks or cement balls, before being placed in nearshore waters or estuaries.

Wild shellfish reefs around the world are in a dire state, but by eating farmed or harvested by hand shellfish you can help prevent further damage. Traditionally shellfish were harvested by dragging a large weighted net across the sea floor, ripping the reef structure from the seafloor and creating a dust cloud that could bury any remaining reef in the area. This both diminishes the local shellfish population and takes away the structure juvenile oysters need so they can settle down for their adult lives. Today 95% of the oysters we eat today are farmed. Farmed shellfish are sustainable because the oysters and mussels filter feed off their environment, i.e. they do not need to be fed, and the harvest methods have minimal impact on the environment. 

If you want to eat shellfish sustainably, ensure to source farmed shellfish which has much less environmental impact. Photo: Pexels

Another way you can help is to lobby your government to restore shellfish reefs in areas where they were historically present so they can clean local waters and protect coastal shorelines. An adult oyster can filter up to 250 liters of water a day and an adult mussel up to 1.5 liters a day. When you multiply that by hundreds or even thousands in a reef structure - that makes a huge difference. National and local governments are starting to draft policies to address these problems. For example, New York City suffered millions in damages from hurricane Sandy in 2012. In a hope to minimize damages from future storms they are restoring shellfish reefs in the harbour. Businesses are also using shellfish reefs to offset the nutrient rich drainage in the water. The Glenmorangie distillery in the UK is planting shellfish reefs in their harbour to offset the runoff from their brewery.

By volunteering, eating sustainably, and lobbying your government we can help bring shellfish reefs back from the brink along with all the benefits they provide, using them as a solution to many environmental problems facing our planet.


Seas The Day investigates current and future conservation efforts being used to combat the issues facing our oceans

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