Oyster Reef Rehab, Restoring the Pearl of the Estuary Ecosystem.

When one thinks of an oyster, there isn’t really a lot that goes through your mind. Yes we eat them, yes they live in salt water and YES when you tread on them with your bare feet you’re often left a little worse for wear. What you may not know is that oysters and the reefs they form have diminished to almost extinction worldwide. It is estimated that approximately 85% of all oyster reefs have been destroyed globally.

Oysters – Kurnell. Photo taken by R.Steel – 2015.



Why does this matter you ask!? What you also may not have known is that oysters are considered to be an ecosystem service, meaning they directly contribute to human well-being. Whilst this may not effect all humans’, oysters do have a MASSIVE impact on the economy in the form of jobs and sales as well as on the health and ecology of estuary ecosystems which does have an effect on the livelihood of many. For these reasons it is vitally important to conserve and restore the oyster reef ecosystem in order to sustain these and many other benefits.

In regards to the economy, oysters are one of the most popular farmed sources of seafood in Australia, especially the Sydney rock oyster, Saccostrea glomerata. By restoring the oyster reef ecosystem we’re not only providing jobs to the commercial fishermen that operate and own the oyster farms but also to the general public, who for some reason, enjoy buying and eating them. Within the Broken Bay area of NSW Akoya oysters Pinctada fucata are also farmed for the production of pearls – and who doesn’t love food that also produces jewellery!?


In all seriousness, in NSW alone, the annual production of Sydney rock oysters is worth over $35 million. This makes oyster farming the most valuable aquaculture industry within NSW. – That is an incredible feat.


When considering the ecological benefits to estuary systems and habitats oysters are considered to be the ecosystem engineers of the estuaries. They have a heavy influence on nutrient cycling, water filtration, habitat structure, biodiversity and food web dynamics. Basically, they keep the estuary functioning. The oyster reefs themselves provide habitat for other marine organisms such as bivalves, snails and algae species, this in turn attracts fish and other larger marine species that feed on these smaller organisms. This makes them hugely important to the survival of many marine creatures. So if there is no oyster reef, there is nowhere for the small organisms to live, and nothing for larger organisms to eat! As oysters are filter feeders they act as a filtration system, eating the organic matter from the water and expelling out the clean water. There are many studies indicating that an oyster is capable of filtering up to 50 gallons of water per day! So as you can imagine, if an entire oyster reef was to be functioning within an estuary, the quality of water would be massively increased compared to an estuary without any oysters.



Oysters – Kurnell. Photo taken by R.Steel – 2015.

So we’re convinced that oyster reefs are a must for our estuaries! But how do we make it happen? and how do we know it’ll work? Simple. Firstly it depends on the environmental conditions – tidal range, salinity, bottom topography and turbidity. Is this an environment that will be able to support an oyster reef? Assuming that yes, we are in an environment that is perfectly suited for an oyster reef the building aspect can begin.
A suggested method for oyster reef building (due to low cost and effort) is to replicate the natural environment as much as possible. Rocks to attach to in a tidal zone that’s suitable. Introducing living juvenile and adult oysters to these environments from elsewhere kick starts the process and promotes the production of spat (the most perfect word to describe baby oysters). This process has been used in many reef restoration programs such as in the James River (Virginia, USA), Atlantic North America and in the Chesapeake region (also USA) and overall seems to be rather successful with the James River proving to be the ideal environment for oyster reefs to thrive and revive.



A life without oysters… Doesn’t sound like that much of a big deal, but that is where you’re misguided. Overall, the restoration of oyster reefs is a topic that truly needs to be discussed and actioned. Not only as an economic benefit in the way that their production provides jobs and seafood but also to maintain and support our existing estuary ecosystems. A life without fancy seafood, jobs in fisheries, or healthy estuary ecosystems… Kind of a big deal now isn’t it!?