Hong Kong created an oyster reef on a dike next to an airport. Canada could learn from it

Oyster breeding has been performing in Hong Kong for hundreds of years. Traditional agricultural practices, namely the harvesting of oysters, then put back the hard substrate, including the shells in the water so that oysters develop, are one of the reasons why oyster populations have not completely disappeared from nature.

Now, farms contribute to key knowledge and provide the oysters themselves to restore natural oyster reefs.

It is estimated that 85% of oyster reefs in the world were lost. And the remaining oyster beds in Hong Kong are not recognized by the government as being ecologically important and, consequently, not granted.

But recent catering projects are trying to change this, according to Marine Thomas, associate director of conservancy conservancy Hong Kong.

Thomas explained that the restoration of oyster reefs is to restore wild habitats – similar to the restoration of coral reefs – rather than restoring oyster reefs for consumption.

A project to restore reefs in Hong Kong benefits from an improbable site: off the Hong Kong International Airport. He used living oysters cultivated in laboratories and local oyster farms to sow the reef. Thomas says it is the first of its kind in the region by trying to establish living reefs along his dike.

Thomas says that oyster reefs can be developed along other recovered land dikes (this is very common in Hong Kong), if these areas had indigenous before before and appropriate ecological conditions, which would be applicable to many areas of the Pearl River Delta.

This approach can also be reproduced in Canada, depending on the location and the type of dike, according to Ramón Filgueira, professor in the Marine Affairs Department of the University of Dalhousie.

But Hong Kong and Canada are both late on efforts in the United States, where awareness of the advantages of oyster reefs grants an increase in the number of fish, regulation of water quality and coastal protection against erosion against storms.

Not just to do

More than a thousand years ago, when Hong Kong was only a collection of small fishermen’s villages, thousands of tonnes per year of oysters were flirted and whole oyster shells were used in the construction of buildings in the Guangdong region. When the shells are burned, they turn into lime, the raw material used to make cement. It was this industry, which exploded in the 19th century, which saw almost all the reefs of wild oyster suppressed.

While people mainly associate oysters with food, they also fulfill several other functions. Oyster reefs regulate water quality by filtering particles, increase fish populations by providing nursery terrains and reefs create natural coastal protection against storms and erosion, the problems that are resolved to intensify due to climate change.

The United States paves the way with the restoration and improvement of oyster reefs, according to Filgueira, which said that there was also a lack of awareness of decision-makers and communities in Canada of the advantages of oyster reefs.

He underlined the flagship project of the Billion Oyster Project in New York, an ambitious rewilding initiative which planted 150 million larvae in its port to improve water quality and protect the shores.

While the artificial maritime walls are built in Nova Scotia, Filiguei said that he thinks that oyster reefs would be a long-term sustainable complement to the structures of which the local community may not be aware.

“If you look at projects and investments in the United States, you cannot compare it with Canadian investment. It’s peanuts.”

Example: in Harris Creek, Maryland, a project to restore the Oyster reefs cost $ 29 million in the United States, which is part of a larger project in the bay of Chesapeake. In three years, he obtained more than that of the increased production of fisheries – everything, from fish to crabs via shrimps, including other crustaceans – which in turn benefits the community of local fishermen, according to Bayden Russell, associate director of ecology and biodiversity at the University of Hong Kong.

“They get more than 100% per year,” he said. “It’s renewable, every year.”

Improbable oyster reef

A bright point in Hong Kong is a project in waters near Hong Kong International Airport. The airport is almost entirely built on recovered land, in an area which was once a flourishing oyster habitat, according to Thomas. But it was a very degraded and difficult environment, she adds. Due to what it was a restricted area, it was de facto and has given the restoration of an oyster reef.

Last year, recycled concrete was placed in the ocean along the 500 -meter dike – because the restoration of oyster reefs requires reintroducing a hard substrate in the ocean so that oysters cling. It was then sown with native oysters and recycled shells, supplied by oyster producers, as well as laboratory cultivated larvae from the University of Hong Kong.

The teams have watched the new reef to see if the plan to stimulate oyster populations along the track works.

Challenges remain, and Thomas will continue to monitor the reef in the next year, but if everything goes as planned, a new flourishing reef will emerge.

Russell says that the airport project was exciting because it was a “demonstration that we can really do it on a large scale”, noting that there were at least 750 kilometers from Littor

Oyster reefs belong to it: researcher

Beyond that, the idea that oyster reefs can exist in Hong Kong should be replanted in the minds of people, according to Daniel Pauly, principal researcher of the Sea Around US project at the University of British Columbia.

“People must realize that the default frame for a coast like Hong Kong is to have an oyster reef, and thus rebuild an oyster reef would not present something new, but rebuild something that was there before.”.

Hong Kong is updating its biodiversity strategy and its action plan, which will describe the priorities of the next decade.

Thomas recommends that the government is doing more to protect coastal marine ecosystems of the city and expand its protected marine areas to include hot biodiversity hot spots.

“Hong Kong can be a very urbanized area, but it is extremely biodiversity. It represents only 0.03% of Chinese waters, and yet 25% of all the marine species recorded (in China) are in Hong Kong,” she said.

About five percent of the waters are designated as marine parks or marine reserves, which are protected areas under the law of the city managed by the Department of Agriculture, Fisheries and Conservation. She wants to bring this to at least 10%, which is always lower than the global target of 30%.