The dense underwater forests off the east coast were once marked as a shipping hazard. Fur seals, seahorses, weedy sea dragons, rock lobsters, and fish used to live in the stands of giant kelp.

In the past 50 years, the giant kelp has all but disappeared. Warm waters pushed southward by the east Australian current have killed off most of the brown algae.

The Great Barrier Reef gets a lot of attention, and a lot of funding. Kelp forests and many other marine environments suffer from an out of sight, out of mind mentality.

He says that kelp has an important job in maintaining water quality. Layton and his colleagues at IMAS have been working on restoration projects for the last two years.

The team has grown and planted giant kelp that is more heat resistant than average.

The coastal waters are also declining. It is difficult to pick which of those factors is more important. He wants the plants to be more resistant to heat.

Seals above crayweed

Seals cavorting above the crayweed beds in Narooma, NSW. Photograph: Aaron Eger

A funding shortfall and the physical challenges of working in rough and rocky environments are some of the reasons for the lag in restoration of kerp.

Restoration efforts around the world are increasing in frequency. The study looked at 259 restoration attempts across 16 countries in order to document successful approaches.

Six projects successfully restored more than 100 hectares of underwater forest, despite the fact that most restoration projects took place on a small scale.

Culturally and economically significant

The review's first author, a PhD student at the University of New South Wales, says that kelp forests are economically and culturally important. The social connections that date back hundreds if not thousands of years are at stake.

Billions of dollars are generated annually by the production of Kelp. It is harvest and refined to yield a compound used in food and cosmetics. In east Asia, kelps are known as kombu, dasima, and Haidai.

Bull kelp

Bull kelp is found along Australia’s southern coastline. Photograph: Grant Callegari Hakai Institute

The first restoration project took place in 1718 when a Japanese monk ordered fishers to throw stones into barren areas. Rock or sand, water rich in nitrogen and phosphorus, and light are some of the materials that need to be grown for kelp.

It takes between 10 and 20 years for projects to make a difference.

Significant government investment is still the exception, not the rule, according to Eger.

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Prof Vergés says there has been more success than they thought. The method of transplant was found to be effective. The biggest predictor of a project's success was close to a forest.

The number one priority should be to protect what we have.

Weedy seadragon

Weedy seadragons are reliant upon kelp forests for habitat. Photograph: John Turnbull

Eger and Vergés traveled to South Korea to visit some restoration projects. It was almost impossible that the place had been barren before. Eger says it was filled with crab, fish, and seaweed. It made me think.

Vergés says that the approach in Japan and Korea is more interventionist than in Australia.

In Australia we have a hands off approach when it comes to managing our marine environment. Nature should come back on its own.

Thorny problem

The most common factor that necessitates kelp restoration in the first place is the invasion of sea urchins.

The restoration projects in Australia, as well as Norway, Japan, Korea and California, have been hampered by urchins.

Vergés says that in California they have lost most of their urchin forest. The sea urchin numbers go up through the roof and they mow down the entire forest.

Eastern pomfret fish above kelp

Eastern pomfret can be found in coastal waters from Queensland to southern New South Wales. Photograph: John Turnbull

There is a possibility of eating the urchins. Hundreds of tons of long-spined sea urchins are commercially harvested each year in the state. The pest is being turned into a profit.

Natural kelp recovery requires the removal of every urchin from a certain area. It is more economical for fishers to move to a new area if they take 70% to 75% of the fish.

He says that they are looking at different ways to work with the fishers. You might be able to subsidise them to spend more time there and remove all the urchins.

Eger says restoration is heartening because of the fast growth of kelp. You can see the forests come back in a year.

Reducing our carbon emissions is the priority. The hope is that we can intervene in the meantime and buy a bit of time for these important environments.