Conservationists are looking into the possibility of planting seagrass in Bermuda’s waters to help to revitalise struggling seagrass beds.

Sarah Manuel, senior marine conservation officer, said in the most recent edition of the newsletter Envirotalk that a reduced number of turtles visiting the island has helped some areas to recover, but researchers are looking into how to bring back lost seagrass meadows.

Dr Manuel said that while some areas of turtle grass remain, most of the seagrass seen returning is manatee grass.

“Manatee grass has a couple of characteristics that allows the plant to recolonise an area relatively quickly once a disturbance, such as turtle grazing, has been removed,” she said.

“It is a fast-growing, flowering plant that produces hard-coated seeds during the summer months. This tough exterior allows the seeds to persist in the sediment in a dormant state, only germinating when conditions are right.

“Turtle grass does not have these characteristics and therefore cannot recolonise an area very quickly.”

Seagrass beds play an important role in the marine environment, offering shelter to fish and lobsters and providing a food source for turtles.

However, seagrass populations in Bermuda’s waters collapsed in recent years because of a combination of factors including shoreline development, dredging and the creation of docks, along with boats anchoring, grounding and mooring.

A surge in juvenile green turtles grazing in Bermuda’s waters put additional pressure on meadows.

In 2020, the Government launched a restoration effort to protect remaining seagrass beds by installing large mesh cages over struggling areas that would limit access to the grasses.

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Dr Manuel said that conservationists in temperate areas have been using eel grass to restore seagrass meadows, so the Marine Conservation Section decided to look into whether manatee grass could similarly be used to restore bare areas that were once home to seagrass meadows.

She said that this summer Treiana Zuill, a Bermudian PhD student at Florida International Research, began to study the sexual reproduction of manatee grass to explore the viability of using manatee grass to restore meadows.

“Methodology for seed-based restoration of manatee grass will not only be useful for Bermuda, but other tropical areas where manatee grass grows,” Dr Manuel said.

“Bermuda is an ideal location to develop these methods because, unlike many places around the globe where seagrasses are in decline, our seagrass loss was not driven by declining water quality.

“Manatee grass is a perennial plant with distinct male and female flowers. Treiana monitored areas of manatee grass at three sites to determine when they flowered and then followed the development of the female flowers through to the fruiting stage.

“The peak period of manatee grass flowering events this year was in late May and fruits were first observed on the plants in early June.

“Now we are waiting to see how long it takes for the fruit to ripen. Once fully ripened, seeds will be collected for planting.”

Dr Manuel wrote that small mesh bags have been tied over shoots to catch seeds when they mature and fall from the plants to be used for planting.

Meanwhile, she said, efforts were made to collect seeds from sediment near manatee grass meadows at Marshall’s Island in the Great Sound and plant those.

“When the seeds were planted we did not know how long it would take for the seeds to sprout or if they were even viable because we do not know how long they have been buried in the sediment,” Dr Manuel said.

“We also do not know how long it takes for the new manatee grass seeds to germinate in Bermuda’s marine environment, or what triggers them to sprout.

“These are all questions that Treiana will be trying to answer in the course of her PhD research.”

She added that as of the end of June, 6 per cent of the seeds collected from Marshall’s Island had sprouted.

“These seedlings have continued to grow,” Dr Manuel said. “While this is definitely not a high success rate, it is an encouraging start.