Nearly 14 tonnes of invasive seaweed removed from local beaches

Youth volunteers from The Nautilus Project have removed more than 3.5 tonnes of invasive seaweed from beaches around Gibraltar over the past fortnight, in a clean-up effort coordinated in response to large quantities of the algae washing ashore.

Their work was in tandem to a Government clean-up effort that cleared a further 10 tonnes of seaweed in 48 hours earlier this week.

The seaweed, whose scientific name is Rugulopteryx okamurae, has been increasingly present in the Strait of Gibraltar during the summer months in recent years.

It accumulates on beaches and quickly decays, creating an unpleasant smell and hindering beach access.

The group of around nine youth volunteers began their clean-up after being alerted by members of the public to significant build-ups of seaweed at Catalan Bay, particularly around the jellyfish nets, which have recently been removed for repair.

They subsequently extended their efforts to Western Beach and Sandy Bay.

In just one day, volunteers at Sandy Bay collected approximately 2,360kg of seaweed using rakes, spades and hand-held nets.

The group was also careful to return any marine life caught in the seaweed back to the sea.

“The youth monitors have been going around the beaches and tackling it,” said marine biologist Lewis Stagnetto from The Nautilus Project.

“At Sandy Bay, they collected 2.4 tonnes of seaweed in one day.”

Additional quantities were cleared from other locations, with 520kg removed from Catalan Bay and 640kg from Western Beach.

Mr Stagnetto described the work as physically demanding but valuable for raising awareness.

He described the youth volunteers’ work as both a practical response and a learning opportunity that highlights the environmental challenges affecting Gibraltar’s coastline.

“Just like with the beach cleans, getting involved and picking up plastic raises your awareness to the actual state of play along the coastline,” he said.

“This really does help to raise awareness of the invasive properties that this algae has.”

Mr Stagnetto believes the seaweed was introduced to Europe through the importation of oysters from Japan into France.

It has since spread along coastlines and thrives in areas with rock structures, where it can establish and dominate local marine habitats.

“This issue wasn’t a problem at Catalan Bay five or six years ago,” said Mr Stagnetto.

“Why do we have it today? Because of the rocks for the car park and the extension area that was put in there.”

“When we go dumping rocks in places, what we have to understand is that that is going to be prime real estate for this algae to grow.”

“Why is this a problem at Sandy Bay? Because we built two new rocky groynes and then a third bar that joins them right out at sea.”

“Again, all prime habitat space.”

“You don't need to take my word for it. Grab a mask and snorkel, jump in and have a look at the rocks yourself.”

“And all you will see in terms of algae is this one species that dominates the whole habitat.”

“It’s essentially destroying the natural habitat that we've had on the seabed in rocky areas here.”

He added that the seaweed grows only on hard surfaces and warned against further coastal developments involving rock infill, which provide ideal habitats for the algae.

“This algae has no natural predators here and smothers local species by blocking light,” he said.

“Every time we continue with the rocks, we’re making the problem worse.”

The Gibraltar Government is also busy at work on the beaches tackling the build-up of seaweed and has engaged contractors to deal with large build-ups including in Western Beach.

Between Sunday evening and Tuesday evening, the Government’s contractors removed around seven tonnes of seaweed from Gibraltar’s beaches, most of it from Sandy Bay.

“The beaches are cleaned as often as needed, which on occasion - as in the build-up to the beach season or after particular spells of weather - can be every day,” a spokesperson for No.6 Convent Place said.

“The amount of algae cannot be reduced by any measures the Department of the Environment could take.”

“It is an alien invasive that is plaguing much of the western Mediterranean and a great deal of research is going into it with no solution being found. “

“All we can do is remove it when it comes to shore, which the Government will continue to do as much as required, despite the costs, and it fully welcomes the work of the Nautilus Project in citizen action to assist.”

A similar clean-up was underway this week in La Linea, where 10 tonnes of seaweed were collecting from the city’s beaches.

Regional authorities in Andalucia are exploring ways in which the seaweed might be put to a commercial use, amid pressure from the fishing sector over the impact it is having on marine life.