Seaweed v humans: the battle for the beach

Takapuna's showcase - and usually pristine - beach got a massive dumping of seaweed last week during a strong easterly swell, leaving the shoreline a lumpy, sand hopper-ridden, rotting mess. 

Some vocal residents want it gone; moved as it has been in previous years by the Council. But in these tougher times, the Council is balking at the $30,000 to $50,000 per clean-up cost - especially when it could be back next week as more rough weather hits. The seaweed has also landed along other East Coast Bays beaches, but Takapuna is the focus of the angst.

Resident Geoff Bonham says the seaweed is a "jolly nuisance". "I've been on at the council for five years to buy a beach cleaning machine," he says, claiming he's only been met by excuses and bureacracy. "Takapuna would be the most popular beach in Auckland - on Saturdays and Sundays over a thousand people would be walking on the beach. If it was cleaned it would look magnificent." Bonham says eventually a front loader will be brought down to shift it, but by then it will be stinking and covered in flies. "They're not exactly Speedy Gonzales." 

Takapuna-Devonport board member George Wood posted pictures on his Facebook page and had the issue blow up on him. When Newsroom called he was down at the local transfer station seeing if the seaweed could somehow be dumped for people to collect for their gardens. 

"There are always people moaning and whinging about seaweed and the sand hoppers that live in it," he says. "Council officers have said that in about three days the tide usually comes in and takes it away. But this time it's come in on a pretty big swell and left it high and dry. It's a pretty difficult problem for council to try and wrestle with. It's an endless job and it's unpredictable as to when it comes in. Getting rid of it ain't easy."  Wood is mulling over ways to move it at a more reasonable cost. "In the past contractors have come in with trucks ... but it costs $30,000 a time just to clean Takapuna .. it's a lot of money." 

Wood says the two main objections to the seaweed are that it's unsightly and detracts from the beauty of the beach, and that it leaves little room to spread a towel on without being covered in sand hoppers that live in the decomposting vegetation. 

The seaweed dump was so vast that some entrances to Takapuna Beach were blocked. Photo: Alexia Russell 

Wood's feedback from residents is split between people who believe this is all a first world problem, about a natural phenomenon; and angry North Shore residents who've seen their rates rocket since the Super City was formed, and who say their area is getting less attention than it did before the amalgamation. "Wait till it gets washed off Takapuna and blown onto Mission Bay Beach and it will be cleaned up in a flash," said one resident - who struck a nerve, as the eastern beaches do have a beach cleaning machine. However, they are dry sand beaches where the sand has been shipped in from Pakiri, so they won't work at Takapuna. 

"At Takapuna we will probably let nature take its course," says Auckland Council's head of operations management and maintenance, Agnes McCormack. "We have to be mindful of the delicate eco-system there." Bobcats would have to be used and they lift the sand with the seaweed. Council staff are keeping an eye on the situation, but she says winter users of the foreshore are more likely to be walkers than sunbathers and there are no health and safety issues there. "On hot summer days we monitor it more closely." 

McCormack says the idea of a specialised sand groomer has been talked about, but it hasn't got to the stage of a trial yet. She says it's not reasonable to compare Takapuna to beaches that are groomed in places such as Europe - "their tourism capacity is massive and they don't groom it just to make it look nice, they groom it to make it safe - to pick up the likes of glass," she says. Some other local boards in Auckland, particularly on the West Coast, are anti-grooming for ecological reasons. 

"A lot of people accept that there is seaweed on the beach because it is a beach ... it's not like overflowing rubbish bins."

Takapuna has been cleaned up on previous occasions, including the World Masters Games earlier this year, when it hosted ocean swimming events. It took 12 hours on that occasion to move more than 11 tonnes of seaweed. But it's a big operation involving heavy equipment and traffic control - the beach needs to be closed - and that's why it's expensive. McCormack confirms that, depending on the volume needed to be moved, $30,000 to $50,000 is an accurate estimate of the cost. 

North Shore councillor Richard Hills says the seaweed is a sign of a healthy beach and a good ecosystem and it is a natural occurence. He points out you could carry out an operation one day and the next week a similar amount could be washed up and it would have to be done all over again. "There are over 600 beaches in Auckland, not all affected by seaweed, but it would be extremely expensive if all areas started requesting regular clean-ups."

The forest of the sea

Increasing amounts of seaweed washing up on land is becoming a world-wide phenomena. Professor Wendy Nelson, an expert with the University of Auckland's School of Biological Sciences who also works for NIWA, co-authored a paper on the issue of nuisance blooms of macroalgae called in part "when seaweeds go bad". The  paper says the "most obvious local impacts of large volumes of macroalgae washed up on beaches, or proliferating within confined bays, are the negative aesthetic and amenity impacts on recreation and tourism, and impacts on marine installations -  accumulations on swimming beaches, blocking access to boat ramps, and clogging nets". Fertiliser is part of the problem - it runs into the sea, and the weed grows dramatically. 

Nelson says she gets more phone calls every year about seaweed being dumped in big amounts on beaches. "My temptation would be to leave it there," she says. "Having said that, there's a really big problem (with seaweed) at the moment at several North Island locations. It's been happening for a few years and it's really getting in the way." It's rotting, it can smell like sulphur, and is potentially unhealthy, she says. "In those cases getting it up on land would be a good idea." 

It's a myth that to use seaweed as compost you have to wash the salt off first. "Salt wouldn't be a problem and it would be great fertiliser," says Nelson.

Perhaps residents should grab a sack each and take it back to their gardens - a system that would be kinder on the environment than bringing in heavy sand cleaning equipment to deal with it. The Council is happy for people to do so, as long as it's just seaweed they're taking. 

"One problem with large equipment such as front end loaders is that you run the risk of damaging life on the beach," says Nelson. Birds' nests, shells and tiny plants all get picked up with the weed, and messing with them can be enormously damaging to coastal erosion."

"It's not straight forward," she says. "You really have to think of what else you're damaging in the process." 

Seaweed may be annoying to bathers trying to avoid jumping critters, but it's a great thing for the marine environment. As small creatures break it down, sea birds feed on those creatures as part of a natural cycle. Nelson says we really should value our seaweed forests and appreciate what they do. It's a 3D habitat, so not only do small fish feed on it but creatures can live in it and life grows on its surfaces.

And here's another complexity - as small pieces of seaweed sink deep into the ocean and are buried, they become a source of carbon. Not a lot of work has been done in factoring seaweed into climate change calculations, but one day it could be earning us carbon credits. 

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