‘Curtain’ shark nets go up and down daily

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iol scitech april 9 Fish Hoek shark nets INDEPENDENT NEWSPAPERS The purpose of the nets at the southern end of Fish Hoek beach is to give the public a swimming area safe from sharks. Photo: Ross Jansen

Cape Town - The Fish Hoek shark nets are there, then they’re gone, then they’re there again. And now they’re gone.

If anyone is confused, the Cape Town city council has reassured the public that this is all part of the plan.

Cape Town, with the help of the KwaZulu-Natal Sharks Board, is developing an entirely new kind of shark net, one that is designed to keep sharks out, rather than the conventional nets that are designed to kill them. What makes Fish Hoek’s “exclusion nets” a world first is that they are being designed to be deployed and raised on a daily basis.

Gregg Oelofse, head of the city’s environmental resource management, said the only way they could test the nets was to deploy them, see the problems, remove them and make adjustments.

“There are exclusion nets in other parts of the world, Hong Kong for instance, but these are all fixed installations, there permanently. We’re developing nets that go in and come out, and we’re working flat out to get them to work. The aim is to be able to deploy them in 40 minutes. If it takes two hours every day, it is a very costly exercise. We need to make sure they work, are efficient and cost-effective. We take the nets out in straps like a long sausage. We want to be able to get to a stage where we drop them easily, like a curtain,” Oelofse said.

The purpose of the nets at the southern end of Fish Hoek beach is to give the public a swimming area safe from sharks. They will be removed at sunset, so that marine life can have free movement at night. They will also be removed in rough seas, which could damage them, and during times when they could pose a risk of entanglement to marine life, such as during the whale season.

City officials deployed the nets for a second time on Friday, and kept them in the water for four hours checking how they worked.

“We’ve had one or two design changes. The first time we had to adjust the moorings, now we’re looking at too much spare net. The nets have two leaded ropes, weights that will put the net on the floor when it is deployed. There are two because of the tidal change. We’ve found that at low tide, when the second weight drops, we have a billowing effect of spare net. We don’t want that because it could create entanglement problems. We’re making changes and will be deploying again this week and will continue until we get it perfect. There are a whole lot of lessons we’re learning as we go along, which is the purpose of having a trial period.”

Staff of the KwaZulu-Natal Sharks Board will come to Cape Town at the end of the month to check on the progress. The city hopes to have most of the design adjustments completed by then. - Cape Times

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