Eco-minded Sardinia Bay Golf & Wildlife Estate has introduced tilapia fish into one of its ponds to assist in controlling the algae and mosquito fern.
This came after estate trustee Ian Robertson noticed just how the weeds seemed to be filling the ponds which are situated all around the development.
The introduction of the fish seems to have met with initial success, but Robertson said it was a case of monitoring the situation to ascertain whether it was, in fact, the fish that were proving effective, rather than other conditions.
He said the project came about after he sent samples of the plants to a company in Johannesburg which cleaned ponds on similar estates and also golf courses.
“They responded to say the plant was mosquito fern and that there were three ways of getting rid of it,” said Robertson.
“One is to sweep the ponds with nets, which is not really practical in our situation.
“Secondly, you can add a substance to the water, but because of our wildlife and the bird species on the estate, putting chemicals into our ponds is not something we want to do.
“The third option is to introduce tilapia fish, which eat this sort of fern.”
Through a contact in Port Elizabeth, the estate was able to secure several hundred of the species and introduced them to the pond adjacent to the third green on the golf course.
“We had to make sure that the tilapia we secured were indigenous and not the Nile tilapia, which are prevalent in north Africa and not suitable for breeding in South Africa,” said Robertson.
“Having secured the right species, we put quite a lot in the pond at the third green.
“Initially I bought a small tin of fish food and my wife [Nina] and I fed them in the beginning.
“But then we were away during December and when we returned we discovered there had obviously been some breeding because there were lots of little ones around the edge of the pond.
“In addition, the algae has disappeared and the mosquito fern has been reduced, so we are hoping the introduction of the fish has made the difference.”
He emphasised, though, that the project was still in an experimental phase.
“There was mosquito fern in the other dams, but it has cleared a little bit, so that may be down to the weather conditions and, perhaps, what we are seeing in this pond is not due to the fish.
“But we will wait for the weather to change and if the mosquito fern grows in other ponds and not in this pond then we know the fish are making the difference.
“And perhaps we can then start transferring into the other dams.”
One of the fringe benefits of introducing the fish, added Robertson, is that they were starting to encounter species of birds previously not seen on the estate.
“In the last three weeks I have seen the grey heron, which is a water heron, that has not been here before.
“There are lots of black-headed herons, but they eat things like frogs, snakes and rats, while the grey heron feeds on fish, so that is really good to see.
“Also, the malachite kingfisher has been spotted, again never seen before, so that is two new species of birds the estate has attracted since the fish have been introduced.”