What began as an experiment to control algae and mosquito fern has become one of Sardinia Bay Golf & Wildlife Estate’s biggest success stories.
When residents Ian and Nina Robertson introduced hundreds of tilapia fish into one of the ponds some five years ago, it hardly occurred to them that this number could swell to thousands.
Yet the couple are thrilled with this outcome.
Aside from doing a sterling job in terms of the problematic plants, they have become premium eating for the piscivores of the sky.
“It’s amazing how well the fish have done,” Ian says, recalling how he had secured two large bucketfuls of tilapia from his son-in-law’s friend who bred them for the dinner table.
He had tasted the fish himself while camping along the Zambezi River and knew that if its tender fillets were morish to humans, they would prove an absolute showstopper among Sards’ feathered visitors.
While this was not the initial reason for decanting them into the ponds, the result has been a bird-watching bonanza for enthusiasts like the Robertsons and the rest of the twitcher community on the Gqeberha estate.
“We have a beautiful grey heron who fishes in the two dams at the bottom end of the estate,” Ian says.
“We also see malachite kingfishers and cormorants. The improvement in birdlife has been a huge bonus.”
The Robertsons find great joy in seeing the ripples in the water at the dam affectionately known as Impala Pan, one of three locations on the property where the fish were first distributed.
The younger tilapia tend to favour the edges of the ponds while the larger ones prefer the sanctity of the deeper water.
The fish, which can grow to 40cm in some cases, tend to reproduce after their first 12 months and can live up to 11 years – provided they are fortunate enough to escape the attention of passing birds.
Those who live in the dam with the bird hide may have the best chance of going the distance as this site is heavily reeded and provides extensive cover.
Like the residents themselves, the tilapia benefit from the estate’s water recycling system that ensures their habitat never runs dry.
Ian’s decision to use tilapia for the algae and mosquito fern issue was based on information he received from a Johannesburg-based company specialising in cleaning ponds at the City of Gold’s own lifestyle estates.
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The firm told him he could either sweep the water features with nets or introduce chemicals that would help address the problem.
Since neither was practical at a nature-centric estate like Sards, he went for the third option – introducing fish that had a natural appetite for mosquito fern.
He had looked at buying some but found them to be quite expensive, so when his son-in-law’s friend arrived with “two big buckets full of them” he could not have been more grateful.
Initially he was not certain whether the move would pay off but more than half a decade later, the proof is in the ponds.
“We are very happy,” he says.