Banana Beach (Pistia) water lettuce invasion. Not the final word.

Banana Beach

It’s been controlled chaos as so many people jumped in, all with good intentions, to help the Banana Beach estuary (Koshwana River), and it’s fishy residents, survive the water lettuce (Pistia) invasion. First there were the local surfers – who started removing the invaders, and rescuing dying fish by running them over and into the shore break. After a few weekends, the water on the sea side of the bridge was cleared, and some fish were looking good.

Then came herbicide?! It seemed to burn through strips but was not effective at all, overall. And more fish were seen dead after this happened. Bigger fish, and tilapia, who can normally handle low oxygen conditions…went belly up.

Then there was the introduction of an airborne bio control agent (weevil) but the wrong species of alien plant was identified, and so that effort bombed.

None of these methods proved successful at all. The water lettuce dominated any attempts to be removed. 99% Coverage.

Then along came Environmental Affairs – represented by Ms. Joanne Hope, an entomologist, who got right involved. After visiting Ground Zero, Ms. Hope was witness to the many dead and dying fish, gasping for air – and trying to escape the oxygen starved water. Some were seen still flapping, a few metres away, on the rocks as they tried a last ditch effort for air. The water lettuce invasion was still blazing, but streaks of brown (dying plants) could be seen, from the herbicide. The dead plants were sinking to the bottom, adding to the already challenging ecological problem. Fortunately, the rope trick, deployed by the surfers, strung across the water at the old bridge…kept the water lettuce at bay, in the area on the sea side of the bridge.

Ms. Hope immediately set out gathering facts and preparing a more carefully thought through recovery plan. She has been liaising with the many people who are concerned and now involved with the problem, and has communicated with Mr. Peter Massyn (EKZN) and Mr. Charlton. Mr. Massyn reports that he has issued a directive to the local municipality, to address the blatant sewage problem. Sewage flows freely into the river, as development has outstripped the capability of the system. Sewage also flows across the main road through the Banana Beach area. This has been the case for years. Since water lettuce thrives on sewage in it’s water, it makes sense that this could have been a major factor in the invasion. Mr Massyn has advised the municipality, that the current sewage system be moved.

Investigation has been carried out as to the source of the water borne epidemic. Satellite imagery has been studied, and many specialists have been consulted. Given that none of the local farm dams in the area are, or have been infested lately, it makes sense then, that the water lettuce could have come through the sewage system or storm water drainage systems servicing the Banana Beach residential area.

From Ms. Hope…

” I have come to an agreement with everyone and have suggested that 1) no more herbicide to be sprayed, 2) manual removal of plants to continue at estuary mouth, 3) biocontrol agents to be released along the edges of the river a little upstream from where the manual removing will be taking place and 4) an inspection of both the Koshwana and Ntshambili rivers be done to try identify the source of the infestations in both rivers (none of the farm dams appear to be the culprits).

So there you have it and all the while more fish will die :(”

Measures that have been achieved since the involvement of Environmental Affairs are as follows:

• The correct from of airborne bio-agent has been requested and could be available within two or three weeks
• Working for the Coast and other volunteer groups have continued with manual removal, and any interested groups or organisations are encouraged to help this way (the removed water lettuce should not be burnt as this kills the Neohydronomus weevil)
• Herbicide is not being used anymore

So it’s not all bad, but certainly is not good either, as so many dead fish litter the Banana Beach area. Dead fish are all over the beach and rocks, and even way up the road…dropped there by people chancing a free meal or souvenir. It’s going to take time and resources. We also have to hope that the municipality, the only people who can really make all the difference, as it is in their portfolio, do so. The sewage plant has been a problem for many years with the water in the Banana Beach river sometimes being so polluted, the stench permeates the air for miles around. The fact that sewage has been pouring across the main road through Banana Beach, for years now, leaves the leaving of the responsibility to the current municipality, a worriesome prospect. We can just hope that the involvement of all these interested groups –  EKZN, Environmental Affairs and local entities as volunteered, we can get these ecologically important rivers, back into a functioning state.

See you at Banana Beach…and bring a rake!