There are many articles like this all over the place.
And almost all of the forums are saying that the carp and catfish have taken over.
Theewaterskloof Fish Clean-up Print E-mail
Friday, 03 August 2007
The City of Cape Town has to spend millions of rands every year to clean water from the city's main supply dam, Theewaterskloof, which has become polluted by massive numbers of illegally introduced alien fish.
The City of Cape Town has to spend millions of rands every year to clean water from the city's main supply dam, Theewaterskloof, which has become polluted by massive numbers of illegally introduced alien fish.
The fish, particularly carp and barbel, are spreading throughout the province's dams and rivers, with devastating consequences for indigenous fish and aquatic plants, the Cape Times website reported on Thursday.
City authorities now want to launch a freshwater fishery at Theewaterskloof in an attempt to reduce the numbers of alien fish by allowing anglers to catch them with no restrictions on numbers, size or season.
They hope to have the project established within a year, and want to encourage previously disadvantaged communities, in particular, to become involved.
If successful, the new fishery will provide a food source, give the freshwater ecosystem a chance to recover and save the city millions of rands on its water-purification bill.
One of the most aggressive of the alien species is the barbel, or sharptooth catfish, which can move over land if it is flat and moist, and which has a rudimentary lung, so it can breathe out of water. Barbel are known for "pack-hunting" other fish.
There are fears that alien barbel and carp may already have reached the Olifants River system, the most important river system for freshwater fish conservation in the country, with eight of its 10 indigenous fish species found nowhere else in the world.
Dean Impson, a scientist at CapeNature, said that alien fish were illegally introduced into the province's rivers and dams by anglers and rural land owners, both for food and recreation. -- Sapa
Article : Alien fish pollute Cape Town water supply
Johannesburg, South Africa
19 July 2007 10:54
