Cape Town, May 21: Predatory imported fish including trout, bass and carp are crowding out many local species in one of the few places in the world still rich in biodiversity.
First introduced in the 18th century and hugely popular with both local and foreign anglers, these fish form an integral part of a burgeoning recreational fishing industry, estimated to contribute some 18 billion rand ($2.6 billion) to the South African economy.
But they are invasive and have already made several species in the area extinct. One site in the Cape Floristic Region where indigenous species are fighting for survival is the Bot River, a tourist attraction which flows through wetlands housing waterfowl and wild horses in a fertile valley of wine farms.
"It's a sad river at the moment," said Dean Impson, aquatic scientist at Cape Nature Conservation. "These are sad rivers from an ecological point of view because they are like little deserts, the alien fish are in them and they've eliminated most, if not all, of the indigenous fish."
A new plan to rid local rivers of the fish has sparked a fresh environmental debate, and could pit the interests of fishing and tourism against those keen to preserve indigenous species.
Some conservationists are hoping to use a controversial natural poison to eradicate the invaders as part of a global effort to save the freshwater fish, which experts say are among the most threatened group of animals on earth.
Impson is among conservationists who -- with backing from the World Bank -- hope the biodegradable poison Rotenone can help shield the Western Cape from alien fish.
Other ecologists fear Rotenone, an insecticide and piscicide derived from the roots of beans, could do more harm than good in the fragile freshwater ecosystems.
a"It's a sad river at the moment," said Dean Impson, aquatic scientist at Cape Nature Conservation. "These are sad rivers from an ecological point of view because they are like little deserts, the alien fish are in them and they've eliminated most, if not all, of the indigenous fish."
A new plan to rid local rivers of the fish has sparked a fresh environmental debate, and could pit the interests of fishing and tourism against those keen to preserve indigenous species.
Some conservationists are hoping to use a controversial natural poison to eradicate the invaders as part of a global effort to save the freshwater fish, which experts say are among the most threatened group of animals on earth.
Impson is among conservationists who -- with backing from the World Bank -- hope the biodegradable poison Rotenone can help shield the Western Cape from alien fish.
Other ecologists fear Rotenone, an insecticide and piscicide derived from the roots of beans, could do more harm than good in the fragile freshwater ecosystems.
Bureau Report
First Published: Monday, May 21, 2007, 00:00