Global Adviser

The British empire killed millions and sowed the seeds of dozens of wars. Then again, it also gave the world brown trout. From the mountain streams of the Indian Himalayas to the wide rivers of Australia, from the Rockies to the Great Rift Valley, wherever Brits went, they took brown-trout fry with them to release into the waters and create little fly-fishing oases that would be forever England. Experts will tell you that the invasive stocking didn't just disrupt local ecology, it was also unnecessary. North America had its own brook and cutthroat trout, while the rainbow is native throughout the Pacific region. This is great news for anglers, of course. The world is full of brown trout, and science practically demands that you catch them.

South Africa is a good place to start. As part of its Africanization program, the government is considering poisoning the trout in its lakes and rivers. This sounds drastic until you get to Dullstroom, on the edge of Kruger National Park, east of Johannesburg. Here, in the waters that feed the grasslands and carve out the escarpments of the Highveld plateau, trout are a plague. The lakes, dams and rivers are overflowing with them. So is the town. Almost every shop, hotel and gas station in Dullstroom features a picture of a seven-pounder curling around a fly. (And no prizes for guessing which delicious, pink-fleshed fish dominates the restaurant menus.)

Fishing isn't all there is to Dullstroom. You can hike and ride horses, and I once saw mountain bikers. But it's primarily a place for fishing freaks. You can cast a rod into public water for as little as $20 a day; for $300 you can spend a weekend in a luxury cabin on its own stretch of river. Some of the best are the four at Salpeterkrans fly-fishing estate (www.salpeterkrans.co.za), which come with hearty evening meals and stunning views of the Klip River, where beauty — and fish — have outlasted an empire.