Lake Victoria

Lake Victoria is a very big lake in Africa.

It is very, very wide. Three countries share it: Kenya, Tanzania and Uganda. Many fishers go out in boats to catch fish. The water flows out of the lake and becomes the Nile River.

Lake Victoria sits high on a plateau in East Africa, 1,134 meters above sea level. Britannica calls it the largest lake in Africa: it covers 69,484 square kilometers, and among the world's freshwater lakes only Lake Superior is bigger. From north to south it stretches 337 kilometers, and its twisting shoreline is more than 3,220 kilometers long.

The lake is shared by three countries. Most of it lies in Tanzania and Uganda, and it also borders Kenya, where a long gulf reaches the city of Kisumu. Big as it is, the lake is shallow: its deepest point is only 82 meters down. Rivers flow in, the largest being the Kagera, but only one river flows out: the Victoria Nile, the start of the long journey of the Nile to the Mediterranean Sea.

Britannica describes Lake Victoria as an irregular quadrilateral, 337 km long from north to south and 240 km across at its widest, with a coastline of more than 3,220 km. Its surface lies 1,134 m above sea level and its greatest ascertained depth is 82 m; its drainage basin covers 238,900 km². Among freshwater lakes only Lake Superior exceeds its area of 69,484 km². The lake lies mainly in Tanzania and Uganda and borders Kenya.

The shores vary. Cliffs about 90 m high back the southwest, giving way to papyrus swamps at the delta of the Kagera River, the largest inflow, which Britannica says may be considered the most remote headstream of the Nile. The northern shore is deeply indented; the Winam (formerly Kavirondo) Gulf runs 64 km east to Kisumu, in Kenya. Ukerewe, in the southeast, is the largest island, and the 62 Sese Islands lie in the northwest. The only outlet is the Victoria Nile at Jinja, Uganda, which Britannica names as the conventional source of the Nile.

Lots of small, colorful fish called cichlids live in the lake.

Some cichlid parents keep their tiny babies safe inside their mouths. A big fish called the Nile perch lives here too. Hippos rest in the water near the shore.

Lake Victoria was once home to an amazing number of small fish called cichlids (say it "SICK-lids"). The American Museum of Natural History counts more than 350 kinds that lived nowhere else. Many cichlids carry their newly hatched babies in their mouths to keep them safe.

In 1954 people put a huge fish, the Nile perch, into the lake so fishers could catch bigger fish. The museum explains that by the late 1970s the perch population exploded, and it ate many of the cichlids. In 1978 cichlids made up about 80 percent of the weight of the lake's fish; within ten years the Nile perch made up more than 80 percent. Tall papyrus plants grow along parts of the shore. Around East Africa's lakes, Britannica adds, hippos are everywhere, and fish-eating birds such as cormorants and kingfishers hunt.

Britannica gives more than 200 fish species for Lake Victoria, with tilapia the most economically important, and between 100 and 200 cichlid species in Lakes Victoria and Kyoga together; the American Museum of Natural History puts the lake's endemic cichlids at more than 350 species. The two sources give different counts. Many cichlids are mouthbrooders, carrying newly hatched young in their mouths, which protects them but limits how many offspring each parent raises.

The museum describes a chain of pressures: gill nets from around 1900 and decades of overfishing; soil and fertilizer washing in from cleared land, feeding algae whose decay used up oxygen; then, in 1954, the introduction of the Nile perch, a predator weighing up to 136 kg. Its numbers stayed low until the late 1970s and then exploded: cichlids were about 80 percent of fish biomass in 1978, while within ten years Nile perch exceeded 80 percent. The museum writes that more than half of the cichlid species may now be extinct or close to it. Britannica adds the invasive water hyacinth and pollution to the threats. Papyrus lines many shores, and hippos and fish-eating birds such as cormorants, darters and kingfishers are part of the lake's life.

Many, many people live near Lake Victoria.

Fishers catch fish to eat and to sell. Boats carry people across the water. A big wall across the river makes electricity from the flowing water.

Britannica says the land around Lake Victoria is one of the most crowded parts of Africa: several million people live within 80 kilometers of its shores. Many people fish on the lake, and tilapia is the most valuable catch. Steamers carry people around the lake, and Kampala, Uganda's capital, lies near the northern shore.

In 1858 the British explorer John Hanning Speke, searching for the start of the Nile, reached the lake and named it after Queen Victoria; Arab traders had known it as Ukerewe. In 1954 the Owen Falls Dam, now called the Nalubaale Dam, was finished on the Victoria Nile at Jinja. It makes electricity from the river and turned the lake into a huge reservoir. A second dam, Kiira, began making power in 2000.

Britannica describes the Lake Victoria region as one of the most densely populated in Africa, with several million people living within 80 km of the shores, and local steamer services circling the lake. The lake's large size moderates its own climate: along the western and northern shores, in a zone 48 to 80 km wide, temperatures rarely rise above the high 20s °C or fall below the mid-10s °C, and rain, heaviest over the lake itself, averages 1,300 to 1,500 mm a year at the shoreline.

The European search for the Nile's source brought John Hanning Speke to the lake in 1858; formerly known to Arab traders as Ukerewe, it was named by him after Queen Victoria, and Sir William Garstin surveyed it in detail in 1901. Plans to raise the lake level were completed in 1954 with the Owen Falls Dam (now Nalubaale) at Jinja, which generates hydroelectric power on a large scale and made the lake a vast reservoir; the Kiira Dam, 1 km away, was completed in 1999 and began producing power in 2000. Britannica lists overfishing, pollution and invasive species as the threats facing the lake in the late 20th and early 21st centuries.