On The Ground in Malawi: Lake Malawi National Park

Lake Malawi National Park is a UNESCO World Heritage Site, containing the highest vertebrate diversity in the world, with an estimated 900 species of cichlid fish. This unique natural wonder is located at the southern end of Lake Malawi (see map).

Lake Malawi National Park was founded in the early 1980’s, to provide some safe breeding grounds for the unique cichlid fishes of Lake Malawi. The park comprises some areas of the southernmost end of the lake, including islands, as well as some forests on the mainland. Chembe, the largest rural village in Malawi, lies inside the park.

Substantial poaching problem

Unfortunately, the park has suffered from a substantial poaching problem. Fishing in no-fishing zones occurs frequently, and poachers take a toll on hippos and other wildlife on the mainland. WWF is working on finding solutions to these problems.

The good news is that virtually all the fish species already discovered are still present, although diminished in numbers. Thus there still is a lot that can be protected.

An inland sea exceptionally clear and deep

Lake Malawi itself is actually an inland sea. Almost 600 kilometres (400 miles) long, and on average about 50 kilometres (30 miles) wide, it is the ninth largest freshwater body in the world. Lake Malawi is also an important fresh-water source - the third largest in Africa.

The lakeside scenery could easily be taken for a seashore. Looking to the horizon, one sees only water meeting the sky. During stormy weathers, waves can be 3-4 metres (10-13 feet) high.

Located in the Great Rift Valley of eastern Africa, the lake is also exceptionally deep: up (or down, if you like) to 700 metres, or 2,300 feet.

Lake Malawi is one of the clearest lakes in the world. In rocky areas, visibility under water is up to 20 metres (almost 70 feet). In bays with muddy bottoms, however, visibility rarely exceeds 3 metres (10 feet). The water is slightly alkaline, with a pH value ranging from 7,8 to 8,5.

Geological changes boosted species-richness

The lake shares a characteristic common to several other deep tropical lakes. Since the seasonal variation in air temperatures is quite moderate, the lake water lacks the vertical cycle characteristic to lakes in cooler regions. Because of this, there is no dissolved oxygen in the water at depths greater than 200 metres (670 feet). Therefore it is unlikely that any vertebrate life could exist deeper than that.

During the last 25,000 years of its existence, the lake has undergone several dramatic geological transformations. This has been one of the reasons for the unique diversity of cichlid fish in the lake.