Lake Malawi Cichlids - Larry Gasiewski (Cichlidmaster)|
Lake Malawi, formerly known as Lake Nyasa, (Nyasa literally meaning Lake) is the ninth largest lake in the world. Its size is approximately 600 km long and 80 km wide at various locations.
Its depth is some 700 meters deep and it’s surface lies 472 meters above sea level. The Lake itself covers an area of just around 31,000 km and is bordered by three countries.
The largest portion of the lake (the western and southern part) belongs to Malawi, the northeastern section to Tanzania, and a long stretch of the eastern coast falls under the jurisdiction of Mozambique.
The lake is considered by some to be an inland sea. During the windy season (between June and mid august) the waves have potential to reach 3 to 4 meters and the lake temperature can reach lows of 15 degrees Celsius (60 F). During the months of mid August to the end of November, the lake is generally calm making water visibility good. The latter half of November brings the rains and a northerly wind that occasionally blows over the lake.
The chemistry of the water is rather constant throughout the year. The pH varies between 7.8 and 8.3. In the middle of the lake and in the deeper areas,
The pH is at the higher end…8.3 Dissolved carbon dioxide is the main reason for the fluctuations of the pH. The conductivity, (a measure of the mineral content) usually ranges between 200 and 260 microSiemens. This is relatively low when compared with the other African rift valley lakes.
During its history, the lake level has dropped considerably on several occasions. In 1988, evidence was found that lake Malawi was much smaller some 25,000 years ago as the water level stood at about 400 meters below today’s level.
It has been estimated that a later of sediment about 40 meters deep has accumulated during the last 25,000 years. This layer of sediment today has a depth of four kilometers, which points to a much greater age for the lake then the previously estimated age of one to two million years. Today, Lake Malawi is estimated to be between 3 and 20 million years old.
There are more than 850 species present in the lake today. The 600 species known are from relatively shallow waters. The other 250 – 300 species await discovery in the deeper layers of the lake.
Book of Cichlids and all the other fishes of Lake Malawi
Malawi Cichlids in their natural habitat