Lake Malawi; It is the third largest lake in Africa, located between Malawi, Mozambique and Tanzania. The length is approximately 600 km and the width is 80 km in some places and the area is 31.000 km2. The depth of some places reaches 700 meters and the world is the seventh largest and the fourth deepest lake. It is also thought to be one of the oldest lakes on the planet. Experts predict that the age of the lake will range from 3 to 20 million years, with no exact date.
Since the lake has existed, its waters have constantly risen and fallen at different times. There is evidence that the lake is about 400 meters shallower than today 25,000 years ago. Since then, a sedimentation of 40 meters has been formed. It is believed that the sediment below the Malawi lake is about four kilometers deep. Because of this sedimentation thickness, researchers think that the lake is old. The lake reached its highest level in 1980, and since then it has risen visibly with fallen levels.
The most interesting feature of the lake is the constant change because of the increase in its biological diversity. The waters of the Malawi Lake have caused the greatest diversity to be found in a single water mass. The Malawi Lake houses about 1000 kinds of fish, more than the numbers in Europe and North America. Some of these are catfish, minnows, killifish, a true sea eel genus, vertebrate eel, and the most exciting cichlids.
The cichlid family of Lake Malawi has seen at least 1500 varieties of cichlids from the same donation over the past 10 million years. Over the past 2 million years, the lake has witnessed the development of more than 700 species of cichlids. Ad Konings now estimates that there are 250-300 varieties to be discovered alongside the 850 varieties already known in the lake. This tremendous number gave the name of Lake Malawi the “game of Darwin”. What is the reason for this high-speed evolution?
One of the most important factors in the evolution of Malawi cichlids is the competition for food and at the same time geographical isolation. Due to the continuous food search, the Malawi Lake cichlids have developed quite interesting ways of feeding. They range from specially developed teeth and camouflage to brave hunting behaviors.
The intensive competition they have for food has made Lake Malawi cichlids an expert in nutrition. Some species living between the rocks are known as mbuna. They have developed large comb-like teeth and are thus able to eat algae on the rocks. These people are not especially in search of algae. In fact, microorganisms in the algae are scanned. A species called Labeotopheus goes one step further by developing a concealed jaw structure, using the cone to develop a tooth closer to the shape and to catch plankton floating freely in a water column.
Without losing ground, the larger Haplochromines have also developed some special forms to keep them permanently. A type of cichlid known as “rubber” or “thick” lips has developed fleshy and cornified lips. These cichlids paste Chilotilapia Euchilus or Protomelas sp “mbenji thick lip” mouths into cracks and crevices in the rocks. The relevant section is completely closed and the fish uses its mouth as a vacuum and absorbs its living things. Other fish such as Chilotilapia Rhoadesii and Trematocranus Placodon have learned to feed on snails. For example, the rhoadesii simply breaks small crustaceans or sucks large ones through the crust.
Another fish, Genyochromis Mento, imitates another cichlid species, Oreochromis. He fools Oreochromis and approaches him enough and bites him and takes a mouthful of scales and runs away. One of the most important reasons for the survival of Malawi cichlids is that some fish learn. All Malawi cichlids are born by mouth from their mothers. That is, the female cichlid keeps the pups in their mouths after they have emerged from the eggs and eggs and will not let them learn to swim freely at all. Caprichromis Orthognathus fish have learned to provide an advantage in the mouth with eggs. These “baby-eaters” cause the mouth full of puppies to strike hard from behind or from the side and cause some puppies to come out of their mouths. Vulnerable offspring become an easy meal.
The best camouflers are fisherman cichlids. For example, the Dimidiochromis Compressiceps type has a literally flattened body and a dark line on its back. Compressicep keeps his head down while hunting in the reed and hunts himself as if he is struck. Nimbochromis Livingstonii (Living Rock) are fed using the most interesting camouflage. There is a brown and white variegated image. In men who make curses, blues are observed. At the time of feeding, it shows the brown and white part (the Malawi cichlids can control their colors to a certain degree), and the coma stays on its side. Smaller fish think Livingstonii is dead and they approach it as easy food. It is actually an easy meal time for Livingstonii.
Camouflage is also found in other forms on Lake Malawi. It is known as Orange-Blotch (Orange stained) or O.B. This color is especially found in Mbuna. O.B.’s stains are seen with brown or black stains on the orange body. This color in the teeth is more obvious. In the wild, male O.B. the probability of finding it is very poor. Among the aquarium hobbyists are known as “Jam Cats” and are a very attractive, highly sought after species. There is also a spotless type. It is known only as orange or O.morph. Although it seems difficult to evaluate these colors as camouflage, it is hard to see these fish in the air where the light is broken in the low places of the reef, and delicious fish-hunting birds are prevented from seeing them.
Genetic isolation is thought to be an effect on the morphology of Malawi cichlids in the reefs. The reefs, separated by open waters, prevent the fish from going there. Fighting against food seems to be easy hunting with the removal of fish from the reefs, and it means that they must be feed for the spring (Bathclarias) or by other open water cichlids (such as Rhamphchromis). In fact, most cichlids do not go very far from riffs and their offspring develop isolated, gene pools do not interfere and genetic codes are transmitted to future generations with fewer variations.
His development and behavior have kept fish scientists busy for the last few centuries. Malawi cichlids are among the most colorful freshwater fish on the planet. If you add the easiness of the three beside these three features, you will understand why the aquarium is the most important commercial center.