Wednesday, 20 July 2011
Today Constance and I went for a swim in the lake, just in front of our room at the hotel. We brought masks and snorkels, in hopes of glimpsing some of the many cichlid fishes that make this lake so famous (to biology geeks like us, anyway). Not only did we see cichlids, but we saw tons of them! There were bright blue ones, yellow ones, pink ones – all easily visible in the beautifully clear lake water. These cichlids, which are found in abundant variety in the great African rift lakes (Lakes Malawi, Tanganika, and Victoria are the largest), are fascinating to biologists for many reasons. First off, they are almost entirely endemic to their respective lakes. For example, the majority of cichlid fishes one finds in Lake Malawi may be found only in Lake Malawi, with other lakes having their own assemblages of species. In addition, these cichlid species are all descended from a smaller number of common ancestors, and have speciated in a spectacular and rather textbook example of adaptive radiation, to fill a huge variety of niches in the lakes’ numerous microhabitats. There are fishes that feed on any type of available food imaginable from insects to other fishes (and even just the scales of other fishes) to algae. For us, this is a thrilling opportunity to witness, first hand, one of the world’s most fascinating natural phenomena, which also happen to be vibrantly colorful and absolutely beautiful.