Tanganyika blackfin (Altolamprologus calvus)
|Size||Male length: 15 cm (2)|
Female length: 10 cm (2)
Classified as Near Threatened (NT) on the IUCN Red List (1).
Altolamprologus calvus belongs to the Cichlidae, a family of freshwater fish that have adapted to a wide range of narrow ecological niches, resulting in the evolution of a huge diversity of species that live in close association (3). This species has a large mouth and a compressed body, with a large dorsal fin running along the entire length of the back (4). Like many cichlids, Altolamprologus calvus occurs in a number of different colour variations, including black, light grey and yellow (2) (3).
Altolamprologus calvus is only found in the southern parts of Lake Tanganyika governed by Tanzania and Zambia (1).
Altolamprologus calvus occupies rocky regions along the shoreline between depths of 3 and 41 metres (2).
The large variety of habitats found within Lake Tanganyika has allowed the cichlids to diversify into numerous species, each specialising in a particular ecological niche and showing a range of adaptations in body shape and behaviour (3) (5). In the case of Altolamprologus calvus, it has become adapted to living amongst rocky environments, where it feeds on tiny crustaceans found on rock surfaces (5) and the young of other fishes (6). Its compressed body allows it to fit into narrow crevices and caves; an ability that has led to the development of an innovative breeding strategy. The female locates a crevice or cave that is too small for the male to enter, and spawns up to 300 eggs. The male then fertilises the eggs by lying over the crevice entrance and releasing sperm into the water. Both sexes guard the developing embryos; the male patrols the outside of the crevice, occasionally leaving to feed, while the female remains in the crevice at all times until the eggs hatch (2). The young continue to be protected as long as they remain within their parents’ territory (6).
As a consequence of deforestation, the soil around Lake Tanganyika and its associated rivers is being extensively eroded, leading to high levels of sediment entering the lake. The excess sediment has its most severe effects on the rocky areas inhabited by Altolamprologus calvus, filling crevices and blanketing its food source (7). This problem is exacerbated by rising levels of toxic heavy metals in the lake’s water (1). Although Altolamprologus calvus appears to be relatively abundant at present, its range is limited and, in the absence of any protective measures, these ongoing threats will inevitably result in population declines (1).
While there are currently no specific conservation measures in place for Altolamprologus calvus (1), the governments of Burundi, Democratic Republic of Congo, Tanzania and Zambia, in collaboration with the United Nations Development Programme and the IUCN, are working to develop management strategies for Lake Tanganyika. As part of the Lake Tanganyika Project they aim to control pollution levels, reduce sedimentation by replanting forests and develop alternative livelihoods for the local people that will not have negative impacts on the lake’s biodiversity (8).
To learn more about the Lake Tanganyika Project visit:
- Lake Tanganyika Biodiversity Project:
Authenticated (19/12/2008) by Dr. Paul V. Loiselle, Curator of Freshwater Fishes, New York Aquarium.
- Crustaceans: diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.
- Dorsal fin: the unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.
IUCN Red List (December, 2009)