A team of scientists from Leiden, Holland have described seven new endemic Haplochromis species from Lake Victoria.
All the species have been known for many years but not formally named, largely because they belong to groups – detritivores and phytoplanktivores – from open habitats that were severely affected by predation by the Nile Perch (Lates niloticus). These groups were once the most abundant fishes, in both numbers and biomass, in offshore habitats, but virtually disappeared during the 1980s so there was little stimulus to produce scientific descriptions.
More recently, however, the Nile Perch has greatly declined due to heavy fishing, and there has been a slow recovery of some planktivores and detritivores. Recent investigations have revealed ecological changes, including changes in diet in these two groups, with macro-invertebrates now the main food source instead of detritus and phytoplankton.
The recovering species also exhibit morphological (physical) changes which may be adaptations to changed environment. Cichlids, in particular East African lacustrine (lake-dwelling) cichlids, are known to be remarkably plastic, ie capable of quickly adapting both their form (including their teeth) and behaviour to new circumstances.
These changes offer a possibly unique opportunity to learn more about ecological and evolutionary processes, but such research first requires the formal "benchmark" description of the study species as they were prior to the changes, using material from past collections.
The majority of specimens originate from the northern Mwanza Gulf and all were collected between 1975 and 1986, before the collapse of the haplochromines. The species chosen were common prior to the mid 1980s; five are probably still present. There are, however, problems matching these "historic" species with what appear to be numerous intermediate forms now swimming in the lake.
The new species are listed below. Names in brackets are temporary names used until now.
Detritivores (four):
Haplochromis antleter (Haplochromis (Enterochromis) 'dusky wine red fin'). The name comes from the Greek word for scooper or dredger, referring to the dredging of mud bottoms, the species’ main feeding technique.
Haplochromis katunzii (Haplochromis (Enterochromis) '75'). Named to honour Egid Katunzi, Director of the Mwanza Centre of the Tanzania Fisheries Research Institute (TAFIRI).
Haplochromis coprologus (Haplochromis (Enterochromis) 'nigrofasciatus'). The name comes from the Greek for rubbish collector, referring to the species’ detritivorous habits.
Haplochromis vanoijeni (Haplochromis 'red tridens'). Pictured above. Named in honour of ichthyologist Dr Martien van Oijen, a pioneer of the Haplochromis Ecology Survey Team (HEST) of Leiden University that started fieldwork on Lake Victoria in 1977.
Phytoplanktivores (three):
Haplochromis sphex (Haplochromis 'citrus'). The name is from the Greek for wasp, referring to male coloration - yellow with black stripes. This species is pictured at the top of the page.
Haplochromis bwathondii (Haplochromis 'kribensis'). Named to honour Philip Bwathondi, formerly Director General of TAFIRI.
Haplochromis pancitrinus (Haplochromis 'yellow'). The name is composed of the Greek words for completely and yellow, referring to male coloration.
For further information see: de Zeeuw, M.P., Mietes, M., Niemantsverdriet, P., ter Huurne, S., & F. Witte (2010) Seven new species of detritivorous and phytoplanktivorous haplochromines from Lake Victoria. Zool. Med. Leiden 84 (9): 201-250.