Hoplotilapia retrodens

• Summary
• Classification Schemes
• Images & External Links
• Bibliography
• Full Account

View Printer Friendly

Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	ACTINOPTERYGII	PERCIFORMES	CICHLIDAE

Scientific Name:	Hoplotilapia retrodens
Species Authority:	(Hilgendorf, 1888)

Assessment Information [top]

Red List Category & Criteria:	Vulnerable   D2   ver 3.1
Year Assessed:	2010
Assessor/s:	Witte, F., de Zeeuw, M.P. & Brooks, E.
Reviewer/s:	Darwall, W. & Smith, K.
Justification: The population density of this species was known in the past. The current population density is not known, and the species has declined dramatically since the 1970s. The main threat to this species which was responsible for its dramatic decline in the early 1980s was the introduction of the Nile Perch (Lates niloticus) to Lake Victoria. As this can be found throughout the lake, it is very likely this species is found at very few locations, and it is therefore assessed as Vulnerable. This species has not been seen since 1991, although there has been reduced survey effort in these areas since 2002. More information may show that this species qualifies for a higher threatened status, or may even be classified as Possibly Extinct.
History:	1996 – Extinct

Geographic Range [top]

Range Description:	This species is endemic to Lake Victoria. It has been recorded in surveys carried out in Kenya, Tanzania and Uganda (Greenwood 1981).
Countries:	Native: Kenya; Tanzania, United Republic of; Uganda
Range Map:	(click map to view full version)

Population [top]

Population:

This species has declined in numbers dramatically since 1980. Frequency of occurrence data per 5 minute trawl across shallow sand in Mwanza Gulf (Witte et al. 1992) show a decrease from 81% in 1979-82, to 0% in 1987/88 and 1993/95. The shallow sand stations where this species used to occur were rarely sampled after 2002. However, during the past decade this species was also very rare or absent in other suitable habitats.

Population Trend:

Unknown

Habitat and Ecology [top]

Habitat and Ecology:	The species has been found over sandy substrate in the littoral and sub-littoral zone. The species is an oral shelling/crushing molluscivore.
Systems:	Freshwater

Threats [top]

Major Threat(s):

The main threat to this species is predation by Nile Perch (a potentially reversible threat). It is also potentially threatened by hybridization due to decreased water transparency (on account of eutrophication and erosion leading to increased sedimentation and runoff) interfering with mate recognition visual cues (Mrosso et al. 2003). This species is fished, although not targeted specifically.

Conservation Actions [top]

Conservation Actions:

Many fish species within Lake Victoria have suffered severe and dramatic declines since the introduction of the Nile Perch. Although numbers of the perch have now decreased, the degradation of the water quality is also thought to be having a significant impact on some fish species. More research is needed to monitor this species and how it is affected by these threats, as well as establishing the extent of its range within the lake. Policy based action is needed to decrease the degradation of the lake, as well as to prevent over fishing. Protected areas should also be established.

Bibliography [top]

Greenwood, P.H. 1956. A revision of the Lake Victoria Haplochromis species (Pisces, Cichlidae), Part I. Bulletin British Museum of Natural History (Zoology) 4: 223-244. IUCN. 2010. IUCN Red List of Threatened Species (ver. 2010.3). Available at: http://www.iucnredlist.org. (Accessed: 2 September 2010).