SANBI

Rationale (Changed due to Same category but change in criteria)

Serranochromis meridianus occurs in relatively low numbers in the Sabie Sand tributaries (Inkomati River System) (Kleynhans 1982, 1984). The natural population is experiencing continuous decline as a result of habitat degradation (over-abstraction, reduced water quality, increased sedimentation and siltation) (Kleynhans 1982, 1984, Skelton 1987). Criteria A2ace applies as a decline of more than 50% of the population and a decline in area of occupancy (AOO) has occurred in the last ten years with an estimated generation length of three years. Furthermore the species has a extent of occurrence (EOO) ranging from 1250 km² to 4551 km² and an AOO ranging from 40 km² to 44 km² with two to three locations (uncertain location in Mozambique). It is listed as Endangered A2ace; B1ab(ii,iii,v)+2ab(ii,iii,v).

Distribution

Endemic to the Sabie Sand River tributaries of the Inkomati River System (Skelton 1987). Serranochromis meridianus has also been recorded in the coastal plain between the Inkomati (Mozambican coastal plain) and Limpopo rivers (Gaigher 1969, Skelton 1987) as well as from the Ngobezeleni Lake close to Sodwana Bay in Kwa-Zulu Natal, South Africa. These Lake records are uncertain and need verification, hence the Kwa-Zulu Natal records have been excluded for this assessment until further verification processes. This species has been translocated to various dams on tributaries of the Sand River in the Kruger National Park (Skelton 1987).

Habitat View more ecological information

Population trend

Trend

Kleynhans (1984) reported S. meridianus to have a restricted distribution in South Africa and occurs in low numbers in their natural distribution in the Sabie and Sand river tributaries. During these four surveys S. meridianus represented only 1.1% to 1.6% population density of the total fish community in the Sand River (19 specimens out of 2521 fish collected) (Kleynhans 1982, 1984). In the Sabie River, Potgieter (1974) estimated a population density of S. meridianus at 1.1% of the total fish community. During recent surveys in the Sabie-Sand River System (Roux and Selepe in prep) only 19 S. meridianus individuals were recorded. At five monitoring sites in the Sand River and tributaries, 18 individuals were recorded out of a total of 1212 fish collected (1.4% of total fish collected with a CPUE of 0.11). In the Sabie River in the Kruger National Park only one individual was recorded out of a total of 971 fish collected (0.1% of total fish collected with a CPUE of 0.01). These results clearly indicate the low population densities of this species within its restricted range. More than a 50% reduction in population size is inferred based on low CPUE and a reduction in area of occupancy in the last ten years, as the species has an estimated generation length of three years. No information is available on the status of the translocated populations within dams in the Kruger National Park. The records from the coastal plains could be a result of the species spreading there during flood periods; however, these dispersed individuals do not form viable subpopulations and are extirpated soon after the flood conditions. Further the construction of the Coromano Dam prevents future movement to the coastal plains. Hence the records in the Mozambique coastal plains will be considered uncertain until surveys are conducted to confirm the species' presence.

Threats

Habitat degradation is the main threat caused by over-abstraction, large rural settlements, forestry activities and reduced water quality. Increased sedimentation levels have changed the instream habitat and resulted in the loss of pools. To date all calls for the implementation of the Ecological Flow Reserve required for the Sabie Sand River System have been unsuccessful.

Conservation

The natural distribution range of this species falls partly within the Sabie Sand Private Nature Reserve and Kruger National Park. Unfortunately these conservation areas have no control of what happens upstream and do not receive enough water for the normal ecological functions of the river. The receiving water is also of poor quality. This species has been successfully translocated to a number of large dams in tributaries of the Sabie River within the Kruger National Park.

References

[@article{18475,
 author = {Skelton, P.H.},
 title = {A Complete Guide to the Freshwater Fishes of Southern Africa},
 year = {2001}
}
,@book{2426,
 address = {Gland, Switzerland and Cambridge, UK},
 author = {Baillie, J. and Groombridge, B.},
 publisher = {International Union for Conservation of Nature},
 title = {1996 IUCN Red List of Threatened Animals},
 year = {1996}
}
,@article{2426,
 author = {IUCN},
 title = {IUCN Red List of Threatened Animals},
 year = {1990}
}
,@book{2426,
 address = {Gland, Switzerland and Cambridge, UK},
 author = {Groombridge, B.},
 publisher = {IUCN},
 title = {1994 IUCN Red List of Threatened Animals},
 year = {1994}
}
,@electronic{2426,
 address = {www.iucnredlist.org},
 author = {IUCN},
 title = {The IUCN Red List of Threatened Species. Version 2017-3},
 year = {2017}
}
,@article{2566,
 author = {Skelton, P.H.},
 title = {South African Red Data Book - Fishes},
 year = {1987}
}
,@techreport{2572,
 address = {Lydenburg},
 author = {Kleynhans, C.J},
 title = {Die ekologie van skaars en moontlik bedreigde vissoort van Transvaal},
 year = {1982}
}
,@phdthesis{2572,
 author = {Kleynhans, C.J. },
 school = {University of Pretoria},
 title = {Die verspreiding en status van sekere seldsame vissoorte van die Transvaal en die ekologie van sommige spesies.},
 year = {1984}
}
,@phdthesis{4626,
 author = {Gaigher, I.G.},
 school = {Randse Afrikaanse Universiteit},
 title = {Aspekte met betrekking tot die ekologie, geografie en taksonomie van varswatervisse in die Limpopo en Inkomati riviersisteem.},
 year = {1969}
}
,@article{20160,
 author = {Pott, R McC and Le Roux,P.J},
 journal = {Newsletter of the Limnological Society of Southern Africa},
 pages = {13--16},
 title = {Breeding behavior of Serranochromis meridianus. Jubb, 1967},
 volume = {10},
 year = {1968}
}
,@phdthesis{20160,
 author = {Potgieter, F.J. },
 school = {Randse Afrikaanse Universiteit},
 title = {`n Ekologiese studie van die rooiborskurper Tilapia melanolpeura (Dumeril, 1859) (Pisces : Chiclidae) in Transvaal met verwysing na geassosieerde varswatervissoorte.M.Sc verhandeling},
 year = {1974}
}
,]

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