Environmental Assessment
Volume C-4.3
Slurry Pipeline
Fish and Aquatic Resources
Ambatovy Project
124
January 2006
polyactis
; and the clupeid, Savagenella madagascariensis. Five of these eight
endemics are currently ICUN Redbook listed (2004).
Among the endemic species, the eleotrid,
Ratsirakia legendrei,
(IUCN listed as
“Vulnerable”) was the most ubiquitous occurring at five of the 15 sites. Not only
was
R. legendrei
the most prevalent endemic species, but it also had the highest
densities recorded among all 27 species. Generally, abundance was high at
un-disturbed primary forest sites and low at deforested or modified locations.
It was found as far east as the site on the Sahanandrazana River (Site 060+600;
Volume J, Appendix 3.1, Attachment 2, Table 6) which slightly extends the
eastern highlands distribution as previously mapped by CAMP 2001
(Figure 4.3-1).
Other endemics with moderate distribution include the bedotids, R. alaotrensis
(four sites) often in sympatric with
R. legendrei,
and
B.madagascariensis
(four
sites), and the cichlid
Paretroplus polyactis
(three sites).
Bedotia exhibits a high incidence of single-basin endemism within the genus.
B. madagascariensis
is listed as “Near Threatened” in the IUCN Redlist (2004).
Bedotia has been found almost exclusively in clear, silt-free habitats (Loiselle
and Stiassny 2003), but was present in relatively disturbed habitats of the
pipeline LSA near the lowlands and northern end of the slurry pipeline study
area.
Similar to the Bedotia,
Rheoclès alaotrensis
exhibits high incidence of single-
basin endemism, and prefers clear, silt-free, well-oxygenated habitats. This
species is reported to have suffered fragmented distribution (Loiselle and
Stiassny 2003) and is listed as “Vulnerable” in the IUCN Redlist 2004. Its
distribution in the study area also extended east to the Sahanandrazana River, in
association with
Ratsirakia legendrei
.
Sauvagenella madagascariensis
was collected in large numbers from one
primary site (107+200) only. This endemic species is restricted to eastern coastal
drainages, mostly in forested small rivers and streams, but occasionally found in
brackish waters (Stiassny 2003). It is not listed and the populations appear to be
stable.
