Environmental Assessment
Volume C-4.3
Slurry Pipeline
Fish and Aquatic Resources
Ambatovy Project
126
January 2006
Paretroplus polyactis
listed as “Vulnerable” in the IUCN Redlist 2004, was
collected from three river sites but in low numbers. It is generally more
prevalent in coastal lagoons and lakes; including the brackish habitats of the
Pangalanes waterway.
Ambassis fontoynonti
, listed as DD (data deficient) by the
IUCN Redlist was present in small numbers at two sites only. Similarly, the
other two endemics,
O. macrolepidota,
and
K. sauvagii
, were present in small
numbers at some of the sample sites but little is known of their range or
populations and they are not listed by the IUCN.
Aquatic Invertebrates
A large number of endemic aquatic macro-invertebrate taxa are present in the
streams and rivers within the slurry pipeline study area; however the current level
of identification limits the description of taxa. Several of the more significant
groups encountered were:
•
Atyidae
(freshwater shrimp); these have a high degree of endemism
(77%), with 26 species in four genera existing on the island
(Raharivololoniaina 2004). Within the slurry pipeline study area they
were one of the more abundant taxa in Group II (similarity analysis)
during the survey.
•
The
Odonata
(dragonflies) with seven families, was also common in the
LSA. Madagascar is noted for its rich
Odonata
fauna. The number of
endemic species and genera of the
Odonata
in Madagascar are
remarkable. Of 52 genera, 12 are endemic; of the 181 named species
and subspecies, 132 are endemic and most of the endemic species are
concentrated on the forested eastern edge of the island (Donnelly and
Parr 2003).
Significant Habitats
The Torotorofotsy Wetlands is a unique ecosystem. It is considered one of the
most valuable ecosystems in the study area because of its ecological function and
biodiversity, and has recently been declared a Ramsar Site. The ecology and
biology of the Torotorofotsy Wetland is sensitive to water level and water quality
fluctuations. Populations of important regionally endemic fish species (
Rheoclès
alaotrensis
and
Ratsirakia legendrei
) were present in the wetlands associated
sampling sites along the pipeline route. However; although unique, the
Torotorofotsy Wetlands is not pristine habitat. It exhibits considerable habitat
disturbance along the marsh edge and the slurry pipeline will follow an
abandoned railway across northern end, reducing potential effects on the
wetlands.
