Environmental Assessment
Volume B-4.3
Mine
Fish and Aquatic Resources
Ambatovy Project
249
January 2006
morphologic and riparian characteristics, they are considered sensitive aquatic
habitat.
Systems draining to the Torotorofotsy Wetlands are important for their role in
maintaining and regulating the water levels and water quality of the marsh
system. The Torotorofotsy Wetlands is a unique ecosystem in the region and in
Madagascar. 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 (see Volume B, Section 4.5).
The ecology and biology (habitat diversity, habitat continuity, critical habitats for
reproduction) of the Torotorofotsy Wetlands is sensitive to water level and water
quality fluctuations. The Torotorofotsy Wetlands and adjacent marshes,
especially Mokaranana, contain valuable communities of mid-altitude marsh
fauna. This includes a mixed taxonomic community of resident and transient
marsh birds, fish, invertebrates and small mammals. Populations of important
regionally endemic fish species (either
Rheocles alaotrensis
or
Ratsirakia
legendrei
) were present in all wetlands-associated sampling sites. However;
although unique and sensitive, the Torotorofotsy Wetlands is not pristine habitat.
It exhibits considerable habitat disturbance along the marsh edge and in the
watersheds (an abandoned railway across the northern end, moderate to heavy
logging, disturbed marsh edge from agriculture and grazing, and watercourse
manipulation for rice production) and consequently several exotic fish species
have already invaded portions of the wetlands and moved upstream into tributary
drainages.
4.3.4
Issue Scoping
4.3.4.1 Issues and Key Questions
The primary issues identified with respect to the potential impact of the project
on the aquatic biota and environment in the mine area are:
•
Loss (potential extirpation or extinction) of locally endemic fish or
important aquatic invertebrate species as a result of the removal or
disturbance of aquatic habitat in streams and wetlands by mine
construction and operation and elimination of the local population of the
species in these habitats.
•
Riparian habitat degradation (loss of vegetation canopy food source and
instream habitat features) and impairment of stream water quality
(sedimentation) as a result of deforestation and disturbance to forest
stream ecosystems associated with development of the mine and
ancillary facilities.
