Environmental Assessment
Volume E-4.3
Tailings Facility
Fish and Aquatic Resources
Ambatovy Project
185
January 2006
4.3.6
Key Question FA-2: What Effect Will the Project Have
on the Abundance of Aquatic Biota and Survival of
Endemic or Native Species?
4.3.6.1 Impact Pathways
The abundance and survival of fish and other aquatic biota can be affected by
activities during tailings construction, operation and closure phases. Changes will
result primarily from:
•
community (habitat) modification;
•
changes to fish and ecosystem health; and
•
restoration activities.
Community (Habitat) Modification
Presence, abundance and survival of fish and aquatic biota is directly linked to
habitat. Physical habitat assessments have been discussed in Key Question FA-1;
the use of these ecosystems by fish species and/or macro-invertebrates will be
expanded here.
Removal and drainage of existing watercourses and water bodies eliminates the
capability of the local area to support fish and other aquatic biota, and may also
result in the mortality of biota within the disturbance area. Change in flows and
water quality can directly affect the life history function of fish downstream of
the tailings facility. Disturbance of fish and invertebrate populations will also
occur during watercourse crossings associated with the service corridor. Loss and
disturbance of the aquatic communities will occur during the construction,
operation and closure of the tailings facility.
Fish and Ecosystem Health
Fish and ecosystem health effects result when the physical or chemical
characteristics of water vary outside the normal tolerance range of fish or other
aquatic biota. Change in health can result from construction and/or operation of
the tailings facilities and associated infrastructure. Ecosystem health can be
affected by contaminants (from spills, effluent discharges and air emissions),
changes in water quality (entrained sediments, introduced contaminants) and
quantity (flows), with lethal, sub-lethal or chronic effects on fish and aquatic
biota.
