Environmental Assessment
Volume B-4.3
Mine
Fish and Aquatic Resources
Ambatovy Project
257
January 2006
volume and physical or chemical characteristics (i.e., water temperature, oxygen,
sediment and nutrients).
A total of 16.2 km (estimated 4.3 ha wetted channel) of 2
nd
order stream will be
directly lost to mine disturbance; while 10.8 km (estimated 3.3 ha wetted
channel) of 3
rd
order stream will also be last. These slightly larger streams
generally contained important fish and invertebrate communities and contained
both natural and disturbed habitats (Volume J, Appendix 3.1, Attachment 1,
Table 10). A majority (70%) of 2
nd
and 3
rd
order streams were classified as
natural (IHIA Class A) or largely natural with few modifications (IHIA Class B)
based on habitat integrity assessments (Kleynhans 1996) of the aquatic and
riparian habitats.
Table 4.3-6 Aquatic Habitat Loss as a Result of the Displacement of Streams and
Ponds by Mine Disturbance
(a)
Habitat Type
Number and Mean
width (m)
Channel Length
(m)
Est. Wetted Area
(ha)
Streams 1st order
73 (0.55)
48948.44
2.92
Streams 2nd order
16 (2.63)
16226.96
4.27
Streams 3rd order
7 (3.06)
10790.18
3.30
Ephemeral Ponds
22
-
4.09
(a)
Within mine footprint and boundaries of watersheds (Ankaja, Sakalava, Torotorofotsy, Antsahalava, Sahamarirana
and Sahaviara) affected by removal of channels, flows, connectivity and ponds.
Analysis of fish species composition at the sample sites correlated the presence
of predominately indigenous (endemic and native) fish species to the presence of
largely natural forest stream habitat. Habitat loss and alterations will jeopardize
existence of these populations. The remaining sites (30%) in the direct mine
disturbance area displayed moderate to critical levels (IHIA Classes C to F) of
existing habitat disturbance, with a mixture of indigenous and exotic fish species.
The footprint of the mine will eliminate a majority (22 of 30) of the ephemeral
ponds unique to this area. However, six of the ponds remaining outside of the
mine area are in the proposed Ambatovy azonal conservation area. In addition,
similar looking ponds have been found in the proposed off-site azonal
conservation area, which holds promise for additional off-site conservation of
this rare pond ecosystem (Volume B, Section 4.1). Although it does not appear
that fish use these water bodies, diverse and possibly un-described populations of
aquatic macro invertebrates and plankton use the ponds in addition to their
potential role for semi-aquatic or terrestrial and avian fauna.
