Environmental Assessment
Volume E-4.3
Tailings Facility
Fish and Aquatic Resources
Ambatovy Project
169
January 2006
Table 4.3-1 Habitat Characteristics of Sampling Sites in the Tailings Local Study
Area
Site
IHIA Class
(a)
Habitat Description
TMT001
E
Channel modifications with loss of natural biota and ecosystem function.
Presence of exotic fish fauna including the predator
Channa maculata
.
TMT002
E
Upstream site in tailings area. Channel modifications with, loss of natural
biota and ecosystem function. Indigenous vegetation replaced by exotics.
TMT003
F
Critically modified. Extensive modification of streambed, channel, flow
regime, and presence of exotic predator fish
C. maculata.
TMT004
D
Upstream site in tailings area. Largely modified, considerable loss of natural
habitat, biota and ecosystem function. Presence of exotic vegetation.
TMT005
D
Largely modified, considerable loss of natural habitat, biota and ecosystem
function. Replacement of indigenous vegetation and presence of exotic fish.
TMT006
D
Wetlands site. Largely modified, loss of natural habitat, biota and ecosystem
function. Presence of exotic vegetation and fish.
(a)
Based on the IHIA model (Kemper 1999).
Generally, species diversity was moderately high (range seven to eight species) at
all sites but abundances were low except for two species each of endemics
(Bedotia madagascariensis and Sauvagella madagascareinsis) and exotics
(Oreochromis macrochir and Tilapia zilli). The high total abundance (all species)
occurred at sites TMT001 and TMT003, and may be associated with higher
heterogeneity in habitat type (larger streams, increased instream cover).
Although no clear pattern emerged between diversity and habitat characteristics,
significant temporal difference in species association and abundances was
observed between high flows and low flows at, at least three sites (TMT003,
TMT005 and TMT006), suggesting some seasonal movement or migration
within the watercourses.
Most of the fish found in the streams were relatively small-bodied species, and
were not highly used locally for food fish. However, among the exotic food fish
species,
Tilapia zilli
was collected (in high abundances) at all sampling sites in
the tailings LSA. Other common exotics used locally as food fish were
Tilapia
rendalli, Osphronemus goramy,
and
Oreochromis niloticus
. Potential food fish
included the
Anguilla
(eel) species and the snakehead; but information was not
obtained on their use. Some local use is made of smaller species (
Bedotia
madagascarensis
) captured in reed traps.
