Environmental Assessment
Volume C-4.3
Slurry Pipeline
Fish and Aquatic Resources
Ambatovy Project
119
January 2006
Biology Department, University of Antananarivo, is awaiting expert confirmation
and species determinations.
Periphyton
(benthic algae) samples were collected during the dry season
sampling; these have been archived for future analysis.
Resource Use
Information on artisanal fisheries was obtained on an opportunistic basis by
observations or conversations with residents within the areas sampled during
field programs.
Information Review and Data Analysis
Published and unpublished literature on the freshwater ichthyofauna and aquatic
ecosystems of Madagascar and the project region, conservation status reports on
the native fisheries, and local experts were consulted during compilation of the
report. Multivariate analytical techniques were used to assess the community
assemblage of fish and macro-invertebrate field data.
4.3.3.3 Results
Aquatic Habitat
Aquatic habitat characteristics at the pipeline LSA are highly variable, reflecting
the high diversity in both watercourse and habitat types traversed by the pipeline
route. Watercourses sampled ranged from small (i.e., width 1.95 m, discharge
0.04 m
3
/s) to large (i.e., width >180 m, discharge >50 m
3
/s) streams and rivers
(Hydrology; Volume C, Section 3.6). Although pH ranged from 6.2 to 7.8, most
of the water bodies in the LSA were neutral (pH 7); water temperatures ranged
from 17.5 °C in headwater regions (site R2+000) to 29.5 °C at higher order sites
near the coast. The most prevalent substrate types were fines, cobbles, gravels,
and to a lesser extent, gravel, bedrock and mud. Instream cover varied
considerably by watercourse size, but consistently included leaf litter, small and
large woody debris, and overhung vegetation.
The slurry pipeline passes through three major land use sub-areas: the western
section, within the forest corridor (corridor zone); the central section, passing
around primary forest fragments through an area of tavy (tavy zone), and the
eastern section, which contains secondary vegetation and a higher density of
agricultural use (agricultural zone). Land uses directly influence the habitat
conditions and potential sensitivity to construction of the aquatic ecosystems of
the watercourses within each sub-area. Based on the IHIA classification of
