annexc - Newmont Mining Corporation

Annex C2 – Aquatic Resources Supplemental Information C2 - 3
None of the fish species that were recorded from the Study Area are on the IUCN Red
List. The majority of fish in the Study Area are caught for eating, but only a few are
important food species (SGS 2004c). Based on observations made during the Geomatrix
study, there seemed to be a focus by local residents on catching the various catfish or mud
fish species, as well as the tiger fish and African Pike when these latter species were
available.
FISH SPECIES DIVERSITY
SGS (2004c) found the highest diversity of fishes in the dry season was found in the Pra and
Mamang Rivers near their confluence at Kotokuom; whereas, the highest diversity during
the wet season was in the Pra River at Teshie Praso. They concluded that differences in
diversity during the dry and wet seasons appear to be due to migratory behaviour of fish.
Geomatrix (2008c) found the highest diversity during the wet season in the upper Pra River
and the Abesu Stream new Old Abirem. As discussed above, however, these results are
likely due to high water levels during the wet season where fish are more dispersed in the
flood plain and/or water depths made fishing gear less efficient.
During the dry season, Geomatrix found the highest diversity in the main stem Pra and
Mamang River sampling sites. The highest diversity and largest catches were in the middle
reaches of both rivers in the Study Area. Smaller catches and lower diversity in the
tributary stations were thought to be indicative of movement of fish from these areas and
into the main stem reaches during the low flow period.
Fish appear to move from the Pra River and Mamang River during the wet season into the
tributaries for spawning, rearing and refuge from the high flows in the main river channels.
Fish then return to the main stem rivers as flows decrease in the tributaries during the dry
season. Some tributaries dry up completely while others retain some flow and/or pools of
water where remaining fish are able to survive until the next wet season.
BENTHIC INVERTEBRATES DISCUSSION
SGS (2004c) collected benthic invertebrate samples at each of the sites where they
conducted fish sampling. Diversity and biotic indices indicated that the most enriched or
polluted river was the Mamang River at Nkwanten during the dry season (SGS 2004c).
During the wet season, the reach with a benthic fauna indicating the least water quality
degradation was the Mamang River at Kotokuom. During the dry season, the highest
diversity of macroinvertebrates was in the Mamang River at Kotokuom (22 species). The
lowest diversity was also recorded for the Mamang River at Mamanso during the dry season
(8 species). Diversity in the Pra River was similar at all sites and did not vary much between
wet and dry seasons (11 to13 species). The highest species diversity during the wet season
was 32 species at Mamanso on the Mamang River. The lowest diversity during the wet
season (11 species) was at Teshie-Praso on the Pra River (SGS 2004c).
Akyem Gold Mining Project November 2008 FINAL EIS