3.11
Butre
The Butre beach is located east of Dixcove in the Ahanta West District Appendix 8. The beach is mainly sandy one with few rocky outcrops Figure 24. The beach is also a landing site for the
fishers.
The Butre lagoon is an open lagoon and relatively long. The rocky outcrops are largely located at the mouth where the lagoon enters the sea. Of scientific interest were the mats of the bivalve,
Brachydontes sp. and the algae Enteromorpha flexuosa at the entrance of the lagoon. The lagoon is flanked by extensive mangrove species and associates as well as other coastal scrubs including
Sessuvium portulacastrum. Portions of the mangrove have been degraded through cutting for firewood. Numerous species including crabs, gastropods, lizards e.g., monitor lizard, fishes
inhabit the rooting system of the mangroves. The northwestern side of the lagoon has an extensive forest with numerous vultures.
Figure 24. Left Butre estuary entering into the sea Right Rocky outcrops at the mouth of the estuary at low tide.
3.11.1 Water quality
Levels of water quality parameters measured in the Butre estuary were generally within acceptable levels Appendix 9. Of concern, however, was the very low DO levels recorded in
the estuary. It was observed that the fringes of the lagoon along the scrubs were used by the community as places of convenience. These levels could impact adversely on aquatic life in the
estuary.
Hg, Cd and Pb were not detected in the estuary. The levels of Zn, Cu, Fe and As, however, exceeded the WHO recommended limits for aquatic life and pose a potential threat to aquatic
life.
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3.11.2 Biodiversity
3.11.2.1 Macrobenthic fauna The organisms found on both the outcrops and boulders constitute the rocky shore fauna of the
area Table 17. In all, a total of 16 individual epibenthic taxa were encountered. These consisted seven gastropods, two bivalves, and seven crustaceans Table 17. The gastropods dominated the
fauna numerically especially the upper shore littorinid, Echinolittorina pulchella.
The macroalgal species observed included five chlorophytes, four phaeophytes and five rhodophytes Table 17. There was no clear dominance macroalgae except that Ulva fasciata and
Enteromorpha flexuosa were comparatively abundant.
An important observation was the cluster of Brachydontes sp. found in the inletopen of the lagoon to the sea Figure 25. Appreciable numbers of Ostea tulipa were also observed in the
inlet. These species possibly preferred marine environments with sea water slightly diluted by fresh water from land drainages for their survival.
Table 17. Inventory of rocky shore fauna and macroalgae of the Butre rocky beach
Mollusc Crustacean
Macroalgae Gastropod
Echinolittorina pulchella Echinolittorina cingulifera
Echinollitorina. granosa Thais haemastoma
Nerita atrata
Patella safiana Siphonaria pectinata
Bivalvia
Ostea tulipa Brachydontes sp.
Xanthid sp. Cthamalus dentata
Panopeus sp. Callinectes sp.
Uca tangeri Grapsus grapsus
Pagurus sp.
Chlorophyta Greens Boodlea composita
Boodlea psispusila Cladophora prolifera
Enteromorpha flexuosa Ulva fasciata
Phaeophyta Browns
Padina durvilea Ralfsia expansa
Chnoospora minima Basispora africana
Rhodophyta Reds
Centrocera clavulatum Bostrychia radicans
hapteromanica
Gelidium corneum Gymnogongrus nigricans
Lithothamnia sp.
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Table 18. Number of species of fauna and macroalgae at Butre Taxa
No. of species Percentage
Fauna Gastropods
7 43.75 Bivalves
2 12.50 Crustacean
7 43.75 Total
16 100.00
Macroalgae Chlorophyta
5 35.71 Phaeophyta
4 28.57 Rhodophyta
5 35.71 Total
14 100.00
Figure 25. Mouth of Butre estuary depicting populations of Brachydontes sp. and Ostrea tulipa
3.11.3 Critical Features and Conservation Significance
