high BOD levels indicate excessive amounts of dissolved organic matter DOM in the lagoon possibly from decomposing E. Clatharata, aquatic vegetation and organic waste discharges from
the surrounding communities. Levels of Cu, Zn and Fe recorded here were also below WHO acceptable standards Appendix 9.
3.3.2 Biodiversity
3.3.2.1 Macrobenthic fauna A total of 105 individual macrobenthic fauna belonging to two major groups were recorded. Of
this number, polychaetes constituted 79 and ‘Other’ taxa recorded constituted 21 Table 5 Polychaete taxa was dominated by Capitella capitata indicating presence of organically-enrich
pollutant, which is consistent with the observation of the water column. Capitella capitata is an opportunistic polychaete that has been considered an important universal indicator of organic
pollution in marine sediments e.g. Mendez et al., 2000. The presence of populations of C. capitata in the lagoon represents an index to evaluate disturbance impact related to organic
load.The ‘other’ taxa was represented by a fish larva, a mysid and chironomids.
Table 5. Abundance of macrobenthic faunal groups in Domunli lagoon
Taxa Abundance
Percent Abundance
Polychaetes 83
79 Others
22 21
Total 105
100
3.3.2.2 Avifauna There were a total of 41 individuals belonging to nine species of shorebirds were recorded at the
Domunli lagoon. Of the numerical abundance, waders accounted for 32 individuals 78 and five 5 species 56. Shorebirds placed in the ‘others’ category reported 9 individuals 22
and 4 species 54. No terns were observed.
Table 6. Abundance of major shorebird groups recorded at Domunli lagoon.
Common name Scientific name
Abundance
Waders
Whimbrel Numenius phaeopus
6 Grey plover
Pluvialis squatarola 4
Common sandpiper Tringa hypoleucos
7 Greenshank
Tringa nebularia 4
Sanderlings Calidris alba
11
Total Waders 32
OTHERS
Pied kingfisher Ceryle rudis
3 Little egret
Egretta garzetta 1
Africa jackana Actophilornis africanus
2 Reef heron
Egretta gularis 4
Total Others 9
39
3.3.3 Fisheries
3.3.3.1 Fishing Effort Although fishing is still carried out by a few members of the community, its importance has
diminished over the years due to the abundance of mats of Enteromorpha clathrata and the recent algal bloom in the lagoon. Fishers indicated that since 2009, minimal fishing is carried
out in the lagoon, although large quantities of fish have been observed. The algal bloom made catchability of fish low and contributed to the destruction of the predominant cast net used in the
lagoon for fishing Figure 4. Other organisms collected from the lagoon include fiddler crabs, periwinkles and mud skippers.
The sandy beaches adjacent to the Domunli Lagoon are important for beach seining, with extensive activities occurring from Bonyere to Elonyi. The main livelihood of the community
members is crop farming, mostly of palm nuts, coconut and cassava, and livestock pigs and sheep. According to the inhabitants, chickens were no longer reared after bird flu destroyed
most of their flocks. The farms are located behind the mangroves and are accessed by a small wooden bridge across the lagoon.
Figure 4. Algae clogging the meshes of a newly constructed cast net after a bout of fishing
3.3.3.2 Experimental Fishing An experimental fishing for one hour in the early hours of the morning, using the cast net was
conducted Table 7. The total weight of fish caught in one hour was 76 g amounting to Five Ghana Cedis GH
₵ 5.00 per hour.
40
Table 7. Result of experimental fishing at Domunli lagoon Family
Species TN
ASL cm AW g
Cichlidae Sarotherodon melanotheron
1 9.5 10.0
Mugilidae Mugil cephalus
4 15.6 16.5
Elopidae Elops lacerta.
2 7.9 12.5
Ostreidae Crassostrea tulipa
- -
500
TN = Total number; ASL=Average Standard Length; AW = Average Weight
The fish species consisted of both brackish-water S. melanotheron and typical estuarine species Mugil cephalus and Elops lacerta. However, indications from inhabitants of the area suggested
a dominance of tilapia species, fiddler crabs Uca tangerii and oyster. A very high average of 42 fiddler crab holes was counted per square metre at the exposed banks of the coconut lagoon. The
estuarine sesarmid crab Sesarma huzardi was also reported to occur in the area, but not in abundance.
3.3.4 Critical Features and Conservation Significance
