57
4.5 The Littoral community
Occurrence, richness and diversity
As presented in Table 17-19, the littoral invertebrate communities of the three water bodies include oligochaetes, polychaetes, insects, gastropods, bivalves and
crustaceans. The polychaetes found belonged to the families Capitellidae, Nereidae, Cirratulidae and Opheliidae while the insect larvae encountered were dipterans of the
families Chironomidae Aedinae and Ceratopogonidae, and odonatans of family Coenagriidae. The gastropods collected were from the families Potamididae, Patellidae,
Neritidae, Muricidae and Littorinidae while the bivalve families were Mytilidae, Ostreidae and Arcidae. Crustaceans present were barnacles
Ballanus pallidus
, and hermit crab.
Oligochaeta, Capitellida and Chironomidae were present in all three water bodies while the gastropods, bivalves and crustaceans were found at only Whin, except
Potamidiae which was also present at Butuah. The other littoral fauna occurred in one or two of the wetlands. A total of 14 families of littoral macrofauna were collected from
Whin, 8 from Essei and 4 from Butuah Table 20. Of the three wetlands, Whin had the most rich and diverse littoral invertebrate
community
d
= 2.16, H’ = 2.41 Table 21. Diversity was same for Butuah and Essei
H’ = 1.50 although richness differed slightly. Distribution of the individuals among the various invertebrate groups was highly even in Butuah and Whin
J’ 0.
9
than Essei J’
= 0.72
. The littoral communities of the two lagoons were highly similar C
s
0.6, but these communities were not much similar to the Whin community Table 22.
58
Table 17: List of littoral macroinvertebrates of the Essei Lagoon in the Sekondi-
Takoradi Metropolis CLASS
ORDER FAMILY
OLIGOCHAETA POLYCHAETA
Capitellidae Nereidae
Cirratulidae INSECTA
DIPTERA Chironomidae
Ceratopogonidae Aedinae
ODONATA Coenagriidae
Table 18: List of littoral macroinvertebrates of the Butuah Lagoon in the sekondi-
Takoradi metropolis
Table 19: List of littoral macroinvertebrates of the Whin Estuary in the Sekondi-
Takoradi metropolis
CLASS ORDER
FAMILY SPECIES
OLIGOCHAETA POLYCHAETA
Capitellidae Onuphidae
INSECTA DIPTERA
Chironomidae Aedinae
CLASS ORDER
FAMILY SPECIES
OLIGOCHAETA POLYCHAETA
Capitellidae Nereidae
INSECTA DIPTERA
Chironomidae Ceratopogonidae
GASTROPODA Potamididae
Tympanotonusfuscata
59
CLASS ORDER
FAMILY SPECIES
GASTROPODA Potamididae
Tympanotonusfuscata
Muricidae
Thais hemastoma Thais forbesi
Neritidae
Neritasenegalensis
Littorinidae
Littorinapunctata Littorinacingulifera
Tectariusgranosus
Patellidae
Patella safiana
BIVALVIA Mytiliidae
Pernaperna
Arciidae
Anadarasenelis
Ostreidae
Crassotreatulipa
CRUSTACEA
Balanuspallidus
Hermit crab Table 20: Richness of littoral invertebrate families of the three water bodies
INVERTEBRATE GROUP
NUMBER OF FAMILIES ESSEI
BUTUAH WHIN
OLIGOCHAETA 1
1 1
POLYCHAETA 3
2 INSECTA
4 2
2 GASTROPODA
1 4
BIVALVIA 3
CRUSTACEA 2
TOTAL 8
4 14
60
Table 21: Richness and diversity indices for the littoral invertebrate communities of the three water bodies
Water body Margalef‘s Richness
d Shannon
– Wiener diversity
H’ Pielou‘s evenness J’
Essei 1.12
1.50 0.72
Butuah 0.95
1.50 0.93
Whin 2.16
2.41 0.91
Table 22: Sorensen’s similarity index for pairs of littoral invertebrate communities
of the three water bodies Essei
Butuah
Butuah 0.61
Whin 0.27
0.31
Composition of littoral invertebrate fauna
The Essei community was dominated by Oligochaeta, Capitellidae and Chironomidae 19.3 , 29.2 and 36.9 respectively while the Butuah community
was dominated by Oligochaeta, Chironomidae and Potamididae Tympanotonus fuscata with compositions of 24.2 , 31.8 and 21.2 respectively, with Ceratopogonidae also
constituting 16.6 Fig. 19. Whin was dominated by Oligochaeta 18.3 , Capitellidae 12.4 and Littorinidae
Littorina punctata
14.2 . The composition of the other fauna varied between 0.5 and 8 in the wetlands.
61
Figure 19: Percentage composition of littoral invertebrate groups in the three water bodies
Littoral fauna diversity at various stations of the wetlands
In the Essei Lagoon, Station A had the lowest richness and diversity of littoral fauna
d
= 0.42, H’ = 0.35 while Station B had the highest
d
= 1.06, H’ = 01.35 Fig.
20. Diversity and richness seem uniform at the other stations. Diversity and richness of the littoral community in Butuah is higher at Stations A
d
= 1.21, H’ = 1.39 and C
d
= 1.13,
H’ = 1.44 than the other stations. The highest richess and diversity of littoral invertebrates in the Whin Estuary was recorded at Station A
d
= 1.64, H’ = 2.09 while
Station B recorded the lowest
d
= 0.48, H’ = 0.14. Very little variations occurred among
the other stations.
62
Figure 20: Richness and diversity of littoral invertebrates at the different stations of the three water bodies
63
4.6 The Fish Community
Kategori