International Journal of Aquaculture, 2016, Vol.6, No.22, 1
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Fourteen species of macro invertebrates were encountered during the study period, with arthropods recording the
highest number (9 species) followed by mollusc (3 species) and annelids (2 species).
Chironomus larvae
recorded
6.05% in station B and 3.5% in station in station C while station A and D recorded 0%.
Tubifex tubifex
were
recorded the mean abundance of 52.45% and 44.19% and in stations A and C respectively while stations A and D
recorded 0%.
Eristalis tennax
was 17.93% and 9.80% in stations B and C respectively, whole stations A and D
recorded 0% each.
Libellula
sp were 13.43%, 4.80%, 6.05% and 7.57% in station A, B, C, and D respectively.
Gienurus gratus
were recorded 29.11%, 3.28%, 3.75% and 16.42% respectively.
Ranatra sp
were 2.02% and
4.32% in stations B and C respectively.
Pisticus marginalis
were 2.02%, 4.90%, 7.46% and 7.59% in stations A,
B, C, and D respectively.
Ephimera dentica
were 25.37%, 1.52%, 0.86%, and 24.05% is stations A, B, C, and D
respectively.
Baetis rhodani were
24.37%, 1.52%, 0.86%, and 25.05% in stations A, B, C, and D respectively.
Valvata piscinalis
were 3.54% and 6.05% in stations A and D respectively, while
Magaritifera
sp was recorded
only in station A throughout the study period; it recorded 1.49%. Stations B, C, and D recorded 0% throughout the
study period.
Lymnae
sp were 0.86% and 4.80% in station B and C respectively, while stations A and D recorded
0% throughout the study period.
Macrobdella decora
were 2.31% and 3.54% in stations C and B, while stations A
and D recorded 0% during the study period.
Species diversity indices (Table 2) calculated using different indices showed that station B recorded highest in
species richness (44.00%) and lowest in station A (22.00%). Shannon-Weiner H was 3.13% and 2.90% in station B
and D respectively. Shannon-Weiner J recorded highest in station A (0.96%) and lowest in station B (0.80%).
Simpson 1-D recorded highest in station A (0.96%) and lowest in station B (0.80%). Simpson 1/D was highest in
station (23.77%) and lowest in station C (11.81%). Berger-Parker D recorded in station recorded the highest values in
station B (0.19%) and lowest in station C (0.10%). McIntosh D & E recorded highest in station A (0.74% and 0.96%
respectively), and lowest almost similar values in station B and C (0.22% and 0.21% respectively). Brillouin Index
recorded highest in station B (0.94%) and lowest in station D (0.53%). Margalef recorded the highest value in station
B (7.19%) and lowest in station D (0.81%).
Table 2 Diversity indices of Macro Invertebrates at the various stations
Diversity Indices
Stations
A
B
C
D
Shannon-Weiner H
2.99
3.13
2.99
2.90
Shannon-Weiner J
0.96
0.83
0.80
0.94
Simpson 1-D
0.96
0.93
0.92
0.95
Simpson 1/D
23.77
14.14
11.81
19.62
Berger-Parker D
0.10
0.19
0.18
0.10
McIntosh D
0.87
0.77
0.74
0.84
McIntosh E
0.96
0.86
0.83
0.95
Evar
-1.29
0.22
0.21
-0.49
Brillouin Index
2.56
2.94
2.80
2.53
Margalef
5.23
7.19
7.01
4.81
Species Richness
22.00
44.00
42.00
25.00
Figure 2 shows the dendrogram of macro invertebrates based on their degree of tolerance threshold to Wurukum
Abattoir Effluent. It showed that
Chironomus larvae, Eristalis tennax, Tubifex tubifex, Valvata piscinalis,
Macrobdella decora
were highly tolerant to the effluent
Chironomus larvae, Libellula sp, Pisticus marginalis,
Gienurus gratus, Libellula sp
were moderately tolerant to the abattoir effluent, while
Ephimera dentica, Baeti
srhodani, Gerris remigis
and
Valvata piscinalis
were least tolerant to the abattoir effluent.
Abundance biomass comparison curve (ABC) of macroinvertebrates
Station A showed no disturbance (unpolluted) condition; hence the curve for biomass lied above the abundance
curve with a wide margin between the abundance and biomass curve (Figure 3).
