Study on the abundance and composition of crabs in Uta Ewa brackish water was carried out between
January and May 2012 at two sampling stations. The physicochemical parameters of the water were measured
in situ
using standard methods according to APHA (1998). Crabs species were collected at two sampling stations using square
lift net trap, while at low tide, crab species were collected by hand-picking at random and preserved in a chest box for
identification. Air and Water temperature ranges from 27.9-31.6 °C and 28.2-28.9 °C respectively, while Dissolved
Oxygen and Salinity were between 3.28-4.09 mg/L and 7.5-12.9 ppt respectively. The results of the physicochemical
parameters were within limits of the National Environmental Standards and Regulations Enforcement Agencies for
aquatic life. A total of 107 crabs were collected from the two sampling stations.
Goniopsis pelii
was the most abundant
in Station 1 accounting for 57.9%, followed by
Callinectes amnicola
26.3%, while in Station 2,
Callinectes amnicola
was the most abundant accounting for 46.6% of the percentage abundance. Station 2 had the highest Shannon diversity
index of 1.22, while Station 1 had 1.15. The abundance and composition of crab species in the study areas is an
indication that the area is an important ecological zone for benthos macroinvertebrates conservation.