Studies were carried out to determine relationships between morphometric and dimorphic variables of freshwater crab, Potamon ebonyicum. Parameter measurements were taken from side to side (left and right); and from tip to the extremity of characteristic features, to ensure that values were obtained at the widest points. The dimorphic variables showed positive correlation and linear relationship between male and female. Nonlinear relationship was recorded in most variables morphologically.  Regression analyses revealed poor correlation between carapace length (CL) and weight, and between carapace width (CW) and weight. There was a positive correlation between CL and CW of both sexes. The findings could be a guide for determining condition factor.  They could also be useful in field identification and further classification of freshwater crab.

Ebonyi River basin of south east Nigeria is home to the freshwater crab Potamon ebonyicum, which are consumed indiscriminately by inhabitants and tourists. Bulk of the crab meat is obtained by crabbing. A preliminary survey of pathogenic bacteria associated with vulnerable morphological part of the crab species was carried out in the basin. Bacteria were isolated from abdominal flaps of the male and female crab. A total of 53 bacterial isolates consisting 4 bacteria species such as Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aereus and Aeromonas hydrophila were recorded. Percentage composition of each bacterial species was recorded in the reproductive features of the samples. Pseudomonas aeruginosa (72%) and Staphylococcus aereus (48%) were dominant among other bacterial species in the abdominal flaps of the male and female crab. Population of E. coli (4%) was significantly low and only recorded in the abdominal flap of the male crab. The results of the study showed clearly that the reproductive feature of freshwater crab was vulnerable to pathogenic microorganisms. The edible crabs from sampled site were contaminated with bacteria species which were considered by Centre for Food Safety as hazardous to human health. Investigation on sample from other area would enhance regulation on aquaculture, handling, processing and consumption of freshwater crab.

This work investigated survival and growth performance of male and female Potamon ebonyicum, at different Stocking Densities (SD) with 38% crude protein fish feed, in intensive culture system for six weeks. Experimental treatments were three in number viz., TI, TII and TIII. The TI contained only female, TII contained equal number of male and female, and TIII contained more females than male. The SD ranged from 1 crabT-1 to 3 CrabsT-1. All the male and female crabs survived first half (3 weeks) of the experimental period. Survival period of more than four weeks was recorded in the treatments with more than one female. Growth rates were insignificant and unevenly distributed. Yield was higher in the treatment with equal number of male and female than in the other ones. There was insignificant change in the growth rates as compared to records of previous investigations with the crab species. The narrow gap in the size of small ones, weight differential and their growth rates might assist aqua culturists to adapt SD and forecast yield in the freshwater crab. It could be suggested however that increment in the number of females during high density culture might enhance yield.

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