Study of Burrows of the West African Freshwater Crab (Sudanonautes Africanus, Milne–Edwards, 1869) on the Banks of Asejire Reservoir, Nigeria (Published)
The experiment was carried out at the banks of Asejire reservoir and seventy five burrows were examined. The sexes were determined and ratio was about 3:2 females to males. Average biggest size was about 14.5cm for females and 14cm for males. The exponential (b) calculated showed a positive allometric growth for the length–weight relationship of S. africanus at the study area. The species make burrows of different sizes which are inclined or straight in shape. About 70% of the burrows were inclined in shape while about 30% were straight. They were all inhabited by one crab at a time. Average depth of the examined burrows ranged between 30cm and 65cm. Positive correlations were established between the burrow diameter and crab weight; between the burrow depth and length of S. aficanus also between the weight of the crabs and the type of burrow made in relation to the developmental stage in that adult were seen more in the incline burrows while juvenile in the straight burrows. However some burrows during the wet season had colorless water and the water was odourless. Almost all the burrows had oily surface which were due to activities of crab in the burrow.
Keywords: Burrow, Freshwater-Crabs, Length-Weight, Sexes, Shapes