Identification of inland Freshwater Crab Species Niche and Biology: A case Study of Wasteland/Watershed Areas in Minna Environs

Abstract

Survey Was carred out to identify burrows/holes of crabs in three (3) sites covering three hectares of watershed fieldl in the Main campus of Federal University of Technology, Minna. Two hundred and seven (207)burrows/holes of crabs were identified and 60 were dugged out to collect the crabs, 20 holes per site and 5 holes per sampling in each site, the length of burrows measured between 21.1-95 cm deep. Fifty five (55) crabs werecollected, the size of crab varies comprising of (nymphs (10), juvenile (10) and adult (35(fifteen male,twentyfemale)) indicating their reproductive and growth activities.The crabs were observed resting at the entrance ofthe burrows at dawn and dusk (6- 8am and 6-8pm). They withdrew to the hole quickly on perceiving any strangesound or movement, Standard chart was used to indentified species. Species identified is Afrithelphosa monodosa.Matured male were morphologically different from female, though the size and shape are the same, female haveslub on their antenna and posses porch at the anterior end. The matured females were gravid between April-May,with ovl small eggs of 10 cm diameter, orange in colour 10-20 eggs, clustered and stringed in each porch.The성브보s were laid in between May and June, in late June, female porches were emptied indicating the egg were laid.At commencement of rains, the eggs hatched under favourable conditions of more rainfall which provided moist and reduces temperature of the soil. The soil became water logged and burrows filled with water. The6emmencement of rainfall motivate them to bring out fresh soil cast outside the entrance of the burrows indicating there is a crab residing in that burrow in most cases. They feed vigorously during rainy season and hibernate in dry season. This study shows that crabs ecology and biology has the potentials of being cultured for their great nutritional and resourceful value.