S. M. C. Ezeugwu*

Some limnological studies of an aquatic habitat used for fishing and irrigation in Ngala, Borno State, Nigeria

The limnological characteristics of the aquatic habitat were studied with special emphasis on water temperature, calcium hardness and chlorine levels as they affect the abundance of Bulinus globosus and Bulinus forskali on one hand and their interfactorial effects on the other. The single regression analysis showed that calcium hardness was the only factor that showed direct significant (P<0.05) positive effect on abundance of B. globosus and B. forskali. Similarly, water temperature was significantly (P<0.05) negatively correlated with chlorine and calcium hardness levels.

Application of biostatistics to the effects of water velocity on the Adistribution of Bulinus globosus and Bulinus forskali in an irrigation scheme in Borno State, Nigeria

The distrubution of Bulinus globosus and Bulinus forskali in relation to the water velocities in the research site was investigated. Station 6 had the highest mean velocity of 22.82 cm sec. The analysis of variance for all the stations showed a very highly significant (P<0.01) defined as negative. Station 4 with a zero velocity (stagnant) had the highest number of both snails indicating an inverse relationship between velocity of water flow and abundance. The regression analysis indicated that increase in water velocity had a non-significant negative effect on the distribution of B.