Observations on the growth and population dynamics of Bulinus rohlfsi in an outdoor laboratory at Volta Lake, Ghana.
Two cohorts of Bulinus rohlfsi were reared separately in an outdoor laboratory at Volta Lake, Ghana. One group was kept in lake water with a mud substratum, the other in lake water without mud. Both cohorts were able to tolerate water temperatures ranging from 22.0 to 35.5 degrees C, but growth and survival were significantly greater for the cohort with mud. The overall intrinsic rate of natural increase, r, per fortnight was 1.096 for the snails having the mud substratum and 1.642 for the cohort not having it. The 'r' values were strongly influenced by high early fecundity of the snails in lake water only and low early fecundity of the snails with mud. Oviposition among the latter cohort was suppressed at times of high turbidity in the water above the mud substratum, caused primarily by suspended clay.
D000818:Animals; D002033:Bulinus / Q000254:growth & development*; D005298:Fertility; D005618:Fresh Water; D005869:Ghana; D011157:Population Dynamics; D013696:Temperature