Growth And Production Of Three Species Of Molluscs In Six Low Alkalinity Lakes In Ontario, Canada
Growth pattern, growth rate, and annual production of three species of molluscs were estimated from six low alkalinity lakes in south-central Ontario. A hydrobiid snail, Amnicola limosa, had the lowest levels of production and slowest growth rate of the "first summer" cohort in the lowest alkalinity lakes. This species failed to reproduce in one of the lowest alkalinity lakes in 1980 and has been very rare since then. Neither growth nor production of two species of pisidiid clams, Pisidium casertanum and Pisidium ferrugineum, appeared to vary consistently with alkalinity concentration. Production and growth differences between populations in two intermediate alkalinity lakes indicate that factors other than alkalinity per se may be responsible for results obtained here.