TAXONOMY, DISTRIBUTION, AND ECOLOGY OF THE FRESH-WATER BRYOZOANS (ECTOPROCTA) OF EASTERN CANADA

The freshwater Bryozoa (Ectoprocta) are one of the most poorly known f aunal groups in Canada. A recent survey of 80 freshwater habitats in e astern Canada (from Ontario to Newfoundland) revealed 14 species of br yozoans, representing 56% of described species in North America. The g reatest numbers of species and specimens were found in alkaline waters (pH 7.0-9.8) near lake outflows, wherever hard substrates were presen t. Paludicella articulata, Cristatella mucedo, Fredericella indica, an d Plumatella fungosa are among the most frequently encountered, widely distributed, and eurytopic species. Pottsiella erecta and Plumatella fruticosa are rare, and new to eastern Canada. Lophopodella carteri, a n exotic Asian species discovered in Lake Erie in the early 1930s, has become firmly established in the lower Ottawa and upper St. Lawrence rivers. Detailed notes on taxonomy, morphology, distribution, and ecol ogy are given for each bryozoan. New limits of tolerance to water temp erature, pH, and calcium and magnesium hardness are established for se veral species. A taxonomic key to the freshwater bryozoans of eastern Canada, including a key to statoblast types, is presented for the firs t time.