Water-borne conidia of aquatic hyphomycetes: seasonal and yearly patterns in Catamaran Brook, New Brunswick, Canada

Over a period of 5 years, monthly samples of water-borne conidia were colle cted at two sites, bridge and mouth, in Catamaran Brook, a third-order salm on stream in New Brunswick, Canada. Conidial concentrations and number of a quatic hyphomycete species peaked in October; a smaller peak was generally observed in June. Evenness was lowest in October. The number of species in the five 12-month periods varied between 46 and 56 (bridge) and 41 and 47 ( mouth); over the entire period, 75 (bridge) and 70 (mouth) species were ide ntified. Of these, 30 and 26, respectively, occurred in every period. The a verage ranks of the 12 dominant species (based on yearly conidium productio n) could be divided into two groups of no significant differences: ranks 1- 7 (bridge) and 1-10 (mouth), respectively, and 2-12 (both sites). Monthly a bundances of the 12 top-ranked species were examined for correlations. Sign ificant correlations found in periods measuring between 1 and 4 years were rarely validated in subsequent periods.