Parasitic isolates of Saprolegnia diclina Humphrey from Coho salmon (Oncorhynchus kitsutch Walbaum) were grown under controlled laboratory conditions to test the effect of environmental parameters on growth. This study points out the significance of medium selection and methods of determining growth in introducing variability into the results of experimental studies of parasitic Saprolegniaceae. The results indicate that there is a significant effect of temperature and pH on growth and morphological development while the effects of phosphate concentration, aeration and nitrogen sources appear to be as significant but vary with medium used or method in determining growth. / Science, Faculty of / Botany, Department of / Graduate