Zooplankton were enumerated and total zooplankton biomass
was estimated from a 50 mL concentrated water sample collected
using a 12 L Schindler plankton trap from a depth of 0.5 m and
fixed with formalin (2%).
Sub-samples of approximately 10 mL
were removed from each field collected sample and settled for at
least 24 h using Utermo¨ hl algal settling chambers
Zooplankton biovolume was determined by using the same
microscopy and enumeration techniques as were used when
determining P. parvum cell density, with additional measurements
taken of appropriate dimensions of each individual that
enabled geometric estimation of organism biovolume