The average residence time of zooplankton in a lake is 6 months (tz = 6 months). planktivorous fish (fish that eat zooplankton) graze upon the zooplankton and consume 30% of the net zooplankton productivity. the planktivore conversion efficiency is 20%, meaning that 20% of the zooplankton biomass consumed by the planktivores is converted into planktivore biomass. therefore the net productivity of the planktivores is 0.30 x 0.20 or 6% of the zooplankton productivity. if the average residence time of carbon in the planktivores is 2.5 years (tp= 2.5 year) estimate the ratio of the average planktivore biomass to that of the zooplankton biomass in the lake.