Production of Eudiaptomus intermedius in Lake Santo Parmense

In Lake Santo Parmense, an oligotrophy high-mountain lake in the Northern Apennines, zooplankton is mainly constituted by two species: Eudiaptomus intermedius and Daphnia longispina. E. intermedius is a univoltine species that reproduces for a short period, in May-June, after the thaw. In the present research the production of this species was estimated using the method of Petrowich et al. (1964); this method has been applied to the smoothed data of density and biomass (for every development stage) over a period of five months, from mid-June to mid-November. Total production is 96.3 mg of dry weight per m 3 ;; the most important contribution comes from the copepodite III stage. The ratio P/B is 3.14. The production of E. intermedius has also been estimated using Boysen Jensen's method: the results disagree considerably from those obtained using the method of Petrowich et al. The seasonal evolution of the production estimated using Boysen Jensen's method was analyzed taking into account the trend of death rates of the different development stages.