Life history, biomass and production of two planktonic cyclopoid copepods in a shallow subtropical reservoir

Two planktonic cyclopoid copepods (Tropocyclops prasinus and Mesocyclops longisetus) were raised in the laboratory to obtain life history information (duration of embryonic and post-embryonic development, reproductive performance, longevity, and stage-specific length and weight values). Animals were maintained at 20 and 25°C, and fed ad libitum. Development times were temperature dependent when food was not limiting, with shorter periods of embryonic and post-embryonic development and decreased longevity at 25°C. Laboratory data on the duration of development and biomass, together with population dynamics data obtained in the field, were used to estimate summer and winter biomass and production of these species in a shallow reservoir, Lagoa Dourada, Brazil. The maximum production rate of T. prasinus, attained during summer, was 2.8 mg dry weight (DW) m−3 day−1 and the highest daily production:biomass (P:B) ratio was 0.29, whereas for M. longisetus the maximum production rate was 1.4 mg DW m−3 day−1 and the highest daily P:B ratio was 0.39, in the winter. Over short time intervals (every other day), there was great variability of the species production rates. Species production rates were low compared to values reported in the literature for the same or other species of equivalent sized copepods from both tropical and subtropical regions.