TEMPERATURE-DEPENDENT ALLOMETRIC MODELS TO ESTIMATE ZOOPLANKTON PRODUCTION IN TEMPERATE FRESH-WATER LAKES

Empirical relationships between body size and temperature, and daily P IE of temperate freshwater zooplankton species were derived from the l iterature. Body size explained 81% of the variation in daily PIE of zo oplankton at temperatures less than or equal to 10 degrees C and 48% a t temperatures >10 degrees C. The two relationships did not differ in slope but significantly differed in elevation. The regression models w ere then applied to zooplankton samples collected from a midlake stati on in Lake Ontario to predict zooplankton seasonal production. Product ion estimates from the regression models, when compared with estimates from the egg ratio method for the same data set, were similar for cla doceran species, four and 10 times higher for two copepod species, and two times higher for total zooplankton production. In general, these differences are within the range expected based on previous studies th at compared different production models. The regression models can pro vide quick, independent estimates of zooplankton production to complem ent estimates based on traditional, species-specific methods. Furtherm ore, the models can be used in conjunction with automated synoptic ins truments, such as optical plankton counters and temperature probes, to provide production estimates that better represent large, complex sys tems such as the Great Lakes.