Selective predation by Neomysis mercedis in Lake Washington1

Feeding experiments and examination of gut contents show that Neomysis mercedis is an effective predator on zooplankton in Lake Washington. Daphnia is consistently preferred to other prey; Diaptomus and Cyclops copepodids and nauplii are always underrepresented in mysid diets. This pattern of selectivity is consistent with the hypothesis that a large population of Neomysis formerly excluded Daphnia from the lake.