“…Our study addresses this issue by examining the fluid interactions in Craspedacusta sowerbyi Lankester 1880, a freshwater, upstream-foraging, rowing hydromedusa (Hydrozoa: Olindiidae). Originating in the Yangtze river system in China, C. sowerbyi has been introduced into small lakes, ponds, and water-filled quarries in North America, Europe, and Asia (Kramp, 1951), where it is known to prey on motile, sensitive zooplankton such as rotifers, copepods, and cladocerans in the 0.2-2-mm size range (Dodson and Cooper, 1983;Spadinger and Maier, 1999;Jankowski et al, 2005). Here, we quantify morphological characteristics, fluid flows around swimming individuals, and estimates of encounter volume rate to evaluate the mechanics of C. sowerbyi's stealth predation.…”