Summary: 69
Limnol. Oceanogr., 49(1), 2004, 69­75
2004, by the American Society of Limnology and Oceanography, Inc.
Predation efficiency in visual and tactile zooplanktivores
Tom A. Sørnes1
and Dag L. Aksnes
Department of Fisheries and Marine Biology, University of Bergen, N-5020 Bergen, Norway
Abstract
Gelatinous zooplanktivores (medusae, siphonophores, and ctenophores) and visual zooplanktivores (fish) interact
through competition, predation, and commensalism. In the search for key factors governing the outcome of com-
petition, we examined the instantaneous predation efficiency and its light dependency. The visual predator Gobius-
culus flavescens and the tactile predator Bolinopsis infundibulum were used as experimental models for the two
predation modes. The predation rate of G. flavescens was adequately described by Holling's curvilinear disc equa-
tion, and that of B. infundibulum was proportional to prey density. However, because of superfluous feeding, the
feeding rate of B. infundibulum differed from the predation rate and approached the asymptotic limitation at high
prey levels. The predation rate was reduced for G. flavescens at irradiances 5­10 mol photons m 2
s 1
, whereas
light had no significant impact on the feeding pattern of B. infundibulum. Provided sufficient light, the predation
rate of G. flavescens was several orders of magnitude higher than that of B. infundibulum. These results are consistent

Source: Aksnes, Dag L. - Institutt for biologi, Universitetet i Bergen

Collections: Environmental Sciences and Ecology; Biology and Medicine