%0 journal article
%@ 0142-7873
%A Möller, K., St. John, M., Temming, A., Diekmann, R., Peters, J., Floeter, J., Sell, A., Herrmann, J., Gloe, D., Schmidt, J., Hinrichsen, H., Möllmann, C.

%D 2020
%J Journal of Plankton Research
%N 6
%P 702-713 
%R doi:10.1093/plankt/fbaa044
%T Predation risk triggers copepod small-scale behavior in the Baltic Sea
%U https://doi.org/10.1093/plankt/fbaa044
6 
%X Predators not only have direct impact on biomass but also indirect, non-consumptive effects on the behavior their prey organisms. A characteristic response of zooplankton in aquatic ecosystems is predator avoidance by diel vertical migration (DVM), a behavior which is well studied on the population level. A wide range of behavioral diversity and plasticity has been observed both between- as well as within-species and, hence, investigating predator–prey interactions at the individual level seems therefore essential for a better understanding of zooplankton dynamics. Here we applied an underwater imaging instrument, the video plankton recorder (VPR), which allows the non-invasive investigation of individual, diel adaptive behavior of zooplankton in response to predators in the natural oceanic environment, providing a finely resolved and continuous documentation of the organisms’ vertical distribution. Combing observations of copepod individuals observed with the VPR and hydroacoustic estimates of predatory fish biomass, we here show (i) a small-scale DVM of ovigerous Pseudocalanus acuspes females in response to its main predators, (ii) in-situ observations of a direct short-term reaction of the prey to the arrival of the predator and (iii) in-situ evidence of pronounced individual variation in this adaptive behavior with potentially strong effects on individual performance and ecosystem functioning.