The ubiquitous oceanic copepod Calanus finmarchicus plays a key role as prey for major fish stocks in the North Atlantic Ocean and adjacent seas. Despite over a century of research on effects of food and temperature on growth and development in C. finmarchicus, the effect of predation risk on these processes remains elusive.
In this seminar, I will present results from a recent lab experiment where I tested how food level and a fish chemical cue influence development and growth in C. finmarchicus. I found that both factors positively affected development rate; copepods reached adult stage earlier both in response to high food and to the predator cue. Food also increased growth and lipid accumulation. In contrast, perceived predation risk resulted in reduced size and lipid fullness, and the response was often stronger than that to food. These results demonstrate that predation risk influences life history investments in Calanus, and suggest that present and future patterns in copepod size and population dynamics may also reflect differences in predation risk.