Using a game theoretic and mechanistic model, researchers from the Centre for Ocean Life showed how traits influencing predator-prey interactions shape the diel vertical migrating behavior of copepod communities.
Diel Vertical Migration is the daily movement of marine organisms from the depths of the oceans to the surface. It is such a widespread phenomenon that it is believed to be the biggest migration of the planet in terms of biomass. Diel Vertical Migration is primarily an antipredator response, organisms migrating to the depths during daytime to avoid zones of high light levels and back to the surface at night to feed in resource-rich waters.
However, diel vertical migrations are typically modelled considering light levels but not trophic interactions. Here, we take notions from economic principles (game theory) to derive migration patterns for a small food web. Specifically, we show that considering trophic interactions explain the peculiar non-linear diel vertical migrations patterns observed for a size range of copepods. Moreover, we show that considering trophic interactions allows to model reverse vertical migrations (see figure). To our knowledge, this is the first time that a mechanistic model is able to capture effectively reverse vertical migrations.
Figure legend: Day (red) and night (blue) position of zooplankton in the water column. Here, the model was parametrized for a 185m deep water column located in an American fjord (Dabob Bay, Washington) where reverse migrations are observed. We believe this is the first time that a mechanistic model can reproduce reverse vertical migrations.
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Pinti Jérôme, Kiørboe Thomas, Thygesen Uffe H. and Visser André W. (2019) Trophic interactions drive the emergence of diel vertical migration patterns: a game-theoretic model of copepod communities Proc. R. Soc. B 286