Can we apply economic principles to fish ecology and diel vertical migration? It appears that the way fish and zooplankton behave in the presence of other individuals can be derived from mathematical notions first developed to describe the interactions between several economic players.
In a paper appearing in The American Naturalist, two researchers from the Centre for Ocean Life of DTU (Denmark) modeled the optimal habitat selection strategies of plankton and fish in a water column. Their set-up allows both individual prey (zooplankton) and predators (fish) to choose their position at day and at night. This is the first time that a model has investigated the optimal position of both prey and predators in a water column with such a resolution. The model reproduces features of diel vertical migrations that are observed in nature. For example, at low predation pressure, zooplankton remain near the surface whereas a higher predation pressure induces zooplankton migration between the surface (to feed, at night) and the depths (to hide, during daytime). Fish follow a similar route to maximize their food intake.
A deeper knowledge of these complex migration processes is necessary as they play a role in global biogeochemical cycles. Zooplankton and fish actively transport carbon to the depths during diel vertical migrations, therefore removing carbon from the surface. The surface being coupled with the atmosphere, this drawdown of carbon helps reducing the atmospheric CO2 concentration. A better understanding of these biological processes will enable scientists to provide better estimates and predictions of atmospheric CO2 concentrations.
Read the paper here
Jérôme Pinti and André W. Visser 2019 AmNat Predator-Prey Games in Multiple Habitats Reveal Mixed Strategies in Diel Vertical Migration