ipos framework: linking fish swimming performance in altered flows from laboratory experiments to rivers

The current understanding of the effects of turbulence on the swimming performance of fish is primarily derived from laboratory experiments under pressurised flow swim tunnels and open‐channel flow facilities. These studies have produced valuable information on the swimming mechanics and behaviour of fish in turbulent flow. However, laboratory studies have limited representation of the flows fish experience in nature. The flow structure in rivers is imparted primarily by the highly heterogeneous nonuniform bed, and the flow is generally much more complex than in laboratory experiments. The goal of the current work is to direct future laboratory and field studies to adopt a common framework that will shape the integration of both approaches. This article outlines four characteristics of turbulent flow, which we suggest should be evaluated when generalising results from fish turbulent studies in both the laboratory and the field. The framework is based on four turbulence characteristics that are summarised under the acronym IPOS: intensity, periodicity, orientation and scale.