Schematic overview of the tracking method.

<p>We provide initial information by creating a 3D model of the fish, calibrating the cameras and initialising the fish position by clicking the snout and tail position in the images from every camera (I). For every time step, we segment the fish in the images from all cameras and predict the fish position, orientation and body curvature based on previous frames (II). The predicted parameters are then used to initialise an optimisation algorithm. This algorithm finds the set of parameters (body curvature, position and orientation) that minimises the difference with the high-speed video frames (III). Once the optimisation has been performed for all frames, we compute the centre of mass and, by inverse dynamics, the resultant forces and torques over time (IV).