A depiction of an Utrom sport - fish fighting.

The basic concept is two or more competitors trying to wrestle a an enormous fish out of the water. The "modern" version is to get the fish into another isolated pool before anyone else; but the old way was to slaughter it as soon as it was brought out onto land - and then eaten in the ending ceremonies.
They'll usually wear colored bands and nets to distinguish themselves - such as the lady here with red.

The decision to change had two factors. The first was animal welfare and feelings about "sporting animals". The other was more about certain fish being too good to lose - choosing to spare it and breed it in hopes of having more fish that are just as good.