The main reason chum salmon have teeth is for eating other salmon and fish and being able to chew up those salmon and fish before swallowing it.
Another reason for chum salmon to have teeth is for attracting mates.
Yes that's right the chum salmon teeth are also used for attracting other salmon they want to mate with as well as use the teeth for eating other fish and salmon species in the waters where they are.
The Chum Salmons teeth help them chew up their prey as well as being attractive to other salmon they want to mate with.
Chum salmon are philogenetically more evolved than other salmon species, except pink salmo.
Large teeth, like hooked noses, kypes, colored bars and stripes are all secondary sexual characteristics.
These sexual characteristics serve two purposes.
The most obvious one is to attract potential mates - maybe we're to assume that girl chums salmon like guy chums salmon with big teeth.
Another purpose of the chum salmon teeth is to warn away the competition.
A large Alpha male may be more intimidating to smaller males by possessing large teeth along with the large body.