What does it all mean?
Male vs. Male: Males will fight to assert dominance, as in many other species. The dominant male will fend off others so he has the very best chance of fertilizing as many eggs as possible
Nosing, test digging: Females will essentially ‘smell’ for areas with upwelling water to place their redds, and test it out. Upwelling water ensures a flow of oxygenated water to the eggs and alevin in the redd.
Quivering: This behavior serves a sort of nudging along, encouraging the female to dig and ultimately release eggs. Quivering impacts the sensitive cells on the female’s lateral line, stimulating action from the female.
Crossover: Dominant males swim back and forth over a female’s back to watch for encroaching males
Digging: There are several forms of digging – the test dig, excavation dig, and digging to cover eggs.
Distinguish chum salmon male vs. female:
Males are typically larger with a slight hump, vertical ‘tiger’ stripes, large hooked noses, and jaws filled with large teeth – from which the moniker dog salmon was derived.
Females are generally smaller and streamlined, with a dark horizontal ‘racing stripe’ down the lateral line.