About Chromis dispilus Griffin, 1923
Taxonomy and Naming
The New Zealand demoiselle (Chromis dispilus), formally described as Chromis dispilus by Griffin in 1923, is a damselfish species belonging to the genus Chromis.
Distribution
It is found off rocky coasts between North Cape and East Cape of New Zealand's North Island, at depths down to approximately 60 meters.
Size
Adults of this species reach a total length between 15 and 20 centimeters.
Male Territoriality
Male New Zealand demoiselles are highly territorial, and defend their nesting areas from other males and individuals of other species.
Egg Guarding
These aggressive males guard the eggs that females have laid in their territory.
Spawning Period
Spawning takes place between the months of December and March.
Territory Size at Medium Density
In areas with medium population density, this fish typically has the largest territories and nesting grounds.
Spawn Output and Density
Like most territorial fish species, New Zealand demoiselles tend to produce more spawn at higher population densities of their own species than at lower densities.
Aggression and Conspecific Density
Aggression levels are also higher at higher conspecific densities, and lower at lower densities.
Aggression by Reproductive Stage
Additionally, aggression levels are higher during spawning than during the egg defense period.
Hormonal Correlate of Aggression
Higher levels of aggression in males are linked to elevated plasma concentrations of the androgens testosterone and 11-ketotestosterone.
