Size-based dominance hierarchies in the New Zealand freshwater crayfish (koura) Paranephrops zealandicus.

The article presents a study which determines if dominance hierarchy based on size exist among freshwater crayfish (koura) Paranephrops zealandicus of New Zealand. It mentions that when two wild koura was paired, it shows that the larger koura was dominant against the smaller one. It adds that an increase in size disparity results to reduce aggressive behavior.