Sexual size dimorphism and sex ratio in Müller's pearlside (Maurolicus muelleri)

Abstract.

From a series of samples from the Norwegian Sea and fjords, we demonstrate sexual size dimorphism in Maurolicus muelleri, and geographical variation in the degree of dimorphism. The dimorphism was smaller in the Norwegian Sea than in the fjord populations. In fjords, males had a lower maximum size and higher mortality than females. One-year-old females weighed on average about 50% more than males in fjords, but this weight difference was reduced to about 10% among 3-year-old fish. Possible causes of this decreasing sexual size dimorphism are discussed.