Sexual Dimorphism in the Cyclopterid Fish Eumicrotremus orbis

Abstract

Eumicrotremus orbis exhibits marked sexual differences in the size and number of the taxonomically important dermal tubercles and in coloration. The tubercles in females are larger and more numerous than those in the males. Mature females are pale green whereas males are dull orange to reddish-brown. Eggs taken from ripe females collected during January and February 1967 averaged 2.0 mm in diameter. Each female carried an average of 202 eggs. The presence of recently hatched juveniles suggests that E. orbis spawns in February.