Reproductive cycle and sexual maturity of the anglerfish <i>Lophiomus setigerus</i> in the East China Sea with a note on specialized spermatogenesis

The reproductive cycle and sexual maturity of the anglerfish Lophiomus setigerus were examined. Spermatids were released from the germinal cysts into the lumina of the seminal lobules, and both spermatids and spermatozoa were present in the lumina of the seminal lobules and sperm ducts. Spermatogenesis and vitellogenesis occurred throughout most of the year. The testes of males were full of spermatozoa throughout the year, with spawning from May to November. Males and females reached sexual maturity at a mean total length and age of 178 mm, 3.3 years and 303 mm, 6.1 years, respectively. There were clear seasonal cycles in the gonadosomatic index (I G ) and hepatosomatic index ( I H ) in females. The mean I G of females increased rapidly with ovarian development while the mean I H decreased from the middle of vitellogenesis to final maturation. Mean values of I G and I H in males increased with testicular development.