Observation of reproductive system and gonad development of male jumbo flying squid Dosidicus gigas in south-east Pacific Ocean

The reproductive system in male jumbo flying squid Dosidicus gigas was observed using anatomical and histological methods. It was found that the reproductive system consists of testis containing numerous spermaductus closely connected between each other,vas deferens,vesicula seminalis,prostate gland,spermatophore sac,penis, and genital pore. There are immovable germ cells in the spermaductus. The germ cells develop from outside to inside in spermaductus,mature spermatozoa are found in the middle of spermaductus( spermatophore lumen,SL), and spermatozoa are transported to spermatophore by SL. The gonadal development is divided into five phases in which stageⅠand stageⅡare immature stages,and stage Ⅲ,stage Ⅳand stage Ⅴ are mature stages. Male testes are unsynchronized development,and there are differences in gonad development by traditional visual discrimination and histological methods,especially in immature stages.