MATURATION OF ARROW SQUIDS NOTOTODARUS-GOULDI AND SLOANII WITH AGE INNEW-ZEALAND WATERS

Sexual maturation with age was analyzed for arrow squids Nototodarus g ouldi and N. sloanii in New Zealand waters. A total of 654 specimens o f N. gouldi and 771 specimens of N. sloanii were aged successfully usi ng the statolith micro-structure. Based on the results of ageing, the relationships between age and some gonad somatic indices were analyzed . The maturation patterns of both species are similar to each other, t hough the sample number of mature N. sloanii is not sufficient. The ch ange of gonad somatic indices suggests that males start to mature from around 200 days old. Testis somatic index (TSI) reaches a maximum at about 270 days. Females start to mature at the time when TSI reaches t he maximum in males. The development of ovary, oviduct, and Nidamental gland occurs simultaneously, and copulation also occurs at the same p eriod. It is suggested that spawning may occur within two months after copulation, considering the period of copulation and a single year li fe span of arrow squids.