Reproductive aspects of the rose shrimp Parapenaeus longirostris (Lucas, 1846) in the Gulf of Cadiz (southwestern Iberian Peninsula)

摘要

Parapenaeus longirostris (Lucas, 1846) is an abundant penaeid species which inhabits the Eastern Atlantic, from Portugal to Angola, and the Mediterranean Sea. This species is of great interest to fishermen in the Spanish waters of the Gulf of Cadiz. The present study on the reproductive cycle of P. longirostris was based on the analysis of monthly commercial samples and fisheries research surveys carried out in this region.rnThe species shows two spawning peaks throughout the year, the first peak occurring in late spring and the second one in the autumn. The larger mature females mainly spawn in the spring, whereas smaller adult females spawn in autumn. Females' cephalothorax length (CL) at first maturity was between 21.5 and 22 mm CL. In males thejoining of the two sections of the petasma takes place at between 12 and 15 mm CL, being always separated at sizes lower than 11 mm CL. The size at which 50% of males have a joint petasma was estimated at 12.9 mm CL. The spermatophoric mass on the coxae of the fifth pereiopods was present from a size of 13 mm CL, the size at first maturity being estimated at 14.8 mm CL. The conditioning factor is related more to growth events than to ovarian maturation, and a relationship was found between them. Relative fecundity was estimated at 7486 eggs/g of female, with fecundity ranging from 21410 to 186856 eggs. Females at the stage of both advanced ovarian development and readiness to spawn occurred at depths greater than 100 m.