Gametogenesis and maturity stages scale of Raja asterias Delaroche, 1809 (Chondrichthyes, Raijdae) from the South Ligurian Sea

Abstract

This study was aimed at the acquisition of basic life-history information on Raja asterias through an objective approach in the assignment of maturity stage, using both histological techniques and a multivariate analysis aimed at macroscopic evaluations of the reproductive system. The samples examined were collected from landings of commercial trawl vessels from the port of Viareggio. From July 2001 to August 2002 a total of 351 specimens, 166 females and 155 males, were purchased. A description of the main stages of oogenesis and spermatogenesis is presented here. Moreover, on the basis of the maturity stage definition, maturity ogives were constructed. Length at 50% maturity was estimated to be 51.7 cm and 56.1 cm total length for males and females respectively. Finally an informal table for the maturity stage assignment, which can be useful for a quick and easier definition both on board and in the laboratory, is formulated.