Spermatogenesis and sexual maturation in male blue shark, Prionace glauca Linnaeus (Elasmobranchii: Carcharhinidae), off Southeast and South Brazil

Abstract

The spermatogenesis in the blue shark, Prionace glauca, was observed. This shark is usually caught by surface longliners based in Itajaí, Santa Catarina State, Brazil. The histological samples were extracted from testes of a male (with 236 cm in length and 45 kg in weight). Transversal tissue cuts of 7 µm width were dyed with hematoxiline-eosine and a few with Guimsa. The slides were observed and the images recorded by a video system analyser connected to a microscope. The sexual maturity of this species was also studied through the relationship between clasper and shark length. The clasper calcificacion was also observed. Data were obtained from commercial fishing cruises (March-April, 1997, June-July, 1998, September-October, 1998 and February, 2002) and from longline research cruises during March-April, 2003 - 2006, July, 2003 and September,2002 - 2007 (n = 599). For the blue-shark, the seven spermatogenesis stages were detected and described. Males begin clasper calcification from 200 cm and presented claspers fully calcified with 240 cm in total length.