Sperm production in the red claw crayfish Cherax quadricarinatus (Decapoda, Parastacidae)

The objective of this study is to evaluate the effect of body size, temperature and annual cycle on sperm production in Cherax quadricarinatus. Sperm count and sperm mortality were estimated, the reproductive system was weighted, and macro and microscopical analysis of the testes and vasa deferentia were conducted. Sperm count and weight of the reproductive system are strongly related to male size, in contrast to sperm mortality. The spermatophore structure presented macro and microscopical differences between sizes. Males higher in size have more adherent spermatophores. This species has a reproductive cycle related to sperm production. Sperm count and weight of the vasa deferentia rise in summer, while the weight of the testes increases in winter. During the spring, the sperm cord presents a higher density than in other seasons. The temperature seems to affect sperm production being 27 and 29 °C the best assayed conditions. The present results are relevant information to obtain the best sperm viability selecting male size, season of sampling and the best temperature for the reproductive stock and future assays of spermatophore cryopreservation for this species aquaculture.