ANNUAL CYCLE ON SPERM PRODUCTION IN THE RED CLAW CRAYFISH Cherax quadricarinatus

BUGNOT, ANA B.; LÓPEZ GRECO, LAURA S.*

VERACRUZ, MEXICO

Congreso; WAS AQUACULTURE 2009; 2009

WAS AQUACULTURE SOCIETY

Cherax quadricarinatus is a freshwater crayfish that is cultured in several countries. Until now, studies concerning the reproduction of this species have been focused on females. However, it has been demonstrated that sperm production can affect reproduction of shrimps in captivity. In this context, the objective of this study is to evaluate the effect of annual cycle on the sperm production of C. quadricarinatus. Table 1. Seasonal cycle on sperm production and reproductive system weight in C. quadricarinatus. Mean ± DS. Different superscripts indicate significant differences between seasons (p < 0.05). N = 10 males for each season. Fifteen adult males (70 to 110 g) were selected from San Mateo S.A. farm (Chajarí, Argentina) during 2007. Sperm count, sperm mortality and reproductive system weight were estimated. Macro and microscopic analysis of the testes and vasa deferentia were conducted. One way ANOVA followed by Fisher LSD test were employed (level of significance: 0.05). Table 1 shows the differences in sperm count, reproductive system weight, vas deferens weight and testes weight. No macroscopic differences were observed, however, microscopic analysis showed a decrease in the production of spermatophore components (Fig. 1). Figure 1. Histological section of distal vas deferens of C.quadricarinatus (stained with ematoxylin Eosin) A) a male sacrificed in autumn. Scale: 100 µm. B) a male sacrificed in spring. Scale: 200 µm. SC: sperm cord. These results demonstrate that males of C. quadricarinatus present an annual reproductive cycle characterised by an increase in sperm count and vas deferens weight in summer which lead to a high quality spermatophore in this reproductive season. In autumn, vas deferens weight decreases due to the end of the reproductive season. In winter, testicular weight rises probably due to a great production of sperm in preparation for the next reproductive season. And during spring, sperm seems to move towards the vas deferens because testicular weight declines, although secretion of components of the spermatophore remains low.