The modulating effect of temperature on sexual differentiation and sex reversal in the freshwater crayfish Cherax quadricarinatus (Parastacidae).

VAZQUEZ, F.J., TROPEA, C., SANCHEZ DE BOCK, M., LOPEZ GRECO, L.S

Coquimbo, Chile

Congreso; Mid-Year Meeting of the Crustacean Society; 2007

The Crustacean Society

Temperature (T) is one of the most important modulating factors on reproduction in the freshwater crayfish C. quadricarinatus, “red claw”. The influence of T on ovarian maturation and juvenile growth has been addressed. This work was aimed at studying the effect of temperature on sex differentiation and sex reversal as a possible factor for the culture of this species. Two kinds of experiments were carried out. In the first, recently hatched undifferentiated juveniles (20mg) were exposed at 27°C (control group), 29°C and 31°C and in the second experiment, juveniles females (200mg) were exposed at the same temperatures. Twice a week the animals were weighted and sexed. Both assays were run during 150 days. The results demonstrate that T is not a determinant factor on sexual differentiation but it has a significant (p<0.05) effect on sex reversal. The main type of sexual reversion is the change of sex from females toward intersex females although the reversion toward males was statistically significant (p<0.05) at 29°C. The assayed temperature of 29°C also induced greater somatic growth and early acquisition of sexual maturity in females so it is consider as an interesting factor to apply for the culture of the species. Financial support: UBACYT 2004-2007 (project X143), ANPCYT (PICT 2004-953), Antorchas Foundation (project 4248-138). POSTER PRESENTATION.