Effect of light quality and eyestalk ablation on ovarian maturation in Penaeus monodon

Abstract

Prawns were subjected to the following treatments: blue light, red light, natural light, and natural light plus unilateral eyestalk ablation. Unablated prawns under blue and natural light developed stage III ovaries; under red light ovarian maturation reached only stage II. Ablation resulted in full maturation of ovaries and subsequent spawning. The external changes of the ovary were generally the same for both the ablated prawns under natural light and the unablated under different light qualities. Under blue light, however the ovary at stage III had numerous atretic cells and the diameter of its ova was more uniform. The maturation stage and mean gonadosomatic indices were high for the ablated and low for the unablated prawns.