Survival, maturation, fecundity and hatching rates of unablated and ablated Penaeus indicus H.M. Edwards from brackishwater ponds

Abstract

Penaeus indicus H. M. Edwards harvested after three months of rearing in brackishwater ponds and averaging 6.9 g for females and 5.6 g for males were stocked in two 12 cu m flowthrough ferrocement tanks at 240 females and 200 males per tank. The females were ablated on one eyestalk in one tank and remained unablated in the other tank ; all males were unablated. Ablated females spawned up to 7 times per female; unablated females spawned up to only 3 times during the two month duration of the experiment. Ablated females produced a total number of 17.5 x 10⁶ eggs, 6.6 x 10⁶ nauplii, and an average of 23,480 eggs/spawning and 37.8 % hatching rate from a total of 757 spawnings. Unablated females produced a total of 2.0 x 10⁶ eggs, 1.1 X 10⁶ nauplii, and an average of 26,990 eggs/spawning and 53.9 % hatching rate from a total of 74 spawnings. Survival of ablated females was 53.5 % compared to 69.4 % for unablated females ; males in both tanks averaged more than 90% survival.