Factors affecting induction of maturation and spawning of the tiger prawn, Penaeus esculentus (Haswell), under laboratory conditions

Adult tiger prawns, Penaeus esculentus, were held under varying conditions of temperature, photoperiod and tank size for assessment of ovarian maturation and spawning. Both eyestalkablated and unablated females were studied. Maturation and spawning of unablated females was favoured by conditions of warm temperature (26°C) and long days (14.5 h), whereas ovarian maturation did not occur at lower temperature (20°C) and short days (12 h). Tank size was a critical factor with unablated females, as maturation and spawning occurred in a large tank (3.2 m 2, 0.9 m depth) but did not occur in small tanks (1 m 2, 0.3 m depth) despite favourable temperature and photoperiod conditions. Ablated females matured under both short-day, low-temperature conditions and in small tanks, but the success rate was greater with long days and warm temperatures in large tanks. Ablated females showed ovarian maturation during the second intermoult period after ablation, but unablated females required three or four intermoult periods of the appropriate environmental treatment before onset of maturation. Successful mating was rare in small tanks, but occurred frequently in large tanks.