Reproductive Response of Penaeus stylirostris to Temperature Manipulation

The effect of temperature manipulation on the reproduction of Penaeus stylirostris was investigated as a possible method for increasing larval production. Six 3.66 m diameter black tanks were stocked with unilaterally eyestalk enucleated females and intact males. Temperature was designed to vary between 20 and 28 C at a rate of 2 C per day in the "Fast" treatment and 2 C per week in the "Slow" treatment; upper and lower temperatures were maintained for 10 days before another cycle was initiated. In the "Ambient" treatment, temperature averaged 27.8 ± 0.9 C.
During the 105 day study maturation, mating and larval production were highest in the Ambient tanks. Temperature manipulation as tested in the Fast and Slow treatments did not produce any burst of mating and spawning activity at the upper ends of the cycles to compensate for the steady production in the Ambient group. Thus, the temperature regimes examined did not afford any practical advantage.
The effect of temperature on mating was marked. In the Slow treatment which most closely mimicked natural seasonal temperature change, mating began initially when the temperature increased to 25 C. Throughout the study mating occurred more frequently at the higher temperatures, and these results suggest that the optimal temperature range was 27–29 C for reproduction. However, the shrimp did mate at all temperatures encountered. It is notable that this tropical species can successfully reproduce at temperatures as Iow as 20 C.