Temperature effects on growth, feeding rate and feed conversion of the Pacific white shrimp ( Penaeus vannamei)

Abstract

Effects of temperature on growth, feeding rate and feed conversion ratio (FCR) of juvenile Pacific white shrimp, Penaeus vannamei (Boone), were quantified in a series of four experiments. In each of experiments 1 to 3, a single size class of shrimp was reared at three constant temperatures (23, 27, 30 °C) and at an ambient temperature control (mean 26.2 °C). In the three experiments, mean shrimp stocking sizes were 3.9, 10.8 and 16.0 g, respectively. Shrimp growth and feeding rate increased directly with temperature in each experiment, but the increases varied among the three size classes so that thermal effects on growth and feeding were size-specific. FCR of small shrimp was not different among the three test temperatures while FCR of medium-and large-sized shrimp varied with temperature. Differences in growth response among size classes was the basis for a fourth experiment, in which two size classes were grown at three temperatures. Growth and feeding rate were again directly related to temperature and varied inversely with size. FCR was primarily related to size; larger shrimp grew less efficiently. Large temperature coefficients, particularly between 23 and 27 °C, demonstrate that P. vannamei growth is extremely sensitive to small changes in temperature. These data also indicate that temperature optima (temperature of fastest growth) is size-specific and decreases as shrimp size increases. For small shrimp (< 5 g), temperature optima may be greater than 30 °C while for large shrimp, the temperature optimum is about 27 °C. These findings appear consistent with the distribution of P. vannamei during its natural life history. For P. vannamei farmers, these data indicate that for all sizes reduced growth and feeding can be expected when pond temperature is below 23 °C and for large shrimp when pond temperature is 30 °C or greater.