A high-performance temperature-control scheme: growth of sea cucumber Apostichopus japonicus with different modes of diel temperature fluctuation

The effects of four modes of diel temperature-fluctuation with two designated fluctuating temperatures (15 +/- A 3A degrees C and 18 +/- A 3A degrees C) on the growth and energy budget of young sea cucumber, Apostichopus japonicus Selenka, were studied to develop a highly efficient temperature-control scheme for aquaculture of the species. Sea cucumbers with a mean wet body weight of 8.0 +/- A 1.2 g (mean +/- A SD) were allocated to each treatment randomly with five replicates. After a 38-day trial, specific growth rate (SGR) and food conversion efficiency (FCE) decreased with increasing temperature in constant-temperature treatments. Among the four modes of temperature fluctuation, SGR of sea cucumbers reared under a mode which simulated the natural fluctuation of the temperature (mode C) of seawater was significantly higher than that of sea cucumbers reared at the corresponding constant temperatures. This enhancement of growth rate by use of mode C was attributed to higher FCE and lower energy allocated to respiration and feces. In large-scale culture, a temperature-control mode designed based on mode C could enhance not only growth but also efficiency of food utilization by the young sea cucumber.