Effects of light intensity and light duration on growth performance and ovarian development in red swamp crayfish Procambarus clarkii (Girard, 1852)

The objective of this study is to explore the effects of light intensity (600 ~ 1800 lx) and photoperiod (4 ~ 24 h) on the growth performance and ovarian development of red swamp crayfish (Procambarus clarkii). The feeding rate (FR), weight gain rate (WGR), specific growth rate (SGR), condition factor (CF), hepatosomatic index (HSI), gonadosomatic index (GSI), and mature oocyte ratio in the ovary were measured. The results of the study showed that the first-order effect of photoperiod and light intensity has significant impacts on FR, WGR, SGR, CF, HSI, GSI, and mature oocyte proportion of P. clarkii; the second-order effect of photoperiod and light intensity has significant impacts on the FR, SGR, and CF of P. clarkii; and the interaction effect of photoperiod and light intensity has significant impacts on WGR, SGR, CF, HSI, GSI, and mature oocyte proportion of P. clarkii. Within the range of conditions in this study, as the photoperiod extended, the FR, WGR, SGR, CF, HSI, and GSI gradually increased. As the light intensity increased, the FR, WGR, SGR, and CF first decreased and then increased, while HSI and GSI showed a gradually increasing trend. The results indicated that the change of light intensity (enhanced or weakened) and the extension of photoperiod in the range of conditions in this study could promote the growth and ovarian development of P. clarkii. The photoperiod and light intensity have important effects on the growth and ovarian development of P. clarkii. The results in this study provided a theoretical basis for biological research of P. clarkii and basic data for artificial reproduction and intensive culture of P. clarkii.