An effective facility decreases disease transmission and promotes resistance ability of small sea urchins Strongylocentrotus intermedius: A potential application in the longline culture

Abstract

Mass mortality of small sea urchins Strongylocentrotus intermedius in summer greatly decreases the production efficiency of the longline culture. An effective facility that separates sea urchins from each other and separates sea urchins from macroalgae was proposed to address this problem.Here, a laboratory simulation was conducted for ~6 weeks to investigate survival, food consumption, feeding behavior and resistance ability of S. intermedius cultured in a newly designed facility (the experimental group) and commonly used facility for sea urchins (the control group) at high temperature (23 °C). The present study found that significantly lower morbidity occurred in the experimental group than that in the control group. The disease challenge assays consistently showed that the experimental group had significantly lower morbidity compared to that in the control group. These results suggest that the new facility potentially decreases the disease transmission of sea urchins of longline culture in summer. Further, the critical thermal limit (CTmax) and Aristotle's lantern reflex in the experimental group were significantly greater than those in the control group, suggesting that the new facility leads a better acclimation to the high water temperature for cultured sea urchins.The present study suggests an effective facility specialized for the longline culture of sea urchins, which has great application potential to improve the production efficiency at high water temperatures.