Family Growth and Survival Response to Two Simulated Water Temperature Environments in the Sea Urchin Strongylocentrotus intermedius

Abstract

Heat tolerance is a target trait in the selective breeding of the sea urchin Strongylocentrotus intermedius, as it plays an important role in the survival and growth of cultured S. intermedius during summer. We investigated family growth and survival response to two temperature treatments to evaluate the genotype by temperature interaction (GEI) in the family selection of S. intermedius. Sea urchins from 11 families were exposed to two simulated water temperature environments—high temperature (HE) and control temperature (CE)—for 12 months, with each experiment divided into four periods (P1, stress-free period I; P2, stress-full high period; P3, stress-response period; and P4, stress-free period II) based on the temperature changes and the survival. Test diameter (TD), body weight (BW), and survival rate (SR) in HE and CE were measured monthly. Effects of family, temperature, and family-temperature interaction on TD, BW, SR, and specific growth rate (SGR) for BW were examined. In CE, BW differed significantly between families in P2, P3, and P4, while TD differed significantly between families in P3 and P4 (p < 0.05). In HE, family had significant effects on BW in P4, and on TD in P3 and P4, while temperature had significant effects on SR, TD, and BW in P3 and P4 (p < 0.05). GEI effects were not significant for TD or BW; however, family ranking changes revealed the existence of GEI in SR. The GEI results indicate the necessity of applying family selection in CE and HE for SR, but not for TD or BW. These results may provide a guide for aquaculture and selective breeding of S. intermedius under temperature pressure.

Interactive effects of family and stocking density on survival and growth of the sea urchin Strongylocentrotus intermedius

“…For test diameter growth rate, however, a significant family by density interaction effect was found, meaning that families' test diameter growth responded differently to stocking density variation. In S. intermedius , our studies (Chang et al, ; Zhang et al, ) reported the significant family by environment interaction effects on survival, growth and feed conversion rate. A preliminary hypothesis is that, when the environment variation is large in scale, significant family by environment interaction effects on growth rate are easily found, whereas when the environment involves the extreme factor level, a significant family by environment interaction effect on survival is easily found.…”

“…Its offspring should be cultured in a relatively lower stocking density. Family reranking effect has been proven to be the main reason causing significant family by environment, diet, and temperature interactions by our studies on S. intermedius (Chang et al, ; Wang et al, ; Zhang et al, ) and other studies in other aquatic animals (Pierce et al, ).…”

“…Several studies had documented significant family effects on growth in other aquatic species reared in the sea (Kvingedal et al, ; Swan, Thompson, & Ward, ) or in the laboratory (Dupont‐Nivet et al, ; Pierce et al, ). Although studies of S. intermedius have also shown significant family effects on growth traits (Chang et al, ; Wang et al, ; Zhang et al, ), these results were all based on laboratory experiments. The present study is the first report of a significant family effect on the growth of sea urchins reared in the sea.…”

“…All these similar conclusions suggested that genetic factors played important roles in the growth of the aquatic animals, including S. intermedius . In terms of mortality or survival, a significant family effect was more likely to be found in the long‐term experiments and extreme environments than in the short‐term and benign ones (Chang et al, ; Wang et al, ; Zhang et al, ). Our results support this hypothesis and indicate the genetic difference in S. intermedius when it was cultured in the sea.…”

“…Moreover, in S. intermedius , completely different culture methods or diets caused significant family by environment interaction effects on growth traits (Wang et al, ; Zhang et al, ). However, when families were cultured in extreme temperature, even though a slightly changed temperature did not cause significant family by environment interaction effect on growth, it caused a significant family by environment interaction effect on survival (Chang et al, ).…”