Prior knowledge of the correlations among commercially important traits in Glyptocidaris crenularis can be used to guide development of breeding and aquaculture programs for this species.We evaluated the phenotypic correlations between somatic and gonadal traits in G.crenularis during two sample periods(October 2010 and April 2011).The coeffi cients of variation(CV%)for body weight(BW),redness(a*),yellowness(b*),gonad wet weight(GW),and gonad index(GI)were>20% in both periods,while those of other traits were very low.GW was signifi cantly correlated with somatic traits(diameter,height,and body weight)in both periods,although the correlation coeffi cients ranged from 0.473 to 0.636(P<0.01).Gonad moisture content(GC),a*,and lightness(L*)were not signifi cantly correlated with somatic traits(P>0.05).The color trait b* was negatively correlated with somatic traits(test diameter,test height,and body weight)during the period when the gonads were well developed(April 2011,P<0.05).We observed little difference in the nature of the phenotypic correlations between the two sample periods.The high variation in the somatic and gonad weight traits in G.crenularis suggests there is considerable potential for selective breeding.However,our results suggest that gonad quality traits cannot be selected indirectly by selecting for body weight.Our study provides an insight into the method for improving the breeding and aquaculture of G.crenulari. Prior knowledge of the correlations among commercially important traits in Glyptocidaris crenularis can be used to guide development of breeding and aquaculture programs for this species. We evaluated the phenotypic correlations between somatic and gonadal traits in G.crenularis during two sample periods (October 2010 and April 2011). The coeffi cients of variation (CV%) for body weight (BW), redness (a *), yellowness (b *), gonad wet weight (GW), and gonad index (GI) were> 20% in both periods, while those of other traits were very low. GW was signifi cantly correlated with somatic traits (diameter, height, and body weight) in both periods, although the correlation coeffi cients ranged from 0.473 to 0.636 (P <0.01) .Gonad moisture content (GC), a *, and lightness (L *) were not signifi cantly correlated with somatic traits (P> 0.05). The color trait b * was negatively correlated with somatic traits (test diameter, test height, and body weight) during the period when the gonads were well developed (April 2011, P <0.05) .We observed little difference in the nature of the phenotypic correlations between the two sample periods.The high variation in the somatic and gonad weight traits in G.crenularis suggests there is considerable potential for selective breeding. However, our results suggest that gonad quality traits can not be selected indirectly by selecting for body weight. Our study provides insight into the method for improving the breeding and aquaculture of G. crenulari.