FISHERY BULLETIN: VOL. 73, NO. 1 



temperature and salinity. Maximum survival of 

 the 2-day-old larvae (807f contour) was estimated 

 to occur at temperatures between 18.5° and 

 24.5°C and salinities between 22 and 28.5%o 

 (Figure 7). 



The analysis of survival after 6 to 8 days of 

 rearing beyond the veliger stage indicated that 

 the linear and quadratic effects of temperature 

 and the interacting effect of temperature and 

 salinity were the more important variables 

 affecting survival. Response surface estimation 

 predicted 80% survival at temperatures between 

 8.5° and 26.5°C and salinities above 12o/oo (Figure 

 8). A significant difference (1% level) was cal- 

 culated by the analysis of covariance for the 

 2- and 6- to 8-day survival polynomials. The 

 veliger larvae showed a much greater tolerance 

 to low temperatures and a wider range of salini- 

 ties than the early embryos. 



Growth of the veliger larvae was most affected 

 by the interacting effect of temperature and 

 salinity, the quadratic effect of salinity, and the 

 linear effect of temperature. Maximum growth 

 (60% contour) was estimated to occur at tempera- 

 tures between 18° and 38°C and salinities above 

 16.5%o (Figure 9). The axis of the growth con- 

 tours are observed to lie diagonal to the factor 

 axes showing the effect of the temperature- 



40 



3 



< 

 a: 



a. 



5 



30 



20 



10 



10 20 30 



SALINI TY (%„) 



40 



Figure 8. — Response surface estimation of percent survival 

 of Mulinia lateralis veliger larvae after 6 to 8 days of 

 development at experimental temperature and salinity com- 

 binations given in Calabrese (1969). 



salinity interaction. There was a significant 

 (1% level) difference between the polynomials 

 estimated for the 6- to 8-day survival and growth 

 indicating that the higher temperatures required 



ClJ 



tr 



I- 

 < 



LiJ 

 Q. 



2 



40 



30 



tr 



< 



20- 



10- 



10 20 30 



SALINI TY (%„) 



40 



Figure 7. — Response surface estimation of percent survival 

 of Mulinia lateralis larvae after 2 days of development 

 at experimental temperature and salinity combinations given 

 in Calabrese (1969). 



Figure 9. — Response surface estimation of percent growth 

 of Mulinia lateralis veliger larvae after 6 to 8 days of 

 development at experimental temperature and salinity com- 

 binations given in Calabrese (1969). 



90 



