FISHERY BULLETIN: VOL. 80, NO. 3 



amounts of yolk and oil (coefficients of variation 

 27% and 25% for yolk and oil, respectively) and 

 little «3%) difference was found in energy con- 

 tents. The oil globule accounted for an average 

 55% of the dry weight and 71% of the total energy 

 of the egg. Yolk accounted for 38% of dry weight 

 and 29% of energy. The two sources combined 

 provided an average 2.036 cal/egg. 



Yolk contained an average 5,652 cal/g, which 

 agrees with Phillips' (1969) estimate of 5,660 

 cal/g gross energy for digested protein. Lipid 

 extraction analyses of yolk from three of the 

 seven spawned females showed that only 3.8% of 

 dry weight was lipid material. 



Embryos and larvae from the seven different 

 females consumed their yolks linearly (Fig. 1). 

 At hatching an average 58% of the original yolk 

 energies remained, and they were totally utilized 

 between D-6 and D-7, the time when active feed- 

 ing began. Analyses showed no significant dif- 

 ferences in yolk utilization rates but highly 

 significant differences in intercepts (P<0.01), 

 further indication of the differences in original 

 yolk reserves. 



Initial oil energy contents per egg ranged from 

 0.8 to 2.5 cal (Table 2) and differed significantly 

 between batches (P<0.05). An average 86% of 

 these initial amounts remained at hatching and 

 71% was present on D-7. Analyses of covariance 

 indicated that the utilization rates from fertiliza- 

 tion to feeding (Fig. 2) also were significantly 

 different (P<0.05). With the exception of one 

 batch, embryos and larvae consumed their oil 

 energies so that approximately the same 

 amounts of energy remained on D-7. 



The rates at which oil globule calories were 

 utilized and the ages at complete oil energy 

 absorption (D-20 to D-29) appeared related to 



0.8 



Si! 0.6- 

 O 



< 



O 



>- 



04- 



02- 



FEEDING 



I 



food concentration (Fig. 3). Starved larvae and 

 those in 0.01 Artemia/m\ concentrations con- 

 served oil, whereas those fed progressively 

 higher concentrations consumed energy at faster 

 rates. Analyses of covariance showed significant 

 differences in oil consumption among batches 

 within each food concentration. Tests of food con- 

 centrations and oil consumption within batches 

 showed all to have highly significant differences 

 (P<0.01) in intercepts, and two of the four 

 batches had significant slope differences 

 (P<0.05). 



Exogenous Sources 



Larvae in all experiments began active feed- 

 ing 5 d after hatching. Average stomach con- 

 tents, presented as the average number of in- 

 gested Artemia and their equivalent calories, are 

 presented in Table 3. These data were further 

 used to calculate daily food rations (Table 4). 

 With some exceptions, larvae increased their 

 exogenous energy intake in direct relation to 

 food availability and age in all food concentra- 

 tions except 0.01 Arte?nia/m\. Larvae in this low 

 concentration showed no particular trend. 



Energy Outputs 



Growth 



Embryonic and prefeeding larval growth, 

 measured in assimilated tissue calories, differed 

 significantly among the seven batches (P<0 .01). 



2.5-1 



2.0 



LU 



5 1.5- 



O 



—J 



< 



u 



=i 1.0- 

 O 



0.5 



oJ 



HATCHING 



FEEDING 



DAYS AFTER FERTILIZATION 



DAYS AFTER FERTILIZATION 



Figure 1.— The consumption of yolk calories by seven differ- 

 ent batches of striped bass embryos and larvae cultured under 

 identical conditions. 



Figure 2.— The consumption of oil globule calories by seven 

 different batches of striped bass embryos and prefeeding lar- 

 vae. 



464 



