hatching, attained a mean dry weight of 0.5 mg at 25, 19, 18 and 12 days after 

 hatching in temperature treatments of 18, 21, 24 and 27°C, respectively. 



There was a tendency for later fed groups at each temperature to grow at a 

 greater rate than those receiving their first food earlier in the experiment. Table 

 16-1 shows the instantaneous growth coefficients calculated for delayed 

 feeding groups at each temperature, using the same data that were presented 

 graphically in Figure 16-2. In each case, the growth rates of the earliest fed 

 groups were lower than those of groups which had been starved before 

 receiving their first food. This growth compensation seldom permitted later fed 

 groups to overtake those fed earUer, but did serve to partially offset the growth 

 setback that resulted from later initial feeding. 



An additional effect of delayed initial feeding was a retardation of structural 

 development which was observed at all temperatures. Figure 16-3 shows an 

 example of the degree of developmeantal retardation which may occur among 

 larvae of the same chronological age as a result of a delay in the timing of 

 initial feeding. Among developing larvae, each developmental event appeared to 

 coincide with the attainment of a particular larval length or dry weight. As a 

 result, factors Uke temperature and nutritional state have a marked effect on 

 the degree of structural development larvae of a particular age may achieve. 



DISCUSSION 



Among the fish species that have been investigated in the past, there appear 

 to be several alternative patterns of survival following the delayed initial 

 feeding of larvae which have consumed most or all of their yolk reserves. The 

 northern anchovy, Engraulis mordax (Girard) (19) and the herring, Clupea 

 harengus (4), both may survive food deprivation to a point beyond which 

 continued survival is possible but ultimate recovery is not. The grunion, 

 Leuresthes tenuis (Ayres) (24), on the other hand, can recover from food 

 deprivation nearly up to the point of death through starvation. Observations 

 reported here using striped bass and those of May (24) using grunion, are very 

 similar. For neither species are the concepts of a "point-of-no-return" or of a 

 "critical period" at yolk absorption appropriate. In the striped bass, as in the 

 grunion, protracted food deprivation results in a suspension of further 

 structural development, and a gradual reduction in dry weight during starvation 

 as the costs of continued maintenance are met at the expense of body tissues. 



The experiments of May (24) was performed at one temperature. In this 

 study a range of temperatures was used. Temperature has been repeatedly 

 shown to have a controlling influence on the rate of growth of fish larvae 

 maintained on unlimited rations (e.g., 14, 16, 20). Similarly, temperature 

 affects the rate of weight loss during starvation (18). Data presented in Figure 



243 



