LAURKNVK BIOENERGETIC MOIiEI. KOR WINTKR FLOUNDER LARVAE 



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0.0 100.0 200.0 300.0 400.0 SOO.O 600. 700.0 800.0 900.0 1000.0 1100.0 

 DRY HEIGHT <UG> 



FIGURE 7. — Critical, minimum prey densities, below which feed- 

 ing longer than the available photoperiod would permit to obtain 

 energy for calculated growth and metabolic processes, over the 

 weights range from hatching to metamorphosis for winter 

 flounder at 8°C. 



0.0 100.0 200.0 300.0 100.0 500.0 600.0 700.0 800.0 300.0 1000.0 1100.0 

 DRY UEIGHT <PG> 



FIGURE 9. — Nonassimilated energy of winter flounder larvae 

 at 8°C over the range of dry body weight from hatching to 

 metamorphosis and at different planktonic prey concentrations. 

 Numbers for each simulation indicate prey concentration in 

 calories per liter; 6.7-21.7 cal/liter simulations are in ascending 

 order from top to bottom. 



Physiological Energy Utilization 



Predicted daily metabolic energy utilized by 

 winter flounder larvae from hatching to metamor- 

 phosis (Q_, Equation (5)) showed a decrease 

 shortly following hatching which later increased 

 until initiation of metamorphosis when there was 

 a leveling off (Figure 8). Energy expended was 

 substantially higher at the lower prey concentra- 



0.0 100.0 300.0 SOO.O 400.0 900.0 SOO.O 700.0 000.0 900.0 1000.0 1100.0 

 DRY UEIGHT IUG> 



FIGURE 8. — Metabolic energy utilized by winter flounder larvae 

 at 8°C over the range of dry body weight from hatching to meta- 

 morphosis and at different plankton concentrations. Numbers 

 for each simulated line indicate prey concentration in calories 

 per liter. 



tions with the differences minimized with increas- 

 ing concentration. Predicted daily unassimilated 

 energy, or energy not utilized in physiological 

 processes and lost to the larval system, followed 

 a similar trend to metabolic energy (Figure 9). In 

 general, the ratio of nonassimilated to metabolic 

 energy overall factor combinations was approx- 

 imately 1:2. 



Required Food Ration and 

 Growth Efficiency 



Predicted daily caloric food requirements (Fig- 

 ure 10, Equation (7)) after an initial decrease 

 following first feeding (10-30 fig dry weight) in- 

 creased until the beginning of metamorphosis 

 (500 fig), after which the rate of increase slowed 

 until complete metamorphosis (1,000 fig). Food 

 requirements were greater at lower prey concen- 

 trations with decreasing differences at higher 

 concentrations. Conversion of caloric values of 

 daily food requirements by division by mean ca- 

 loric values of the copepod life stages per unit 

 weight showed the numbers of nauplii or older 

 stages necessary for consumption (Figure 11). 

 Actual feeding experiments demonstrated that 

 larvae do not prey entirely on one particular 

 copepod life stage. The stages they consume are 

 more a function of larval and copepod size. 

 Smaller larvae initiate feeding on nauplii and 

 gradually eat increasingly greater percentages of 



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