710 



Fishery Bulletin 89(4), 1991 







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Figure 3 



Condition of the hepatic tissue of larval northern anchovy after 0, 1,4, and 6 days of starvation (white bar = 0.01 mm). (Upper left) 

 fed larvae. White vacuolated areas may be glycogen deposits. (Upper right) 1 day of starvation. No vacuolated areas and no cellular 

 deterioration. (Lower left) 4 days of starvation. Damaged membranes and dark nuclei. (Lower right) 6 days starvation. Hepatocytes 

 atrophied, nuclei shrunken and pycnotic. 



Hepatocytes of larvae starved for 6-7 days had 

 atrophied, making the nuclei appear to be more densely 

 distributed. Nuclei were pycnotic and irregular in 

 shape. Such larvae were about 55% less responsive to 

 predators than fed larvae. 



Discussion 



Starvation may affect responsiveness of larger anchovy 

 larvae in a fashion similar to the one here described 

 for 9 mm larvae. Preliminary measurements by Folk- 

 vord (1985) indicated that newly metamorphosed juve- 

 nile anchovy (35 mm SL) were less likely to respond if 

 deprived of food. When deprived of food for 5 days, 

 only 50% of the fish responded to predatory attack 

 whereas 100% of fed fish did so. Hakanson (1989) 

 analyzed the lipid contents of fed and starved anchovy 



larvae of similar age and reared at similar tempera- 

 tures as in this study. He found a decrease in the con- 

 tent of triacylglycerol, an energy storage component, 

 after 3 days of starvation. On the other hand, we found 

 that the glycogen reserve in the liver was nearly 

 depleted after one day of starvation. Lipid reserves 

 greatly increase after metamorphosis (J.R. Hunter, un- 

 publ. data) and consequently such a decrement in 

 avoidance behavior with a few days of food depriva- 

 tion may be limited to the larval and early juvenile 

 period. Yin and Blaxter (1987) also determined a 

 decrease in the response rates of unfed yolksac her- 

 ring, cod and flounder larvae to tactile stimuli, espe- 

 cially after the point of no return (PNR). These authors 

 determined a similar effect in the response rate of older 

 Clyde herring larvae (36 days, 14 mm) to contact with 

 a pipette after the PNR (6 days of starvation at 9-10 

 °C). A starvation-induced decrease in vulnerability to 



