226 



Fishery Bulletin 93(2). 1995 



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Figure 7 



Anterior and posterior intestinal mucosal cell height in summer flounder, 

 Paralichthys dentatus, during ad libitum feeding ( ) or starvation ( • ). (A-B) 6-day- 

 old larvae; (C-D) 16-day-old larvae; (E-F) 33-day-old larvae; (G-H) 60-day-old ju- 

 veniles. Symbols represent the arithmetic mean of samples of 9-10 animals ±Stan- 

 dard Error. Asterisks indicate a statistically significant difference between fed and 

 starved fish groups at a particular sampling time. 



tain for populations in nature (O'Connell, 1976; 

 Theilacker, 1986; Fraser et al., 1987; Setzler- 

 Hamilton et al., 1987). Confinement in experimen- 

 tal tanks influences growth rates and morphometries 

 of laboratory-reared larvae (Blaxter, 1975; Arthur, 

 1976). At present, the applicability of morphometric 

 indices seems more reliable and feasible for reared 

 larvae, where age and historic information are known 

 and feeding can be controlled. 



Given the inherent problems of laboratory-to-field 

 calibration and the dynamic changes in body propor- 



tions due to allometric growth and progressive ossi- 

 fication of developing larvae, Theilacker (1978) con- 

 cluded that no single morphological feature can be 

 singled out as a consistent indicator of larval condi- 

 tion. Because some of the variability associated with 

 field-collected larvae is accounted for by differences 

 in age of larvae, interpretation of the data requires 

 the ability to determine age. Ageing of summer floun- 

 der from daily growth ring deposition is difficult on 

 field-collected larvae of mixed age (Dery, 1988, 

 Szedlmayer and Able, 1992). Therefore, the use of 



