220 



Fishery Bulletin 93(2). 1995 



12 24 36 48 60 



Time (h) 



Figure 1 



Summer flounder, Paralichthys dentatus, 6-day-old larvae. Morphometric, gravi- 

 metric, and biochemical changes during ad libitum feeding ( ) or starvation (• ). 

 (A) standard length; (B) dry weight; (C) eye diameter/head height ratio; (D) pec- 

 toral angle; (E) RNA:DNA ratio; (F) total proteins. Symbols represent the arith- 

 metic mean of samples of 9-10 animals ±Standard Error. Asterisks indicate a 

 statistically significant difference between fed and starved groups at a particu- 

 lar sampling time. 



creased their dry weight by more than 206% of the 

 initial value, whereas the starved group remained 

 unchanged. This weight difference was significant 

 at 72 hours (* 18 =4.46, P<0.001), 120 hours « 18 =5.54, 

 P<0.001), and 192 hours (* 18 =4.06, P<0.001). The 

 eye:head ratio of both groups differed at 192 hours 

 (* 18 =4.28, P<0.001; Fig. 3C). At 72 hours (* 18 =5.38, 

 P<0.001), 120 hours (* 18 =7.89, P<0.001), and 192 

 hours U 18 =6.85, P<0.001) the starved group had a 

 lower mean pectoral angle than did the fed group 

 (Fig. 3D). The RNA:DNA ratio showed an initial rise 

 from 2.88 to 3.41 and to 3.26 in fed and starved larvae, 

 respectively (Fig. 3E). After 24 hours, both groups 

 showed a decline, but starved larvae declined to a much 

 greater extent, resulting in significant differences be- 

 tween the two groups at 120 hours (< 18 =4.85, P<0.001 ) 

 and 192 hours « 18 =5.18, P<0.001). By day 8, starved 

 larvae had ratios 62.4% lower than those of fed larvae. 

 Mean total protein of starving larvae was also signifi- 



cantly lower than that in fed fish, a difference detect- 

 able after 192 hours tt 18 =4.19,P<0.001; Fig. 3F). 



Samples of 60-day-old metamorphosed juveniles 

 were taken at 72, 144, and 216 hours (Fig. 4). Mor- 

 tality in the starved group began after 10 days. While 

 the mean standard length of both groups was differ- 

 ent at 216 hours (* 18 =4.01, P<0.001; Fig. 4A), mean 

 dry weights of the starved and fed groups were sig- 

 nificantly different from each other at each sampling 

 time (* 18 =2.95, P=0.009, at 72 h; Fig. 4B). In 9 days, 

 fed juveniles grew in length at a daily specific rate of 

 3.1%/day, whereas starved larvae grew at 0.7%/day. 

 During the same time, fed fish gained weight at a 

 rate of 10.1%/day, whereas starved fish lost 1.9% of 

 their body mass every day. The eye diameter to head 

 height ratio in both groups varied in a similar man- 

 ner (Fig. 4C). A significant difference in the shape of 

 the pectoral angle was only detected at 216 hours 

 U 18 =3.15, P=0.006; Fig. 4D). Mean RNA:DNA ratios 



