food was introduced. Fish exposed to the low level 

 had some success locating the food, and approx- 

 imately 50% of the pellets were consumed. Control 

 fish successfully consumed all of their ration 

 within 5 min. 



After 1 wk, feeding success on low- and 

 high-dose fish started improving gradually. At the 

 end of the study, the control and low-level fish fed 

 normally, while the high-level fish consumed 50% 

 of their ration. 



Analyses of variance of wet weight, dry weight, 

 kilocalories per gram ash-free dry weight, and 

 percent fat between concentrations, weeks, and 

 tanks yielded the following results (Tables 1, 2). 

 There was a significant decrease in wet weight 

 (P<0.05), dry weight (P<0.01), and percent fat 

 (P<0.01) with increasing concentration (Table 2). 

 Concentration levels varied significantly (P<0.05) 

 (Table 1): Wet weight was less at 6.0jLii/liter than 

 controls and did not vary significantly between 3.5 

 jul/liter and controls or between 3.5 and 6.0 n\/\\ter. 

 Dry weight was less at 6.0 jul/liter than at 3.5 

 /xl/liter and controls but did not vary significantly 

 between controls and 3.5 jul/liter. Percent fat was 

 less at 6.0 and 3.5 /xl/liter than in controls. There 

 was no significant difference in percent fat 

 between 6.0 and 3.5 fxl/liter. 



There was a significant increase in dry weight 

 (P<0.05) during the last week at all exposures 

 (Table 2, Figure 1). There was no significant 

 difference between treatments in kilocalories per 

 gram ash-free dry weight (Table 2). The sig- 

 nificant interaction between concentration and 

 tank (P<0.05-Table 2) is a result of experimental 

 design in which certain tanks were always at a 



Table l.-Mean wet wet and dry weights and fat caloric content 

 of one control and two test groups of striped bass, Morone 

 sajcatilis, exposed to benzene for 4 wk. 



Treatment 



mean 



concentration 



Oi I/liter) 



Variable^ 



Wet 

 weight 



(g) 



Dry 

 weight 



(g) 



Fat 

 (%) 



Ash-free 



dry weight 



(kcal/g) 



Control 



Low level (3.5) 



High level (6.0) 



Total number 

 of fish 



12.7135 

 12.6062 

 2.3951 



315 



10.8721 

 10.8137 

 0.7242 



315 



45 



45 



'The three treatments used three replicate tanks per treatment 

 sampled at 0, 1, 2, 3, and 4 wk. Tests for wet and dry weights had 

 seven fish/tank per week; tests for percent fat had four fish/tank 

 per week; and tests for kilocalories/gram ash-free dry weight had 

 three fish/tank per week. 



^Duncan's new multiple-range test of differences between 

 means of treatment levels was performed. Means grouped above 

 with same bar are not significantly different at the 5% level. 

 Means not grouped with same bar are significantly different at 

 the 5% level (Duncan 1955; Pachares 1959). 



high or low concentration. No significant variation 

 occurred between tanks. 



Discussion 



Although acclimated, fish in all treatments were 

 stressed from crowding and insufficient water 

 movement. This was unavoidable because space 

 and equipment were limited. Consequently, the 

 control fish did not grow at the same rate as 

 similar fish held in larger tanks at this facility. In 

 spite of these limitations, significant relative 

 changes in growth rate and fat content did occur 

 between exposure treatments. Wet weight, dry 

 weight, and fat content decreased with increasing 

 concentration as expected. This was probably due 



Table 2.-Analysis of variance of treatment effects of benzene 

 concentration (>il/liter), week, and tank number on wet weight 

 (g), dr>- weight (g), kilocalories per gram ash-free dry weight, 

 and percent fat of juvenile striped bass, Morone saxatilis. 



Dependent variable and 

 source of variation 



df 



Sum of 

 squares 



Mean 

 square 



F 

 ratio 



Proba- 

 bility 



Wet weight: 

 Concentration 

 Week 

 Tank 



Concentration-week 

 Concentration-tank 

 Week-tank 

 Concentration-week- 

 tank 

 Within (error) 



Total 



Dry weight: 

 Concentration 

 Week 

 Tank 



Concentration-week 

 Concentration-tank 

 Week-tank 

 Concentration-week- 

 tank 

 Within (error) 



Total 



Kilocalories per gram 

 ash-free dry weight: 



Concentration 



Week 



Tank 



Concentration-week 



Concentration-tank 



Week-tank 



Residual (error) 



Total 



Percent fat: 

 Concentration 

 Week 

 Tank 



Concentration-week 

 Concentration-tank 

 Week-tank 

 Residual (error) 

 Total 



2 

 4 

 2 



8 

 4 

 8 



16 

 270 



5.511 



7.750 



3.050 



11.673 



11.255 



11.673 



15.516 

 235.675 



2.756 

 1.938 

 1.525 

 0.909 

 2.814 

 1.459 



0.970 

 0.873 



3.16 

 2.20 

 1.75 

 1.04 

 3.22 

 1.67 



P< 0.05 



NS 



NS 



NS 



P< 0.05 



NS 



1.11 NS 



314 302.103 — — — 



2 



4 

 2 

 8 

 4 

 8 



16 

 270 



314 



2 

 4 

 2 



8 

 4 

 8 



16 



44 



1.165 

 1.232 

 0.420 

 0.933 

 1.214 

 1.367 



2.166 

 29.137 



37.634 



0.076 

 0.404 

 0.284 

 1.177 

 0.147 

 0.667 

 1.222 



3.977 



0.583 

 0.308 

 0.210 

 0.117 

 0.304 

 0.171 



0.135 

 0.108 



0.038 

 0.101 

 0.142 

 0.147 

 0.037 

 0.083 

 0.076 



5.40 

 2.85 

 1.94 

 1.08 

 2.81 

 1.58 



P< 0.01 



P< 0.05 



NS 



NS 



P< 0.05 



NS 



1.25 NS 



0.50 

 1.33 

 1.87 

 1.93 

 0.49 

 1.09 



NS 

 NS 

 NS 

 NS 

 NS 

 NS 



2 383.902 191.951 13.42 P< 0.01 



4 

 2 

 8 

 4 

 8 

 16 



99.539 



52,878 



138.843 



55.000 



190.733 



228.929 



24.885 

 26.439 

 17.355 

 13.750 

 23.842 

 14.308 



1.74 

 1.85 

 1.21 

 0.96 

 1.67 



NS 

 NS 

 NS 

 NS 

 NS 



44 1,149.824 — 



NS = not significant. 



696 



