seen at 48 hours post-exposure; only 35 percent of nauplii exposed to 185 ppb 
Cu had molted to Stage III, as opposed to nearly 70 percent at lower copper 
levels. (Figure 18-5.) Analysis of variance for naupliar MLV indicated a 
significant (p=0.01) difference between control (2 ppb), intermediate (18-186 
ppb), and highest (350 ppb) copper levels. Swimming speeds significantly 
increased at sublethal copper levels but rapidly declined at or near the lethal 
level (Figure 18-6.) The shift in distribution of linear velocities for test groups 
at these three exposure levels is clearly illustrated by frequency histograms 
(Figure 18-4). 
In the third experiment, B. improvisus nauplii (from South Carolina) were 
exposed to Cu levels ranging from control (3 ppb) to 190 ppb for 24 hours at 
25°C. Following video taping at 24 hours, nauplii were transferred to filtered 
seawater with algal diet and reared at 25°C. At 24 hours post-exposure 
mortality at 190 ppb was 100 percent; at 150 ppb, 20 percent. Rearing to 
cyprid stage indicated no significant mortality differences between controls 
and nauplii exposed up to 98 ppb Cu. However, development time appeared 
delayed by Cu exposure as low as 50 ppb (Table 18-4). 
Figure 18-5. Mortality 24 Hours Post Exposure and Percent 
Larvae Molting to Stage III, 48 Hours Post Exposure, for 
Balanus amphitrite Stage II Nauplii Exposed to Various Copper 
Concentrations for 24 Hours at 20°C. 
281 
