Table 18-1. Mean Linear Velocities (MLV) of Stage II 
Barnacle Nauplii Exposed to Different Temperatures 
for 24 Hours. 
Species 
Temp. 
(°C) 
N 
MDP 
(Sec) 
MLV ± sd 
(mm/sec) 
T test 
BA 
28 
12 
8.5 
0.81 ± 0.23 
NS 
BA 
20 
24 
9.0 
0.71 ±0.34 
BA 
15 
22 
7.1 
0.58 ± 0.20 
P=.20 
BIS 
25 
26 
7.4 
1.18 ± 0.56 
NS 
BIS 
20 
26 
6.0 
1.09 ± 0.43 
BIS 
15 
25 
8.0 
0.72 ±0.43 
P=.05 
BIN 
26 
13 
7.3 
1.56 ±0.62 
P=. 10 
BIN 
22 
17 
9.4 
2.43 ± 0.64 
BIN 
10 
14 
8.0 
1.25 ± 0.64 
P=.05 
CF 
25 
26 
7.2 
1.46 ±0.48 
P=.05 
CF 
20 
40 
6.4 
1.92 ±0.67 
CF 
15 
40 
6.0 
1.89 ±0.62 
NS 
nauplii from Rhode Island adults exhibited a decreased velocity above 22°C. A 
comparable reduction in velocity with Rhode Island nauplii also occurred with 
Chthamalus fragilis above 20°C. Yet overall, naupliar swimming speeds appear 
to be greater in the Rhode Island animals when measured within this 
temperature range. 
Brood Variability 
Linear swimming velocity in nauplii obtained from different broods of 
South Carolina adults was assessed under similar temperature, salinity, and 
light regimes to evaluate brood variability. Linear velocities were found to be 
similar among six broods (Table 18-2). Examples of MLV distributions within 
test groups of B. amphitrite , C. fragilis , and B. improvisus are shown in Figure 
18-4. Control groups usually have linear velocity distributions which 
approximate normal or are skewed to the left. 
278 
