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Fishery Bulletin 96(3), 1998 
Figure 2 
Laboratory setup (bottom) used to determine electrotaxis in early benthic-phase American 
lobsters Homarus americanus and capture efficiency of five electrode configurations (top). 
flicking in N. norvegicus was not involuntary, but 
rather the animal’s natural escape reaction induced 
by the electric stimulation. We have found only two 
reports of electrotaxis in crustaceans in which tail 
flicking and movement toward the anode were ob- 
served: one for the penaeid shrimp Penaeus 
duorarum (Higman, 1956) and the other for the rock 
lobster, Panulirus cygnus (Phillips and Scolaro, 
1980). 
It was apparent from these observations that the 
strong electrotactic response of EBP lobsters could 
be used to develop a quadrant-like field-sampling 
device. Table 1 gives the results of experiments with 
five different electrode configurations and EBP ani- 
mals sheltered under cobble on sand substrate. These 
tests confirmed the unidirectional nature of the elec- 
trotaxis. Of the 81 (59%, n = 137) animals that 
emerged from the cobble shelters, all moved directly 
to the anode. There was a significant difference be- 
tween electrode configurations in the mean number 
of animals caught (ANOVA, P<0.001). The best cap- 
ture rate (2.6 animals per trial, or 85% of the total 
population) was obtained with a semicircular cath- 
ode, straight anode and horizontal configuration (con- 
figuration 3 in Fig. 2), and the worst capture rate 
(0.8 animals, 25% of the population) was obtained 
with the circular cathode, plate anode, and vertical 
configuration (configuration 4 in Fig. 2). There was 
a significant difference between electrode configura- 
tions in mean capture time for the first animal 
(ANOVA, P=0.008, LSD post-hoc test) but no signifi- 
cant differences in capture times for the other two 
animals in each trial. Animals tended not to emerge 
at the same time but in sequence, with the first, sec- 
ond, and third animals emerging after an overall 
average of 26.3, 51.6, and 64.5 seconds. In all trials 
combined, one animal was caught in 91%, two in 60%, 
and all three in 23% of the trials. The lower and 
slower capture rate of the second and third animals 
in each test is probably related to the position of the 
animals in the rock pile. The EBP lobsters placed in 
close proximity exhibit intense aggressive behavior 
(Lawton and Lavalli 1995), which would tend to re- 
sult in an overdispersed distribution within a 
bounded habitat like the test rock pile. In this situa- 
tion some animals will be closer to the anode, and 
