T. Koike et al., EFFECTS OF UNDERWATER BRIGHTNESS ON JAPAN ESE SPINY LOBSTER BEHAVIOR DURING NIGHTTIME SCOTOPHASE, Nippon Suisan Gakkaishi, 59(10), 1993, pp. 1689-1694
Using an automatic sensing instrument developed for observing the beha
viour of crawling creatures, the authors investigated the influence of
different underwater light intensities on the behaviour of Japanese s
piny lobster, Panulirus japonicus, under light and dark alternating cy
cles of 24 hours. When the downward irradiance during light period was
3.3 x 10(2) lx and that during the dark period was more than 5.2 x 10
(-3) lx, the spiny lobster's behaviour during the dark period were lar
gely disturbed: locomotor frequency was less than 1/4 in comparison wi
th that under 0 lx conditions in the dark period. Such a response was
continuously maintained during the experimental period of 31 days. The
locomotor frequency did not decrease at all when the downward irradia
nce during the dark period was less than 2.3 x 10(-5) lx. On the other
hand, there was hardly any difference in locomotor frequency during t
he dark period when the downward irradiance during the light period wa
s of 3.5 x 10(-2) lx and 3.3 x 10(2) lx. In consequence, it was unders
tood that Japanese spiny lobster locomotive behavior was considerably
suppressed whenever underwater brightness increased even slightly duri
ng the nighttime.