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Abstract

Octopuses function as important prey and predators in many continental-shelf marine ecosystems. Understanding activity cycles
of octopuses should help define their mode of foraging and potential resource utilization and, therefore, their niche within the marine
community. Unfortunately, little is known concerning activity cycles of octopuses, especially during their juvenile life-history stages. Here,
I present observations on juvenile activity in Octopus bimaculoides Pickford and McConnaughey, 1949 over three observational weeks in
a semi-natural laboratory setting. Octopuses on average were nocturnal, but some individuals were active during daylight hours in all three
observational weeks. Nocturnal activity cycles may decrease the risk of predation on juveniles by visual fish predators hunting during
daylight hours. However, inter- and intraspecific competition with other octopuses in different life history stages, including adult O.
bimaculoides and adult and juvenile Octopus bimaculatus Verrill, 1883 is also likely during nighttime hours. Further studies are needed on
the relative influence of predation and competition on octopus activity cycles and the resulting consequences for octopus populations.

Item Type:	Article
Authors/Creators:	Sinn, DL
Keywords:	cephalopod, octopus activity, juvenile ecology, niche partitioning
Journal or Publication Title:	American Malacological Bulletin
Additional Information:	Copyright © 2008 American Malacological Union, Inc
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