Aspects of the natural history of pelagic cephalopods of the Hawaiian mesopelagic-boundary region.
Pacific Science 49(2): 143-155.
ABSTRACT: Pelagic cephalopods of the mesopelagic-boundary region in Hawai'i have proven difficult to sample but seem to occupy a variety of habitats within this zone. Abralia trigonura Berry inhabits the zone only as adults; A. astrosticta Berry may inhabit the inner boundary zone, and Pterygioteuthis giardi Fischer appears to be a facultative inhabitant. Three other mesopelagic species, Liocranchia reinhardti (Steenstrup), Chiroteuthis imperator Chun, and Iridoteuthis iris (Berry), are probable inhabitants; the latter two are suspected to be nonvertical migrants. The mesopelagic-boundary region also contains a variety of other pelagic cephalopods. Some are transients, common species of the mesopelagic zone in offshore waters such as Abraliopsis spp., neritic species such as Eupryma scolopes Berry, and oceanic epipelagic species such as Tremoctopus violaceus Chiaie and Argonauta argo Linnaeus. Others are apparently permanent but either epipelagic (Onychoteuthis sp. C) or demersal (Nototodarus hawaiiensis [Berry] and Haliphron atlanticus Steenstrup). Submersible observations show that Nototodarus hawaiiensis commonly "sits" on the bottom and Haliphron atlanticus broods its young in the manner of some pelagic octopods.
| Haliphron atlanticus. Female near bottom, swimming with
slow medusoid motion of arms and web. Note egg mass held near the mouth, wounds in dorsal
surface, and missing arms.|
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MPEG video (769 Kb)
| Nototodarus hawaiiensis. Resting on bottom, with dark
bands across head and body. Then, swimming by flapping fins and jetting.|
AVI video (1,364 Kb)
MPEG video (664 Kb)
| Tremoctopus sp. Cruising, with ventral four arms tucked
in toward the mouth. Then, it nearly hits the submersible, somersaults dorsally, and jets
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MPEG video (824 Kb)
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