Quote:Observations of wild hunting behaviour and bioluminescence of a large deep-sea, eight-armed squid, Taningia danae



Tsunemi Kubodera, Yasuhiro Koyama and Kyoichi Mori



ABSTRACT

Our newly developed underwater high definition video camera system took the first live images of adults

of the mesopelagic large squid, Taningia danae, between 240 and 940 m deep off Ogasawara Islands,

western North Pacific. The resulting footage includes attacking and bioluminescence behaviours, and

reveals that T. danae is far from the sluggish neutrally buoyant deep-sea squid previously suspected. It can

actively swim both forward and backward freely by flapping its large muscular triangular fins and changes

direction quickly through bending its flexible body. It can attain speeds of 2–2.5 m sK1 (7.2–9 km hK1)

when attacking bait rigs. They emitted short bright light flashes from their large arm-tip photophores

before final assault, which might act as a blinding flash for prey as well as a means of measuring target

distance in a dark deep-sea environment. They also emitted long and short glows separated by intervals

while wandering around the double torch lights attached to the bait rig, suggestive of potential courtship

behaviours during mating.