Sea Technology

AUG 2013

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sea jellyfsh Atolla wyvillei. This display, or drifter mode. known as a burglar alarm, consists of a For the giant squid expedition, it was depropagated wave of light that pinwheels ployed as a drifter and attached to a foat at around the surface of the bell and is bethe surface with 730 meters of line. In this lieved to function as a last ditch "scream" confguration, the legs were removed and for help when the jellyfsh is caught in the two polyvinyl chloride fns were attached to clutches of a predator. This bright, showy the anodized aluminum frame. The package display has evolved to attract the attenwas released to drift unattended for at least tion of a larger predator that may attack 30 hours, which was the maximum recording Medusa with e-jelly. the jellyfsh predator, thereby affording an time with two 380 watt-hour, lithium-ion batopportunity for escape. tery pods powering the camera, digital video In prior expeditions, the e-jelly, comrecorder (Stack DVR2-130), LED illuminators prising 16 blue (470-nanometer) and CTD. LEDs mounted in a circle and A satellite tracking beacon epoxy encapsulated, was de[MetOcean (Dartmouth, Canada) ployed with the Eye-in-the-Sea CABO Iridium Beacon] and a observatory, a benthic camera VHF beacon and strobe (Novatsystem deployed by submersible ech RF-700C6) were attached to or ROV. In that confguration, the foat and used to locate the the e-jelly was cabled to the EyeMedusa, which was recovered in-the-Sea and drew power from using the ship's A-frame and capthat system's batteries. stan winch. For the giant-squid hunt, the e-jelly was redesigned to be Submersibles Triton with e-jelly. (Photo Credit: Kelvin Magee) self-powered so that it could be During June and July 2012, the used as a standalone unit with two submersibles made approxieither the Medusa or the Triton mately 100 dives totaling 500 submersible. Three e-jellies were built and housed in Telehours to an average depth of 630 meters. dyne Benthos (North Falmouth, Massachusetts) spheres and The submersibles were a three-person Triton and a twopowered by D cells with magnet-controlled power switchperson Deep Rover. They were also used as observation/ es. In order to optimize visibility for these midwater deploycamera platforms. Because the bathymetry of the dive site ments, two e-jelly boards were mounted back to back, with indicated bottom depths extending much deeper than the the D cells sandwiched in between. 1,000-meter depth limit of both submersibles, the subs were tethered as a safety precaution during operations. The Medusa polypropylene tether was managed on large, manually conThe Medusa was designed to be deployed without the trolled reels. For the Triton, the reels were deployed from use of a submersible or ROV. It is a compact (66 centimeters the 32-foot Northwind tender, and for the Deep Rover, they long, 66 centimeters wide, 86 centimeters tall), relatively were deployed from the 18-foot Zodiac rescue boat. light (about 300-pound) package that can be launched from The location of the dives was selected in part because a ship or even a small boat with a davit. It has an operational this is where Kubodera captured the frst still images of the depth of 2,000 meters and can be deployed either in lander giant squid and where a number of giant-squid tentacles 52 st / August 2013 www.sea-technology.com

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