Feature ArticleThe Kraken Revealed
By Dr. Edith Widder
The holy grail—the first video recording of a live giant squid in the wild, filmed by Medusa.
The first video recordings of a live giant squid Architeuthis dux filmed in its natural habitat were collected in July 2012 during an expedition off the coast of the Ogasawara Islands, 600 miles south of Tokyo, Japan. Although there have been other attempts to accomplish this feat, including two multinational efforts off New Zealand's coast in 1997 and 1999, all previous endeavors have failed.
The 2012 expedition was initiated based on the success of Dr. Tsunemi Kubodera, who captured the first still images of a giant squid off Ogasawara in 2004. For those images, he used a baited fishing line outfitted with a camera that was programmed to take a picture every 30 seconds. After three years of attempts, he succeeded. Kubodera captured a series of still images of a giant squid attacking bait on a line at 900 meters. The enormous public interest that followed encouraged the Japan Broadcasting Corp. (NHK) based in Tokyo, Japan, to finance the most ambitious attempt to accomplish the Holy Grail of natural history filmmaking—filming the giant squid in its natural habitat. The Discovery Channel partnered with NHK and helped finance the eight-week expedition.
The ship used for the expedition was the privately owned luxury yacht Alucia. The boat was leased from its owner, Ray Dalio, founder of the Bridgewater hedge fund. Three camera platforms were deployed from the ship for filming, including two manned submersibles and an unmanned lander. The two submersibles were a Hawkes Ocean Technologies (San Francisco, California) two-person Deep Rover and a three-person Triton Submarines LLC (Vero Beach, Florida) submersible 3300/3, both capable of diving to 1,000 meters. The third platform was an unmanned camera platform called the Medusa, which was developed by the Ocean Research & Conservation Association (ORCA), based in Fort Pierce, Florida, in collaboration with Dr. Justin Marshall, Lee Frey and Andrew Sherrell, with funding from the Australian Research Council, as a low-cost way to deploy the ORCA Eye-in-the-Sea, an unobtrusive deep-sea observatory.
Cameras and Illuminators
An emphasis on using stealth and lures, both optical and chemical, set the expedition apart from previous giant-squid hunts. Infrared light used with infrared-sensitive cameras—the standard means of observing photophobic animals on land—is encumbered by the poor penetration of long-wavelength light in seawater, which hinders unobtrusive observation of biological activity in the ocean.
Standard cameras restrict viewing distances to less than one attenuation length (1.5 meters for 700 nanometers light). The much larger viewing volume needed to observe large animals in their natural state was achieved by combining low-light-level (LLL) cameras with far-red illumination. The submersibles were outfitted with ultrasensitive, high-resolution color electron multiplying charge coupled device (EMCCD) cameras specially designed by NHK for this underwater application. The Medusa used an off-the-shelf, low-light, high-resolution, black-and-white, closed-circuit television camera (Super Circuits PC164C-EX2) with 600 lines of resolution at 10-4 lux.
Illuminators were epoxy-encapsulated LED arrays. Each array was populated with 690-nanometer LEDs (Epitx L690) that emit 4 milliwatts. These LEDs were selected for their narrow bandwidth (full width at half max 25 nanometers) that limited the short-wavelength light that might be detectable by the squid. Most deep-sea inhabitants have only one visual pigment with a sensitivity maximum that is centered in the blue between 470 and 490 nanometers, which might suggest that red-light illuminators would be invisible to them.
However, visual pigments have a broad spectral sensitivity range extending more than 100 nanometers at half maximum and an impressive dynamic range covering several orders of magnitude. The range can lead to considerable overlap between the long-wavelength tail of the visual pigment sensitivity curve and the short-wavelength tail of the LED emission curve. Although this overlap is not apparent when curves are plotted on a linear scale, the same data plotted on a logarithmic scale reveals that 'invisible illumination' may be visible. The full extent of the visibility depends on the absolute sensitivity of the visual system in question.
The optical lure that was built by ORCA for this expedition was dubbed the electronic jellyfish, or e-jelly, because it was designed to imitate the bioluminescent display of the common deep-sea jellyfish Atolla wyvillei. This display, known as a burglar alarm, consists of a propagated wave of light that pinwheels around the surface of the bell and is believed to function as a last ditch 'scream' for help when the jellyfish is caught in the clutches of a predator. This bright, showy display has evolved to attract the attention of a larger predator that may attack the jellyfish predator, thereby affording an opportunity for escape.
In prior expeditions, the e-jelly, comprising 16 blue (470-nanometer) LEDs mounted in a circle and epoxy encapsulated, was deployed with the Eye-in-the-Sea observatory, a benthic camera system deployed by submersible or ROV. In that configuration, the e-jelly was cabled to the Eye-in-the-Sea and drew power from that system's batteries.
For the giant-squid hunt, the e-jelly was redesigned to be self-powered so that it could be used as a standalone unit with either the Medusa or the Triton submersible. Three e-jellies were built and housed in Teledyne Benthos (North Falmouth, Massachusetts) spheres and powered by D cells with magnet-controlled power switches. In order to optimize visibility for these midwater deployments, two e-jelly boards were mounted back to back, with the D cells sandwiched in between. To continue this article please click here.
Dr. Edith Widder is a deep-sea biologist, a specialist in bioluminescence and technology development, and CEO, senior scientist and co-founder of the Ocean Research & Conservation Association, an organization dedicated to the study and protection of aquatic ecosystems and the species they sustain through development of innovative technologies and science-based conservation action.
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