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THE MAINE EVENT: FALL 2003 Predation by Gelatinous Zooplankton in the Gulf of Maine MISSION DISPATCH 14 • Thursday, September 25, 2003 Location: Oceanographer Canyon (40° 13' N, 68° 12' W) Dispatch by Harry Breidahl - Marine Education Society of Australasia [MESA] Working at sea has its rewards and last night was one of those times that really etch themselves in one's memory. Firstly, there was the brilliant sunset, a riot of incredible orange and pink hues for which I have no words and that photography simply won't do justice to. Following the brief time taken to enjoy this evening spectacle, we returned to the business of marine science and what would turn out to be an unforgettable sub dive. It was JOHNSON SEA-LINK II (JSL) dive 3454 with Marsh Youngbluth alongside sub pilot Tim Askew Jr. in the front chamber. Occupying the aft chamber were HBOI video specialist, Brian Cousin, and sub tech Jim Pierce. Using a submersible to explore oceanic midwaters can never be described as dull or routine. There is always an air of expectation that something really spectacular exists in the darkness. That's why most of us on board are on the aft deck to welcome the return of the JSL. We are eager to learn what kinds of animals were seen and collected. 
And spectacular is what we got from dive 3454. Approaching the sea floor of Oceanographer Canyon, at close to 900 meters (3000 feet), Marsh and Tim were greeted by a slow-moving 4.5 meter (15 foot) deep-sea shark (a Greenland shark - Somniosus microcephalus - much deeper than and very far south of it's normal range). Marsh recorded this amazing encounter on video and at around 12.30 am (0030 hours) the dry lab was packed with scientists, sub techs and ships crew for the premier showing of "JSL II meets Jaws" (albeit a relatively gentle kind of Jaws). 
The tape was shown over and over again as we witnessed the large shark suddenly, but gracefully, appear from the epibenthic darkness
surrounding the submersible. The mottled gray giant swam purposefully into the sub's lights and gently crashed into the acrylic sphere
just in front of Tim's face. The audio commentary on this section of the tape will probably not get a 'for general viewing' rating but,
thankfully, neither the shark nor the sub were damaged. Once the behemoth realized this large, yellow-trimmed thing (the sub) wasn't edible,
she turned and slowly swam away with JSL II trailing close behind. After a short pursuit, it was back to the collection of siphonophores
and other deep-sea creatures small enough to fit inside the sub's sample buckets.
In addition to the collection of Nanomia cara, one of the detritus sample buckets contained a second specimen (about 30 cm in length) of the cirrate octopus Stauroteuthis syrtensis. A cousin of this red/orange octopus had been collected near the same depth (725 m) in Oceanographer Canyon earlier in this research cruise. At that time our attempts to photograph the octopus were not successful. On this go around we had the plankton kreisel set up in the main temperature-controlled lab, ready for just such a find. The chilling 60 C aboard )
ship matched the temperature where the animal lived. I watched in awe as this alien cephalopod swam and drifted around in the kreisel.
At times it jetted forward with a spiraling, cork-screw motion. The octopus could also flare the webbing between it's eight arms to take
on the appearance of a living parachute. In this pose the octopus provided a clear view of the small pseudo-suckers along its arms.
These organs have evolved to bioluminesce. Why this morphological change happened is unknown. Some people speculate that the eerie
blue-green glow emanating from the tentacles serves to attract prey. We confirmed that this pelagic octopus feeds on small (3 mm sized)
copepods (the diapause phase of
copepod Calanus finmarchicus),
and apparently sucks them past the beaks around its mouth. Three dozen individuals,
in perfect condition, were found in the stomach.
The oceanic midwaters that stretch from 200 meters (650 feet) to 1000 meters (almost 3300 feet) below the waves are vast and almost completely unexplored. How many more treasures, such as skulking sharks and wily octopus, remain to be discovered? Fun facts for the day • Sharks and bony fish are both regarded as fish. However sharks and rays have a skeleton made of cartilage rather than solid bone. Sharks and rays are therefore referred to as cartilaginous fishes. All other fishes, the kind that have bones, are called bony fish. • There are two major kinds of animals in the Animal Kingdom. Backboned animals (called vertebrates) and animals without backbones (called invertebrates). We already know that a calycophoran siphonophore, called Praya, can grow up to 40 meters (130 feet) in length. This size makes the siphonophore one of the longest invertebrates in the world. The most massive invertebrates are the little known giant squids that inhabit the deep-sea.  
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