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THE MAINE EVENT: FALL 2003 Predation by Gelatinous Zooplankton in the Gulf of Maine MISSION DISPATCH 9 • Saturday, September 20, 2003 Location: Georges Basin (42° 19'N, 67° 30'W) Dispatch by Harry Breidahl - Marine Education Society of Australasia [MESA] At 7.15 am (that's 0715 hours, if we use the ship's 24 hour clock) the R/V Seward Johnson pulled away from the dock at Gloucester, Massachusetts and headed out to sea once again. Both near the shore and well out to sea we were shrouded 
in marine fog produced by the warm, moist winds from Hurricane Isabel meeting the cool waters of the Gulf of Maine.
Thankfully the seas were not as unsettled as expected but they were lumpy enough to bring back that familiar zig-zag stagger
we all acquire as we make our way about the rolling vessel.
Captain Ralph van Hoek began sounding the fog horn as we departed the dock at Gloucester. Despite passing through a couple of partially sunny patches, the fog horn was still moaning at 8.15 pm (2015 hours ship time) when we arrived at Georges Basin. By this time the marine fog had really set in. After three days on shore the whole science party was inching to get JOHNSON SEA-LINK II (JSL II) back into the water but the fog put an end to that possibility. With visibility close to zero it was unsafe to launch, or more importantly recover, the submersible. This news came as a blow to the scientists but there was an alternative. In our case, we opted to deploy another vehicle that was sitting on the aft deck, unused to date. This technology is a rather ungainly but colorful concoction of pipes, cables, electric motors, lights and cameras called an ROV (ROV = Remotely Operated Vehicle). An ROV is an unmanned, deep-sea exploration platform that is lowered into the sea via a cable and controlled by an operator who remains on board. For tonight the ROV's cameras would replace human eyes. The ROV controller was Alan Fuller, one of the sub crew, and he 'piloted' the ROV from inside a small shipping container on the 01 deck of R/V SEWARD JOHNSON. 
The sub crew were able to set-up the ROV quickly and by 9 pm (2100 hours ship time) it was on its way down to 700 feet
(just over 200 meters). Once the ROV had been launched, we were all keen to follow its progress but the small control room
was crammed with electronic gear, TV monitors and the like. It was so cramped that we had to take turns to step into and out
of the container to watch the ROV's monitors that showed the distribution and abundance of undersea creatures.
Part of this exercise was a trial to see how effective this particular ROV would be as a research tool. Other oceanographic research institutions use ROV's extensively but in our case it was quickly revealed that the ROV was far more limited than human observers in a submersible, such as JSL II. The TV images transmitted by the ROV only covered a small field of view but did return some interesting results, especially as the ROV returned to the surface. In the last 130 feet (40 meters) over 20 colonies of Nanomia cara were seen as sinuous, ghostly images on the main TV monitor. They were surprisingly close to the surface, with one Nanomia cara seen just at 10 meters (32 feet). Once the ROV had completed its mission and was secured on deck, a MOCNESS net tow was launched into the foggy mist. Another tow will be conducted tomorrow morning, followed by a CTD cast. We're hoping that warm sunshine will clear the air and allow a sub dive at 1.00 pm (1300 hours ship time) and then again at 8.30 pm (2030 hours). Today's Feature Creature - Beroe cucumis - by Brian Ortman )
Thus far for The Maine Event 2003 cruise my favorite animal is the ctenophore Beroe cucumis. Ctenophore is the scientific name
for a group of gelatinous creatures commonly known as comb jellies. While most ctenophores eat zooplankton, Beroe preys
exclusively on other jellies, in this case Bolinopsis infundibulum. We have captured Beroe ranging in size from less than
an inch (2.5 cm) to a foot (30 cm) in length. They are football-shaped and are essentially nothing more than a large mouth
that opens into a giant stomach. These predatory jellies can stretch to ingest organisms larger than themselves. Beroe are
perfectly adapted eating machines and are truly the "Jaws" of the midwater jelly world.
Fun fact for the day ° ROV stands for Remotely Operated Vehicle so have a go at working out what the acronyms AUV and HOV designate.   |  |
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