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THE MAINE EVENT: FALL 2004 Predation by Gelatinous Zooplankton in the Gulf of Maine MISSION DISPATCH 2 • Wednesday, September 15, 2004 Location: Wilkinson Basin Dispatch by Celeste Mosher - Harbor Branch Oceanographic Institution 
Once underway from Gloucester to Oceanographer Canyon, Captain George Gunther gave a safety
briefing. We each tested our PFDs (personal floatation devices) and had a demonstration of how to
put on a survival suit.
We arrived on station at Oceanographer Canyon in the Southeastern Gulf of Maine at approximately 1130 at which time Keith Martin guided a CTD cast to collect seawater from below 300 meters. Since we are expecting to capture live creatures from the deep, it is important to fill aquaria with seawater of similar temperature and solute concentrations. The first submersible dive was scheduled for 1300, and all scientists helped prepare for the dive by attaching sampling devices to the sub, filling out dive log sheets, and organizing the various lab stations. Since their arrival, the sub crew has been busy testing the hydraulics, lights and other control mechanisms that make the JSL a versatile and efficient piece of engineering. Excitement was in the air as we were all ready to start what we came out here to do. We hope to learn more about ecological processes that regulate the abundance and diversity of mid-water zooplankton living in the deep-water canyons on the southern margin of Georges Bank and within the basins of the Gulf of Maine. 
The sub carries four persons on every dive, two scientists and two sub crew. Tim Askew, Jr., the
pilot on the first dive, was accompanied in the sphere by
Marsh as the lead scientist. Jimmy
Nelson and I folded ourselves into the aft "dive chamber" with plenty of warm clothes to ward off
the chill that is inevitable. The sea water temperature around us will dip to 4 C at 3,000 ft.
What a fantastic opportunity for me as this was my first submersible dive! We collected and preserved many physonect siphonophores in situ with the rotary sampling gear of the JSL. We observed a variety of creatures in the water column including scyphozoans (true jellyfish), ctenophores, amphipods, krill, sergestids, snipe eels, squid and more krill. Krill is the common name (also called euphausiids) for certain small, crustacean zooplankton that are a major source of food for fishes, marine mammals and a variety of pelagic and benthic invertebrates. 
Upon returning to the surface, the canisters containing zooplankton were emptied, cleaned and
re-installed on the JSL for the second dive at 2030. This time Ulf Bamstedt and Tim were in the
sphere; Ebba Olsson and Jimmy were aft. The dive was Ebba's first time in a submersible as well.
On their dive, they used the detritus samplers to collect delicate gelatinous fauna, including
ctenophores, siphonophores and scyphozoans (Image C). These animals will be photographed and
identified by David Shale,
Per Flood,
and Francesc Pages.
It was quite amusing to see them wander about staring into little sample jars for minutes at a time and mumbling, "I have never seen this
animal alive."
By the end of a long day we were all a bit tired, but many of us were still working in the lab well after midnight to process samples and waiting to help with a MOCNESS tow that started down at 0245. Who knows what we'll find next! 
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