08/23/03 - Gonostomatids & dolphins
Two late night Tucker Trawls brought in an assortment of fish, shrimp, and jellies (see data log for 22 August). The most fascinating were three Gonostomatids. These are mid-water fishes that have photophores running the length of their slender bodies and their ventral side. The first one collected measured eleven centimeters, a near average of the next two. The bodies are a dark gray, with iridescent silver on either side of the body. For their size, their teeth appear quite formidable. One can only imagine how bizarre they truly look when traveling through the ocean, their bodies glowing from bioluminescence.
After steaming ahead to the Northern Lophelia Banks site during the night, morning greeted us with beautiful white capped seas. Fortunately things were not rough enough to abort the sub dives, and Andrea Quatrini and Art Howard went down on the first. Aside from observing and recording species diversity, the primary goal of the morning dive was to collect footage for a film about deep sea exploration. Armed with a high definition video camera, and the submersible's once again fully operational underwater camera, they were able to get 280 still photos and some terrific footage.
Mid-day between dives, more transects were run. The more sonar impressions we have of the ocean floor's topography, the better understanding we will have about the possible life forms such an area might support. As more transects are taken, a more complete ocean profile can be diagramed for a particular site. Interpretation of such diagrams can then determine where the most profitable next dive site will be.
Between sub dives, the plankton net was deployed. Plankton was needed for isotope sampling, and some was readily retrieved. Since today's afternoon dive was in the same location as the morning dive, transects were made in the general vicinity. The speed of the vessel was enough to create white-capped wakes around the bow, and soon a group of dolphins was swimming in and out of the wake. A group of scientists and others congregated on the ship's bow to watch these beautiful mammals perform their graceful dance. The dolphins leaped and turned, avoiding the ship by what seemed merely inches, only to appear once again, frolicking in the sunlit spray. When at last we once again reached our dive site, slowing to no wake, it was with regret that we bid adieu to these marvelous performers as they swam off toward the horizon.
The second dive of the day proved very successful. A healthy area of coral was found harboring a myriad of organisms within its branches and polyps. An unidentified species was observed by Jeremy Potter in the stern of the sub. It appears to be the same critter seen briefly by Doni Angell while on yesterday's morning dive, 60 miles away. The depths were similar, which could account for similar species.
One of the most interesting parts of this afternoon's dive was witnessing a galatheid crab attempting to eat a Myctophid all the while trying to defend his catch from other crabs. A battle of wills ensued, and the last thing scientist Martha Nizinski saw from the aft sub compartment was the galatheid still attempting to shove the wiggling fish in its mouth while crawling away from his pursuers.
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