Friday, November 13, 2009

Deep-sea fish captured on camera


The deepest living fish ever spotted in the southern hemisphere have been caught on camera.The bizarre-looking pink creatures were photographed at a depth of 7,560m (24,800ft), swimming in the Kermadec Trench off the coast of New Zealand. An international team has been studying this area using a submersible, built to withstand immense pressures. Last year, the same team recorded another fish at 7,700m (25,300ft) -the deepest ever filmed. These were found in the Japan Trench, which is in the Pacific, north of the equator. Both expeditions form part of the Hadeep project, which aims to expand our knowledge of life in the oceanic trenches, the deepest parts of the ocean floor. The deep-sea fish seen near New Zealand look remarkably similar to last year's find: they are pale pink in colour, with bulbous bodies and long tails. But they are in fact a different species.The fish from both hemispheres look very similar The Kermadec Trench fish are a species known as Notoliparis kermadecensis, while the Japan Trench creatures are Pseudoliparis amblystomopsis. Professor Monty Priede, director of the University of Aberdeen's Oceanlab, which leads the Hadeep project, said: "The intriguing thing is that each of the trenches seems to have been colonised by these fish, despite being in different hemispheres. "Presumably [they evolved] from some shallower, similar ancestor." He added: "These species are never found outside the trenches - they are very isolated. You can think of the trenches a bit like islands." In 2008, these fish were filmed at depths of 7,700m in the Japan Trench The fish were photographed using a camera-laden, deep-sea submersible, which was connected to a ship and controlled from its surface.The submersible is designed to work at very high pressures The probe was loaded with rotting fish, designed to lure deep-sea creatures, allowing them to be caught on camera and studied. But, unlike in 2008, this year the team was unable to capture footage of the fish. The primary submersible carrying the video camera equipment was lost during an earlier descent. Alan Jamieson from Oceanlab, who is leading this project, said he was devastated at the loss of the £150,000 piece of equipment. He told the Natural Environment Research Council's (Nerc) Planet Earth website that it was "the sum of nearly six years worth of planning and designing, and two-and-half years of operations" and that is was "now officially lost at sea". The subject of which fish are the deepest is a contentious one. In 1960, Jacques Piccard and Don Walsh descended to 10,910m (35,790ft) in the Marianas Trench, which is the deepest place in the oceans.DEEP SEA DIVISIONS Bathyal zone: 1,000-3,000m (3,000-10,000ft)Abyssal: 3,000-6,000m (10,000-20,000ft) Hadal: 6,000m-11,000m (20,000-36,000ft) In his book Seven Miles Down, Piccard wrote that he spotted a type of flatfish. However, at a depth of 10,000m (33,000ft), experts say the pressure would have forced the windows to start caving in, making it difficult to see out. So the official record for the deepest fish is held by Abyssobrotula galatheae, which was dredged from the bottom of the Puerto Rico Trench at a depth of more than 8,370m (27,460ft) in 1970. However, it was dead by the time it reached the surface. The Oceanlab team's Japan Trench find holds the record for the deepest living fish. Professor Priede said he expected that some fish would eventually be spotted at even greater depths. The Hadeep project is funded by the Nippon Foundation and Nerc. This research cruise involved Oceanlab, the University of Tokyo's Oceans Research Institute and New Zealand's National Institute of Water and Atmospheric Research (Niwa). By Rebecca Morelle Science reporter, BBC News

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