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Under the Antarctic Ice--Bald Rockcod
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Under the Antarctic Ice--Bald Rockcod

July 12, 2010
Under the Antarctic Ice--Bald Rockcod (Pagothenia borchgrevinki) Swimming beneath the Antarctic ice, a bald rockcod (Pagothenia borchgrevinki) is photographed by "seal cam." Seal cam is an on-going National Science Foundation (NSF)-supported project where scientists use seals as their "eyes" to see what goes on underneath the Antarctic ice. Antarctic Weddell seals are a predator of the bald rockcod. Bald rockcod are found throughout Antarctica and the Antarctic Peninsula, South Orkney Islands and South Shetland Islands, from 0 to 695 meters depth. Bald rockcod are commonly seen with the sea ice along the Antarctic shore and have been observed clinging to the underside of thick ice shelves. The toothfish can grow up to 28 centimeters in length. A well-adapted hunter, the lateral line sensory system of the bald rockcod can detect prey by recognizing the low vibration frequencies emitted by swimming crustaceans. Bald rockcod eat free-swimming, shelled pteropod mollusk, ice krill, copepods, decapod crustacean larvae, chaetognaths, amphipods and juvenile fish. [Image 7 of 7 images in a series. Back to Image 1.] More about this Image Researchers Lee Fuiman from the University of Texas, Austin, Randall Davis from Texas A&M University, Galveston, and Terrie Williams from the University of California, Santa Cruz, equipped 15 Antarctic Weddell seals with video cameras, infrared LEDs and data recorders. As a result, they've gained new insight into the habits of two very important Southern Ocean fish species: the Antarctic silverfish (Pleurogramma antarcticum) and the Antarctic toothfish (Dissostichus mawsoni). The seals--marine predators--serve as guided, high speed midwater sampling devices for fish that have been especially difficult to study. New information about the behavior and distribution of these species indicates some existing theories may need to be revised. Seal cam does have limitations, however, it is a promising technique and could be used to study other pelagic and deepwater fish and invertebrates that are otherwise impossible to observe in their natural environment.


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