Announcement

Collapse

Welcome to Moorcock's Miscellany

Dear reader,

Many people have given their valuable time to create a website for the pleasure of posing questions to Michael Moorcock, meeting people from around the world, and mining the site for information. Please follow one of the links above to learn more about the site.

Thank you,
Reinart der Fuchs
See more
See less

Deep-sea fish croaks for love

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Deep-sea fish croaks for love

    Navy biologist detects first call from the abyss.
    28 April 2004
    MARK PEPLOW


    Sounds made by a deep-water fish have been encountered for the very first time. Although the identity of this voluble creature remains a mystery, scientists believe it uses its call to find mates in the dark ocean depths.

    Shallow-water fish such as croakers and toad-fish are known to make a limited range of sounds, but deep-water fish, which are those that live far from continental shelves at depths greater than about 500 m, have not been heard before.

    "These guys have the first good data on noise from an abyssal critter," says Adam Summers, a comparative physiologist at the University of California, Irvine, who was also scientific adviser for the fishy film Finding Nemo.

    The sounds were recorded by four underwater microphones (hydrophones) at the bottom of the ocean between the Bahamas and the coast of Florida. The listening posts are owned by the US Navy's Atlantic Undersea Test and Evaluation Center, which normally listens for approaching submarines.

    Susan Jarvis of the Naval Undersea Warfare Center in Newport, Rhode Island, was tracking sperm whales with the hydrophones to work out how the creatures respond to artificial sounds in the ocean. When she heard some unusual croaking sounds from about 600 m below the surface, she contacted David Mann, a marine biologist at the University of South Florida, to see if he could identify them.

    "Susan sent me the raw files for these sounds, and I immediately thought: 'That sounds like a fish sound'," he recalls. The research appears in the May issue of the Journal of the Acoustical Society of America1.

    Bladder racked

    Mann estimates that the fish is not more than 20 cm long. Larger fish tend to sing baritone, and the mystery creature is an alto. Marine biologists have speculated that some deep-sea fish could produce sounds by rubbing specialized muscles along ridges on their swim bladder, like dragging a stick along iron railings. The new sound fits that theory, says Mann.

    He has also ruled out the possibility that a whale could be making the noise. One recording followed the fish for about half an hour as it dived from 550 m to 700 m. A whale would have had to surface in that time, he says. Furthermore, whales use high-pitched sounds for echolocation and lower notes for communication; Jarvis's recordings sit in the middle range of the oceanic orchestra, which is normally dominated by fish.

    The sound is almost certainly a mating call, believes Mann, because this is the most likely reason for the fish to risk giving away its position to potential predators. "There is no light down there, so it is absolutely logical that they make sounds to attract a mate," agrees Summers.

    Mann also concludes that the fish are quite rare, as he has failed to find similar calls in hydrophone recordings from other parts of the world. Since the sounds could be heard more than 4 km away, the fish may have very few potential mates, he adds.

    These recordings are the first step to learning more about how the fish reproduces, says Mann. Deep-sea fish like the blue grenadier (Macruronus novaezelandiae) are now being fished aggressively, which may threaten many species that live in the same areas of the ocean.

    "These fish are often very long-lived, very slow to reproduce, and very easy to wipe out, especially when we know nothing about the population in the first place," Mann says.

    Mann now hopes to use an underwater vehicle to identify and track the sound, in order to get photographs of the creature.
    \"No, I think Space is a dimension of Time. My theory is that Time is a field and that Space exists as an aspect of Time.\" Michael Moorcock

    \"All I know about anything is \"I wasn\'t. I am. I will not be.\" Michael Moorcock

  • #2
    Voracious Fish Found in Maryland Lake


    April 29, 2004, 8:21 AM EDT


    WHEATON, Md. -- Authorities plan to drain a Maryland lake after an angler caught a Northern snakehead, the same voracious nonnative fish that infested a pond only miles away in 2002.

    State officials said the 19-inch fish, an Asian species that can wriggle on land for short distances and eats so many smaller fish it can destroy an ecosystem, was pulled out of Pine Lake in Wheaton Regional Park Monday afternoon.

    The lake north of Washington, D.C., feeds a tributary of the Anacostia River, which empties into the Potomac River.

    State biologists used electric shocks Tuesday to try to get a rise out of any other snakeheads, but none appeared. Wire mesh was placed over a pipe that leads out of the lake to prevent any others from escaping. Draining of the lake could begin as early as Thursday, officials said.

    The caught fish is believed to be about 4 years old, but how long it was in the lake, how it got there and whether it is male or female is not known, said Steve Early, assistant fisheries director for the Department of Natural Resources.

    Early said the state does not foresee a serious environmental threat, because only one snakehead was found and it's not spawning season for the fish.

    The snakehead was most likely dumped into the lake by its owner, Early said.

    In the summer of 2002, snakeheads were found breeding in a private pond in Crofton, about 20 miles east of Wheaton. More than 1,000 juvenile snakeheads and six adults were recovered when state officials poisoned the pond and two others to keep the fish from spreading.

    All the Crofton fish were traced to a Maryland man who discarded two fish after buying them live in a New York market.

    That episode prompted the state to pass a law allowing the state to inspect private properties for invasive species and take action to contain them.

    In 2002, the Department of the Interior banned the import of 28 species of snakehead, including the Northern variety, according to a spokesman.
    \"No, I think Space is a dimension of Time. My theory is that Time is a field and that Space exists as an aspect of Time.\" Michael Moorcock

    \"All I know about anything is \"I wasn\'t. I am. I will not be.\" Michael Moorcock

    Comment

    Working...
    X