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Carcharodon carcharias, more commonly known as the great white shark, is the largest predatory fish in the oceans. It is  typically found in coastal waters between about 54 and 75 degrees Fahrenheit. The great white shark inhabits the epipelagic zone, also known as the sunlit zone, which is the top “layer” of the oceans: The section of water from the surface of the sea down to approximately 200 metres. The lighting this close to the surface is sufficient to allow visual predators such as the great white to use their eyesight as they hunt their prey. Despite the scary movies and occasional horror stories found in the news, humans are not the shark’s preferred cuisine; rather, the adult great white primarily seeks out marine mammals to prey on and large animal carcasses to scavenge from.

Whatever one’s personal feelings about great whites, they are undeniably a valuable part of the ecosystem. As a high level predator, a severe depletion in great white populations could lead to an explosion in the populations of marine organisms lower in the food chain, which could in turn alter the ecology of the entire area.

Already considered vulnerable by the International Union for the Conservation of Nature, a potentially alarming new study indicates that there are significantly fewer great white sharks inhabiting the waters near the California coast than scientists had previously believed.

The San Francisco Chronicle is reporting that biologists believe only 219 full-grown or near-grown adults populate the coastal waters between Bodega Bay and Monterey each fall.

University of California, Davis researcher Taylor Chapple says he’s surprised by the low number of great whites counted in the first-ever census of the marine predators.

The results are being published this week in the journal Biology Letters.
The researchers used high-resolution photos of the sharks taken over three years to determine their number.

Times Live

Though the number of sharks came as a surprise to researchers, it is yet unclear whether the low number is due to a natural trend, or whether other factors are at work.

“This low number was a real surprise,” said lead author and doctoral student Taylor Chapple in a UC Davis press release.

“It’s lower than we expected, and also substantially smaller than populations of other large marine predators, such as killer whales and polar bears. However, this estimate only represents a single point in time; further research will tell us if this number represents a healthy, viable population, or one critically in danger of collapse, or something in between.”

[. . .]

“The decline of sharks in the global oceans underscores the need for careful assessment and monitoring of remaining populations,” the researchers wrote in the study.

The Epoch Times

Hopefully further research will shed some light on the cause(s) of the unexpectedly low shark population, and will determine whether the current trend will be reversed.

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Comment Preferences

  •  Maybe this has something to do with it? (8+ / 0-)

    Proposed California ban on shark fin soup

    Environmentalists and others argue that the fin trade encourages shark-finning -- a practice in which fishermen cut the fins off of live sharks and throw the rest of the animal overboard.

    (I'm sure this isn't the only reason for low numbers of sharks.  It's unsettling, anyway.)
    •  shark fin soup isn't made with great whites (6+ / 0-)

      it's smaller sharks, IIRC.

      •  So it may not be a factor in this data (4+ / 0-)
        Recommended by:
        sricki, Larsstephens, marina, BusyinCA

        ...but the fact remains that the population of the globe's shallow-water sharks is down by about 90% in the past quarter century. This apex predator species of the sea has been the unfortunate focal point of the "perfect storm".

        It's been the combination of bad press/public relations that originated with the film "Jaws" leading to annual summer hunts in the guise of fishing contests, and the gustatory tastes of Asian cuisine that call for the taking of these animals from the sea and the disposal of more than 99% of their living bodies back into the sea to die a long, slow death without their dorsal fins. The latter all so some folks won't be disappointed by the absence of 'special soup' for their parties...

        "Of all the forms of inequality, injustice in health care is the most shocking and inhumane." -- Rev. Dr. Martin Luther King, Jr.

        by frisco on Sat Mar 12, 2011 at 09:57:07 AM PST

        [ Parent ]

  •  They all enrolled in law school? (6+ / 0-)

    You have exactly 10 seconds to change that look of disgusting pity into one of enormous respect!

    by Cartoon Peril on Fri Mar 11, 2011 at 10:13:58 PM PST

  •  I have had both great awe and great fear.... (6+ / 0-)

    for Great Whites ever since I saw 'Jaws' at the drive-in at far too young an age. The fear just keeps my eyes sharp for fins when surfing...the awe has had me watching Shark Week for many years...and draws me to diaries such as this (really, I swear, the fact that sricki wrote it has naught to do with it).  ;)

    I think that our oceans are in peril...and the fact that the 'top dogs' are in decline does not bode well AT ALL. From our polluting of our global waters...to climate change and a warming of the Seas...I think we are only just now seeing the beginning of the catastrophic environmental effects.

    Great diary, sricki...

    Never argue with a fool, onlookers may not be able to tell the difference.

    by Kysen on Sat Mar 12, 2011 at 12:19:24 AM PST

  •  Shit... how terrible. (3+ / 0-)
    Recommended by:
    Tinfoil Hat, Larsstephens, BusyinCA

    Accomplished PREDATORS dying generally means that most PREY has already died.  

    We are witnesses to the collapse...

    •  That could be true (5+ / 0-)

      but as the researcher pointed out, more data is needed to figure out if this is a normal dip in the population cycle or something more serious. In this case I think it might be something else. It could be Humboldt Squid.

      Humboldt Squid are not giant, but they do get to be several hundred pounds. Unlike Giant Squid, they eat absolutely anything, and display a high degree of intelligence. As the fish we like to, er, fish are generally high level predators are fished out, it means that a new predator can take it's place in the food chain. Humboldt Squid populations and ranges have exploded in recent years for that reason. The squid could be crowding out the Great White Shark. (Though now that I think of it I remember the Great White preying on seals; I doubt even the Humboldt Squid is that ambitious.)

      Anyway, that's pure speculation on my part.

  •  Tips and Recs for using IUCN (4+ / 0-)

    as well as a great well written diary.

    "Don't fall or we both go." Derek Hersey 1957-1993

    by ban nock on Sat Mar 12, 2011 at 01:04:46 AM PST

  •  Young female great white shark, (5+ / 0-)

    caught and safely released in the GOM, aprx 5-6 feet long. Had the most perfect set of teeth I've ever seen (I had my right hand in there with a pair of pliers to loosen the hook).


    I hope she is still cruising somewhere (looking for a Republican meal).

    "Double, double, toile and trouble; Fire burne, and Cauldron bubble... By the pricking of my Thumbes, Something wicked this way comes": Republicans Willkommen auf das Vierte Reich! Es ist nicht mehr Angelegenheit.

    by Bluefin on Sat Mar 12, 2011 at 03:43:58 AM PST

    •  Cool! Have you seen this? (4+ / 0-)
      Recommended by:
      sricki, Larsstephens, Bluefin, BusyinCA

      Research that's being conducted at the Cape Eleuthera Institute in the Bahamas on Deep-Water Sharks.

      It is fantastic stuff! And it's done in coordination with The Island School so that high school sophomores and juniors are among the less than 100 researchers on the planet that have seen and studied some of these remarkable fish.

      "Of all the forms of inequality, injustice in health care is the most shocking and inhumane." -- Rev. Dr. Martin Luther King, Jr.

      by frisco on Sat Mar 12, 2011 at 10:06:44 AM PST

      [ Parent ]

      •  Hadn't known of them, very interesting. (3+ / 0-)
        Recommended by:
        frisco, sricki, BusyinCA

        I was fortunate to have raised my kids near South Padre Island, spent as much time as possible on/in the water. A school like that would have been a great experience.
        Being out there on the bluewater is like nothing else, you see so much neat stuff.
        Ms. Great White and I went around and around for about 30 minutes, good thing we were both tired. I carry a fish ID book and always dig on the net for info, wasn't sure of this one until reading the scientific lit on shark dentition, the most positive id method.
        Have caught (and released) many others, but none like this one, she was a beauty.
         (only brought partially out of the water briefly for pics and dehook, her remoras were pissed).

        It's an awesome world.

        Perhaps when we have irradiated and polluted it some more we'll see some truly fantastic mutations. /bitter snark

        "Double, double, toile and trouble; Fire burne, and Cauldron bubble... By the pricking of my Thumbes, Something wicked this way comes": Republicans Willkommen auf das Vierte Reich! Es ist nicht mehr Angelegenheit.

        by Bluefin on Sat Mar 12, 2011 at 04:50:06 PM PST

        [ Parent ]

        •  Yes, two of our daughters have attended there (3+ / 0-)
          Recommended by:
          Bluefin, sricki, BusyinCA

          ...and it's been a life-changing experience for both. One of them wants to be a marine biologist and as an undergrad is going to be an intern aiding in shark research this summer and in a semester abroad program next spring.

          "Of all the forms of inequality, injustice in health care is the most shocking and inhumane." -- Rev. Dr. Martin Luther King, Jr.

          by frisco on Sat Mar 12, 2011 at 05:46:12 PM PST

          [ Parent ]

          •  Good luck to them, I'm sure they will (3+ / 0-)
            Recommended by:
            sricki, frisco, BusyinCA

            love it.
            Teach them some safe boat handling skills and pre-learn something about shark dentition, those teeth tell much.

            "Double, double, toile and trouble; Fire burne, and Cauldron bubble... By the pricking of my Thumbes, Something wicked this way comes": Republicans Willkommen auf das Vierte Reich! Es ist nicht mehr Angelegenheit.

            by Bluefin on Sat Mar 12, 2011 at 06:39:51 PM PST

            [ Parent ]

  •  THe deep water canyon (1+ / 0-)
    Recommended by:
    Larsstephens

    off the coast of louisiana has been a breeding ground for sharks. Corexit continues to be applied to our waters. Connection?

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