Jellyfish swarm cripples Norwegian ferry's engines

Discussion in 'Boat Design' started by Squidly-Diddly, Oct 10, 2011.

  1. rwatson
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    rwatson Senior Member

    Jellyfish are destroying the Japanese fishing industry, and will probably do the same for a lot of other areas.

    All the small fish that eat jellyfish eggs are being caught by fishing boats, so the jellyfish have no predators.

    Good news is - you can eat the jellyfish.

    Betcha in 5 years the only fish on the menu the average man can afford are jellyfish - fried, steamed or marinated.
     
  2. Frosty

    Frosty Previous Member


    Not if they follow laws and make nets the regulation sizes.


    Ille take that bet how much
     
  3. rwatson
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    rwatson Senior Member

    Oh come on! - why don't you look it up on the internet about the pressures on small sizes of fish being taken. The Russians harvest Krill for crying out loud.

    "Record hawls of shirasu whitebait caught off Fukushima Prefecture in the summer of 2010, the large catch was attributed to warmer waters associated with global warming. Other areas recorded lower than usual caches."

    what are Whitebait - 60 foot long fish ????

    "Prof. Shinichi Ue, an expert on the jellyfish at Hiroshima University, told the Yomiuri Shimbun, “Humans have brought about abnormalities in the marine eco-systems that can no longer be corrected...A small fish and fry of large fish have fallen in number, creatures that prey on Echizen jellyfish, which eat zooplankton, also have decreased."

    http://factsanddetails.com/japan.php?itemid=937&catid=24&subcatid=159

    While you are at it, you can educate yourself on the problem the Japanese are having, with their fishing fleet, particularly on the west coast.

    " Japan’s seafood self sufficiency rate has declined from a peak of 113 percent in 1964 to 59 percent in 2006. Tuna, salmon and shrimp are among the most widely consumed seafoods. They are mostly imported. "

    " Overfishing is becoming a serious a problem in Japan. Overfishing in coastal areas has have depleted catches and caused fishing villages to shrink to edge of disappearing. Cod has been fished out in many places and salmon, saury, cuttlefish and crab are much scarcer than they used to be. "


    Do a bit of research before you make uneducated off the cuff remarks.
     
  4. Frosty

    Frosty Previous Member

    There are different licenses for fishing. Yyou dont just go out and fish.

    Different licenses different fish and different nets.
     
  5. cyclops2
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    cyclops2 Senior Member

    I am using keel cooler tubes on a 20" runabout for 2 reasons. Allows a antifreeze closed engine block cooling system & cooling for engine & transmission oils.
    It will keep the Zebra Mussels out also. Manifolds will cook everything else. :)
     
  6. Frosty

    Frosty Previous Member

    It amazes me how Amercans still think engine cooling is raw sea water pased round the block and out.

    I can tell you this method is not used in most other areas anymore.

    Heat exchangers with removable and cleanable cores have been used for many many years, decades. Ive never owned a raw water cooler and seen only one DIY job.
     
  7. Squidly-Diddly
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    Squidly-Diddly Senior Member

    How do water-ballasted boats keep their ballest holds from

    gradually(but I'd think quickly) getting filled up with all manner of sea creatures which tend to die and form deposits of sludge(if not actively bonding to any surface).

    I'm thinking of MacGregors, which might be hauled out and ballasts totally dried out, or if sitting in water, would provide shelter for all sorts of little creatures.

    I don't think they have good access to the ballast tanks for scrubbing.
     
  8. rwatson
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    rwatson Senior Member

    You are right, and on top of that they have raw unfinished fibreglass inside the tanks, and no way of access to scrub them out anyway.

    I guess you could fill them with something poisonous to marine life, but then where could you dump it.
     
  9. michael pierzga
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    michael pierzga Senior Member

    Most marine critters need sunlight or the grub they eat needs sunlight.

    I dont have problems with fouling inside the seawater plumping, I dont antifoul my sea strainer filters....the only fouling will be a corona of growth at the seawater entrance.

    I would think ballast tanks would behave the same.
     
  10. rwatson
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    rwatson Senior Member

    Lack of sunlight is no deterrent. I have been through several quarantine stations where they require internal tanks to have been cleaned. This is the guidlelines

    "• Flush seawater inlets with fresh water or
    enclose a 5 percent detergent solution for
    12 hours to kill newly settled tubeworms.
    • Inspect hulls monthly if vessels are moored for
    long periods.
    • If you have a small boat that is easily removed
    from the water, air drying will kill most small
    pest species in about 24 hours"

    eg http://www.marinepests.gov.au/marine_pests#3


    "How do they get here?

    Marine pests are great hitchhikers. They can attach themselves as biofouling to boat hulls, anchor chains, fishing gear, recreational equipment and internal boat compartments or they may travel in any seawater system on a boat including inside pipes and in bilge and ballast water.

    Marine pests are not selective. They will take advantage of any vessel big or small, from yachts to fishing boats to commercial ships to oil rigs."

    "You can help!

    Remove all pieces of weed and fish from your boat or trailer.
    Drain bilge, hulls, buckets, gear etc. and let them dry.
    Hose all gear, boat and trailer with high pressure fresh water.
    If fresh water wash-down facilities are not available on site, ensure all gear is washed well away from streams and watercourses (including stormwater drains) that may transport spores.
    Wash dive gear thoroughly with freshwater, particularly if you visit an infected site or area."
     
  11. michael pierzga
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    michael pierzga Senior Member

    Sure, the Zebra clam is a well known hitchhiker in the sea water system of a ship. I believe that the authoriies are looking for crittiers in the larval stage.

    Whether this type of fouling is applicable to yachts is the question.
     
  12. hoytedow
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    hoytedow - .-. ..- -- .--. .-- --- -.

  13. Frosty

    Frosty Previous Member

    I like Zebra mussels ,,--Bit O vinigar with pepper and some butterd brown bread lovely jubbely.

    I noticed one or two on the marina the other day , might be time for a little mussel hunt, you gotta sneak up on them and grap them quick.
     
  14. Squidly-Diddly
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    Squidly-Diddly Senior Member

    thing with MacGregor style ballast tanks is they might be getting

    filled, emptied, refilled on a VERY regular basis, each time depositing some of the creatures/bio mass in the water.

    I wonder how many MacGregors that have been using the WB feature "aggressively" are unknowingly going around with 500lbs of sludge and crust.

    One of my ideas for a Super MacGregor was to install 12" round hatches on each side of the tanks, into which bladders could be inserted to:

    transfer ballast port and starboard, for real sailing ability

    carry massive amounts of fresh water, fuel or sewage

    and allow for tanks to be scrubbed clean.
     

  15. michael pierzga
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    michael pierzga Senior Member

    The ability to carry fresh water is critical. The best high performance cruisers do it. Normally a four tank layout. two large main tanks down low plus two tanks of whatever size fits best up under the sheer. Sometimes the ballast is of little practical use but the fresh water in the tanks is always valuable.
     
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