Comment Re:Rampant Jellyfish (Score 4, Informative) 123
It's estimated that now over 50% of the biomass of the world's oceans is jellyfish, in some cases completely displacing all other biosystems. One other human activity vector that has impacted jellyfish populations is shipping, transporting species globally to locations with no predators. The warming of waters by nuclear power may locally cause phenomenon which encourage jellyfish growth also. If you could avoid destroying other marine life, maybe the answer to the cooling intakes is "will it blend?".
Japan’s nuclear power plants have been under attack by jellyfish since the 1960s, with up to 150 tons per day having to be removed from the cooling system of just one power plant.
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That’s just what happened when the Mnemiopsis jellyfish (a kind of comb jelly) invaded the Black Sea. The creatures arrived from the east coast of the US in seawater ballast (seawater a ship takes into its hold once it has discharged its cargo to retain its stability), and by the 1980s they were taking over. Prior to their arrival, Bulgaria, Romania, and Georgia had robust fisheries, with anchovies and sturgeon being important resources. As the jellyfish increased, the anchovies and other valuable fish vanished, and along with them went the sturgeon, the long-beloved source of blini toppings.
By 2002 the total weight of Mnemiopsis in the Black Sea had grown so prodigiously that it was estimated to be ten times greater than the weight of all fish caught throughout the entire world in a year. The Black Sea had become effectively jellified. Nobody knows precisely how or why the jellyfish replaced the valuable fish species, but four hypotheses have been put forward.
from http://www.nybooks.com/articles/archives/2013/sep/26/jellyfish-theyre-taking-over/?pagination=false