This is serious.
KOKONOGI, Japan – A blood-orange blob the size of a small refrigerator emerged from the dark waters, its venomous tentacles trapped in a fishing net. Within minutes, hundreds more were being hauled up, a pulsating mass crowding out the catch of mackerel and sea bass.
The fishermen leaned into the nets, grunting and grumbling as they tossed the translucent jellyfish back into the bay, giants weighing up to 200 kilograms (450 pounds), marine invaders that are putting the men's livelihoods at risk.
The venom of the Nomura, the world's largest jellyfish, a creature up to 2 meters (6 feet) in diameter, can ruin a whole day's catch by tainting or killing fish stung when ensnared with them in the maze of nets here in northwest Japan's Wakasa Bay.
"Some fishermen have just stopped fishing," said Taiichiro Hamano, 67. "When you pull in the nets and see jellyfish, you get depressed."
More below the break.
First some astonishing pictures. I've seen CARS smaller than these things!
Google archive of pictures
Not only are the Nomuras huge - they swarm is vast numbers, invading the Sea of Japan in numbers on the order of 500 million. Before you scoff - a significant mass of the ocean's biomass is in the form of gelatinous creatures - as much as 1/3rd of the total - and jellyfish can thrive in waters so polluted that they are deadly to all other forms of life.
This is part of why they are thriving; warm nutrient rich waters that both feed plankton and kill off competitors for food and predators that think jellyfish are good eatin'. per one academic abstract
The environment of East China Sea (ECS) has been faced by huge stresses from anthropogenic activities and population growth in the Yangtze River drainage basin and the areas along the coasts. Improper use of natural resources and short-term economic objectives have resulted in severe environmental degradation in a fairly short time frame and the degradation has now reached a level where the health and well being of the coastal populations are threatened. The main pollutants are inorganic nitrogen, phosphate, oil hydrocarbons, organic matters and heavy metals. Nutrients cause eutrophication of the coastal waters and the estuarine area and very often stimulate the occurrence of red tides. The environmental pollution of Yangtze River basin directly impact on the state of the marine environment in the ECS.
An accompanying charts (Fig 5 above) illustrates that nitrate concentrations have tripled since 1980. If I understand the causation right, more nitrates mean more plankton blooms. Bad for many ocean critters. Great for jellies. Less competitors and predators. Lots more jellies.
The economic impact for Japan's fishing industry has been ruinous - 30% slashing of catches and, more, a real safety hazard for fishermen.
How dangerous? Keep in mind - these are jellyfish. They sting. What's more, their weight when caught in nets can capsize boats
A 10-ton fishing boat has been sunk by gigantic jellyfish off eastern Japan.
The trawler, the Diasan Shinsho-maru, capsized off Chiba`as its three-man crew was trying to haul in a net containing dozens of huge Nomura's jellyfish.
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The crew of the fishing boat was thrown into the sea when the vessel capsized, but the three men were rescued by another trawler, according to the Mainichi newspaper. The local Coast Guard office reported that the weather was clear and the sea was calm at the time of the accident.
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Experts believe that one contributing factor to the jellyfish becoming more frequent visitors to Japanese waters may be a decline in the number of predators, which include sea turtles and certain species of fish.
Historically, jellyfish swarms occurred about once every 40 years. Then they started happening more often. Now they appear to be an annual occurrence as the Nomura drift from plankton-rich waters off the coast of China and move with the current across the East China Sea to Japan. Normally the waters there are too cold for them to thrive....
Something has changed. What's more. Jellyfish invasions aren't just Japan's problem. They've been swarming all over the world, per this 2008 article
Massive swarms of stinging jellyfish and jellyfish-like animals are transforming many world-class fisheries and tourist destinations into veritable jellytoriums that are intermittently jammed with pulsating, gelatinous creatures. Areas that are currently particularly hard-hit by these squishy animals include Hawaii, the Gulf of Mexico, the east coast of the U.S., the Bering Sea, the Mediterranean Sea, Australia, the Black Sea and other European seas, the Sea of Japan, the North Sea and Namibia.
Science Daily is taking a cautious "Is it related to anthropogenic climate change or not?" tone. Are swarms natural? Sometimes. Are they exacerbated by human changes to the environment? Well... depends, I guess, on how 'natural' it is for the mauve stinger, a jellyfish that had heretofore only bloomed in the Mediterranean to be present in the billions in the colder waters of the Irish Sea:
A massive invasion of deadly jellyfish threatened Northern Ireland's only salmon farm for a second time in two weeks yesterday.
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In the first jellyfish incursion last week, mauve stingers covered an area of 10sq miles to a depth of 35 feet off the coast of Glenarm for seven hours.
The density of jellyfish was too great for workers to reach the cages in which the salmon were kept, about a mile out into the Irish Sea, and those fish not stung to death were killed by the trauma of the incursion.
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Compass jellyfish are common in British waters during the summer, but mauve stingers are relatively uncommon. In recent years the mauve stinger has bloomed in vast numbers in the Mediterranean.
I can't speak to all the causes and nuances of this; I am no marine biologist. I would hesitate to rush to claims that this is wholly related to global warming, as jellyfish species thrive (based on this cursory research) in almost any oceanic environment where there is nourishment and room to float. Regardless, in the case of the giant Nomura jellyfish and Japan, pollution in the East China Sea, compliments of industrial and commercial development in the PRC, appears to come with a sting for itself and its neighbors. And in oceans bereft of the means to support species diversity, including predators, it appears we have a partial, conditional answer to a rather uncomfortable question - What kinds of life are most likely to survive the current mass extinction episode?
So long as there are oceans and nutrient to support plankton growth (those being the conditional terms), it looks like the jellies stand as good chance as any other group of species to coexist with, or perhaps even outlast, the humans.