One of the signs of global warming and the ever-growing hunting in the oceans (following the Japanese government’s decision to re-enable whaling) is the disproportionate culture of the giant Nomura jellyfish, found mainly in the Yellow Sea region between China and Japan, and spreading to the Pacific Ocean.
Nomura is a giant jellyfish, weighing up to 250 kg. To achieve this impressive weight, it devours an enormous amount of food, especially small fish and plankton. In doing so, it joins humans in the depletion of oceans and seas of fish, which has a severe impact on the ecosystem.
Nomura is not poisonous to man. However, its enormous size coupled with its constant need to eat affects the fishing fields. The amount of food it consumes makes it a competitor of sharks, whales, tuna and reef fish – species that are, owing to human activity and pollution, also struggling with a reduction in their food reserves.
The increase in sea water temperature causes the Nomura to reproduce at a faster rate. During development, this jellyfish goes through several stages. From an egg, to a polyp on the rock bottom of the sea, waiting for the right temperature to break away and turn into a little jellyfish that devours everything in its path. In the past, during the winter, the water temperature would decrease, and with it the rate of jellyfish reproduction. Since polyps do not like cold water, they would sink on the bottom and wait for the summer. There, they would become pray and their population would shrink. Today, however, the water is warm throughout the year and there is no biological mechanism inhibiting reproduction.
One mature jellyfish can lay about one billion eggs, but most become food for other fish. Yet, the absence of fish, due to massive fishing, means that there is no one to destroy the eggs and polyps, or the small jellyfish, causing them to breed without limit. It’s a self-sustaining system.
The Japanese fishermen, who noticed that the Nomura was becoming their great enemy, turned to fishing and killing it, in an effort to reinstate balance. But, the defense mechanism of this jellyfish soon became apparent. When they cut Nomura`s body, millions of its eggs would immediately be released into the water. In their attempts to reduce Nomura’s population, these fishermen would only accelerate their rate of reproduction. Thus, as in many other examples, man becomes the greatest enemy of the environment, animals, and of himself.
The Japanese tried to produce a protein from the jellyfish meat, for the food industry. But, the taste proved bland and the cost of handling it too expensive.