Giant jellyfish invade japanese waters
Posted: Sun Oct 23, 2011 9:29 am
Giant jellyfish invade Japan
Millions of 6ft, 440lb jellyfish are congregating off the western coast of Japan, their numbers apparently boosted by rising sea temperatures and a decline in natural predators.
Nomura's jellyfish are one of the largest species of the creature in the world. Their scale was demonstrated in the autumn of 2009, when a 10-ton fishing boat was sunk as the crew tried to haul in a net containing dozens of the creatures.
Increasing numbers of the jellyfish have been recorded in the Sea of Japan since 2002, with experts suggesting the population explosion in recent years is due to the 1.89 degree Fahrenheit increase in temperature in waters off China making conditions more favourable for breeding.
In the early 1900s, according to Professor Shinichi Uye, a leading expert on the species at the Graduate School of Biosphere Science of Hiroshima University, large numbers were only reported every 40 years or so.
Another contributing factor, experts believe, is a decline in the number of predators, which include sea turtles and certain species of fish.
Japan was invaded on a similar scale in the summer of 2005, when the jellyfish damaged nets, rendered fish inedible with their toxic stings and even caused injuries to fishermen. In 2007, there were 15,500 reports of damage to fishing equipment caused by the creatures.
Millions of 6ft, 440lb jellyfish are congregating off the western coast of Japan, their numbers apparently boosted by rising sea temperatures and a decline in natural predators.
Nomura's jellyfish are one of the largest species of the creature in the world. Their scale was demonstrated in the autumn of 2009, when a 10-ton fishing boat was sunk as the crew tried to haul in a net containing dozens of the creatures.
Increasing numbers of the jellyfish have been recorded in the Sea of Japan since 2002, with experts suggesting the population explosion in recent years is due to the 1.89 degree Fahrenheit increase in temperature in waters off China making conditions more favourable for breeding.
In the early 1900s, according to Professor Shinichi Uye, a leading expert on the species at the Graduate School of Biosphere Science of Hiroshima University, large numbers were only reported every 40 years or so.
Another contributing factor, experts believe, is a decline in the number of predators, which include sea turtles and certain species of fish.
Japan was invaded on a similar scale in the summer of 2005, when the jellyfish damaged nets, rendered fish inedible with their toxic stings and even caused injuries to fishermen. In 2007, there were 15,500 reports of damage to fishing equipment caused by the creatures.