Invasion of the Giant Jellyfish! No, Really

"Japanese fishermen brace for giant jellyfish"
CNN (January 19, 2009)

"Giant jellyfish descend on the Sea of Japan, causing untold devastation to coastal villages and leaving a trail of destruction and human misery behind.

"Sounds like a great sci-fi flick. But it's not.

"It's real and it's a nightmare for Japanese fishermen.

"The massive sea creatures, called Nomura's jellyfish, can grow 6 feet in diameter and weigh more than 450 pounds. Scientists think they originate in the Yellow Sea and in Chinese waters. For the third year since 2005, ocean currents are transporting them into the Sea of Japan...."

These outsized jellyfish are a major problem for Japanese fishermen because the creatures blunder into and damage their kilometers-long fishing nets.

This article gives a pretty good overview of what's known - and what's not - about Nomura's jellyfish and their recent appearances in waters near Japan.

What I found most remarkable was what marine biologist Monty Williams had to say about the giant jellyfish and their behavior:

"...It's not clear why waves of Nomura's jellyfish have made it to the Sea of Japan in recent years. Some have speculated that overfishing, pollution or rising ocean temperatures may have depleted the kinds of fish that prey on Nomura's jellyfish in the polyp stage. However, no one is certain, Williams said."

Hats off to Williams, for not jumping on a bandwagon with the sort of unswerving certainty that may have been more common in the 'science' of my youth, than what we experience today.