Spineless by Juli Berwald

Author:Juli Berwald
Language: eng
Format: epub
Publisher: Penguin Publishing Group
Published: 2017-11-07T05:00:00+00:00

Ephyra

13

Stop Waiting

Most jellyfish live a life in two parts. The first part, the polyp, lives attached to a solid surface. It stretches its tentacles out to ensnare its prey and then hauls them in toward its mouth. The polyp can scoot a little, moving beyond its home to a slightly more favorable habitat. After a while, for reasons that are still mysterious, the jellyfish polyp prepares for the second part of its life. It changes its form, schisming into a stack of nascent baby medusae, each one capable of surviving on its own. When the time is right, these ephyrae swim free into the great, open ocean to search for sustenance on which to grow. From my base in Texas, I had explored the biology of jellyfish; the animals’ history both ancient and modern; their genes, movement, glow, senses, nerves, and ecology. Finding these stories was like stretching tentacles and encountering nourishing treasure, all the while moored in the safety of home. But after my feverish revelation about my life and the ocean, I schismed too. The time had come to leave the safety of the surface that supplied support and comfort.

As I was living in Texas, I had the urge to go big. Which could mean only one thing: the giant jellyfish that swarmed the seas of Japan. Giant jellyfish go by several different names. In English, they are Nomura’s jellyfish; in Latin, Nemopilema nomurai; and in Japanese echizen kurage. Kurage is the Japanese word for “jellyfish”; echizen refers to the province where the animal was first reported. Although the lion’s-mane jellyfish is usually considered the biggest jellyfish by length, the giant jellies are tops for weight, tipping the scales at nearly five hundred pounds. Think baby grand piano.

In the twentieth century, large numbers of giant jellyfish were observed off the coast of Japan about once a generation: in 1920, 1958, and 1995. But then they bloomed just seven years later, in 2002. And again in 2003 and in 2004. In the past decade, giant jellyfish have appeared every year, although their numbers do fluctuate significantly.

In 2005 there was a record-setting bloom, with as many as half a billion blimplike invaders passing through the strait between Japan and South Korea each day. Besides clogging fishermen’s nets, the giant jellyfish swarm reduced the fish catch and poisoned the fish. The Japanese Fisheries Agency fielded complaints about jellyfish from more than 100,000 fisherman, and damages were estimated in the range of 30 billion Japanese yen, or $260 million. But 2009 broke the record again, with an increase in giant jellyfish abundance of about 25 percent over 2005. The weight of these mega-medusae caught in fishing nets even sank an ill-fated boat, tossing the crew into the sea, though luckily, no one was injured.

To find out more about the giant jellyfish, I wrote an e-mail to a scientist I had spoken to about jellyfish polyps, Lucas Brotz. He had studied populations of jellyfish around the world, and I thought he might have connections in Japan.

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