Table Of ContentJELLYFISH
J E L LY F I S H
A N A T U R A L H I S T O R Y
L I S A - A N N G E R S H W I N
THE UNIVERSITY OF CHICAGO PRESS
Chicago
Lisa-ann Gershwin is director of the Australian Marine Stinger Advisory Services.
She was awarded a Fulbright in 1998 for her studies on jellyfi sh blooms and evolution,
and she has discovered over two hundred new species—including at least sixteen types
of jellyfi sh that are highly dangerous, as well as a new species of dolphin. She is the
author of Stung! On Jellyfi sh Blooms and the Future of the Ocean.
Th e University of Chicago Press, Chicago 60637
Text © 2016 Lisa-ann Gershwin
Design and layout © 2016 by Th e Ivy Press Limited
All rights reserved. Published 2016.
Printed in China
25 24 23 22 21 20 19 18 17 16 1 2 3 4 5
ISBN-13: 978-0-226-28767-6 (cloth)
ISBN-13: 978-0-226-28770-6 (e-book)
DOI: 10.7208/chicago/9780226287706.001.0001
Library of Congress Cataloging-in-Publication Data
Gershwin, Lisa-ann, author.
Jellyfi sh : a natural history / Lisa-ann Gershwin.
pages cm
Includes index.
ISBN 978-0-226-28767-6 (cloth : alk. paper) — ISBN 978-0-226-28770-6 (e-book)
1. Jellyfi shes. 2. Natural history. I. Title.
QL377.S4G46 2016
593.53—dc23
2015034610
Th is book was conceived, designed, and produced by
Ivy Press
210 High Street, Lewes
East Sussex BN7 2NS
United Kingdom
www.ivypress.co.uk
Publisher Susan Kelly
Creative Director Michael Whitehead
Editorial Director Tom Kitch
Art Director James Lawrence
Commissioning Editor Kate Shanahan
Editors David Price-Goodfellow and Amy K. Hughes
Design J.C. Lanaway
Illustrator Vivien Martineau
Species Illustrations David Anstey
Picture Researcher Katie Greenwood
Editorial Assistant Jenny Campbell
Cover photograph © Doug Perrine/Nature Picture Library
C O N T E N T S
Introducing the Jellyfi sh 6 CHAPTER TWO CHAPTER FOUR
Introducing the Ocean 9
Irukandji Jellyfi sh 154
About Th is Book 12
Immortal Jellyfi sh 74
Hula Skirt Siphonophore 156
Stalked Jellyfi sh 76
Australian Spotted Jellyfi sh 158
CHAPTER ONE Sailors on the Wind 78
Spotted Jelly 160
Platyctenes 80
Freshwater Jellyfi sh 162
Portuguese Man-of-war
Tadpole Larva 82
and Blue Bottle 34 Jellies with Bite 164
Battering Ram Jellies 84
Prism Jellies 36 Santa’s Hat Jelly 166
Gorgons of the Pond 86
Giant Heart Jelly 38 Flying Saucer Jellyfi sh 168
Herpes Jellyfi sh 88
Clapper Jelly 40 Leaf-crawler Jellies 170
Purple People Eater 90
Fire Bodies 42 Splendid Bell Jelly 172
Brackish Goddess 92
Sea Gooseberry 44
Lizard-tail Jellyfi sh 46 CHAPTER FIVE
Upside-down Jellyfi sh 48 CHAPTER THREE
Deadly Box Jellyfi sh 50
Nomura’s Giant Jellyfi sh 194
Lion’s Mane Jellies 52
Black Sea Nettle 114 Sea Walnut 196
Bazinga! 116 Th e Nobel Jelly 198
Bonaire Banded Box Jelly 118 Pseudo-Irukandji 200
Purple Ropy Jelly 120 Sea Tomato 202
Th ree-legged Box Jelly 122 Obelia 204
A Pelagic Stauromedusa 124 Long Stingy Stringy Th ingy 206
Enigmatic Fossil “Medusae” 126 Common Salp 208
Wheel Salps 128 Blue Blubber 210
Moon Jellyfi sh 130 Atlantic Sea Nettle 212
Venus’s Girdles 132
Glossary 214
Further Resources 218
Index 220
Picture Credits 223
Acknowledgments 224
6
Introducing the Jellyfish
I n t r o d u c I n g
t h e J e l l y f I s h
Jiggly, flowing, mesmerizing, alien, delicious, stingy, lethal—jellyfish are many things to many people. To the fisherman,
they may be a nuisance, sometimes a costly one. To the swimmer, they mean painful and even dangerous stings.
To the artist, they may stimulate and inspire. To certain entrepreneurs, they are promising sources of innovation
and profit. To the curious, they are endlessly weird and fascinating.
JellyfIsh as a group hold some astonishing records. The far longer than normal, or are covering vastly larger areas, or
world’s most venomous animal is a jellyfish, the Australian are considerably denser than usual. It can be challenging to
Deadly Box Jellyfish (Chironex fleckeri, page 50). The largest tease apart what is happening in these cases. Are the jellyfish
invertebrate discovered in the twentieth century is a jellyfish, simply misbehaving, or is human activity impinging on their
the so-called Black Sea Nettle (Chrysaora achlyos, page turf and stimulating rambunctious reactions? Regardless,
114)—though it is practically a toy compared to the lion’s jellyfish are a problem when they threaten lives or livelihoods.
mane jellies of the North Atlantic (Cyanea spp., page 52),
Below Jellyfish run the full gamut from than a grain of sand to others longer than
which can reach three meters (ten feet) across the body and
beauty to beast, from lovely to lethal. They a blue whale. Some, like Pyrosoma (left),
drag tentacles nearly 30 meters (100 feet) long. One jellyfish are united by their gelatinous bodies, drifting are herbivores, eating phytoplankton.
lifestyle, simple organ systems, and ability to Others, like the Flower Hat Jelly Olindias
helped scientists win the Nobel Prize (page 198). Another
bloom prolifically. Jellyfish come in an array (center), are carnivores, eating zooplankton.
grows ten percent of its body length per hour (page 208). And of shapes and sizes, from those barely larger And some, like the blubbers (right), are both.
the world’s first known case of true biological immortality
was discovered in the diminutive and aptly named Immortal
Jellyfish (Turritopsis dohrnii, page 74).
The Problem with Jellyfish
We have always been put off jellyfish by their stings,
and these creatures have long drifted under the radar
scientifically and industrially. But a couple of decades ago,
jellyfish started becoming harder to ignore. People began
reporting problems, which often interfered with human
enterprise, and as the frequency of these reports increased
it led to further attention and thus even more reports.
Most of the problems involve jellyfish blooms, or large,
concentrated swarms. Jellyfish bloom as a natural part of their
life cycle. But increasingly, it appears, some blooms are lasting
7
Introducing the Jellyfish
What Is a Jellyfish? are squishy aquatic creatures, some drifting and some
Despite the sensational attention given to jellies in the transparent, that span different animal groups. But
media, many people are still not sure what, exactly, jellyfish even the experts cannot agree on the group as a whole:
are. They are animals, though they lack recognizable body some exclude pelagic tunicates (salps and their kin), while
parts like faces and bones and, in most, a brain and a heart. others include them, as we do in this book (pages 70–71).
They are invertebrates, which means they have no vertebral Despite their strangeness, jellyfish, like all animals,
column, or spine, but they belong to different invertebrate must catch food, reproduce, move around, and protect
groups. Some are in the same category as the corals, sea themselves—and they do so without brains, bones, or blood.
anemones, and sea fronds; others belong to the lineage Jellyfish have been making do for hundreds of millions of
that eventually gave rise to humans, and even possess a years, since before brains, bones, and blood evolved, and their
rudimentary heart and brain but are so primitive simplicity works for them. They can subsist on a broad variety
evolutionarily that we bear few features in common. of food—or even no food at all—and they can reproduce in
It is also important to keep in mind that not all squishy, an exciting variety of ways, with or without a mate. And in
drifting, transparent aquatic creatures are jellyfish. Many their different life stages, they can move or not move, and they
species of squid and even a few octopus species, for example, get along just fine. It is no wonder they have persisted for so
are transparent and squishy, and some even drift on the long. They have mastered the art of survival.
currents. Some fish, particularly the larvae of eels, are The weird and wonderful world of the jellyfish contains
transparent and gelatinous (jelly-like). Certain drifting, many splendid surprises, from their remarkable ability to
gelatinous sea cucumbers look more like jellyfish than clone replicates of themselves that are so unlike one another
many jellyfish do. Even the minuscule, spherical Sea Sparkle that they have been classified as different creatures, to their
(Noctiluca scintillans), an algae-like organism, could be tenacious persistence in conditions that most other animals
mistaken for a jellyfish. But none of these creatures are find utterly unlivable, to their delightful shapes and color
jellyfish. This means the answer to the question “what patterns and mesmerizing movements. The strange
is a jellyfish?” is as slippery as jellies themselves: Jellyfish otherworldliness of jellyfish makes them simply fascinating.
8
Introducing the Jellyfish
Group Examples Main impacts
True Jellyfi sh
Sea nettles, moon jellies, Clogging intake pipes of power
Cnidaria: Scyphozoa:
Purple People Eater plants and ships; stinging
Semaeostomeae
Blubber Jellies
Bazinga, barrel jellies, sea blubbers, Clogging fi shing nets and intake
Cnidaria: Scyphozoa:
cabbage jellies, Sea Tomato pipes of power plants and ships
Rhizostomeae
Coronate Jellies Santa’s Hat Jelly, Flying Saucer Shifting ecology of Norwegian
Cnidaria: Scyphozoa: Coronatae Jellyfi sh, thimble jellies fj ords; consume larvae and plankton
Box Jellyfi sh Stings very painful and may be
Box jellies, Irukandjis
Cnidaria: Cubozoa lethal or cause severe illness
Water Jellies
Predation on and competition
Cnidaria: Hydrozoa: Bell jellies, Nobel Jelly
with fi sh eggs, larvae, and plankton
Hydroidomedusae
Siphonophores
Long stingy stringy thingies, Stinging; strong predation on
Cnidaria: Hydrozoa:
Portuguese Man-of-war and competition with other species
Siphonophora
Comb Jellies Predation on and competition
Sea walnuts, sea gooseberries
Ctenophora with fi sh eggs, larvae, and plankton
Salps and Th eir Kin Grazing on phytoplankton;
Salps, pyrosomes, doliolids
Chordata: Tunicata compete with other species
siphonophore true jellyfi sh salp box jellyfi sh
comb jelly coronate jelly blubber jelly water jelly
9
Introducing the Ocean
I n t r o d u c I n g
t h e o c e a n
It has been said that our planet should actually be called Ocean rather than Earth, because nearly three-quarters of it is covered
in water. This aquatic portion (72 percent of the planet’s surface) is the domain of the jellyfish, which are found from pole to pole,
from the surface to the depths. Scientists have developed terminology to describe the multitude of different oceanic zones that
exist. Some of these terms are used throughout the book, including in the fact panel that accompanies each species account.
In general, we divide the ocean into zones guided by Horizontal Ocean Zones
either vertical position in the water column or horizontal The “horizontal” ocean zones begin at the coast, where
coverage based on relationship to landforms. Within these land and water meet. The area of the shoreline that is
zones, numerous habitats characterize different ecosystems traversed by the tide each day is called the intertidal zone;
and define the flora and fauna that live there. These zones are only the hardiest organisms generally survive here, due to
similar in function to the mountains, deserts, rivers, and lakes the extreme temperature, salinity, and wet/dry and motion
that divide up the three-dimensional habitats on land and pressures associated with the incoming and outgoing tide.
define the ecospace in which certain organisms can thrive. Jellyfish sometimes become stranded in the intertidal zone
Right The Great Barrier
Reef in Australia is famous
for its corals. The
mesmerizingly clear blue
water that entices us so, is
generally low in nutrients.
This type of ecosystem is
one of the types of habitat
where jellyfish flourish.
