[INTRODUCTION]

It seems the ocean’s chain of life is actually a fragile, silken web. If just one strand is removed, the whole thing unravels. And it may never be whole again.
—MARLA CONE, Los Angeles Times environmental writer

Standing in a sandstone quarry in central Wisconsin takes us back 500 million years to a time when life on earth was very different from what it is today (see plate 16). No bones, no claws, no teeth had yet evolved. Nothing with jaws. Creatures with shells were just beginning to form. Mostly jellyfish and their kin, and perhaps some worms. Soft-bodied drifting creatures, and some that stuck in the sand. Some perhaps with photosynthesizing symbionts, similar to today’s corals. But no spectacular coral reefs. No vast filtering mussel beds. No sharks slicing through the water as schools of fish flee for their lives.

The tiny hamlet of Mosinee is the gateway to not one, but seven of history’s most magnificent and unlikely events. Stacked one on top of the other like pages in a history book are seven successive bedding planes, each with hundreds of jellyfish fossils stranded together in seven separate accidents of timing. It is rare enough for jellyfish to fossilize, but to have an entire stranding event so perfectly preserved—seven times—is simply splendid.

The “footprints” they left behind through their “excavation” behavior tell the story of their fateful wrong turn, some larger, some smaller, some four-parted, some five-parted, all high and dry. But there is another thing this tells us, something more ominous: large swarms of jellyfish have been a frequent occurrence for a long, long time . . . and they probably aren’t going to go away.

It is most likely, to some extent, just what jellyfish do.

But what if there was something that we humans are doing that was favorable to jellyfish? What if we are fishing out their predators and competitors and making the seas more toxic so that sensitive species couldn’t survive? And what if warming waters speed up their metabolism and make them breed and grow faster while simultaneously stripping the ocean of oxygen so that heavy breathers like fish and crustaceans gasp for air? These are not actually “what-ifs”—these are real, and this is their story.

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Imagine if fish vanished and shrimp ran out and oysters disappeared and what if, except for the occasional slug sliming its pathway along the seabed or the worms still thriving in the sediments, jellyfish dominated the oceans? If I offered evidence that jellyfish are displacing penguins in Antarctica—not someday, but now, today—what would you think? If I suggested that jellyfish could crash the world’s fisheries, outcompete the tuna and swordfish, and starve the whales to extinction, would you believe me?

Yep, jellyfish. Most people have never spent more than a moment of their lives, if that, thinking about jellyfish. But things are changing. The climate is changing. Pollution is increasing. Fish stocks are vanishing. Oceans are becoming more acidic. Species composition is rearranging. And jellyfish populations are exploding into superabundances and exploiting these changes in ways that we could never have imagined—not only exploiting the changes, but in some cases driving them. As seas become stressed, the jellyfish are there, like an eagle to an injured lamb or golden staph to a postoperative patient—more than just a symptom of weakness, more like the angel of death.

From jellyfish that grow to the size of refrigerators to others as small as a few grains of sand, and from swarms that blanket hundreds of miles to species that kill healthy adults in two minutes flat, jellyfish are ubiquitous in marine environments. And with increasing frequency and force, they are making their presence known. Emergency shutdowns of nuclear power stations. Disabling of America’s most powerful nuclear-powered supercarrier. Causing the disruption and relocation of filming of a recent major Hollywood movie—twice. Nearly stopping an Olympic triathlon. These are just a few of the many recent inconveniences caused by jellyfish blooms.

Jellyfish blooms signal a much more serious problem, one with long-term consequences to our ecosystems and food security. Ecosystems are stressed, and jellyfish are taking advantage.

They have been around at least 565 million years, and probably far longer. And they haven’t needed to change their body form or their lifestyle in all that time . . . because they work. Jellyfish are among the world’s most successful organisms, having survived freezes, thaws, superheated conditions, shifting and rearranging of continents, mass extinctions, meteor strikes, predators, competitors, and even man. And all the while, as creatures around them evolved tails and feet and brains and learned to breathe and fly, jellyfish have persisted just as they are.

Yes, you can laugh about them being spineless and brainless with no visible means of support, but you’ve got to admit, these multimillennial survivors are doing something right . . . and lately, it seems that they’ve been doing a lot more of it than normal.

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I began studying jellyfish on 22 December 1992, at a time when they were so completely unfashionable to work with that people would simply look at me and blink . . . and blink again, unsure of what to say. The “big news” in the very small jellyfish research community at the time was that Frank Zappa had just written a song about Nando Boero, an Italian scientist who had named a new species of jellyfish after Zappa a few years earlier.

In 1998, while working on my PhD at Berkeley, I was awarded a Fulbright Fellowship to examine the effects of jellyfish blooms on commercial fisheries in Australia. But it soon became clear that such a project was not yet possible, because most of the species were unidentified or wrongly identified, simply because of lack of local expertise and—lack of scientific priority to develop the expertise. So I became involved with trying to sort out the classification. Fifteen years and 160 new species later, the incidence and effects of jellyfish bloom problems have become much more obvious all over the world. Stings to tourists. Clogging of fishing nets. Aquaculture kills. Emergency shutdowns to power and desalination plants. A great many jellyfish bloom incidents have caused companies and governments many millions of dollars, and these costly incidents appear to be increasing in frequency.

Dr. Claudia Mills of the Friday Harbor Laboratories of the University of Washington is one of the pioneers in the study of jellyfish blooms. Claudia is a tall woman with a commanding presence and a playful smile. Her science is clean and meticulous, while she conveys a sense of wonder and admiration for her subjects. Pondering jellyfish unhurriedly from her office, which overlooks the laboratory docks and off into the picturesque Puget Sound, she became concerned about what others saw as an unrelated collection of anomalous events; in Claudia’s view, however, these seemingly isolated blooms looked like a growing problem. That was in 1995. Today we have much more data, far more workers, and hundreds of published papers, and yet a few still question whether there is indeed a problem. In fact, a big hoopla erupted on this very issue in early 2012 when a group of experts announced that a global increase in blooms is unsubstantiated (Condon et al. 2012). This was unfortunate wording, and the media had a field day with it. The simple truth is that jellyfish swarms come and go like blooms of flowers as a normal part of their life cycle—always have and always will—in response to environmental stimuli. We are increasingly fishing out their predators and competitors, and we are altering the physical properties of the seabed and chemical properties of the oceans to favor jellyfish. And we are more frequently using the oceans, putting our bodies and industries into the pathways of jellyfish blooms. But despite our increasing use of the sea, we have surprisingly few datasets about jellyfish.

You see, the problem is that nobody foresaw the potential for these simple creatures to wreak the havoc they are now causing all over the world, and so very few long-term datasets exist from which we can quantify the degree of change.

Wild animal populations rise and fall continuously to some degree . . . it’s just the nature of nature. But long-term trends—and more importantly, huge declines or inclines over the short term—cry out to be explained.

Lucas Brotz did just that. As a master’s student at the University of British Columbia, he investigated the question of jellyfish blooms. Out of 66 large marine ecosystems covering the world’s coastal waters and seas, Brotz found quantifiable jellyfish trends in 45, the overwhelming majority of which showed an increase, while only 2 showed a decrease and 12 were stable (Brotz 2011). Furthermore, Brotz found significant correlations between jellyfish blooms and human activities. His thesis is available on the Internet. It’s worth a read.

One must be cautious in today’s political and economic world, where words can be twisted and evidence is often ignored. If you hear someone say, “jellyfish blooms are bunk,” start asking questions. They are not bunk; jellyfish bloom as a normal part of their life cycle in response to environmental stimuli. The more stimuli, the more response—it’s not all that complicated. If you hear someone say, “There’s not enough data to show that jellyfish are increasing,” this doesn’t mean there’s a lack of data that jellyfish are causing problems—oh, they’re causing plenty of problems. While you need a trend to predict future events, you don’t need a trend to detect that something is a problem now. And you don’t need a PhD to take a punt that ideal conditions for mayhem might result in mayhem.

We would be astonished if a doctor told us, “We have only just noticed this growing cancerous tumor and I’m not sure what it means; let’s just wait and see if it becomes untreatable.” As the patient wanting to survive, we expect aggressive action to fix the problem rather than a sit-and-wait approach to collect more data.

As with many such complicated issues, there are essentially two ways to approach this: (1) from the standpoint of scientific enquiry, or (2) from the perspective of management. Science seeks to quantify a problem in order to understand its origins and predict its future. Management seeks to minimize negative effects now and in the future, regardless of origins and explanations. It’s just two different ways of looking at the same thing. One is not better or worse than the other—it is not a competition! They simply seek different outcomes. But we confuse the two at our own peril. As a scientist, I will argue the importance of data and understanding until the cows come home. But as a practical person wanting safer, healthier, more sustainable oceans now—not waiting 40 or 100 years until we finally have sufficient long-term data for scientific consensus—I will argue that jellyfish blooms are a problem that needs to be dealt with, pronto.

Jellyfish as organisms may or may not be experiencing a sustained global increase, but there can be no doubt that the incidence and severity of problems they are causing globally are increasingly reported (Mills 2001; Purcell 2012). Either way, the havoc that jellyfish are causing is difficult to ignore, and our lack of long-term comparative data in most regions leaves us vulnerable to being caught by surprise as blooms cause trouble and ecosystems falter. In all likelihood, yes, jellyfish probably are on the increase worldwide, as human-impacted ecosystems change to become less favorable to some species and more favorable to jellyfish.

In addition to Brotz’s thesis work, a persuasive argument is to be found in the intersection of two recent studies. Dr. Ben Halpern of the National Center for Ecological Analysis and Synthesis in Santa Barbara, California, and his colleagues created a scoring system to rank the human impacts on 232 marine ecoregions around the world (Halpern et al. 2008). Meanwhile, Dr. Jenny Purcell of Western Washington University tabulated a variety of environmental indicators and found that 6 of Halpern’s top 10 rankings, plus 8 others in the top 100, coincide with regions of notable recent jellyfish blooms and high indicator values (Purcell 2012). Many of Halpern’s other higher-ranking ecoregions may well be experiencing jellyfish bloom problems too, but remain undocumented for whatever reason—as the old saying goes: absence of evidence is not the same as evidence of absence.

Furthermore, harmful and costly jellyfish incidents are likely to increase in severity and frequency as our oceans become more and more stressed by man-made disturbances—“anthropogenic perturbations,” they are called.

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A great many books—some of which are fascinating reads—have been written on climate change, overfishing, and the pollution of our ecosystems. But there is a pattern to these books that I believe is not completely accurate, and is perhaps somewhat misleading. They leave the reader with the feeling that if we would just stop polluting, everything would be okay—that if we would just stop overfishing, the oceans would return to normal. These ideas sound good, but are not what we observe actually taking place.

It is a very egocentric view to assume that Homo sapiens, wise as we are, hold all the levers of change. We pollute, but we cannot so effortlessly unpollute. We overfish, but we cannot so easily restore fish populations to normal. There is another variable in the equation that is invisible to us. As invisible but as real as low pressure is to a hurricane. As invisible but as real as DNA is to the existence and daily functioning of our own bodies. As invisible but as real as a poisonous vapor. Jellyfish.

Anthropogenic disturbances and jellyfish blooms are not mere hypothetical concepts. The causes and effects are happening around us now—we don’t have to wait hundreds of years to see if it’s all true. We can see evidence of degradation all around. And the problems all tie in together; they are all part of a cascade of events leading to a very changed world from the one we know. You can go to a marina near you and see introduced species and lots and lots of jellyfish now. You can go snorkeling and see bleached and dying reefs now. You can go fishing and see changed relative species abundances now. You don’t need to spend money to go to some exotic tropical or polar locale. You don’t need a PhD to figure out the chemistry or understand the biology.

Don’t take my word for it—ask your own questions. Go to any public aquarium or marine theme park and ask why they have so many species of jelly fish on display but no Yangtze River dolphins. Go to the beach—any beach, anywhere—pick up a handful of sand, let it trickle through your fingers, and notice how much of the grainy mixture contains tiny fragments of plastic. Go to your local fishmonger and ask when was the last time they carried Atlantic halibut, or Newfoundland cod, or California white abalone, or Chesapeake Bay scallops, and why the price was so high. Google terms like “jellyfish blooms” or “jellyfish climate change.” Read the literature and make up your own mind.

So many bits and pieces of evidence are around us all the time, but few see them in a connected way. When we think of overfishing, we forget that the warming waters of climate change are reducing the dissolved oxygen, making it harder for fish to respire and survive, and thus further contributing to the loss of fish. When we think of pollution, we think of smelly nasty corners of marinas, or beer cans and plastic drink bottles washed up on beaches, but we don’t think about the heavy metals or pesticide residues accumulating in our food supply and in our own bodies as a result . . . or about the excess nutrients flowing into estuaries and bays, creating vast dead zones . . . or about the many exotic species transported around the world in ballast water every day . . . or about the changes in ocean pH caused by carbon dioxide, leading calcium carbonate to leach out of snails’ shells and corals’ skeletons. And we hardly ever consider the consequences of jellyfish inheriting disturbed ecosystems—from the jellyfish perspective it is certainly a perfect Hollywood ending, but from the human perspective, it is more like Hitchcock or Poe.

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This book is not meant to be an exhaustive account of the perturbations vexing marine ecosystems, nor even a complete treatise on jellyfish bloom biology. Rather, I have written this as an overview to give a feel for the depth and breadth of the problems that arise where disturbances and jellyfish intersect. Many of the stories relate directly to jellyfish blooms, while others relate indirectly through the destructive effect that they have on the marine ecosystem or its inhabitants.

I hope that as you read this book, you will come to realize two things: that the statistics and stories recounted herein are just a small sample of the total problem of ecosystem degradation, and that jellyfish blooms are the inevitable outcome of extreme changes in the marine environment.

Normally, predicting the future is the suspicious enterprise of palm readers and fortune-tellers. However, in this case, the scientific evidence is overwhelming, with a very large number of independent datasets all pointing to the same trends. The conclusions presented here are conservative, and the predictions stemming from them are scientifically reasonable. It is hard to imagine that they will not come to pass, despite being socially unfathomable and essentially apocalyptic. In the words of Professor Jeremy Jackson of the Scripps Institution of Oceanography (2010, 3772), “The question is not whether these trends will happen, but how fast they will happen, and what will be the consequences for the oceans and humanity.”

In my view, anthropogenic disturbances are merely different types of stimuli that trigger a common biological response. And more often than not, they work synergistically. This is the story of the response—the role that jellyfish play in driving weakened ecosystems to a new stable state, their state.

How inappropriate to call this planet Earth when it is quite clearly Ocean.

—ARTHUR C. CLARKE