The more research is conducted on the effects of trawling, the harder it is to make a case for why it is allowed—anywhere, ever. It’s especially hard to argue for high seas bottom trawling, the kind that dredges up roughly twice the area of the United States every year and, since the United Nations couldn’t agree on terms, is currently unregulated. Now, a study published in Proceedings of the National Academy of Sciencesadds to the mounting evidence that our hunger for piscine protein is laying waste to parts of the planet we have never even seen, leading to lasting changes in the sea floor that prevent recovery.
Trawls are bulldozing millions of square miles of the sea floor every year. A new study in PNAS says that if such fishing is sustained, this is all that will be left. Image from Gewin 2004
To manage modern fisheries, scientists have to quantify and monitor populations of animals that live hidden in the vast depths of our oceans. Simply getting the data needed to get a glimpse of what is there now can be difficult, but it’s downright maddening when they try and look backwards to understand how populations of species have changed over time. Some areas have detailed catch records—others, don’t. Sometimes you get a few good decades of government data followed by long gaps in information. But that doesn’t mean the data aren’t out there; sometimes, information is hiding where you least expect it. Scientists have collected fisheries data from photographs, newspapers, and local cultural leaders. Now, a trio of ecologists have tapped another unexpected resource to fill in a 45 year gap in fisheries data in Hawaii: restaurant menus.
Roughly three-quarters of the Earth’s surface is covered with water. As I stand on a beach in Hawaii and look out over the vast, blue expanse in front of me, I am overwhelmed by the immensity of the Pacific Ocean. My brain wrestles with numbers far beyond its capacity to visualize. In that moment, it is incomprehensible that even seven billion humans could deplete such a boundless and unimaginable resource. Yet, I know that we are. We are emptying the oceans of their fish, one species at a time.
Today, 85 percent of the world’s fisheries are either fully exploited, overexploited or have already collapsed. Combined, the world’s fishermen catch 2.5 times the sustainable number of fish every year. Scientists predict that if current trends continue, world food fisheries may collapse entirely by 2050. “We are in the situation where 40 years down the line we, effectively, are out of fish,” explains Pavan Sukhdev, special advisor to the UN Environment Programme.
What we need are better management strategies. Now, researchers from the Center for Ocean Solutions at Stanford University are turning to the past for advice. Loren McClenachan and Jack Kittinger used historical records to reconstruct fish catches for the past seven hundred years to see if earlier civilizations did a better job than we are at managing their fisheries. The authors were able to characterize historical catch rates in the Florida Keys and Hawaii by reviewing a variety of historical sources, including species-specific catch records from the 1800s and archaeological reconstructions of population densities and per-capita fish consumption.
“Seven hundred years of history clearly demonstrate that management matters,” said Loren McClenachan, co-author of the study and assistant professor of environmental studies at Colby College. In Florida, fisheries were characterized by years of boom and bust through sequential collapse of high-value species, many which are still endangered or extinct today. The Keys fisheries were set up for failure – unlike other historical island communities, the Keys were highly connected to other markets, increasing fisheries demand. Furthermore, they have historically lacked a centralized management system. But, while fisheries in the Florida Keys have always been poorly supervised, fisheries in Hawaii were once far better than they are today.
Annual fisheries catch per reef area for the Florida Keys and Hawaii over time.
“Before European contact, Native Hawaiians were catching fish at rates that far exceed what reefs currently provide society,” said Kittinger, co-author and early career fellow at the Center for Ocean Solutions. Native Hawaiians pulled in over 15,000 metric tons of fish per year, and these high yields were sustained over several hundred years, despite a dense Hawaiian population. “These results show us that fisheries can be both highly productive and sustainable, if they’re managed effectively.”
Much of the management system in Hawaii was tied to class and gender. For example, most offshore fishing was done by a professional fishing class who were familiar with their local environment. If they wanted to fish, they had to ask their chiefs, who regulated the fishing gear and canoes. The most valuable (and vulnerable) species like turtles and sharks were reserved for high chiefs and priests, reducing fishing pressure.
The key to the Hawaiian’s success lay in using a diverse suite of management measures. Many of the methods they used are similar to strategies employed in fisheries management today, including protected areas, community-based management, regulation of gear and effort, aquaculture, and restrictions on vulnerable species.
Perhaps the greatest difference between management then and now, however is that in native Hawaiian society, rules were strictly enforced. “Rules were accompanied by robust sociocultural institutions,” the authors write. The ancient Hawaiians did not hesitate, and punished transgressors with corporal punishment. “Clearly, we don’t recommend this,” said Kittinger, “but it’s easy to see there’s room to tighten up today’s enforcement efforts.”
He’eia Fishpond in Kane’ohe Bay, Hawaii. Image c/o Paepae O He’eia
Other differences exist as well. For example, while aquaculture was used by the native Hawaiians, these fishponds were maintained for different reasons than we farm fish today. Fishponds did not contribute substantially to total fish production, but instead served as food security during tough times. As such, Hawaiians stocked fishponds with very different species than modern farms. Fishponds contained small, algae-eating species, requiring little from the sea to support them. Modern aquaculture, in contrast, relies heavily on wild-caught feeder species to support lucrative, luxury species like salmon. Five pounds of wild-caught fish are needed to produce one pound of farmed salmon, and instead of acting as a backup for when wild fish are scarce, fish farms make up a whopping 50% of our consumed fish production.
Kittinger and McClenachan hope that understanding successful management strategies by historical societies will lead to better management of our current resources. “The evidence we present from historical reconstructions shows that reef fishery sustainability has been achieved in the past,” they write, “which can guide actions for a more sustainable future for reefs and the communities that depend on them.”
Reference: McClenachan, L & JN Kittinger (2012). Multicentury trends and the sustainability of coral reef fisheries in Hawai‘i and Florida. Fish and Fisheries, doi: 10.1111/j.1467-2979.2012.00465.x
Every once in a while, you write something you really, really like. You write something you like so much, you wish you could write it again, over and over. Well, I happen to have a few of these posts that I have written previous to my move here, and I want to share them with you. They’ll be labelled as “Observations,” indicating they were originally posted on my old blog, Observations of a Nerd. Enjoy!
Mouse, my adorable cousin, showing off a bubble
“Christie! Christie!” My four-year old cousin tugs eagerly on my jacket. “I wanna see the fishes.”
“Ok, Tuna, we can go see the fish.”
My little cousin loves the word ‘tuna’. She says it all the time. Tuna, tuna, tuna. Everything is a tuna-face or a tuna-head. She doesn’t even like tuna (she doesn’t eat it), but she loves the sound of the word rolling off her tongue. Finally, her nanny threatened that if she kept saying ‘tuna,’ we’d have to start calling her it. My ever so adorable cousin’s response was, of course, “TUNA!” So now that’s her nickname. She’s Tuna.
I’m waiting in line with her and her sister at the Rainforest Cafe in the Burlington Mall. They love the Rainforest Cafe. There’s a giant mechanical alligator out front that they can’t seem to get enough of. Mouse (as I now call Tuna’s older sister) is convinced that it’s real. Who am I to burst her bubble?
But now, in line, their eyes are instead drawn to the entrance arch of fish tanks. As a marine biologist, I feel obligated to tell them about the fish.
“You see that one? That’s a butterflyfish. And that one — that’s a grouper. Oh! And that little colorful one there — that’s the Hawaii State Fish. It’s name in Hawaiian is Humuhumunukunukuapua’a. Can you say Humuhumunukunukuapua’a?”
My two cousins look at me like I’m insane. I guess they’re a little young to try and learn Hawaiian fish names.
“Christie! Christie!” Tuna grabs my jacket again. “Are there any tuna?”
“Tuna. Tuna. TUNA!” Mouse grins at her sister, and the two burst into giggles.
Their attention quickly drifts to shooting back and forth funny words like Tuna and Pizza, and instead I am left with my little cousin’s innocent question derailing my thoughts.
Tuna. One of my favorite fish. Large, majestic creatures built for speed and strength. Even a rudimentary understanding of how perfectly suited they are as open ocean predators leaves one in awe of evolution’s handiwork. A sleek, streamlined design, with specialized circulation and muscles to provide warmth and power even in cold water — they are truly incredible fish.
There are many kinds of tuna: Albacore, Bigeye, Blackfin, Bluefin, Karasick, Longtail Skipjack and Yellowtail. Even within a ‘kind’ like Bluefin there is Northern Bluefin, Southern Bluefin, and Pacific Bluefin.
They’re all similar in that they’re unbelievably delicious.
I remember the last time I ate tuna. I would love to say it was a long time ago, but it wasn’t. I slipped into the take-out sushi place as quietly as possible, but the little bells attached to the door handle announced my entrance.
“Wat can get fo you?” the nice man behind the counter asked.
“I’ll have the Spicy Ahi Maki, please.” Once my treat was handed over, I made quick work of the bright red fish smothered in my favorite chili mayo. The soft, tender flesh melted in my mouth, tasting of decadence. Within a matter of minutes it was all over.
As soon as I walked out the door, though, it hit me. The guilt. You should know better, I chided myself. The tuna fisheries, by and large, are a disgrace. Many are overfished and on the verge of collapse. Take the Mediterranean Bluefin tuna fishery, the largest fishery for Bluefin in the world, for example. Tuna are caught young in massive numbers and corralled in cages offshore where they’re fattened for the sushi and sashimi market. If the Mediterranean Bluefin tuna fishery is not closed now, some scientists project that the tuna in that part of the world will be functionally extinct in just two years.
Of course, I know that the tuna I ate wasn’t likely to be Bluefin. It wasn’t Albacore, either, as Albacore is the tuna you get in cans, not the kind served in sushi bars (though it can be found under the name “Shiromaguro” if they have it). While the Japanese are much pickier about their labeling, giving each species a different name, in the states, Ahi or Maguro can refer to just about any tuna species, though most often it refers to Bigeye, Yellowfin or sometimes Skipjack. It’s only if you get Toro, the fatty tuna that will cost you an arm and a leg, that you’re likely to be eating Bluefin.
But ordering tuna in a restaurant is a bit like playing ecological Russian Roulette. Rarely do restaurants know or care where their fish comes from, only that they got it at a decent price. Even if they think they know and think they care, they’re often wrong. A recent study which genetically tested ordered tuna in restaurants found you may be served anything from the critically endangered Southern Bluefin to Escolar, a disgusting fish known to cause illness when eaten. Most (79%) of the menus did not say what species was served, and when asked, almost a third said the wrong species while another 9% had no idea.
The problem, of course, is that it matters which species you eat. All Bluefin fisheries are unsustainable, and eating them ensures their doom. Meanwhile, Yellowtail and Bigeye, though better off, are approaching the same fate — though if caught with pole and line (the slower and more expensive way to fish), they could be sustainable. Only Albacore and Skipjack have healthy and well managed stocks right now, though if we lean more on them to make up for losses in the other three major fisheries, it’s likely they, too, will be in trouble. Despite warning after warning, government agencies all over continue to keep quotas for most species well above sustainable levels.
As if that’s not bad enough, members at the recent CITES meeting rejected legislation that would have limited the trade of tuna between countries. It seems that the politicians just don’t care enough, and it’s up to the public to make it clear that driving these species to extinction is not something we’re willing to stand for. To do that, we have to stop supporting the market… to stop going out to little take out sushi places and getting the Spicy Ahi Maki.
I tried to console myself that, living in Hawaii, it’s possible that the tuna I just ate was Skipjack, pole-caught locally… but I know better. Pole-caught fish are more expensive, and it’s not likely the cheap take-out sushi place is splurging for the local variety just for kicks, especially if they aren’t advertising the fact. No, that delicious meat was likely Yellowfin or Bigeye purse-seined or long-lined in some foreign country and shipped, frozen, to Honolulu to be eaten by cheap people like me.
The feeling that washed over me in that instant was not unlike the feeling you get when you drunkenly sleep with your ex a month or so after the breakup. Sure, it seems like a good idea at the time, and for a brief moment you feel pure pleasure. But you wake up the next morning coated with filth and regret. The truth is, you’ve only made things worse. You glare at yourself in the mirror, pissed that you were so stupid. But the worst part is the unshakeable feeling that lingers for days. You feel… well, there’s really no nice word for it. You feel like a slut.
That’s what you are, you know my conscience spits at me. You’re a tuna slut.
“Christie! Christie!” My cousin’s pleas snap me back.
“What is it Tuna?”
“You’re a toushie-face!” They erupt into laughter. The two are completely out of control. With the artful skill only an older cousin can have, I draw their attention back to the fish, explaining the different types and little facts about how they live. They’re mesmerized. Soon enough we’ve been seated, ordered our food, and had a nice lunch surrounded by the chaotic jungle of the Rainforest Cafe.
Later that evening, the girls kiss and hug me goodnight. “Goodnight Mouse, Goodnight Tuna,” I whisper to each. As they head upstairs with their parents to bed, I sip a glass of my uncle’s homemade red wine and can’t help but think about the plight of tuna.
A fish so beloved by so many like myself, yet its very survival is threatened by that adoration. The trouble is that it’s just hard to give up something we love so much. If I — a marine biologist armed to the teeth with the knowledge of exactly how bad the problem is — still cannot restrain myself from indulging, it seems hopeless to expect that the world will. If we continue to fish for bluefin and other tuna like we do now, there is no ambiguity about the result. They will disappear. Probably within my lifetime, maybe even sooner. And before they disappear, they’ll become so hard to find that a slice of sashimi will be as expensive as Beluga caviar is now.
It’s possible that regulating agencies will come to their senses and limit the catch, thus allowing tuna species to rebound before they’re completely gone — but they sure as all hell don’t seem inclined to. Some have had the idea of rolling moratoriums, where certain fishing locations are banned for several years, then others the next few years, to allow wild populations time to recover. Or maybe they could instate tuna credits, allowing fish-hungry nations like Japan to eat their fill while others abstain. There are a lot of ways politicians could help prevent overfishing — none of which, of course, they seem to want to do.
It’s also possible that we’ll find a way to farm tuna, taking the pressure off of falling wild stocks. As it stands now, many species of tuna are caught young and kept in pens until they’re big and fat enough to be slaughtered. But this isn’t really farming in the truest sense because they still have to be wild-caught first. Tuna species, particularly the plummeting Bluefin, have proven to be extremely difficult to aquaculture. They take 12 years to mature, and apparently, don’t find large aquariums or offshore corrals very romantic, so they don’t produce the next generation in captivity. Some have had luck using drugs to trick them into producing eggs, but the method was expensive and labor intensive, and it has yet to be seen if the young produced are healthy. While this does produce hope, it’s limited, and it’s hard to see commercial aquaculture technology rising fast enough to the occasion to save these species.
I can’t help but wonder if, in fifteen or twenty years, I’ll even be able to order maguro if I take my cousin out to a nice sushi restaurant so she can try the fish she’s nicknamed after.
Even if I can, I hope that when I suggest it, she glares, then sighs like she’s sick of explaining this kind of thing to ignorant people like me. Her generation will have learned from our mistakes. They will do better. She will remind me that tuna are rare and beautiful fish; that they’re aren’t that many left, and if we keep ordering tuna and continuing the demand for their meat, they will disappear altogether.
And, she’ll likely say, I’m a grown woman now — so stop calling me Tuna.
For more information about sustainable seafood choices, take a look at the Monterrey Bay Aquarium’s Seafood Watch List for your area. In particular, you can help protect the wild tuna by ordering other, more sustainable sushi. For examples, check out SustainableSushi.Net.
Learn more about the plight of the tuna and what you can do to help at SaveTheBluefinTuna.Com.
This past weekend, I sat down at my computer hell-bent on writing this post. I knew I couldn’t about write about just anything – not for my first real post on Scientific American. I mean, sure, I’ve written for the guest blog a couple times, but this is different. This is my blog. I have been obsessing about this post for weeks. Without realizing it, I was standing in front of the thickest writer’s block I’ve ever seen, a wall so dense that I spent all weekend thinking about this post and still got absolutely nowhere. Suddenly, there I was: less than 12 hours before my post was to be published, and not a single word of it written. I just needed a topic, I figured. A really, really good topic.
I named this blog “Science Sushi” for two reasons. The first was that I wanted an image that would explain how interesting and great science can be when it’s kept simple. No over-inflated results, no tenuous connections to barely-related concepts – just the research, all by itself, stripped of the scientific jargon that usually makes it inaccessible. The word “raw” kept coming to mind – that I reveal the “meat” of a study, or expose its “tender flesh.” At some point, while throwing those words around, I imagined a plate of nigiri, but overlaying the rice were atoms and animals and all the cliche images of science instead of raw slabs of fish. Suddenly my brain was filled with visions of hand rolls bursting with DNA helices and gene sequences served alongside an Erlenmeyer flask instead of a tokkuri of sake. The visual was too powerful to ignore. So, Science Sushi it was.
Of course, the second reason (and probably the reason why the words “raw” and “tender” magically transformed images of science into nigiri and temaki) is that I love sushi. No, not love – love is what I feel for my job and my family. The emotion I feel towards sushi is such a deep passion that I don’t have a good word to describe it. It’s the first thing I think of when someone asks what my favorite food is, or what I’m in the mood for. I could eat it at every meal and never grow tired of the sweet taste of tender raw fish and sticky rice with just the right touch of shoyu and wasabi.
Duh!, I thought to myself, that’s what I have to write about! As I sifted through idea after idea, it just seemed entirely too appropriate that this post focus on the food that inspired my blog’s title and that has such a special place in my heart.
My favorite food has an interesting past. While we now think of the freshest seafood neatly wrapped in rice and seaweed, sushi began as a way of preserving fish. Early Southeast Asian peoples realized that if they packaged salted fish in fermented rice, it kept for a long time and could travel inland. That’s where sushi got it’s name – the word comes from “zushi” which meant “sour-tasting” in an archaic language form. It wasn’t until the 19th century that nigiri was created and fresh fish became the norm. Even still, sushi was mainly a Japanese dish – only at the end of the 20th century did sushi begin to go global. Now, sushi restaurants are common worldwide, and in some areas, like here in Hawaii, they are found on every corner next to Starbucks.
Why did sushi become so popular? In part, the onset of modern technologies like jumbo jets allowed globalization of fisheries in an unprecedented way. Fish caught on one end of the world could suddenly be sold ‘fresh’ on the other. The other part, of course, was good marketing. In the 1970s, Japanese culture and cuisine was sold to the world as the epitome of sophistication and health. As developed nations started to feel the economic weight of rising obesity rates, healthy foods became more and more popular – sushi among them. Nutritionally speaking, it’s well established that fish is one of the healthiest sources for protein and is also conveniently packed with Omega-3 fatty acids and other good fats. Rice is one of the better forms of carbohydrates out there, and even the seaweed that wraps sushi rolls, called nori, is full of soluble dietary fiber.
It’s not that I’m trying to scare you out of eating sushi – clearly, all the knowledge in the world hasn’t scared me. No, if only eating sushi were such a risk that more people avoided it. Our sudden appreciation of Japanese cuisine has had catastrophic affects.
As an article in TIME yesterday pointed out, fish are the last wild food. We once turned to the wilderness for all our meat. A few centuries ago, when we gazed out across the American prairies, we were overwhelmed by the seemingly endless supply of meat in the form of the buffalo. There were, quite literally, tens of millions of them. But even tens of millions were no match for human hunters, and what once was a sea of shaggy beasts dwindled to a handful of isolated populations on the verge of extinction.
Our approach to the endless bounty of the sea was no different. The oceans just seemed so deep that it was hard to believe that we could ever pull the last of a species from the vast watery abyss. Yet in the past century or so, fishery after fishery has collapsed, leaving our seas empty in comparison. You might not have noticed fewer fish in your supermarket, but according to the U.N. Food and Agricultural Organization, 70% of global fish species are overexploited or depleted. The rise in popularity of sushi furthers this trend, and prime sushi species like the beloved tuna are the latest casualties of our inaccurate view of the oceans.
Perhaps, as Douglas Adams phrased it in Last Chance To See, we are not truly sadder and wiser after all our experiences – instead we are merely sadder and better informed.
We know that we must change how and what we eat, including making smarter choices when it comes to sushi. The upside is that this is something you – and I – can do. Monterey Bay Aquarium’s Seafood Watch has tailored their efforts specifically to sushi-lovers. If you want to really understand why these choices matter, just talk to Casson Trenor, author of Sustainable Sushi: A Guide to Saving the Oceans One Bite at a Time and the website SustainableSushi.net. For him, the sustainable sushi comes from a deep love of the food, and his desire to see his children and their children be able to enjoy it like he does.
I couldn’t agree more. While sushi is my favorite food, I don’t eat it as much as my heart desires. While on occasion I might overindulge (and become a ‘tuna slut’), I do know better, and keep my sushi habit in check despite the constant temptation here in Hawaii. My love for sushi is like one of my friend’s love for sweets – sure, she could happily eat brownies at every meal, but she doesn’t because she knows the consequences. In this case, the science has been unequivocally clear: the consequences of eating sushi with reckless abandon means one thing – oceans without fish.
So there you have it. That’s the science of sushi, raw and direct. It’s not as pretty a picture as we might like, but it’s not hopeless. Hopefully, the fact that you read this post all the way through until this point is a good start. Hopefully, you’ll take to heart some of the sobering truths. Hopefully, you’ll make ecologically smarter choices when it comes to eating healthy. And hopefully, hopefully, you and I can sit down to a nice plate of nigiri in 50 years and not feel like we’re eating the last of my favorite food.
At some point, while throwing those words around, I imagined a plate of nigiri, but overlaying the rice were atoms and animals and all the cliche images of science instead of raw slabs of fish. Suddenly my brain was filled with visions of hand rolls bursting with DNA helices and gene sequences served alongside an Erlenmeyer flask instead of a tokkuri of sake. The visual was too powerful to ignore. So, Science Sushi it was.
