Save the sashimi: rising mercury levels in Hawaiian ahi indicate a global problem

Broiled, blackened, seared or raw, ahi is one of America's most popular seafoods. But a new study suggests toxic mercury levels in tuna are on the rise, and may cause serious problems in decades to come. Photo by Angelo DeSantis c/o Wikimedia Commons
Broiled, blackened, seared or raw, ahi tuna is one of America’s most popular seafoods. But a new study suggests toxic mercury levels in tuna are on the rise, and may cause serious problems in decades to come. Photo by Angelo DeSantis c/o Wikimedia Commons

Tuna are some of the most popular fishes on Earth. Globally, more than 4.3 million tonnes of tuna are caught every year, valued at more than $5.5 billion dollars. Yellowfin tuna, the species most commonly labeled as ahi in sushi restaurants nationwide, is the preferred tuna in developed nations like the US and the UK, but the world’s favorite sashimi may soon be stricken from the menu, as scientists have found that mercury levels in tuna are rising at a rate of 3.8% or more annually. More importantly, the rapid rise suggests a growing global problem that may lead to unsafe mercury levels in many fishes, even ones that are now considered completely safe. Continue reading “Save the sashimi: rising mercury levels in Hawaiian ahi indicate a global problem”

Tuna | Observations

This week I’m in Miami for the first-ever ScienceOnline Oceans! I’ll be sharing my experience with you all soon, but to tide you over, here is my favorite ocean-themed post from my old blog, Observations of a Nerd

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.

Continue reading “Tuna | Observations”

Tuna | Observations

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.