When it comes to lunch, tuna fish offers it all. It's high in protein and flavor, and it's economical too! But more and more people are concerned about tuna due to questions about sustainability — specifically issues of overfishing and damage to ocean ecology. There are also questions about high levels of mercury.
And yet I do love my tuna fish sandwiches! So I went to an expert with this question: should I feel guilty buying and eating canned tuna?
For seafood questions, there's one immediate and obvious place to ask: Seafood Watch. The Monterey Bay Aquarium Seafood Watch program is a well-known and incredibly useful resource that collects and consolidates research to help consumers and restaurants make sustainable choices in seafood.
I check the Seafood Watch app on my iPhone when I buy fish and seafood. They use a stoplight trio of red, yellow, and green stamps to assign seafood one of three categories: Avoid, Good Alternative, and Best Choice. When I search for tuna in their app, nearly twenty options pop up in all three of these categories, from Tuna, Yellowfin (Avoid, when caught using the purse seine method) to Tuna, Skipjack (Best Choice, when caught using the troll or pole method).
Learn More About Seafood Watch
I appreciate Seafood Watch's careful research and the clear way they present the options to consumers, but I was a little perplexed by the array of options. I turned to Sheila Bowman, the Manager of Culinary and Strategic Initiatives at Seafood Watch with my tuna questions; I wanted to really understand whether it's still a good choice to buy tuna, and if so, how to shop for it.
Sheila is a passionate and lively advocate for sustainability, and she's been with the Monterey Bay Aquarium for over 20 years and clearly loves her job. "Sheila," I asked — "how should we be thinking about canned tuna?"
There are many species of tuna.
The first thing to understand, she said, is, "Not all tuna is created equal. There are multiple species."
The best tuna, and perhaps the one most commonly found in cans on grocery store shelves, is skipjack, also known as light tuna. The problem with skipjack, from a consumer's viewpoint, said Sheila, is that it's often a slightly unappealing light gray or tan color. So skipjack isn't overfished, especially compared to the highly sought-after sushi grade bluefin tuna.
Another tuna that is frequently found in the can is albacore, the white tuna. "It's a big success story," said Sheila. "Albacore tuna populations are in reasonable shape now."
But if you don't mind the color of skipjack, it's the best choice, since it's rarely found on the plate, as in sushi — just in the can. Therefore it's not overfished, and it tends to be caught in ways that are the most sustainable.
How it's caught matters a lot.
Skipjack, albacore — either way, it really matters how it's caught. "In both cases," said Sheila, "you’ll start to see more and more all-important info of how it’s caught."
The thing to look for, said Sheila, is pole/troll caught tuna. "Ironically, the best ways to fish for tuna (and most other fish) is the oldest way: on a line or a pole. "It's how we used to catch tuna in the early 1900s — all pole-caught. Funny as it seems, that’s a great way to catch fish! You catch one on a hook, and if it’s too small or the wrong fish, it can go back in." This kind of fishing limits bycatch — the waste of other fish or sea life that get caught up in a big net.
Another thing Sheila said we should look for is tuna that is "FAD-free.” FAD stands for fish aggregating device, and it's essentially an object fishing operations throw in the water to encourage fish to group up in huge schools. Fish love to cluster together, and they'll do this around virtually any object in the open ocean. "Like lions on the plain, they group up," laughed Sheila. While it's easier and quicker to catch a large quantity of fish when using a FAD, it's extremely difficult to catch only the tuna or other target species; a great deal of bycatch gets in too.
This slower way of catching fish does make a difference in price. "Instead of $1.60 a can it’s often $4 a can," explained Sheila. But she pointed out that some sustainable and FAD-free tuna varieties, particularly ones sold at Safeway and Walmart, can still be found in that lower $1.60 to $2 price range.
What about mercury?
Sheila was quick to say that her organization doesn't speak to health issues, like mercury or BPA in the cans themselves; they focus on sustainability questions. That being said, there are sustainability issues that affect mercury in fish. The longer a fish lives, the more mercury it accumulates in its body. Sheila explained that methods that catch smaller fish, like troll and pole fishing, are not only more sustainable but also healthier and safer for us.
So, is it OK to buy canned tuna?
"I would absolutely buy canned tuna," said Sheila. "There are Best Choices there, if you know what to shop for. In the world of seafood that’s where you want to be." But she acknowledges that she wouldn't eat it daily, for reasons of mercury buildup. "Maybe a few times a month. But it's a great cheap source of protein."
Thanks so much Sheila!
Quick Shoppers Guide to Canned Tuna
Shopping for sustainable canned tuna? Here are the main things to look for.
- Skipjack tuna is best. Some albacore tuna is also a good pick.
- Troll/pole caught tuna is best. Avoid purse seine and net methods.
- FAD-Free is good. Also look for the FAD-free designation.
Personally, I often buy Wild Planet tuna, which is a bit more expensive, but holds to these standards of sustainability. There are also the FAD-free options Sheila mentioned at Walmart and Safeway, and she also pointed out an economical troll/pole canned tuna at Whole Foods.