By Mark Jones
The tuna was perfectly prepared, lightly seared, perfectly seasoned. It was a meal fit for a seaside bistro, but I wasn’t oceanside. I was in Ironwood, Mich. Delicious as the meal was, it was no locavore meal.
We had stopped in Ironwood, a town in Michigan’s Upper Peninsula, looking for thimbleberry jam. Thimbleberries,Rubus parviflorus, are in the raspberry family, with fruit made up of individual drupelets just like a raspberry. They ripen to a true red color, tasting both sweet and tart. The ripe fruit is incredibly delicate and spoils quickly. I’ve never seen them for sale as picked fruit and can’t find any reference to commercial cultivation. Thimbleberries are foraged. Thimbleberry jam is a specialty item, rarely found outside the UP.
Our stop in Ironwood failed to yield thimbleberry jam. Hungry, we decided to grab lunch. Ironwood is more than 900 miles from the closest Atlantic port, more than 1,500 miles from the Seattle fish market. Ironwood isn’t the pole of inaccessibility, but it is close. Ironwood is far from any tuna port, and yet seared tuna was on the menu.
The concept of food-miles is frequently related to sustainability. It is not at all uncommon to see bragging about local food being the more sustainable option. I’ve been indoctrinated to believe the farther food travels, the less sustainable it is. I entered Ironwood looking for a hyper-locavore product. Pangs of guilt about tuna consumption so far from the ocean hit me as I left Ironwood.
Tuna in Ironwood is a technical marvel. Likely, the tuna arrived in Ironwood frozen and sealed in plastic. It was likely prepped, placed in a multilayer, vacuum-sealed package, and super-frozen, cooled to -60° C soon after it was caught. It was kept cold and in the controlled atmosphere made possible by the plastic for its trip to Ironwood. Super-freezing can preserve the fish almost indefinitely. No need for air transportation — a slow boat or truck will do just fine provided the temperature is maintained.
My guilt over tuna in Ironwood sent me looking for the CO2 footprint of tuna the lunch choices. The October 24, 2022 issue of Nature contained the data I was looking for. My guilt was unwarranted. Tuna in Ironwood is lower GHG than any of the other animal proteins appearing on the menu. Better than a burger. Better than a turkey sandwich. My assumptions that the long supply chain, the excessive food miles, and the energy required to maintain refrigeration would give tuna a high GHG footprint were wrong. Tuna are wild-caught. The fuel consumption in chasing and harvesting them is a large part of the GHG footprint, but small compared to the emissions associated with agricultural production of meat.
Tuna in Ironwood taught me a few things. Local is not always better for the environment. Local consumption provides other benefits, but lower GHG emissions isn’t assured. Food-miles aren’t a great indicator. Tuna in Ironwood taught me making more sustainable choices is not instinctive. More sustainable, even for someone well versed in sustainability, is hard. It requires thought and study. Data are readily available — if you’re willing to take the time.
Filed Under: Commentaries • insights • Technical thinking
