In our home, tuna has always been a staple Real Food. Spicy Bluefin tuna rolls are a favorite of my husband when dining at Japanese restaurants. I’ve always taken care to source low mercury, sustainably caught tuna in order to prepare quality tuna steaks for dinner, tuna melts for lunch, or tuna salad for lunchboxes, quick snacks or just a dollop on a bed of greens.
However, a year ago, I began reading the reports about the spreading radiation plume in the Pacific from the continuing Fukushima nuclear disaster. I delved into the migratory patterns of various species of tuna. The more I read, the more concerned, and quite frankly, confused I became. I started to question my choice of tuna for regular consumption as a result.
Realizing that my family’s health can’t be wagered on guesses or half truths, I tried to gather as much information as I could to be sure that I have the whole information about the issue. I will now present my findings.
Pacific bluefin tuna spend their early months swimming in the radiation plume in Japan, where they are born. Afterwards, during their entire life, they swim back and forth across the Pacific. For instance, one tuna nicknamed Terry crossed the Pacific no less than 3 times in the span of only 20 months, each time coming very close to Japan. To the right is a chart showing his epic swim.
This information gleaned from Terry the tuna is not new. As early as the 1950′s, albacore tuna were known to swim thousands of miles, as shown in this second chart to the right. The open circles off the California coast indicate where they were released and the solid circles closer to Japan indicates where they were recaptured.
All species of tuna are thus, highly migratory, indeed. This means that almost throughout their entire lives, they swim long distances. It is generally agreed upon that these migrations are large, even though their patterns are still ill-understood.
The same nomadic patterns are present in the cases of the Atlantic based tuna. According to National Geographic, high tech tags of Atlantic bluefin tuna revealed the following:
Two giant bluefins tagged within minutes of each other off the coast of Ireland were documented by a team of international scientists. These two fish swam to opposite sides of the Atlantic Ocean–ending up more than 3,000 miles (5,000 kilometers) apart. One of the fish traveled 3,730 miles (6,000 kilometers) southwest to waters about 186 miles (300 kilometers) northeast of Cuba. The other remained in the eastern Atlantic and moved off the coasts of Portugal.
According to the Food and Agriculture Organization of the United Nation (FAO)s, all species of tuna, not just bluefin and albacore, are considered highly migratory, again with the reasons for these patterns not well understood. Here is a list of the tuna species and their locations according to a report by the FAO:
Bluefin tuna (Thunnus thynnus) since the adoption of UNCLOS , in the northern Pacific has been identified as a different species, Pacific bluefin tuna (Thunnus orientalis), while bluefin in the Atlantic has been re-named Atlantic bluefin tuna. It is mostly found in temperate waters of the Atlantic, including the Mediterranean, and Pacific Oceans.
Albacore tuna (Thunnus alalunga), which lives in tropical and temperate waters worldwide.
Little tuna (Euthynnus alleteratus and E. affinis), with E. alleteratus, found in tropical and subtropical waters of the Atlantic, including the Mediterranean, the Black Sea, the Caribbean Sea and the Gulf of Mexico, and E. affinis in the Indian and Pacific Oceans. It is noted that presently, E. alleteratus is called little tunny and E. affinis is called kawakawa.
Southern bluefin tuna (Thunnus maccoyii), can be found in temperate waters of the southern hemisphere in the Atlantic, Indian and Pacific Oceans.
Skipjack tuna (Katsuwonus pelamis) is found in tropical and temperate waters worldwide.
Yellowfin tuna (Thunnus albacares), also with a worldwide distribution in tropical and sub-tropical more temperate seas, but absent from the Mediterranean.
Frigate and bullet tuna (Auxis thazard and A. rochei) found in the Atlantic (including the Mediterranean Sea where only A. rochei is found), Indian and Pacific Oceans.
Bigeye tuna (Thunnus obesus), found in the Atlantic (but absent from the Mediterranean), Indian and Pacific Oceans.
Blackfin tuna (Thunnus atlanticus) found in the western Atlantic in tropical and warm seas.
So, what is the result of this swimming feature of tuna?
The fact that tuna swim great distances, constantly moving and migrating, should be an alert that tuna in the Pacific more than likely will have passed through the growing Fukushima radiation plume at some point in their lives, probably numerous times.
This is especially true with long lived varieties like albacore (11-12 years) and bluefin (up to 20 years. With much smaller life span, tuna like the skipjack (about 8 years), less so.
Is the Fukushima Radiation a Real Problem?
The answer to this question varies. Some reports say yes, the Pacific based radiation plume from Fukushima is a serious problem and growing worse as 300 tons of radioactive water pour into the Pacific every single day with no end in sight for years. Unbelievably, Japan’s government only acknowledged the urgency of the situation in September 2013.
The most unsettling data to date is that the continued outflow of radioactive water from Fukushima now no longer just contains cesium isotopes. It now also contains the more worrisome strontium-90 which is a bone seeking isotope.
On the other hand, a comprehensive assessment by the World Health Organization (WHO) claims that radioactive particles that are making their way to North American waters will have a limited effect on human health, with concentrations below WHO safety levels.
Who is right then?
One thing is true, Fukushima is a nuclear disaster never before experienced in human history so all theories and probabilities are on the table.
“We still don’t know the answers to many important questions concerning the impacts of Fukushima radio nuclides on the oceans. For example, we still don’t have a good handle on how much radioactivity was released, and we don’t fully understand where it has ended up, and that holds for the ocean waters, seafloor sediments, and for marine biota, such as tuna.” – says Dr. Ken Buessler. He is a world expert in marine radioactivity with the Woods Hole Oceanographic Institution in Massachusetts and leads an international research team tracking Fukushima’s trails in the Pacific.
It seems Best to Be Cautious
From a personal point of view, having known someone who died of radiation induced cancer 15 years after the Chernobyl disaster, I believe caution is our only alternative. The governments at the time said the fallout that blanketed parts of Europe was no threat to human health. The truth was that his wife lost most of her hair, but has survived, although they tragically had a daughter born a few years after the disaster who developed leukemia. As a result, I don’t take the long term, cumulative effects of radiation lightly and interpret official reports (like the one published by the WHO) with a grain of salt.
If you choose to interpret the data as a non- threat to human health, and ignore the radiation levels within safe limits, that is of course your choice. I choose to play it safe for my children’s sake. My approach is both practical and cautionary as long as more information is gathered and the extent of the problem studied further. Given that this particular migratory fish is prone to swimming close to Japan multiple times during its lifetime, this approach of mine includes avoiding all tuna from Pacific waters.
Since much of the time, the ocean of origin for tuna is unknown or not labeled, this would mean avoiding all tuna in most cases. This is exactly what I’ve been doing for the past six months or so – all tuna avoided. Period.
The complaints of my family about the absence of tuna dishes (which everyone loves), has caused me to continue to search for a source of tuna I would feel comfortable serving. I recently discovered a skipjack tuna from Portugal (source) that I’ve started to purchase. I felt at this time, this tuna would be safe to eat, since Atlantic based tuna do not enter the Pacific during their lives.
However, this situation most likely will change in the coming years. Predictions are for the Fukushima radiation plume to continue growing, eventually entering the Arctic and then the Atlantic Oceans, as the disaster is far from contained. For now, however, if tuna origin can be accurately confirmed, I will buy and eat it – but only from the Atlantic Ocean and other non-Pacific sources.
What do you think about seafood in general, and the consumption of tuna? Do you have certain data to support your view/ decision? What are the Pro- s and Con- s for continuing tuna consumption?