The story of Fukushima’s 2011 nuclear disaster stirred deep anxieties worldwide about radioactivity in the ocean and its effect on seafood. In the early weeks after the reactors melted down, tiny traces of radioactive isotopes such as cesium-134 and cesium-137 were indeed carried by ocean currents and even detected in migratory fish species like Pacific bluefin tuna that travel thousands of kilometres across the Pacific. But if you look at the latest research and monitoring data over the past decade, the real picture is more reassuring than most people imagine.
Scientists have carefully measured radiation in Pacific fish and shellfish for years. A major scientific synthesis published in Communications Earth & Environment shows that after the first year, the amount of radiation from the Fukushima accident present in seafood became very small relative to the natural background radiation already in fish and gradually dropped to levels indistinguishable from what existed before the accident. Even in regions where seafood consumption is very high, radiation from Fukushima-derived cesium made up only about 2% of the total ingestion dose, with the rest coming from natural radionuclides like polonium-210 and lead isotopes that have always been part of the ocean ecosystem. Polonium-210, for example, occurs naturally as part of uranium decay in the environment and accumulates in marine life — and it contributes far more radiation than the Fukushima fallout.
Regulatory bodies like the U.S. Food and Drug Administration (FDA) and the Washington State Department of Health have repeatedly tested imported and local seafood for radioactivity over many years. The FDA reported that of nearly 1,750 samples tested over about a decade, only three showed detectable cesium — but even those were at amounts far below levels considered unsafe for public health. Independent seafood testing off the U.S. Pacific coast has found extremely low levels of cesium isotopes — so low that they pose no known risk to people who eat the fish.
Another important point is that many radionuclides are already part of everyday diets worldwide. Polonium-210, for example, is present in all seafood because it is naturally in seawater and is taken up by marine organisms; scientists have found that the radiation dose from polonium in seafood is generally far higher than from Fukushima-derived cesium, even shortly after the accident. This does not mean that polonium-210 is “safe” in any absolute sense — all radiation exposure carries some risk — but it frames how small the added impact from Fukushima actually is in comparison.
In the Indian context, where seafood is a valued part of diets in coastal states and union territories, regulatory monitoring focusses on actual safety thresholds, not fear. India’s food safety authorities, like counterparts elsewhere, require that imported foods (including seafood) meet strict safety standards before they are allowed into the market. While India does not import large quantities of Pacific tuna directly from Japan, any imported seafood is screened, and domestic fisheries are subject to national safety checks. The International Atomic Energy Agency (IAEA) has also repeatedly assessed that outside waters very close to Fukushima, radionuclide levels in seafood are significantly below thresholds of public health concern and that any extra radiation contributes only a small amount to natural background exposure.
Concerns about long-term releases of treated water from Fukushima into the Pacific, which began in 2023 and will continue for decades, are regularly discussed by scientists. Some of that water contains tritium, a radioactive isotope of hydrogen that does not accumulate in fish or humans, and its levels are heavily diluted in the vast Pacific. Independent modelling — including research published in 2024 — finds that the added tritium in seawater remains far below safety limits for drinking water and poses very low risk to ecosystems and human consumers.
In simple terms: yes, traces of Fukushima-related radioactivity did enter the ocean and have shown up in some fish, but years of data show that levels are low, decreasing over time, and far below levels expected to cause health problems. Natural sources of radioactivity in the environment — things like polonium-210 that occur in all oceans — are a much larger part of the radiation people already get from food and the environment. Monitoring by health authorities continues, but current science does not support alarm or drastic dietary changes for seafood consumers in India or elsewhere.