Fish Near Japan’s Damaged Nuclear Plant Not Safe to Eat: “Finless” Porpoises Haven’t Gotten the Memo

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Finless porpoises (N. p. sp.), China

Japan’s coastal waters are home to the cute “finless’ porpoise (neophocaena phocaena sunameri), so named because in place of a dorsal fin it has instead a saddle patch of rough skin.  These small porpoises tend to restrict themselves into discrete regions of shallow coastal areas, and unfortunately there is a group that lives in the Sendai Bay-Tokyo Bay region of Japan, locus of the earthquake, tsunami, and now the contaminated water from the Fukushima nuclear reactor.
Their diet varies from population to population, but basically finless porpoises eat fish and cephalopods (squid and octopus), and the calves in at least some regions hone their hunting skills by finding demersal, or bottom dwelling, fishes.  For the population in Sendai Bay/Tokyo Bay region, this means that they will be swimming in radioactive isotope contaminated water, eating contaminated fish, and the youngest porpoises will be the worst off because they select fish from the most contaminated part of the water near the bottom.
This article from the Wall Street Journal reports:

The water that the troubled Fukushima plant began releasing on Monday has radioactive iodine-131 contamination that is around 100 times more than Japan’s limit, and cesium-134 and cesium-137 of some 50-70 times. However, more dangerous water leaking from the plant is at 10,000 times the safe limits for these contaminants.
Scientists say the marine area around the Fukushima plant will likely be contaminated for several years, but the size and currents of the Pacific Ocean will disperse the radioactivity to minute, harmless levels farther from shore. Iodine’s radioactivity fades relatively quickly. It has a half-life of eight days, which means that the radioactivity halves every eight days.
Cesium 137 is a much bigger worry. With a half-life of 30 years, it accumulates in ocean sediment. Shellfish live on the sea floor, accumulating and concentrating the cesium in their bodies.
“We’re talking about a few generations” before the radioactivity of cesium in the marine environment fades, Dr. Boxall said.
Fisheries aren’t operating in the 20-kilometer exclusion zone around the Fukushima plant. But if marine radioactivity levels increase, they would probably need to extend the zone, he added.

The finless porpoise already faces an uphill battle for survival, it struggles with the all too familiar suite of problems, including pollution, reduced food supply, and incidental death related to fishery practices.  Although these porpoises are sold as food in Japanese fish markets, it is debatable whether the porpoises are deliberately caught or whether the fishermen sell the porpoises that accidentally get tangled in their nets.
There seems to be an affection for these remarkable porpoises, maybe because they are tough little survivors able to tolerate extremes of salinity (often going into estuaries and up rivers), and very shallow water – as the recent story of the rescue of one young finless porpoise found a mile inland in a rice paddy following the tsunami shows- or maybe it is their appealing looks.  Because their neck vertebrae are not fused, they are able to move their heads much like Beluga whales, giving them a comically cute aspect.  And among the young Japanese, these little porpoises have been absorbed into the “Anime” (comic characters) culture, you will find the finless porpoise introduced here if you can sit through the first part.
And who knows, with fishing forbidden a whole area will in effect become a preserve – if these little porpoises have the ability survive the effects of the radiation over the next few years, the respite from fishing nets may offset some of the damage.
Then again, they might just glow in the dark.
Food Habits of Finless Porpoises Neophocaena phocaenoides in Western Kyushu, Japan

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