Whale meat just became even less appetizing. Conservation groups have revealed that Norwegian exports of minke whale to Japan contained damaging levels of toxic pesticides, making that meat unfit for human consumption. It’s a discovery that could cue a swifter decline in the appetite for whale.

The news emerged this month, when the Environmental Investigation Agency (EIA) and the Animal Welfare Institute (AWI) revealed documents showing that the Japanese government rejected imports of Norwegian whale meat because tests showed samples contained pesticides at twice the limit Japan imposes on its imports. The meat harboured chemicals such as aldrin, dieldrin, and chlordane, thought to play a role in causing birth defects, neurological harm, and some cancers if humans consume them in high quantities.

Norway continues to run a large scale whaling industry—the country took a record catch of 736 minke whales in 2014—but surprisingly, it doesn’t exist for Norwegians. “Fewer than five percent [of Norwegians] eat whale meat regularly,” says Kate O’Connell, a marine wildlife consultant from the AWI, explaining that they see it as old-fashioned fare.

By comparison, Japan is a much bigger market. “Japan has always been the main consumer of whale products,” says Clare Perry, the head of the EIA’s oceans campaign. But even there, it’s losing its appeal. “It’s not fashionable at all. There’s an older generation in Japan that have a nostalgia about eating it, but it’s not in any way a staple diet,” she says. Nevertheless, a chunk of the Norwegian catch is still exported there annually: 137 tonnes of Norwegian minke have entered Japan in the last two years.

Proof of pesticide poisoning may somewhat sour that appetite, something that even a global hunting ban hasn’t been able to quash. There are three remaining countries that continue to hunt and eat whale commercially — Norway, Japan, and Iceland—and each one ignores the worldwide ruling against this activity.

In 1982 the International Whaling Commission completely outlawed commercial whale hunting. “That applies to all countries that are members of the IWC. Japan, Norway, and Iceland are all members of the IWC,” Perry emphasizes. The Convention on Trade in Endangered Species (CITES) also bans the trade in minke meat to protect the species, which isn’t endangered but has experienced a dramatic population dive since whaling began. “There’s concern over whether the hunt is sustainable,” Perry notes. (Norway insists that it is, which explains why it still awards itself an annual catch quota of more than 1000 whales, one the IWC doesn’t acknowledge.)

When the international moratorium came into force in the 80s, Norway objected to it, which afforded the country a legal loophole that allows it to continue the hunt while maintaining its IWC membership. Norway, Iceland, and Japan also reject the CITES ban, a move that technically permits them to continue with the trade. “From our perspective Norway should be abiding by those treaties,” Perry says.

Until that happens, it seems like pesticide contamination is the whales’ best defence—though it’s also bound to harm the whales. The chemicals identified in the minkes’ meat are agriculture products that would most likely have entered the ocean via agricultural run-off. Some of the pesticides, like dieldrin and chlordane, have been banned in the European Union and the United States because of their toxic effects. Because they’re persistent pollutants, however, they’ve lingered in the ocean. By entering the food chain and bioaccumulating within it, the chemicals eventually find their way into the bodies of larger mammals like whales. “If we think it’s potentially dangerous for us to eat, you can imagine it’s not particularly healthy for a whale,” Perry says.

As Norway’s appetite for the meat dwindles, it continues to pursue markets elsewhere for its whales. But that may grow more challenging, especially since the recent meat scare isn’t the first the country has caused. In fact, in the past, shipments of Norwegian whale meat have been found to be infested with bacteria and also to contain potentially dangerous levels of mercury.

Within Norway, there are ongoing efforts to try and revive the meat’s appeal, and there are even generous government subsidies in place to try and support the industry and keep this historical practice alive. “It is clear, however, that without an export market, the Norwegian whaling industry will continue to struggle,” O’Connell says.

In that sense, perhaps for whales the pesticides are a morbid kind of defence against the minority that still has a taste for their meat.