Brown bear cubs in Japan are dying of starvation due to lack of salmon

Eight out of 10 brown bear cubs born this year in a remote part of northern Japan have died due to a lack of salmon. Experts blame rising sea temperatures for the climate crisis, writes The Guardian.

Along with acorns, pink salmon are an important food source for the approximately 500 brown bears living on Hokkaido’s Shiretoko Peninsula, a UNESCO World Heritage Site known for its spectacular coastline and wildlife.

Local authorities reacted with alarm after a tour boat operator spotted a hungry bear cub desperately searching for food on the peninsula’s east coast this month. The bear was reported to be turning over rocks and rummaging through piles of beached seaweed in search of food.

Pink salmon hatched in Hokkaido rivers spend the winter at sea and return to Shiretoko streams to lay eggs between August and October. Brown bears usually lie in wait for salmon as they move upstream, but due to a shortage of river fish, they are forced to swim out to sea.

“Some of the bears have lost a lot of weight,” Katsuya Noda, a tour boat operator, told the Asahi Shimbun. “It’s not easy for them because there are no fish in the rivers, just like last year.”

Experts said sea surface temperatures off Hokkaido remained above 20C from mid-July to early August 2021, 5C above the average for this time of year.

Researchers at Hokkaido University have warned that if global warming continues at its current rate, sea temperatures around the island will rise by 10°C in the 2090s compared to levels in the 1980s.

Masami Yamanaka, a researcher at the Shiretoko Nature Foundation, told Asahi that a shortage of salmon combined with a poor acorn harvest is having a devastating impact on brown bear cubs. “An estimated 70% to 80% of the cubs born this year are dead,” Yamanaka said. “This is a really serious situation.”

Fishermen caught 482,775 pink salmon in the rivers of Hokkaido, Japan’s northernmost main island, between July 25 and September 5, 2020, but only 23,298 last year, according to the Hokkaido Salmon Breeding Association. Given statistics showing good catches occurring once every two years, the 2022 catch was surprisingly small.

A shortage of acorns has been blamed for a rise in bear attacks on people in Hokkaido and other parts of northern Japan when they venture into populated areas in search of food.

A total of 1,056 brown bears were caught and killed in Hokkaido in the year to April 2022, the highest number on record and the first time the number has exceeded 1,000, according to the prefectural government. Of the total, 999 brown bears were killed to prevent damage to crops or because they were considered dangerous to local populations.

The number of people injured or killed in incidents involving bears during the same period was 14, and crop damage was estimated at ¥262 million (£1.44 million), the highest ever.