SHIGA, Jun 06, 2025 (News On Japan) - The catch of ayu, a fish long considered a delicacy and regional staple of Lake Biwa, has fallen to a record low, prompting local fisheries to call on the Shiga prefectural government for urgent action.
The annual peak season for ayu fishing typically begins in December with the opening of the "yana" fishing method. However, this year has brought an alarming decline.
"Ayu are few and far between. This is the worst it’s ever been," said Kimura Tsuneo, a director at the Kitafunaki Fisheries Cooperative. "We used to catch about 500 kilograms a day with a single trap. Now we’re getting just 10 to 20 kilograms at best."
In another traditional method known as "eri" fishing, which uses fixed net structures to funnel fish, the results have been equally dismal.
"They’re completely gone," said Teruyo, the wife of fisherman Mitamura Susumu.
"You can’t even sense they’re there anymore," added Mitamura.
Asked how it looked during abundant years, Mitamura said, "The nets would be thrashing with fish jumping everywhere."
"Now, catching even one kilogram is a struggle. With fuel costs, it’s barely worth going out."
Ayu have historically accounted for 40 to 50 percent of the total fish catch in Lake Biwa, forming the backbone of Shiga’s fishing industry. But over the past decade, numbers have steadily declined. This year’s catch has dropped to just 17.6 tons—the lowest on record—threatening not just livelihoods but also local food traditions.
"Our cauldrons are usually boiling with ayu and wakasagi," said Tamura Aiko, president of Tamura Freshwater. "But this year, there’s been no ayu since January. We haven’t cooked a single batch."
One traditional dish especially affected is tsukudani, simmered lake fish in soy sauce and sugar, commonly made with young ayu. Production has come to a halt due to the lack of raw ingredients.
According to Shiga Prefecture’s fisheries division, the primary cause of the poor harvest is last year’s extreme heat, which raised lake water temperatures and prevented them from cooling to suitable spawning levels in autumn. Additionally, a shortage of plankton meant that many larvae could not grow after hatching.
In response, local fishery groups and industry stakeholders submitted a formal request for countermeasures to Governor Mikazuki this week, including the release of adult ayu.
"We are considering how to effectively utilize artificial rivers and conduct targeted fish releases," said Governor Mikazuki Taizo.
The prefecture is also planning to expand spawning grounds in cooler rivers and time the release of hatchlings to align with falling water temperatures.
"The climate is the biggest factor," said Kimura. "It really feels like Lake Biwa is becoming an increasingly inhospitable place for fish."
Source: YOMIURI
