1,200 Tons Of Mackerel & Sardines Wash Up On Hokkaido; Japanese Fishers, Scientists Don't Know Why
Officials in Japan have admitted they are struggling to determine why hundreds of tonnes of fish have washed ashore in recent days. Earlier this month, an estimated 1,200 tonnes of sardines and mackerel were found floating on the surface of the sea off the fishing port of Hakodate in Hokkaido, forming a silver blanket stretching for more than a kilometre.
On Wednesday, officials in Nakiri, a town on the Pacific coast hundreds of miles south of Hokkaido, were confronted with 30 to 40 tonnes of Japanese scaled sardines, or sappa, which had been observed in the area a couple of days earlier.
Local fishers scrambled to collect the fish, fearing their carcasses would lower the oxygen content of the water as they decompose and damage the marine environment. “I’ve never seen anything like this before,” a fisher who has worked in the area for 25 years told the Mainichi Shimbun. “It was only around last year that we began to catch sappa in Nakiri. It makes me wonder if the marine ecosystem is changing.”
Experts have speculated that the migratory fish in both areas had become stranded after being chased to the point of exhaustion by amberjack and other predatory fish. Mass mortality events can also occur when there are sudden drops in the water temperature, causing the fish to go into shock, they added. But no one has been able to confirm the cause. “The cause is unknown at the moment,” Mikine Fujiwara, a local fisheries official, told the newspaper. “We plan to sample the seawater at the site and examine it to uncover the cause.”
EDIT
https://www.theguardian.com/world/2023/dec/14/ive-never-seen-anything-like-this-japan-says-reason-behind-1200-tonnes-of-fish-washing-ashore-is-unknown
= new reply since forum marked as read
From 2021:
Hokkaido sea urchin and salmon decimated amid rare red tide
Shells of dead sea urchins washed ashore in the Hokkaido town of Erimo.
SHINICHI ARAKAWA, Nikkei staff writer
October 9, 2021 22:55 JST
TOKYO -- An unprecedented red tide in Hokkaido has contributed to huge numbers of sea urchin and salmon dying, driving up the price of these fixtures in traditional Japanese New Year's cooking.
The phenomenon is suspected to be related to warmer-than-usual water temperatures amid this summer's intense heat wave, suggesting a link to climate change. The die-off is expected to affect supplies -- and prices -- of uni and ikura, or salmon roe, for the next few years, on top of the economic disruption already wrought by the pandemic.
Fishing cooperatives around the city of Kushiro in eastern Hokkaido, a region known for high-quality Ezo-bafun uni, reported that more than 90% of sea urchins in their respective areas had died as of Oct. 1. The Chirippu cooperative in nearby Hamanaka said about half of its sea urchins were killed.
This not only hit supply near the peak New Year's demand season, but also wiped out masses of young shellfish ahead of the next fishing season. Newly stocked juvenile sea urchins are off-limits for four years until they mature.
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