Fishermen in Ryotsu Bay on Sado Island have reported an unusually large catch of sardines and bluefin tuna this month [1, 2, 3].
The surge in fish populations provides a significant economic boost to the Niigata Prefecture fishing community through higher market volumes and prices.
Market officials at the Sado Fish Wholesale Market said the current situation is the largest landing in several years [2]. The sardine haul reached approximately 70 tons [2]. This abundance of smaller fish has created a feeding ground that attracted larger predators to the area.
Since early May, bluefin tuna have appeared in large numbers [2, 3]. While some reports indicate the surge began on May 2, other accounts noted a particularly large catch on the morning of May 11 [2, 3]. In total, approximately 550 tuna have been landed [2].
Local fishermen said the abundance of sardines was so great it was like building a palace. This phrase reflects the traditional Japanese expression for a windfall of wealth brought by a massive harvest [3].
Water conditions have been favorable this season, which fishermen believe contributed to the migration patterns [2]. The increased supply of high-quality tuna has also impacted pricing. One local fisherman said tuna could be traded at 1,500 yen per kilogram [2].
Officials continue to monitor the landings at the Sado Fish Wholesale Market as the seasonal peak progresses [2, 3].
“The largest landing in several years”
The correlation between the 70-ton sardine haul and the arrival of 550 bluefin tuna illustrates a localized ecological chain reaction. When forage fish like sardines congregate in massive schools due to favorable water conditions, they draw in apex predators, creating a high-value window for commercial fisheries. This event underscores the volatility and opportunity of seasonal migrations in the Sea of Japan.
