IGNEADA, Türkiye, Sept. 4 (Xinhua) -- As Türkiye's nationwide fishing ban ended at midnight Monday, fishermen in the Black Sea town of Igneada set out under a blanket of stars, with hopes riding high on the waves.
Yet by daybreak, the catch told a troubling story: The silvery bonitos, a smaller relative of the tunas and an economic lifeline for the coastal community, were nowhere to be found.
"We started at midnight, and by morning we had about 600 kg of horse mackerels. But we didn't see any bonitos. That's disappointing because bonitos are where we really make our money," said Ozgur Sik, a fisherman with over 20 years of experience, upon arriving at Igneada's harbor.
Nestled along the migratory route from Bulgaria's cooler currents, Igneada, a main hub for distributing fish across Türkiye, is usually abuzz with bonito activity each September -- but not this year, amid rising sea temperatures.
"Bonitos spawn best when the water is around 20-22 degrees Celsius, but this year it's been hotter, largely due to climate change," Sik explained.
"Right now, what is happening in agriculture due to drought is also happening in the sea. Just as crop yields are lower because of high temperatures and drought, so too are fish stocks," he said.
To the locals, Bonitos are more than just fish: They are seasonal treasures relatively easy to catch, higher in value, and vital for small-boat fishermen working against the clock until November.
This week, thermometers read 24-25 degrees Celsius off the coast of Igneada, enough to delay or divert bonitos' migration altogether.
"The fact that we haven't seen bonitos at the start of the season is not a good sign," Erol Kurt, another local fisherman, told Xinhua. "The season lasts only until November, so we have limited time to earn our living."
While bonitos remain elusive, other species are sending signals of their own: Horse mackerels, favoring warmer currents of 18-24 degrees Celsius, are thriving, whereas bluefish, preferring cooler waters of 18-22 degrees Celsius, may arrive later, if at all.
Murat Kapikiran, head of the Istanbul branch of the Chamber of Agricultural Engineers, sees a broader crisis unfolding beneath the waves.
"Rising temperatures directly affect fish growth, feeding, and spawning," he told Xinhua. "Warmer seas also trigger coral bleaching and death, wiping out critical breeding habitats and leaving fish with nowhere to reproduce."
Human activity, he added, is a further turn of the screw. "Marine pollution and coastal construction are destroying what fragile habitats remain, from coral beds to rocky spawning grounds."
According to data released in June by the Turkish Statistical Institute, Türkiye's total marine capture in 2024 fell by 23.3 percent year-on-year, with overall fishery production dropping to 933,194 tons, down 7.6 percent. Among the 290,068 tons of caught sea fish, 49,278 tons were bonitos, ranking second.
A report released on June 16 by the European Environment Agency showed that the Black Sea has warmed considerably since 1870, particularly since the late 1970s. From 1991 to 2024, sea surface temperature (SST) increased by around 0.5 degrees Celsius per decade in the Black Sea.
SST in the Black Sea is expected to increase further by the year of 2100, the agency noted.
If these trends continue unchecked, "the sea may soon reach a breaking point -- no longer able to sustain marine life or provide for humanity as it has for generations," Kapikiran warned. ■
