In Kastamonu's Cide district, fishermen near the harbor noticed the sea suddenly swelling upward about 15 meters from the shore, forming a small whirlpool. Shortly after, a foul odor spread from the sea, which swelled like an explosion.
People present in the area panicked during the event. Following a report, Coast Guard teams were dispatched to the scene and conducted an investigation.
Citizens recorded the moments on their phones
Fikret Gül, who was fishing, described how the sea first swelled, then pulled back down, and rose again. He described the event as "like a bomb exploding" and said it lasted about 10 minutes around 4:00 PM.
Ahmet Yıldız said the sea first swelled, then receded, and rose again. He described the visible formation as "like filth" and noted the foul smell, adding that he had never encountered such a situation in the area he has visited for years.
Erdi Gökağaç, who filmed the swelling with his phone, said that at the same time a pitch-black bulge rose from the sea floor, the event lasted about 10 minutes, and then disappeared toward the shore.
Investigation conducted in the area
İbrahim Yiğit said the event occurred around 7:00 PM about 25 meters beyond the harbor, and they thought trapped pollution might have burst from beneath the sea. Yiğit noted that everyone in the area swims in the sea and requested an investigation.
The Coast Guard conducted a brief inspection and then left. Citizens handed over their footage to the teams.
Expert assessment: occasionally seen in harbors
Kazım Yılmaz, President of the Cide Fisheries Cooperative, said the event was a natural occurrence. According to Yılmaz, waste from the stream accumulates in the harbor, creating whirlpools and gas; when trapped gas bursts, it can cause an island-like swelling on the sea surface.
Yılmaz explained that such events can be seen once or twice especially in summer, and that waste coming from the mountains or left in the stream collects in the harbor during rainy weather. He noted that before storms, whirlpools form around the breakwater and what accumulates at the bottom rises to the surface.
The cooperative president stated that this is a natural phenomenon that occasionally happens in harbors and does not alone indicate an unusual situation.