(FILES) This file photo taken on October 23, 2017 shows people fishing from the Galata Bridge in Karakoy district in Istanbul, as the new mosque is seen in the background. Experts have expressed concern over the decrease of fish in the Bosphorus river. / AFP PHOTO / OZAN KOSE
After half a century of fishing, 65-year-old Fuat, a retired Turkish civil servant, is nostalgic for the good old days when the Bosphorus Strait in Istanbul teemed with fish.
Wearing a black woolly hat, Fuat is one of hundreds of amateur anglers passing their spare time on the Galata Bridge on the European side of Istanbul, trying to fill their buckets.
"I've been fishing since I was 15 years old," he said as he cast his line over the waters at the confluence of the Bosphorus with the Golden Horn, overlooked by the Hagia Sophia and Blue Mosque.
"In the past, there were many fish, the human population was less," he said.
"Those fish are gone now. Those beautiful fish are gone because of the increasing population and careless fishing."
The sight of thousands of amateur anglers crammed shoulder-to-shoulder on the Galata Bridge and on the banks of the Bosphorus all the way from the Marmara to the Black Sea is, for many, one of the iconic images of Istanbul.
The Bosphorus' position connecting the Mediterranean to the Black Sea system makes it a hub for fish and, according to the time of year, can be crammed with prized delicacies like lufer (bluefish), levrek (bass) and palamut (bonito).
Many anglers come for the day and night, lighting fires and bringing samovars for making tea. Small stallholders sell bait, hooks and flies.
While Istanbul is changing at breakneck speed with unimpeded developments, the scenes of fishing are hardly different from those taken in grainy black-and-white pictures from the 1950s.
But the bucolic images hide an uncomfortable truth, experts say. Fish stocks in the Bosphorus have plummeted and this is in no small measure due to the indiscriminate fishing of the hobby anglers.
The careless bycatch of fish species and keeping juvenile fish after they are caught -- officially illegal -- have put the Bosphorus ecosystem in a perilous condition.
Erol Orkcu, head of the amateur and sports fishing association in Istanbul, said there has been a significant increase in the number of amateur fishermen compared to the past as the city's population boomed.
Fish stocks have decreased by around 50% compared to the 1980s and 90s, he said. "Things are deteriorating. The fish population is in decline. Marine conservation is needed," he said.
Pollution and destructive fishing practices are among the major factors behind the reduction in fish stocks.
"Ninety per cent of the fish caught on the Galata Bridge are juveniles, unfortunately. That is not legal," he said.