In a city that was famous for its Mediterranean promenade, its fishermen and its seafood restaurants that faced the cerulean waves, people have grown to fear the sea.

Nobody knows how many bodies were dragged away in the flood that left much of Derna, Libya, in mud-choked ruins a year ago, after a powerful storm caused two aging dams to burst in the mountains above the city. The official death toll is about 4,000, but thousands more remain missing, according to residents and the Libyan authorities, an agonizing number that underscores the dysfunction that residents and analysts say contributed to the disaster and hampered the emergency response.

“Fishing was my favorite hobby,” said Mostafa Saied, 54. “Now I avoid the sea and everything to do with it. There’s a lot of dead bodies in there. I imagine them getting eaten by fish, and I can’t eat it anymore.”

The waters tore his wife, their three daughters and one of their two sons from the rooftop where they were sheltering. He survived only because, running down a stairwell to help a neighbor, he was shielded in the building from the wave. He never found his family’s bodies. His best hope is that workers will find something as they rehabilitate the neighborhood.

All over central Derna, the air rings with hammering and hums with the sounds of heavy equipment as workers in orange vests rebuild the shattered city.