Russia's Fish Fight For Oxygen In St. Petersburg Ponds (PHOTOS)

ST. PETERSBURG, Russia (AP) — As the long Russian winter drags on, fish in the ponds of St. Petersburg become increasingly desperate for oxygen, clustering in vast, thrashing masses at shrinking holes in the ice.

Swimmers who brave the frigid temperatures for an invigorating dip find themselves stroking through swarms of fish that flock to the open water. The fish are so thick that humans can easily reach out and catch them with their hands.

Not only does ice block oxygen that could be diffused into the water from the air, but it also impedes sunlight from reaching oxygen-generating plants and algae in the water.

"The only way to help the fish in this situation is to make more holes in the ice," says Sergei Titov of St. Petersburg's Lakes and Rivers Fish Sector Institute.