(Paris) -- French marine wildlife experts say time is running out for a Beluga whale that's stranded in the River Seine [[ sen ]]. The 13-foot-long whale is swimming between two locks in a basin about 50 miles north of Paris after wandering into the river and swimming upstream from the English Channel last Tuesday. Rescuers are afraid the whale might be dying. They injected it with vitamins over the weekend in hopes of reviving its appetite and strength enough to swim back to the Channel, about 100 miles downstream.