Rescue crews will return to the Red River at daybreak this morning to resume their search for a fisherman who's missing following a boating mishap.  The search was suspended at dark last night.  Bossier Parish sheriff's deputies were called to the Red River near Elm Grove just before 4:00 yesterday afternoon after a boater spotted a man near his wrecked boat, close to a rock jetty not far from the River Bend Marina.  That man was suffering from a head injury and hypothermia and was air-lifted to LSU Hospital just before 5:00.  Rescue workers from the Bossier Parish Sheriff's Department, the Caddo Sheriff's Office, the Louisiana Department of Wildlife and Fisheries, the South Bossier Fire Department, and the Bienville Fire Department immediately began searching for his missing companion but were unable to locate him before nightfall.  They plan to resume their search today.