On September 1, 2005 at 1027 Pacific daylight time, a Bellanca 7ECA, N2686Z, experienced a partial loss of engine power and ditched in the ocean near Malibu, California. The pilot/owner was operating the airplane under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, was not injured; the airplane sustained substantial damage. The local area flight originated from Camarillo Airport, Camarillo, California, about 1000, and was engaged in fish-spotting operations. Visual meteorological conditions prevailed, and a flight plan had not been filed. In a written statement, the pilot reported that after departing from Camarillo, he maneuvered the airplane on a southwesterly heading toward Catalina Island. While en route over the ocean, about 25 miles from the airport, he noticed a decrease in engine power. A scan of the cockpit gauges revealed no anomalies with the exception of a slight rise in oil temperature. As the pilot maneuvered the airplane toward land, the oil temperature continued to rise, indicating about 220 to 230 degrees Fahrenheit; the oil pressure gauge indicated about 60 pounds. While still continuing toward land, the pilot heard a loud "bang" coming from the engine and felt a vibration. Engine oil began to cover the windshield and the airplane continued to lose altitude. With the engine still running, the pilot ditched the airplane in the ocean about 5 miles from the Malibu coastline. The airplane sank to the ocean floor, about 1,200 feet underwater.