Meanwhile, the Japanese decided to evacuate over 12,000 troops from Kolombangara as part of a major retrograde operation in the Solomons. The evacuation was conducted over the course of several nights via barge, commencing on 28–29 September and continuing through until 2–3 October. The Japanese then evacuated Vella Lavella on 6–7 October, bringing the New Georgia campaign to a conclusion. During the evacuation operations, the US Navy claimed to have sunk up to 46 barges, killing several thousand Japanese troops, but ultimately the Japanese evacuation operations were successful. The delay inflicted by the defenders on Arundel allowed the Japanese to improve their defenses around Rabaul and on Bougainville. Many of the troops who were evacuated from Kolombangara took part in the fighting on Bougainville later in the war. The next phase of the Allied advance through the Pacific would see them land at Cape Torokina in November 1943 as part of efforts to secure Bougainville, while further actions were undertaken by the New Zealanders in the Treasury Islands and the US Marines on Choiseul.