This Marine IBA is identified using both tracking data and seaward extensions around breeding colonies. It falls within the Japan Exclusive Economic Zone (EEZ) and the Pacific, Northwest FAO ocean region. The site covers an area of 1160 km2 and is 49 km away from the closet coastline. The depth ranges from 208 to 817 m, mean annual sea surface temperature falls between 13.8 and 14.65 °C and mean annual chlorophyll-a concentrations found to range between 0.58 and 0.69 mg/m3.
4 species trigger IBA criteria at this Marine IBA. BirdLife analyses of tracking data estimates that 698276-1241379 individuals of Streaked Shearwater (LC) from Japan are present at the site during the Non-breeding (Oct-Dec) life-history stage. 144-144 individuals of Short-tailed Albatross (VU) from Izu Shoto are present at the site during the Non-breeding (Apr-Jul) life-history stage. 3750000-4166667 individuals of Sooty Shearwater (NT) from New Zealand are present at the site during the Non-breeding (May-Jul) life-history stage. Seaward extensions around breeding colony; Sanganjima islet include key near-colony areas for breeding populations of Black-tailed Gull (LC) 20000-40000 individuals.
BirdLife International (2020) Important Bird Areas factsheet: Futagojima islets 2 - Marine. Downloaded from http://www.birdlife.org on 30/10/2020.