20 different species of whales and dolphins (cetaceans) can be found in Oman’s waters, including 4 species of great whales. ESO has been engaged in whale and dolphin research in Oman since ESO’s inception in 2004, with a particular focus on the Arabian Sea humpback whale. Dedicated research on Arabian Sea humpback whales has confirmed that this unique sub-population is small (possibly fewer than 100 individuals off the coast of Oman), resident in the Arabian Sea year-round, and isolated from other humpback whale populations. In 2008 the population was designated as Endangered on the IUCN Red List of threatened species. The conservation of this unique population across its regional range is critical to its survival.