Boundaries

This ecoregion lies in the West Papua Province (formerly Irian Jaya) of Indonesia on the island of New Guinea. It incorporates the Volgelkop (Birdshead) and Bomberai peninsulas and the Raja Ampat Islands (Waigeo, Batanta, Salawati, and Misool), which were connected to the mainland as recently as 10,000 years ago. The ecoregion is located in the southwest Pacific Ocean, bordered to the south by the Arafura Sea. It lies on the Birds Head tectonic plate.

Freshwater habitats

The ecoregion includes a number of torrential mountain streams and upland lakes, both of which lack native fish inhabitants above 1800 m (streams) and 2000 m (lakes). The mountain streams at high elevations are generally characterized by steep gradients with rapids and waterfalls (Allen 1991).

Terrestrial habitats

This diverse ecoregion is composed of Vogelkop-Aru lowland rain forests [AA0128], Volgekop montane rain forests [AA0127], Southern New Guinea freshwater swamp forests [AA0121], and New Guinea mangroves [AA1401] (WWF 2001).

Description of endemic fishes

The ecoregion contains one endemic monotypic genus represented by the species Pelangia mbutaensis. Other genera that have large numbers of endemic species in the ecoregion include the Melanotaenia (Melanotaeniidae) and Mogurnda (Eleotridae). Some of these include Melanotaenia ajamaruensis and M. boesmani in the Ajamaru Lakes; M. parva in Lake Kurumoi; M. kamaka and M. pierucciae in and around Lake Kamaka; M. lakamora in lakes Laamora and Aiwaso; M. irianjaya in the Vogelkop lowlands; and M. arfakensis and M. fredericki in the Volgelkop highlands. Mogurnda magna occurs in Lake Laamora and M. aiwasoensis in Lake Aiwaso. Other endemics include Glossogobius hoesei and Pseudomugil reticulatus in the Ajamaru Lakes, Variichthys jamoerensis in Lake Yamur, and Zenarchopterus ornithocephala and Hephaestus lineatus in the Volgelkop lowlands (Allen 1991; Polhemus et al. 2004).

Other noteworthy fishes

Lake Yamur contains an isolated population of bull shark (Carcharhinus leucas), which is otherwise a marine and estuarine species (Polhemus et al. 2004).

Justification for delineation

Freshwater biotas in New Guinea center around foci of high endemicity clustered around tectonic provinces. This ecoregion comprises two regions of endemism recognized by Allen (1991) and Polhemus et al. (2004). The Raja Ampat Islands support several areas of endemism, including Waigeo, Batanta, and Misool. The Volgelkop and Bomberai peninsulas incorporate another endemic region, with particular areas of endemism in the Volgelkop lowlands, highlands, anticlines, and the Fakfak and Kumafa Mountains, all of which boast endemic aquatic taxa.