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This page last revised 01 November 2006 -- S.M.Gon III
TNC Action Sites
Maps & Figures
Hawaiian streams often are steep, with many falls, riffles, and pools.
Hawaiian Continuous Perennial Streams
Two endemic decapods comprise the nativemacro-crustacean fauna, the shrimp ‘ōpae kala‘ole(Atyoida bisulcata) and the prawn ‘ōpae‘oeha‘a(Macrobrachium grandimanus). Several macro-mollusks are inhabitants ofHawaiian streams,. including hīhīwai, or wī(Neritina granosa), brown wī or hapawai (Theodoxus vespertinus)and several species of Melanoides. There are in addition, severalspecies of smaller native crustaceans, mollusks and insects in Hawaiianstreams. Nearly all of the stream-related Hawaiian fishes, macro-crustaceansand macro-mollusks require oceanic larval development, followed by upstreammigration and maturation.
Threats toHawaiiancontinuous perennial streams include modifications of channel, changesinstream flow by diversion of water, siltation via erosion of disturbedwatersheds, direct or indirect pollution of surface or groundwater, andintroduction of alien stream animals that either feed on or competewith nativespecies. Because of the diadromous life cycles of most nativestream macrofauna, intact headwaters and upper stream courses withhighly modified lower courses and mouths limit all but the most hardynative species.
Even the most remote and unaltered streams may be invaded by alienspecies, if those species have oceanic larvae that can disperse between streamsor between islands. Alien prawns, such as the Tahitian prawn (Macrobrachiumlar) and Malaysian prawn (M. rosenbergii) are predatory on almostall native stream elements, have an oceanic dispersal phase, and are aparticularly difficult problem to address. Other significant alien streamanimals include fishes such as cichlids (Cichlasoma spp.), catfish (Clariasfuscus), bass (Micropterus spp.), tilapia (Tilapia spp.),live-bearers, such as mosquitofish (Gambusia affinis), guppies (Poeciliaspp.), and swordtails (Xiphophorus, spp.) and the freshwater clam (Corbiculeafluminea)Protected examples ofHawaiian continuous streams may be found in the Waimanu Estuarine Sanctuary, PelekunuPreserve of The Nature Conservancy of Hawai‘i, KīpahuluValley in the Haleakalā National Park and WaiahuakuaValley in the Hono O Nā Pali Natural Area Reserve.
Two native stream macroinvertebrates: the nerite snail hīhīwai (Neritina granosa) left, and the atyid shrimp 'ōpae kala'ole (Atyoida bisulcata).
Streams of the Ecoregional Portfolio
Twenty viable examples of streams (foureach on five stream-bearing islands) were selected for the ecoregionportfolio. The stream and surrounding watershed, from source to ocean,comprise the stream conservation area. These overlap with uplandecological systems, but typicaly extend into lower elevationalien-dominated areas. Click on the items in the list below to viewstream locations.
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|PortfolioStreams of the Hawaiian High Islands Ecoregion are to be found on thefive largest islands of Hawai'i, Maui, Moloka'i, O'ahu, and Kaua'i.Only these larger islands have watersheds and aquifers sufficient tomaintain continuous perennial stream flow. The portfolio maps at rightdepict the tributary networks of these portfolio streams, whichtypically drain major portions of the native dominated ecologicalsystems. An attempt was made to stratify stream selection acrossportfolio conservation areas.|| |
Selected portfoliostreams for Maui Island occur in two conservation areas: West Maui(Honokōhau & Kahakuloa Streams), and East Maui (Hanawī and 'Ohe'o Streams)
Selectedportfoliostreams for Moloka'i Island are Waikolu, Wailau, Pelekunu, andHālawa. Wailau and Pelekunu are considered among the highestquality streams inthe ecoregion.
Selectedportfoliostreams for Kaua'i Island are Hanakāpī'ai, Limahuli, Lumaha'i, andWaimea. The Waimea drainage in particular is one of the most complex inthe ecoregion.
Selectedportfolio streams for Hawai‘i Island occur in twoconservation areas: Kohala (Waipi‘o & Honokanenui Streams),and Mauna Kea (Honoli‘i & Hanawī Streams)
Selected portfoliostreams for O'ahu Island are Kaluanui, Punalu'u, Kahana, and Anahulu. All four drain from the wet Ko'olau conservation area.