Opae' ula (Hawaiian Volcano Shrimp)

Anchialine ponds are one of Hawaii’s most threatened ecosystems. There are about 700 known anchialine ponds in Hawai’i. Most Hawaiian anchialine ponds are in the youngest lava areas of the Big Island of Hawai’i and Maui. They exist in inland lava depressions near the shore and contain brackish (a mixture of freshwater and saltwater) water. Freshwater is fed to the ponds from ground water that moves down slope and from rainwater. Ocean water seeps into the ponds through underground crevices in the surrounding lava rock.” University of Hawaii at Hilo

According to the signs on site, “Tiny red shrimp, collectively called ‘Opae’ula, are one of the unique features of these anchialine pools and are found only in Hawaii. The shrimp are omnivorous and can live for long periods of time underground in the interstitial groundwater without appearing in the pools. The shrimp have been found in wells located a mile inland. The smaller and more numerous shrimp (Halocaridina rubra) is preyed upon by a larger red shrimp (Matabetaeus lohena).”