Anchialine Pools of Hawai'i

The Eight Anchialine Pool All About ‘Ōpae ‘Ula Shrimp of Hawai‘i Hawaiian Name: Anchialine Pools ‘ōpae ‘ula Scientific Name: of Hawai‘i Halocaridina rubra Photo by Fuku-Bonsai Photo by Mike Yamamoto Common Name: ‘Ōpae ‘ula are small, with a Metabetaeus lohena are red shrimp maximum length of about twice the size of ‘ōpae ‘ula Photo by Mike Yamamoto 1/2 inch (1.25 cm). and have pincers. • ‘Ōpae ‘ula are endemic to Hawaiian anchialine pools; they are found nowhere else on Earth. They are the most common anchialine pool shrimp found in Hawai‘i. • ‘Ōpae ‘ula are typically red, but can also Photo by Mike Yamamoto Photo by Mike Yamamoto range in color from clear to pink. Most Calliasmata pholidota are Antecaridina lauensis look ‘ōpae ‘ula on O‘ahu are red and clear found on Maui, Hawai’i similiar to ‘ōpae ‘ula, but banded, pink, or clear. Island, and the Sinai have small white pincers Peninsula in Egypt. and white eyes. Endangered Species Photo by Mike Yamamoto Photo by Mike Yamamoto Photo by Mike Yamamoto Procaris hawaiana are only Palaemonella burnsi have found in a few pools on transparent bodies that are • ‘Ōpae ‘ula graze on algae that grows in the Maui and Hawai’i Island. under 1 inch in length. pools, keeping anchialine pools healthy by preventing an overgrowth of algae. Endangered Species Kekaha Kai State Park • A berried female ‘ōpae ‘ula typically carries fewer than Photo by Troy Sakihara Photo by Troy Sakihara 20 eggs under her Vetericaris chaceorum are a Periclimenes pholeter was tail. The eggs are very rare species only found first reported in a Hawaiian about 1 millimeter Photo by Mike Yamamoto at two locations on Hawai’i anchialine pool in 2010. in diameter. Island. • ‘Ōpae ‘ula shrimp are known to be long- Photographs by Mike Yamamoto and Troy Sakihara lived; some have lived over 20 years. are courtesy of DLNR Division of Aquatic Resources. Metabetaeus lohena Photo by Paul Okumura Threats to Anchialine Pools Introducing non-native plant and fish species, like tilapia, into the pools can harm the ecosystem by altering the natural behavior of ‘ōpae ‘ula and through the accumulation of plants and sediment in the pools. Stender Yuko by Photo Non-native tilapia Using the pools for bathing is bad for the ecosystem. The brackish water in the pools Illustration by Michael Furuya What is an Anchialine Pool? might make your skin feel better after a • Wai ‘ōpae is the Hawaiian name for day at the beach, but soap, shampoo, and sunscreen contaminate the pool water. • Anchialine is a word derived from the these pools - wai means fresh water Greek word “anchialos,” which means and ‘ōpae means shrimp. Trash pollutes fragile anchialine pool “near the sea.” habitats, and can be harmful to anchialine • Hawai‘i is the only state in the United pool shrimp. • It takes a special environment for an States that has anchialine pools. anchialine pool to exisit, including a location near the sea and a porous • Anchialine pools have been recorded volcanic or limestone substrate. on O‘ahu, Moloka‘i, Kaho‘olawe, Maui, and Hawai‘i Island. • Anchialine pools are bodies of water that are a mix of fresh water and salt • Over 650 of the 700 recorded pools are ‘Ōpae ‘ula are being harvested for sale in water. This mixture of water is known located on Hawai‘i Island. pet stores or as live feed for seahorses and as brackish water. fish. If overharvested, ‘ōpae ‘ula may not • The above-ground area of the pools be able to serve their role in helping to • Anchialine pools have no surface is the epigeal habitat. There is also keep Hawaiian anchialine pool ecosystems connection to the sea, but rise and fall an extensive underground, hypogeal healthy. with the tide. Some pools appear dry habitat where shrimp can live and This brochure was made possible by a Hawai‘i Tourism Authority during low tide. move between pools. Natural Resources Program Grant..

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