Macrobrachium grandimanus

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Macrobrachium grandimanus
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Malacostraca
Order:	Decapoda
Suborder:	Pleocyemata
Infraorder:	Caridea
Family:	Palaemonidae
Genus:	Macrobrachium
Species:	M. grandimanus
Binomial name
Macrobrachium grandimanus Randall, 1840

Macrobrachium grandimanus, also called Hawaiian river shrimp or ʻopae ʻoeahaʻa in Hawaiian, is a species of shrimp. It has an amphidromous life cycle and is endemic to the Hawaiʻi islands.

The Hawaiian river shrimp is light to dark brown in color and grows to eight centimeters in length. It has asymmetric pincer claws unlike any other shrimps in Hawai'i. They scavenge at the bottom of slow flowing streams for animal and plant material. They reproduce year round with an incubation period lasting approximately three to four weeks. After hatching, the larvae gets washed down into the ocean where they spend a month developing before they return to streams to mature.

Historic distribution includes all the main islands in Hawai'i that consist of everlasting streams. They currently can be found high quality streams in Kaua‘i, O‘ahu, Moloka‘i, Maui, and Hawai‘i as well as wetlands, small ponds, and closed off body of waters.

Hawaiian river shrimp are not caught for food or used in any way.

1. Yamamoto M, Tagawa A. 2000. Hawaii’s native and exotic freshwater animals. Honolulu, HI: Mutual Publishing. 200 pp.
2. De Grave, S., Cai, Y. & Wowor, D. 2013. Macrobrachium grandimanus (errata version published in 2019). The IUCN Red List of Threatened Species 2013: e.T197590A147784025. https://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T197590A147784025.en.
3. ffish.asia. (2015, September). Macrobrachium grandimanus [Photograph]. https://ffish.asia/?page=file&pid=56425&lang=e
4. dlnr.hawaii.gov. (2005, October). Freshwater Invertebrates. https://dlnr.hawaii.gov/wildlife/files/2019/03/SWAP-2015-Hawaiian-prawn-Final.pdf
5. Wortham, Jennifer L.; Van Maurik, Lauren N. (2012-01-01). "Morphology and morphotypes of the Hawaiian river shrimp, Macrobrachium grandimanus". Journal of Crustacean Biology. 32 (4): 545–556. doi:10.1163/193724012x637311 ISSN 0278-0372.