Intrusion of Anchialine Species in the Marine Environment: The Appearance of an Endemic Hawaiian Shrimp, Halocaridina rubra, on the South Shore of O'ahu (Hawaiian Islands)

摘要

A single specimen of the endemic anchialine shrimp Halocaridina rubra Holthuis was collected on the reef under a brick in a freshwater extrusion in the lower intertidal at Kawaiku'i Beach Park, Niu Valley, O'ahu, Hawai'i, on 25 December 1998. Repeated collecting efforts at low tides failed to produce more shrimp. The associated fauna includes an anadromous eleotrid fish, Eleotris sandwicensis (the'o'opu 'akupa), isopods Apanthura inornata and Talitroides sp., alpheid shrimp (Alpheus crassimanus), an oligochaete, and gobioid fish (Bathygobius fuscus). Fresh water seeping out across the sand and visible in the area at low tides may have been the source of the specimen. This find may represent a rare occurrence of H. rubra in the reef flat habitat or the intrusion of anchialine species may occur with some frequency after heavy rains when the groundwater flow increases.