Marine Communities and Introduced Species in Pearl Harbor, O’ahu, Hawai’i

Harbours are protected inlets or embayments that provide shelter and anchorage or port facilities for vessels from small craft to giant super tankers or bulk-cargo carriers. Often, but not always, harbours are restricted from the open ocean by narrow entrance channels, and the water quality within the harbours may differ dramatically from the open ocean, usually with higher turbidity, organic particulates, dissolved organic matter, inorganic nutrients and primary productivity. Also, because harbours are usually surrounded by industrial developments and urban areas, a harbour often receives a wide variety of man-related effluents that may remain confined within the harbour because of limited mixing with the surrounding ocean. These environmental characteristics often favor the spread and establishment of introduced marine species from one organic-rich harbour to another. Even before recorded history, vessels moving from one place to another provided a mechanism for the spread of marine organisms from their original habitats to new areas. Known variously as “nonindigenous” “introduced”, “exotic” or “non-native” species, these organisms may become a normal or even dominant component of the harbour communities into which they are introduced. Vessel movement of introduced species on a world-wide scale probably began at least 500 years ago, with long distance transport on slow-moving ships of fouling organisms that had accumulated while the vessels remained at anchor for months or even years in harbours or bays. Pearl Harbor (Figures 1 and 2), called Ke-awa-lau-o-Pu’uloa (The Many Harbors of Pu’uloa), or Awawa-lei (Garland of Harbors) by Hawaiians before European contact (Handy and Handy, 1972), is the largest and most enclosed harbour in the state of Hawai‘i, and, for approximately the last hundred years, has been the site of the largest U.S. Navy base in the central or western Pacific. Hawai‘i and especially the Island of O‘ahu has been a major crossroads of Pacific ship traffic