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DISTRIBUTION OF NONINDIGENOUS BENTHIC SPECIES IN THE SMALL ESTUARIES OF CALIFORNIA, OREGON, AND WASHINGTON
Citation:
Lee II, H, J O. Lamberson, AND K. Welch. DISTRIBUTION OF NONINDIGENOUS BENTHIC SPECIES IN THE SMALL ESTUARIES OF CALIFORNIA, OREGON, AND WASHINGTON. Presented at EMAP Symposium 2001, Pensacola, FL, April 24-27, 2001.
Description:
Nonindigenous species are a major threat to the sustainability and integrity of terrestrial and aquatic ecosystems. San Francisco Bay is the most heavily invated water body in the United States, however, it is not clear whether other west coast estuaries are also heavily invaded. In 1999, Western EMAP sampled the benthic communities in the small estuaries in California, Oregon, and Washington (San Francisco Bay and main portions of the Columbia River and Puget Sound excluded). A total of 27 nonindigenous soft-bottom benthic species were found, which wer about equally divided among polychaetes, mollusks, and crustaceans. In terms of taxonomic composition, there were relatively fewer introduced polychaete species compared to the number of native species, which the introduced mollusks were over-represented. By several indicators, Oregon and Washington were are least as invaded as California. Nonindigenous species constituted 6.8%, 16.8%, and 7.1% of the individuals in California, Oregon, and Washington, respectively. Additionally, nonindigenous species occurred more frequently in Oregon and Washington, present in about 70% of the samples versus 53% in California. However, the absolute density of nonindigenous species was higher in California. The most abundant nonindigenous species in California, Oregon, and Washington were Streblospio benedicti, Hobsonia florida, and Streblospio benedicti, respectively, all of which are surface-deposit feeding polychaetes. Two of the most abundant nonindigenous species in San Francisco Bay, the amphipod Ampelisca abdita and the bivalve Potamocorbula, were hot found in the small estuaries.