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Changes in latitude, changes in attitude - biogeographic patterns of nonindigenous estuarine and near-coastal species in the Northeast Pacific
Citation:
LEE, II, H., D. REUSSER, W. G. NELSON, AND J. O. LAMBERSON. Changes in latitude, changes in attitude - biogeographic patterns of nonindigenous estuarine and near-coastal species in the Northeast Pacific. Presented at 6th International Conference, Marine Bioinvasions, Portland, OR, August 24 - 27, 2009.
Impact/Purpose:
Biogeographic patterns of estuarine and near-coastal invaders in the Northeast Pacific (NEP) are beginning to emerge based on regional surveys by U.S. EPA’s Environmental Monitoring and Assessment Program (EMAP) and the EPA/USGS synthesis of native and nonindigenous species in the “Pacific Coast Ecosystem Information System” (PCEIS) database.
Description:
Biogeographic patterns of estuarine and near-coastal invaders in the Northeast Pacific (NEP) are beginning to emerge based on regional surveys by U.S. EPA’s Environmental Monitoring and Assessment Program (EMAP) and the EPA/USGS synthesis of native and nonindigenous species in the “Pacific Coast Ecosystem Information System” (PCEIS) database. One pattern is the large number of nonindigenous species (NIS), with approximately 70 NIS fishes and 400 NIS invertebrates reported from the NEP (Gulf of California through the Aleutian Islands). With the exception of several NIS found only within the San Francisco Estuary, most established NIS have been found in two or more of the eight Marine Ecoregions of the World (MEOW) ecoregions making up the NEP. In terms of latitudinal patterns, the mid-latitude Northern California Ecoregion was more invaded than the Southern California Bight Ecoregion or the ecoregions encompassing Oregon, Washington, and Puget Sound. The high number of invaders in the Northern California Ecoregion is primarily due to the large number of NIS in the San Francisco Estuary. Puget Sound was the second most invaded waterbody though the extent of invasion decreased below 30 meters. Though less information is available, the three northern ecoregions covering Pacific Canada and Alaska appear to be substantially less invaded. While the larger estuaries and coastal waterbodies were the most invaded, the smaller “pristine” estuaries without international ports or oyster aquaculture were also moderately invaded by a subset of the invaders found in the larger estuaries. In comparison to the estuaries, the continental shelf (30–120 m) off of Washington, Oregon, and California contained very few benthic NIS and they made only a minor contribution to total abundance. The shelf assemblages did, however, contain several species found in both the Atlantic and Pacific. Many of these “cryptogenic” species appear either to be widely distributed species or unresolved species complexes rather than species introduced through human vectors.