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Lower Columbia River Aquatic Non-Indigenous Species (ANS) SurveyContact InformationRobyn Draheim Introduction
Baker Bay at Ilwaco looking NE The Lower Columbia River Aquatic Nonindigenous Species Survey (LCRANS) was conducted to provide comprehensive information about the nonnative species present in the lower Columbia River. A comprehensive list of nonnative species distribution is the first step to understanding invasions, assessing impacts, and developing effective management actions. This two-year investigation provides a baseline for evaluating the rate of species introductions to the river that will allow assessment of the efficacy of ballast water management regulations and contribute important new information to ongoing regional aquatic nonindigenous species (ANS) studies. Despite the considerable volume of shipping received by the five major freshwater and brackish ports on the lower Columbia River) it had not been previously surveyed explicitly for nonnative species. The objective of the LCRANS was to provide a comprehensive survey and analysis of all ANS present in the tidally influenced, 234-kilometer reach of the lower Columbia River from Bonneville Dam to the Pacific Ocean and the tidal portions of the major tributaries. The project included a review of literature, conducted in 2001-2002, and field surveys, conducted in 2002-2003. Due to the size and diversity of habitats the taxonomic scope of the LCRANS, field surveys were limited to free-living plants and animals. The geographic area surveyed encompassed brackish and freshwater marshes, low salinity mudflats, polyhaline beaches, rocky shorelines, protected embayments, large river habitats, tidally influenced agricultural drainages, and urban sloughs.
Baker Bay at Chinook looking SW Survey Results
Fucus We sampled at 134 stations and documented 269 aquatic species (and 55 other distinct organisms that we were unable to identify at the species level) in the lower Columbia River. Of the 269 species identified, 54 (21%) were introduced, 92 (34%) were native, and 123 (45%) were cryptogenic. The literature review and field survey revealed that at least 81 organisms have been introduced into the lower Columbia River since the mid 1800s. The majority of these species were fish (28%), aquatic plants (23%) and crustacea (15 %). The remaining 18% was a combination of mollusks, annelids, bryozoans, cnidaria, amphibians, reptiles and an aquatic mammal. Due to the limitations of this survey, inadequate taxonomic resolution in prior studies, and the abundance of unresolved and cryptogenic taxa, our results are likely a conservative estimate of the ANS invasion of the lower Columbia River.
Tansy Point DiscussionFrom the 1880s to the 1970s a new introduced species was discovered in the lower Columbia about every five years. The frequency of new discoveries ANS is increasing worldwide (OTA 1993, Ruiz et al. 2000), however, and the rate of discovery of introduced invertebrates in the lower Columbia River mirrors this trend. Over the past ten years a new invertebrate species was discovered about every five months. The increasing rate of new discovery is due to increasing frequency of introductions and to the number and type of surveys conducted. It is not possible to separate these effects from the available data. In contrast to the increasing rate or invertebrate discovery, the rate of fish discovery peaked in the 1950s. This trend was likely due to a decline in intentional fish introductions by both individuals and fish and game agencies to increase the diversity of food and game fishes.
Tongue Point The majority of introduced species in the lower Columbia originated in North America. Introduced fish accounted for most of the species with North American origin, while Asia was the native region of 34 percent of the invertebrates introduced via shipping mechanisms in the Columbia River. The high proportion of Asian invertebrates in the Columbia River fauna may be related to shipping patterns. Asian ports are the last port of call for most arrivals to the Columbia River from outside the Exclusive Economic Zone (EEZ). The Columbia River receives more port calls from vessels from domestic ports (59 percent) than it does from international ports (Flynn and Sytsma 2004). About 25 percent of coastal vessel traffic entering Oregon estuaries originated in the highly invaded San Francisco Bay/Sacramento/San Joaquin Delta (Flynn and Sytsma 2004). Short transit times, established populations of introduced invertebrates possibly selected for dispersal by shipping vectors in several domestic ports on the West Coast, and abundant shipping traffic suggests that domestic shipping is a highly important vector for ANS introduction to the Columbia River. This report establishes a baseline on ANS in lower Columbia River. Additional monitoring and sampling is necessary to detect new invasions and to document invasion rate, impacts, and efficacy of management efforts. We recommend a multiple-purpose sampling approach to maximize the potential of detecting additional species and new arrivals. Sampling should target habitats and taxa that are likely to contain new invaders every year; a synoptic survey of the lower Columbia River should be conducted every five years; and additional sampling should target data gaps and survey limitations of this project.
Trestle Bay ReportsThe following are documents currently available in Adobe pdf format: 1. LCRANS Final Report (.pdf file size: 0.9Mb) 1. LCRANS Literature Review (.pdf file size: 1.3Mb)
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