TUESDAY, MARCH 28, 2006

Topic: Continued Development of a Fish Assemblage Assessment Method for Non-Wadeable Large Rivers in Maine and New England: 2002-2005

Authors: Yoder, Chris O., Brandon H. Kulik , and David B. Halliwell

In 2002 we conducted exploratory and developmental work in 100 miles of the Kennebec River between Wyman Lake and Chops Point in Merrymeeting Bay in Maine. This effort produced a standardized, single-gear, boat electrofishing sampling methodology and an initial dataset for exploratory analysis of various assessment tools. This was followed by sampling 160 miles of the Androscoggin River mainstem between Lake Umbagog (New Hampshire) and Merrymeeting Bay and a 40 mile segment of the Sebasticook River in 2003. In 2004, the Penobscot River mainstem from Millinocket to Hamden, the West Branch, and selected tributaries were also sampled. We encountered the challenges common to sampling fish in all of these large rivers including both logistical and technical considerations. This application was further refined in 2005 with surveys of the Allagash, Aroostook, St. Croix, and St. John rivers, which produced a raft-mounted technique. The principal sampling goal is to produce estimates of relative abundance for species that are amenable to efficient capture and for large numbers of sites located along extended river reaches on an annual basis. Sampling effort is expressed in terms of distance sampled and includes fixed distances established by the initial exploratory work in 2002. Strong differences were found in various assemblage parameters and species relative abundances between major habitat types (riverine, impounded, tidal) and along each river (cold to warmwater). The 2005 data served to fill gaps in our understanding of the status of cold water and native faunas. These types of analyses are prerequisite to the primary goal of developing multimetric indices, which are contingent on the description of regional reference conditions. Direct reference analogs are either rare or not representative of the historical potential for these large rivers, thus historical knowledge of the fish assemblage is needed. The U.S. EPA Biological Condition Gradient is one tool that proved useful for visualizing reference condition and understanding how river fish assemblages respond to incremental stressors. This approach has proved successful in assessing fish assemblage quality and response to chemical, physical, and biological perturbations where it has been applied. We will detail progress to date in Maine and describe a continuing strategy for IBI development and its application to other New England rivers.

Speaker: Chris O. Yoder, Research Director, Center for Applied Bioassessment and Biocriteria, Midwest Biodiversity Institute

Chris O. Yoder is involved in the national development of biological assessments and biocriteria, including multimetric index development for wadeable streams and non-wadeable large rivers. He is presently the principal investigator of a cooperative agreement with the U.S. EPA, Office of Water for monitoring and assessment, indicators, and biological criteria development and implementation. He was most recently Manager of the Ecological Assessment Section at Ohio EPA (1989 - 2001) and supervisor and staff member since 1976. His experience also includes service on national, regional, and state working groups and committees dealing with monitoring and assessment, environmental indicators, biological assessment, biological criteria, and WQS development and implementation. Recently he served as a member of the National Research Council committee on the role of science in the TMDL process. He has 35 years of experience in the assessment of fish assemblages and other aquatic organism groups, their associated habitats, and 30 years in water quality management including the integration of multiple indicators of stress, exposure, and response.