The example indicator is modified from other multimetric indicators developed previously to tailor it to a 

 specific geographic region (mid-Atlantic highlands), the characteristic ichthyofauna of the region, and the 

 proposed monitoring framework (regional scale survey design). Some metrics are modified to be more 

 generic {i.e., to include more species) to account for the fact that not all fish species are distributed throughout 

 the target region. Expectations for the responses of various metrics are modified to be more appropriate for 

 the geographic region and extant ichthyofauna. 



In this presentation of a stream fish assemblage indicator for ecological condition, we have re-stated each 

 individual guideline presented in Chapter 1 for convenience and easy reference. In order to demonstrate the 

 application of relevant information to the guideline, we have developed Performance Objectives, or brief 

 descriptions of our interpretation of the specific needs for each guideline based on the specific type of 

 indicator and the proposed monitoring framework. After presentation and discussion of pertinent information, 

 we offer a summary of findings regarding the suitability of the indicator with respect to each guideline. 



Phasel: Conceptual Relevance 



Guideline 1: Relevance to the Assessment 



Early in ttie evaluation process, it must be demonstrated in concept that the proposed indicator is responsive 

 to an identified assessment question and will provide information useful to a management decision. For 

 indicators requiring multiple measurements (indices or aggregates), the relevance of each measurement 

 to the management objective should be identified. In addition, the indicator should be evaluated for its 

 potential to contribute information as part of a suite of indicators designed to address multiple assessment 

 questions. The ability of the proposed indicator to complement indicators at other scales and levels of 

 biological organization should also be considered. Redundancy with existing indicators may be penvissible, 

 particularly if improved performance or some unique and critical information is anticipated from the proposed 

 indicator 



Performance objectives 



1 . Demonstrate that the indicator is linked to an identified assessment question 



2. Discuss its role in contributing information to address multiple assessment questions 



3. Demonstrate the complementarity and minimal redundancy with other potential indicators 



The design of the MAHA study was driven in part by a series of specific assessment questions that collectively 

 would provide the means to determine the status and extent of the condition of stream resources in the region 

 with respect to the societal value of biological integrity (as defined by Karr and Dudley 1981). The principal 

 questions pertaining to stream fish assemblages are presented in Table 4-3 (U.S. EPA 1997). The nature of 

 these questions suggests that an appropriate indicator should focus at the assemblage level and consist of 

 multiple components to address the various aspects of the questions. In addition, to yield representative 

 estimates of status and extent of stream resources with respect to biological integrity, a monitoring framework 

 based on a probability-based survey design is required. The example multimetric indicator, applied in 

 conjunction with the appropriate sampling design, meets all of the requirements to address the principal 

 assessment question. The indicator can address all three components of the principal assessment question 

 by including appropriate metrics (e.g., the number of species considered to be sensitive to human disturbance). 



The indicator is also useful in that the basic fish species and abundance data used to develop it can also be 

 used with little or no additional effort to address other assessment questions of interest (Table 4-3) (U.S. EPA 



4-4 



