Evaluation and Proposed Refinement of the Sampling Design for the Long Term Resource Monitoring Program's Fish Component

摘要

Environmental monitoring programs are frequently designed to track changes in key physical, chemical, and biological features of an ecosystem. As such, these programs provide critical information for detecting changes in system state, investigating causal mechanisms of the observed changes, and making resource management decisions. Because monitoring programs require significant investments of time, money, and human resources to implement and maintain, periodic evaluations of monitoring programs are necessary to determine if the sampling design adequately addresses program goals and objectives. Periodic evaluations also permit assessment of a program's ability to provide adequate and useful information for changing management and science needs. We evaluated the Long Term Resource Monitoring Program's (LTRMP) fish sampling design by analyzing data from stratified random samples collected from 1993 to 1999 in six Trend Analysis Areas (TAAs). Specifically, we investigated whether the sampling design could provide similar information with fewer sampling gears. Our goals were to identify and quantify information provided by each gear used to monitor fish in the LTRMP, develop alternative sampling design scenarios based on our analyses and expert opinion, and engage program partners in a discussion on the relative value of each gear within the present sampling design. Community characterization (presence or absence), community structure (relative abundance within the full community), and detection of annual changes in single-species catch-per-unit-effort (Lubinski et al. 2001) are the primary information provided by the fish component. Our analyses considered differences in these measures among TAAs, gear types, sampling strata, seasonal sampling period, and fish size. Results were made available to program partners through a Web site for review and comment. Based on these analyses, program partners developed a suite of potential options for component refinement.