Evaluation and Proposed Refinement of the Sampling Design for the Long Term Resource Monitoring Program's Fish Component
Abstract : 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.
ARE TWO SYSTEMIC FISH ASSEMBLAGE SAMPLING PROGRAMMES ON THE UPPER MISSISSIPPI RIVER TELLING US THE SAME THING?
We applied an Index of Biotic Integrity (IBI) used on Wisconsin/Minnesota waters of the upper Mississippi River (UMR) to compare data from two systemic sampling programmes. Ability to use data from multiple sampling programmes could extend spatial and temporal coverage of river assessment and monitoring efforts. We normalized for effort and tested fish community data collected by the Environmental Monitoring and Assessment Program‐Great Rivers Ecosystems (EMAP‐GRE) 2004–2006 and the Long Term Resource Monitoring Program (LTRMP) 1993–2006. Each programme used daytime electrofishing along main channel borders but with some methodological and design differences. EMAP‐GRE, designed for baseline and, eventually, compliance monitoring, used a probabilistic, continuous design. LTRMP, designed primarily for baseline and trend monitoring, used a stratified random design in five discrete study reaches. Analysis of similarity indicated no significant difference between EMAP‐GRE and LTRMP IBI scores (n = 238; Global R = −0.052; significance level = 0.972). Both datasets distinguished clear differences only between ‘Fair’ and ‘Poor’ condition categories, potentially supporting a ‘pass–fail’ assessment strategy. Thirteen years of LTRMP data demonstrated stable IBI scores through time in four of five reaches sampled. LTRMP and EMAP‐GRE IBI scores correlated along the UMR's upstream to downstream gradient (df [3, 25]; F = 1.61; p = 0.22). A decline in IBI scores from upstream to downstream was consistent with UMR fish community studies and a previous, empirically modelled human disturbance gradient. Comparability between EMAP‐GRE (best upstream to downstream coverage) and LTRMP data (best coverage over time and across the floodplain) supports a next step of developing and testing a systemic, multi‐metric fish index on the UMR that both approaches could inform. Copyright © 2011 John Wiley & Sons, Ltd.
Morpho-biometric Relationship, Relative Condition Factor and Meat Yield of Distant Scallop Bractechlamys vexillum (Reeve, 1853) in Asid Gulf, Philippines
Understanding the relationships of morphometric and biometric characters of a species allows the prediction of one trait from the other and generate a measure of relative condition. These relationships were studied for the Distant scallop Bratechlamys vexillum (Reeve, 1853) in Asid Gulf. Representative samples collected during the dry season (May 2018, n = 99) and wet season (September 2018, n = 100) were used to analyse these relationships through models of simple linear and power regression analyses, revealing allometric growth patterns. For both periods, it was revealed that shell width (SW) is a slightly better predictor than the height (SH) for total weight (TW) (R2 = 0.90 and 0.92) and the adductor muscle weight (AW) (R2 = 0.78 and 0.80). The strong functional relationship was also observed between TW and AW (R2 = 0.80 and 0.81). The relative condition factors (Kn) were high in both seasons. High meat yields were also observed in May (12.77 %) and September (14.26 %). The significant difference in meat yields (P < 0.05) can be a result of the seasonal difference manifested by the dynamics of energy partitioning during gametogenesis and spawning. These biological metrics are vital inputs in analysing mariculture prospects for the resource and a contribution to the scarce information on the biology of the species.