Fish assemblages as indicators of estuary ecosystem health

摘要: Understanding and managing increasing threat from diverse anthropogenic pressures on estuaries requires impact assessment monitoring indices that provide accurate quantification of change are readily communicable. Although based nekton assemblage structure have obvious appeal to managers, the imperative produce most measures possible has seen a move away simple composite (such as diversity indices) towards complex multivariate approaches. However, methods often poor basis for reporting because they can be difficult report in terms meaningful end user. Effective should construct communicate, relate directly definable biological attributes, fall within predictable ranges unimpacted systems show demonstrable responses known impacts. We use published data 30 natural two artificial develop set assemblage-based summary fit these criteria. evaluated suite parallel both catch per unit effort (CPUE) probability encounter (PoE). Parallel complementary information thus more robust assessments change. Three fell consistent bounds long comparisons were confined same time year remove influence seasonal variability, efficient at differentiating degraded estuaries. Because successful approaches rely PoE rather than CPUE considerable tactical advantages less destructive, allow collection many samples time, treat schooling non-schooling species equivalently.