An integrated exploratory approach to examining the relationships of environmental stressors and fish responses

摘要: The Chesapeake Bay is one of the mostproductive systems in world. It theNation's largest estuary (64,000 square miles)and home to about 13 million people. Itsupports a variety aquatic resources offlora and fauna. However, for past 350years especially last two threedecades, there has been substantialdeterioration natural resources. Manyspecies submerged vegetation andbenthic invertebrates have diminished orbecome extinct. Commercial harvests fish,crab shell fish also declined. In 1983, Agreement was signedby Pennsylvania, Maryland, District ofColumbia, Virginia Commission. Itwas subsequently amended 1987 1992. TheAgreement identified improvement andmaintenance water quality as mostcritical elements overall restorationand protection Bay. orderto restore area conserve thefish resources, causal relationshipsbetween environmental stressors thecomposition health communitiesmust be understood. Multivariate ordination techniques are usefulexploratory tools help elucidate latentenvironmental relationships, define specificbiocriteria generate hypotheses. Geographical information (GIS) ananalytical technique identifying spatialrelationships. this project, an integratedmethodology involving use multivariateordination, statistical, GIS wasadopted. A non-metric multi-dimensionalscaling (NMDS) wasemployed conjunction with other statisticaltechniques (such correlation analysis) andArcView analyze huge data set from theMaryland Biological Stream Survey (MBSS). Theobjectives were intricaterelationships between suite environmentalfactors conditions riverinesystem evaluatethe effectiveness approach inexploratory analyses. results showed that landuse issignificantly related nutrient loading. Toa large extent, nitrates alsoaffecting composition communities some subwatersheds theChesapeake found theapproach adopted study flexible,requiring few model assumptions. But it iscomprehensive reliable, capable ofrevealing impacts environmentalstressors on ecology, structure,composition fishcommunities.