John Wiley & Sons, Ltd.

Evaluating cumulative effects of anthropogenic inputs in Prince Edward Island estuaries using the mummichog (Fundulus heteroclitus)

Estuarine eutrophication as a result of agricultural land use including the use of chemical fertilizers is increasing worldwide. Prince Edward Island, Canada has very high agricultural intensity by international standards with approximately 44% of the land area under production, and some watersheds in excess of 75% agricultural land‐use. The type of agriculture is also intensive with primarily row crops that have high chemical fertilizer and pesticide usage. In light of these stressors, the hypothesis of this study was that mummichog (Fundulus heteroclitus) population parameters would change with point and non‐point source pollution, and that multivariate statistics could be used to draw associations with specific stressors. Fish were sampled on a monthly basis from May through August at seven estuaries spanning a range of land use, nutrient, and contaminant loadings. A suite of environmental variable were simplified into three principal components, PC1 representing agricultural land use, nitrogen loading, and plant habitat, PC2 being dominated by sediment sand/silt distribution, and PC3 largely reflecting P loading and sediment organic matter. There were significant differences in abundance of both adult and young‐of‐the‐year mummichog and these changes associated most strongly with PC1, the largely N‐driven agricultural influences. In contrast, somatic variables such as liver and gonad size did not show strong association with the environmental quality principal component scores. The sand/silt PC2 appeared to have the opposite association with the biological data, with siltier environments correlating to older, larger, less dense populations of mummichog. While pesticide residues were detected in estuarine sediment, there was no clear relationship between these and watershed agricultural intensity or biochemical indicators. There was however a strong relationship between agricultural environmental variables (PC1) and in vitro steroid production that is suggestive of a potential chemical effect. Eutrophication appeared to be a primary stressor affecting mummichog populations as nutrient enrichment was associated with changes in habitat variables and these in turn were associated with high mummichog density. Thus, mummichog population demographics appears to have utility as an indicator of adverse or worsening conditions in estuaries. We concluded that, based on the subset of environmental factors evaluated, the non‐point‐source inputs of sediments and nutrients exerted the greatest influence on mummichog populations in PEI estuaries. Integr Environ Assess Manag © 2013 SETAC

Customer comments

No comments were found for Evaluating cumulative effects of anthropogenic inputs in Prince Edward Island estuaries using the mummichog (Fundulus heteroclitus). Be the first to comment!