Relations between Physical Habitat and American Eel Abundance in Five River Basins in Maryland

• DOI: 10.1577/t02-162.1
• Publication Date: 2004-06-07T19:36:40Z
• Authors: Derek J. Wiley; Raymond P. Morgan; Robert H. Hilderb...; Richard L. Raesly; Durland L. Shumway
• Keywords: Anguilla rostrata; Anguillidae

Abstract Although the American eel Anguilla rostrata occurs in a variety of habitats over large geographic areas, little is known regarding specific habitat relations that regulate distribution and abundance freshwater streams. We evaluated importance 17 physical habitat, chemical, biological variables predicting density five major river basins Maryland. Because artificial structures impede migration all basins, only sites determined to be on unblocked streams or downstream significantly restrict passage were used analysis. Stepwise regression identified model consisting four variables—velocity–depth diversity, log‐transformed distance (km) Chesapeake Bay, noneel fishes, semipassable impassable structure—as best predictor densities. When applied random subset data not for development, correctly predicted 44.4% densities had high mean prediction error (1.86 eels/75 m 2 ) compared with included development (3.33 ). However, Pearson correlation coefficient between observed ( r = 0.64; P < 0.05) indicated was generally successful trends The study results are consistent previous research suggesting lack significant eel–stream associations, although presence velocity–depth regimes may support higher Higher near affect upstream movement suggest eels accumulating these because impeded migration.