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Published: 1987

Total Pages: 49

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Literature dealing with the physical, biological, and chemical effects of commercial navigation traffic in large waterways is reviewed and analyzed. The majority of the information on this topic does not pertain directly to traffic, but deals with sedimentation, water quality changes, or other features of large waterways that are not always caused by passage of a commercial navigation vessel. The major physical effects of traffic are brief periods of often severe turbulence and wave wash. Water drawdown and elevated turbidity can also occur as a result of vessel passage, although environmental effects of these perturbations are usually not severe. A period of turbulence can disturb feeding and respiration of aquatic insects, mussels, and fish larvae. Brief periods of elevated suspended solids and turbidity can affect respiratory structures and sensory apparatus of aquatic organisms; however, these effects are usually temporary. Field studies on navigation traffic are difficult to design and to perform. However, the effects of traffic can be evaluated with carefully designed laboratory and field experiments. Laboratory experiments do not duplicate natrual habitat conditions; however, they provide a mechanism for understanding basic effects of traffic. In the laboratory, test apparatus can be built fo rsubjecting fish eggs and larvae, as well as freshwater mussels, to frequent and infrequent periods of turbulence and elevated suspended solids. Field manipulative experiments in which organisms are caged and trasferred to sites impacted by various levels of commercial traffic provide the best technique for evaluating navigation traffic effects.