Impingement of Fishes on Water Intake Screens of Major Industrial Water Users on the Delaware River With Particular Reference to Anadromous Fish
Proceedings of a Workshop on American Shad
The purpose of this study was to determine rate of impingement of anadromous fish species, to relate how various physical and water quality parameters influence catch rates of individual intake systems, and to monitor the annual downstream migration of juvenile shad through the area of the seasonal pollution barrier. Frequency and abundance of catch was greatest at brackish water stations and least in upriver free-flowing zones. This indicates that the most important factor influencing catch is water intake location along the river system. A total of 97,383 fish (38 species) were collected in 719 samples from 10 stations in the freshwater tidal zone. This represented 28.8% of total fish taken and 84.8% of the anadromous fish. Three brackish water stations produced 240,409 fish (45 species in 370 samples. These collections comprised 71.16% of the total catch and 15.17% of the anadromous fish taken. Besides facility location, fish catch rates are influenced by dissolved oxygen levels, time of year, flooding conditions, light conditions, and tidal stage. During this study, the five most abundant species collected were menhaden, white perch, spot, blueback herring, and bay anchovy. Alewife and American shad ranked eighth and twelfth, respectively.