Northwest Fisheries Science Center

Display All Information

Document Type: Report
Center: NWFSC
Document ID: 6781
Title: Effect of field polarity in guiding salmon fingerlings by electricity
Author/Editor: H William Newman
Year: 1959
Institution: U.S. Department of the Interior Fish and Wildlife Service, Special Scientific Report-Fisheries No. 319
Date: 1959

The relation of field polarity to fish guiding effectiveness was tested under controlled laboratory conditions by using a single–row electrode array sequentially energized so that:  (1) positive polarity was always toward the upstream end, (2) positive polarity was always toward the downstream end, and (3) polarity alternated to cancel out polarity orientation.  No difference in effectiveness was found demonstrating that fish guiding was due to avoidance rather than to electrotaxis.  Variability, measured as variance, decreased as sample size increased but the mean effectiveness was similar for fish release lots of 15, 50, and 100 fish each. 

Notes: 22 pages