Lack of Effect on Embryo Mortality and Fry Growth from Adult Coho Salmon Subjected to Electronarcosis Prior to Spawning

Abstract

The use of electronarcosis as a fish immobilization technique has reemerged in recent years. Previous studies have investigated behavioral effects of the technique. But investigations of the physical and physiological effects on fish of electrical immobilization have focused on different electrical waveforms or higher power densities than are used for electronarcosis. This study was designed to determine whether there was a significant negative effect on embryo survival or fry growth among the progeny of adult Coho Salmon Oncorhynchus kisutch immobilized by electronarcosis prior to spawning as compared with being immobilized by tricaine methanesulfonate or not being immobilized at all (control). Embryo mortality in family lots ranged from 0.67% to 55.05%, with no statistically significant differences among the treatments and the control. There were significant differences in the size of fry from adults subjected to electronarcosis rather than the other two treatments, but in all cases the fry from adults treated with electronarcosis were larger. These findings support the continued use of electronarcosis as a fish immobilization technique.

Received January 24, 2014; accepted April 2, 2014

ACKNOWLEDGMENTS

We thank the staff of Eagle Creek National Fish Hatchery for their logistical support for this study, specifically Larry Telles, Mark Galloway, Steve Semon, Jeff Ellis, and Jeff McLaren. We also thank the personnel of the Columbia River Fisheries Program Office who assisted us in conducting this study, specifically William Brignon and Trevor Conder. The findings and conclusions are those of the authors and do not necessarily represent the views of the U.S. Fish and Wildlife Service. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.