Efficacy of Single-Suture Incision Closures in Tagged Juvenile Chinook Salmon Exposed to Simulated Turbine Passage

Abstract

Reductions in the size of acoustic transmitters implanted in migrating juvenile salmonids have resulted in the use of a shorter incision—one that may warrant only a single suture for closure. However, it is not known whether a single suture will sufficiently hold the incision closed when fish are decompressed and when outward pressure is placed on the surgical site during turbine passage through hydroelectric dams. The objective of this study was to evaluate the effectiveness of single-suture incision closures on five response variables in juvenile Chinook salmon Oncorhynchus tshawytscha that were subjected to simulated turbine passage. An acoustic transmitter (0.43 g in air) and a passive integrated transponder tag (0.10 g in air) were implanted in each fish; the 6-mm incisions were closed with either one suture or two sutures. After exposure to simulated turbine passage, none of the fish exhibited expulsion of transmitters. In addition, the percentage of fish with suture tearing, incision tearing, or mortal injury did not differ between treatments. Expulsion of viscera through the incision was higher among fish that received one suture (12%) than among fish that received two sutures (1%). The higher incidence of visceral expulsion through single-suture incisions warrants concern. Consequently, for cases in which tagged juvenile salmonids may be exposed to turbine passage, we do not recommend the use of one suture to close 6-mm incisions associated with acoustic transmitter implantation.

Received November 8, 2010; accepted February 28, 2011

ACKNOWLEDGMENTS

Funding was provided by the U.S. Army Corps of Engineers, Portland District. We especially thank John Stephenson, Brett Pflugrath, Piper Benjamin, Andrew Gingerich, Ricardo Walker, Kasey Knox, Marybeth Gay, Andy LeBarge, and Bob Mueller (Pacific Northwest National Laboratory) for their valuable assistance. We are grateful to John Skalski and Adam Seaburg (University of Washington) for scientific and statistical advice. Animal facilities were certified by the Association for Assessment and Accreditation of Laboratory Animal Care; fish were handled in accordance with federal guidelines for the care and use of laboratory animals, and protocols were approved by the Institutional Animal Care and Use Committee of Battelle–Pacific Northwest Division. Reference to trade names does not imply endorsement by Battelle, the Pacific Northwest National Laboratory, or the U.S. Government.