Influence of Incision Location on Transmitter Loss, Healing, Survival, Growth, and Suture Retention of Juvenile Chinook Salmon

Abstract

Fisheries research involving surgical implantation of transmitters necessitates the use of methods that minimize transmitter loss and fish mortality and optimize healing of the incision. We evaluated the effects of three incision locations on transmitter loss, healing, survival, growth, and suture retention in juvenile Chinook salmon Oncorhynchus tshawytscha. The three incision locations were (1) on the linea alba (LA incision), (2) adjacent and parallel to the LA (muscle-cutting [MC] incision), and (3) extending from the LA towards the dorsum at a 45° angle, between the parallel lines of myomeres (muscle-sparing [MS] incision). A Juvenile Salmon Acoustic Telemetry System acoustic transmitter (0.44 g in air) and a passive integrated transponder tag (0.10 g in air) were implanted into each fish (total N = 936 fish). The fish were held at 12°C or 20°C and were examined weekly for 98 d. The progression of healing among incision locations and the variability in transmitter loss made it difficult to identify one incision location as the best choice. The LA incisions had a much smaller wound extent (area of visible subepidermal tissue) than MC and MS incisions during the first 28 d of the study. In both temperature treatments, apposition of incisions through day 14 was better for LA incisions than for MC and MS incisions. However, MC and MS incisions were less likely than LA incisions to reopen over time and thus were less likely to allow transmitter loss through the incision.

Received June 24, 2010; accepted April 9, 2011

ACKNOWLEDGMENTS

Craig McKinstry (PNNL) and John Skalski, Richard Townsend, and Adam Seaburg (University of Washington) provided insight on the methods, study design, and statistical analysis. Andrew Solcz, Amanda Playter, Kathleen Carter, Silvia Powell, Jessica Allen, Ian Welch, James Boyd, and Jennifer Monroe (PNNL) assisted with data collection. Andrea Currie (PNNL) assisted with editing. 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 the Battelle–Pacific Northwest Division. Reference to trade names does not imply endorsement by Battelle or the U.S. Government.

Notes

^aThe serosal surface, musculature, and dermis–epidermis were graded separately for the fibrosis, inflammation, and wound healing measures.

^bInflammatory cells include polymorphonuclear cells, mononuclear cells, lymphocytes, and neutrophils.

^cWound healing score was based on fish pathologist Ralph Elston's (AquaTechnics, Sequim, Washington) expert opinion of healing by incorporating all criteria listed.