Comparison of Electronarcosis and Carbon Dioxide Sedation Effects on Travel Time in Adult Chinook and Coho Salmon

Abstract

The immobilization of fish during handling is crucial in avoiding injury to fish and is thought to reduce handling stress. Chemical sedatives have been a primary choice for fish immobilization. However, most chemical sedatives accumulate in tissues, and often food fishes must be held until accumulations degrade to levels safe for human consumption. Historically, there have been few options for nonchemical sedation. Carbon dioxide (CO2) has been widely used for decades as a sedative, and while it does not require a degradation period, it does have drawbacks. The use of electronarcosis is another nonchemical option that does not require degradation time. However, little is known about the latent and delayed effects on migration rates of adult salmonids that have been immobilized with electricity. We compared the travel times of adult Chinook Salmon Oncorhynchus tshawytscha and Coho Salmon O. kisutch through a fishway at river kilometer (rkm) 4, and to rkm 16 and rkm 32 after being immobilized with either CO2 or electronarcosis. Travel times of fish treated with either CO2 or electronarcosis were similar within species. Because of the nearly instantaneous induction of and recovery from electronarcosis, we recommend it as an alternative to CO2 for handling large adult salmonids. Received February 17, 2015; accepted June 27, 2015

Comparison of the Behavioral Consequences and Recovery Patterns of Largemouth Bass Exposed to MS‐222 or Electrosedation

“…Previous studies on recovery in Chinook Salmon O. tshawytscha indicated that nearly all cardiovascular variables (including heart rate and cardiac output) returned to baseline levels within 5 min of recovery (Hill and Forster 2004), which is consistent with the lack of behavioral differences observed in Largemouth Bass. Similar trends have been reported for postsedation recovery of Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus (Balazik 2015) and Coho Salmon O. kisutch (Keep et al 2015). Although electrosedated fish appeared to be behaviorally affected beyond 5 min postsedation, it is unclear whether increasing the holding time would be the correct solution given that (1) increased activity was the only behavioral difference detected and (2) handling and holding periods can also be stressful.…”

Comparative Study on Electric Fish Handling Gloves and Immersion Anesthesia for the Surgical Implantation of Transmitters in Brook Trout

“…Electro‐immobilization, which has been described in several species of warmwater and coolwater fishes, including salmonids (Roth et al 2003; Hudson et al 2011), has been found to produce shorter induction and recovery times compared to immersion anesthetics (Keep et al 2015; Johnson et al 2016). Electro‐immobilization has been used for surgical implantation of transmitters in Lake Trout Salvelinus namaycush with no apparent lethal or sublethal effects (Faust et al 2017).…”

Comparing Immobilization, Recovery, and Stress Indicators Associated with Electric Fish Handling Gloves and a Portable Electrosedation System

“…In contrast to chemical sedatives (e.g., MS‐222), electrosedation has been found to produce the quickest induction times and recovery times (Keep et al. ; Johnson et al. ) and to reduce handling stress in comparison with chemical sedatives, and the fish may be released immediately posttreatment (Bowzer et al.…”

“…As an alternative to chemical anesthetics, electrosedation presents benefits in field settings where low contamination, quick recovery times, and immediate release options are advantageous. In contrast to chemical sedatives (e.g., , electrosedation has been found to produce the quickest induction times and recovery times (Keep et al 2015;Johnson et al 2016) and to reduce handling stress in comparison with chemical sedatives, and the fish may be released immediately posttreatment (Bowzer et al 2012;Trushenski et al 2012b). Advancements in electrosedation technology have provided fisheries scientists with various commercially available systems.…”