James D. Bowker

Chemical and Electrical Approaches to Sedation of Hybrid Striped Bass: Induction, Recovery, and Physiological Responses to Sedation

Abstract Currently, in the United States, there are few sedatives available to fisheries professionals that are safe, effective, and practical. Chemical sedatives, including tricaine methanesulfonate (MS-222), carbon dioxide (CO2), benzocaine, and eugenol may be used to sedate fish, though none of these compounds are currently approved by the U.S. Food and Drug Administration as immediate-release fish sedatives. Another option is the use of electricity to temporarily immobilize fish. Few studies have assessed the efficacy of these options for immediate-release sedation in side-by-side comparisons. We evaluated the use of MS-222 (150 mg/L), CO2 (∼400 mg/L), benzocaine (150 mg/L), eugenol (60 mg/L), and a commercially available electrosedation unit (30 Hz pulsed DC, 60 V, 25% duty cycle, 3-s exposures) to induce hybrid striped bass (white bass Morone chrysops × striped bass M. saxatilis; 510 ± 12 g [mean ± SE]) to stage IV anesthesia or sedation. Induction times were shortest (0.2 ± 0.1 min) when electrosed...

Issues Regarding the Use of Sedatives in Fisheries and the Need for Immediate-Release Options

Abstract The lack of an immediate-release sedative (i.e., one for which no postsedation holding or withdrawal period is required) jeopardizes fish and fisheries research and poses considerable risk to those involved in aquatic resource management and the operation of public hatcheries and commercial fish farms. Carbon dioxide may be used as an immediate-release sedative, but it is slow-acting and difficult to apply uniformly and effectively. Tricaine methanesulfonate (MS-222) is easier to apply but requires a 21-d withdrawal period. The lack of an immediate-release sedative approved by the U.S. Food and Drug Administration (FDA) is a consequence of numerous factors, including the complexities of the approval process, the substantial human and monetary resources involved, and the specialized nature of the work. Efforts are currently underway to demonstrate the safety and effectiveness of benzocaine- and eugenol-based products as immediate-release sedatives. However, pursuing approvals within the current fr...

Induction, Recovery, and Hematological Responses of Largemouth Bass to Chemo- and Electrosedation

Abstract Sedating fish before handling minimizes the risk of injury to both fish and handler and may also minimize the fishs stress response. We conducted two experiments to quantitatively compare induction and recovery times of largemouth bass Micropterus salmoides sedated with tricaine methanesulfonate (MS-222), eugenol, benzocaine, carbon dioxide (CO2), or electrosedation (pulsed DC).We also assessed the fishs hematological profile following sedation with MS-222, eugenol, and electrosedation. Induction times varied significantly among the sedatives evaluated; electrosedation yielded the fastest inductions (0.2 ± 0.1 min; mean ± SE) and CO2 yielded the slowest (3.6 ± 0.1 min). Times to recovery of equilibrium and responsiveness to tactile and visual–auditory stimuli also varied, ranging from 1.8 ± 0.3 to 3.7 ± 0.3 min and from 2.3 ± 0.3 to 4.0 ± 0.3 min, respectively, depending on the sedative used. Plasma cortisol concentrations were elevated at 0.5 h postsedation among fish sedated with eugenol and ...

Chemical and Electrical Approaches to Sedation of Cobia: Induction, Recovery, and Physiological Responses to Sedation

Abstract To support the growing interest in marine fisheries research in areas such as biotelemetry, tagging, and tracking, we assessed the ability of various sedatives to facilitate this research in juvenile cobias Rachycentron canadum (∼300 g), namely, tricaine methanesulfonate (MS-222; 150 mg/L), carbon dioxide (CO2; ∼750 mg/L), eugenol (60 mg/L), benzocaine (150 mg/L), and pulsed-DC electrosedation (100 V, 30 Hz, 25% duty cycle, 5-s exposure). Induction times (CO2 [z] > benzocaine [y] > eugenol [y] > MS-222 [y] > electrosedation [x]), recovery of equilibrium (CO2 [z] > eugenol [z] > MS-222 [y] > benzocaine [y] > electrosedation [x]), and responsiveness to tactile stimulus (eugenol [z] > MS-222 [y] > benzocaine [y] > CO2 [xy] > electrosedation [x]) differed significantly among the sedative treatments (treatments with the same letters are not significantly different). Total handling time from initial sedative exposure to recovery differed among the sedatives as well (CO2 [z] > eugenol [y] > benzocaine [x] > MS-222 [x] > electrosedation [w]), with cumulative means ± SEs of 5.9 ± 0.2 min for CO2, 4.1 ± 0.2 for eugenol, 2.7 ± 0.2 min for benzocaine and MS-222, and 1.0 ± 0.2 min for electrosedation. Physiological responses differed significantly over time, with transient increases in plasma Cortisol, glucose, osmolality, and lactate that were resolved within 6 h. The overall magnitude of the physiological responses differed among sedatives, depending on the response variable; however, in each case, CO2 elicited the greatest response. Although variations in induction and recovery times were observed, it is likely that these differences can be reasonably accommodated within the context of typical research by adjusting the sedative treatments or allowing for longer induction and recovery times as needed.

Efficacy of 35% PEROX-AID (Hydrogen Peroxide) in Reducing an Infestation of Gyrodactylus salmonis in Freshwater-Reared Rainbow Trout

Abstract Gyrodactylus salmonis is a monogenean ectoparasite that can infest a variety of captive-reared salmonid fishes. The physical damage inflicted during severe infestations can cause osmoregulatory disturbances and potentially render individuals more vulnerable to secondary pathogens. If not treated, G. salmonis infestations can reduce growth and survival in affected fish populations. Many chemical compounds have been used to treat Gyrodactylus infestations; however, little information has been published about the use of hydrogen peroxide (H2O2) for Gyrodactylus control. Consequently, we conducted a trial to evaluate the efficacy of H2O2 in reducing a natural infestation of G. salmonis in freshwater-reared, adult rainbow trout Oncorhynchus mykiss. Triplicate tanks of adult rainbow trout (20 fish per tank; length = 45.6 ± 5.8 cm and weight = 1.3 ± 0.4 kg, mean ± SD) were exposed to a static bath of H2O2 at a target dosage of 50 mg/L or hatchery water (sham treatment) for 30 min/d on two alternate days...

Effectiveness of Aquaflor (50% Florfenicol) to Control Mortality Associated with Streptococcus iniae in Freshwater-Reared Subadult Sunshine Bass

We conducted a field trial to evaluate the effectiveness of Aquaflor (50% florfenicol) for controlling mortality associated with Streptococcus iniae in freshwater-reared subadult sunshine bass (female white bass Morone chrysops X male striped bass M. saxatilis). Bacterial samples collected from moribund fish representing a reference population were presumptively identified microbiologically and were later confirmed to be S. iniae by biochemical characterization and polymerase chain reaction. The trial comprised a 1-d acclimation period, 10-d treatment period, and 14-d posttreatment period. During the treatment period, Aquaflor-medicated feed was administered to treated tanks (N = 3) at a target dose of 10 mg of florfenicol x kg of fish(-1) x d(-1), and nonmedicated feed was administered to control tanks (N = 3). At the end of the posttreatment period, mean (+/- SD) cumulative mortality in treated tanks (9 +/- 11%) was significantly (P = 0.040) less than that in control tanks (52 +/- 13%). Analysis of medicated feed samples revealed that treated tanks had received an actual dose of 8.3 mg florfenicol x kg fish(-1) x d(-1) (83% of target). No florfenicol was detected in control feed samples. Although the actual florfenicol dose administered to treated tanks was less than the target dose, the trial was accepted by the U.S. Food and Drug Administration Center for Veterinary Medicine as demonstrating the efficacy of Aquaflor to control mortality associated with S. iniae in cultured sunshine bass populations.

Controlling Mortality Caused by External Columnaris in Largemouth Bass and Bluegill with Chloramine-T or Hydrogen Peroxide

Abstract Columnaris (causative agent, Flavobacterium columnare) is a widespread fish disease of concern among fish culturists in the USA. If left untreated, an entire population of fish may become infected, and morbidity and mortality may reach high levels. In virtually all instances, columnaris outbreaks require intervention to prevent significant losses. A number of sanitizing agents, most notably chloramine-T (CLT) and hydrogen peroxide (HP), have been used to control mortality associated with a variety of bacterial pathogens causing external infections. However, the majority of trials conducted to demonstrate the effectiveness of these chemicals, thereby gaining U.S. Food and Drug Administration approval for their use in treating fish infected with columnaris, have been conducted on salmonids. Accordingly, we conducted seven experiments to evaluate the effectiveness of CLT or HP to control mortality associated with external columnaris in Florida Largemouth Bass Micropterus salmoides floridanus and Blu...

Introduction to a Special Section: Hatcheries and Management of Aquatic Resources (HaMAR)—Considerations for Use of Hatcheries and Hatchery-Origin Fish

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Guidelines for Use of Fishes in Research—Revised and Expanded, 2014

Guidelines for Use of Fishes in Research—Revised and Expanded, 2014 Jill A. Jenkins Chair, Henry L. Bart Jr., James D. Bowker, Paul R. Bowser, J. Randy MacMillan, John G. Nickum, Joseph W. Rachlin, James D. Rose, Peter W. Sorensen, Barbara E. Warkentine & Greg W. Whitledge a U.S. Geological Survey, National Wetlands Research Center, 700 Cajundome Blvd., Lafayette, LA 70506. E-mail: b Tulane University, Biodiversity Research Institute, Belle Chasse, LA c U.S. Fish and Wildlife Service, Aquatic Animal Drug Approval Partnership Program, Bozeman, MT d Cornell University, College of Veterinary Medicine, Department of Microbiology and Immunology, Ithaca, NY e Clear Springs Foods, Inc., Buhl, ID f Nickum and Nickum, Fountain Hills, AZ g Lehman College of the City University of New York, Department of Biological Sciences, Bronx, NY h University of Wyoming, Laramie, WY i University of Minnesota, Department of Fisheries, Wildlife and Conservation Biology, St. Paul, MN j State University of New York, Maritime College, Bronx, NY k Southern Illinois University, Center for Fisheries, Aquaculture, and Aquatic Sciences, Carbondale, IL Published online: 29 Sep 2014.

Efficacy of SLICE Premix (0.2% Emamectin Benzoate) for Reducing Infestations of Salmincola spp. on Freshwater-Reared Rainbow Trout

Abstract Salmincola spp. are ectoparasites of major concern in wild and cultured salmonids. These parasites can cause respiratory distress and facilitate the entry of secondary pathogens. Of particular concern in the United States is S. californiensis, which can infest all Oncorhynchus spp. and is restricted largely to freshwater. Bath treatments with formalin and hydrogen peroxide have traditionally been used to control infestations of some parasitic copepods in cultured salmonids; however, these treatments can be difficult to apply, expensive, and stressful to fish and have not been shown to be effective against S. californiensis. A more effective and efficient treatment method needs to be developed. SLICE (0.2% emamectin benzoate [EB]) is a commercial in-feed treatment that has been shown to be effective for the control of sea lice infestations in seawater-reared farmed salmon and trout. We postulated that EB might also be efficacious for the control of parasitic copepods such as S. californiensis on f...