The safety of Aquaflor 1 (50% w/w florfenicol [FFC]) incorporated in feed then administered to tilapia for 20 days (2Â the recommended duration) at 0, 15, 45, or 75 mg/kg body weight/day (0, 1, 3, or 5Â the recommended dose of 15 mg FFC/kg BW/d) was investigated. Mortality, behavioral change, feed consumption, body size, and gross and microscopic lesions were determined. Estimated delivered doses were >96.9% of target. Three unscheduled mortalities occurred but were considered incidental since FFC-related findings were not identified. Feed consumption was only affected during the last 10 dosing days when the 45 and 75 mg/kg groups consumed only 62.5% and 55.3% of the feed offered, respectively. There were significant, dose-dependent reductions in body size in the FFC-dose groups relative to the controls. Treatment-related histopathological findings included increased severity of lamellar epithelial hyperplasia, increased incidence of lamellar adhesions, decreased incidence of lamellar telangiectasis in the gills, increased glycogen-type and lipid-type hepatocellular vacuolation in the liver, decreased lymphocytes, increased blast cells, and increased individual cell necrosis in the anterior kidney, and tubular epithelial degeneration and mineralization in the posterior kidney. These changes are likely to be of minimal clinical relevance, given the lack of mortality or morbidity observed. This study has shown that FFC, when administered in feed to tilapia at the recommended dose (15 mg FFC/kg BW/day) for 10 days would be well tolerated.

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Carbon dioxide (CO ) has shown promise as a tool to control movements of invasive Asian carp, but its effects on native freshwater biota have not been well studied. The authors evaluated lethal and sublethal responses of juvenile fatmucket (Lampsilis siliquoidea) mussels to CO at levels (43-269 mg/L, mean concentration) that bracket concentrations effective for deterring carp movement. The 28-d lethal concentration to 50% of the mussels was 87.0 mg/L (95% confidence interval [CI] 78.4-95.9) and at 16-d postexposure, 76.0 mg/L (95% CI 62.9-90.3). A proportional hazards regression model predicted that juveniles could not survive CO concentrations >160 mg/L for more than 2 wk or >100 mg/L CO for more than 30 d. Mean shell growth was significantly lower for mussels that survived CO treatments. Growth during the postexposure period did not differ among treatments, indicating recovery of the mussels. Also, CO caused shell pitting and erosion. Behavioral effects of CO included movement of mussels to the substrate surface and narcotization at the highest concentrations. Mussels in the 110 mg/L mean CO treatment had the most movements in the first 3 d of exposure. If CO is infused continuously as a fish deterrent, concentrations <76 mg/L are recommended to prevent juvenile mussel mortality and shell damage. Mussels may survive and recover from brief exposure to higher concentrations. Environ Toxicol Chem 2017;36:671-681. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Management of invasive species, whether prevention, population reduction, or eradication, requires assessment of the invasive species' population status and an assessment of the probability of success of management options. Perceptions of a species' permanence in an environment or lack thereof frequently drives how limited time, financial, and personnel resources are allocated to such efforts. Language we use to describe a non-native species' status largely defines these perceptions and sets boundaries, real or perceived, to potential management actions. Here we discuss the use of a particular term-"established"when confronting management decisions for invasive species. Our objective is to contribute to bridging the gap between the realms of conceptual development and management with respect to use of the term "established". We find that although there are benefits of polysemy and synonymy to conceptual development they present an additional challenge to managers who must weigh the costs, benefits, and potential for success of particular management actions. We also examine how existing conceptual frameworks might be augmented to bridge the theoretical-practical gap, such as more precisely defining potential management actions and explicitly including assessment of risk.

Fish transport costs are a substantial portion of the operational expenses for aquaculture facilities in the USA. Safely transporting higher loading densities of fish would benefit haulers by increasing efficiency and reducing costs, but research evaluating transport for individual species is generally lacking. In this study, Yellow Perch Perca flavescens and Nile Tilapia Oreochromis niloticus were transported for 6 h immersed in water containing AQUI‐S 20E (10% eugenol) at fish loading densities of 240 g/L (2 lb/gal) for perch and 480 g/L (4 lb/gal) for tilapia. Survival was quantified for fish transported in AQUI‐S 20E concentrations of (1) control or 0 mg/L of water, (2) 100 mg/L, or (3) 200 mg/L. Yellow Perch had 98–100% survival, and Nile Tilapia had 100% survival up to through 14 d after transport across all AQUI‐S 20E levels, including the control. Eugenol concentrations decreased rapidly in transport tank water, and fish showed no signs of sedation by the end of transport. We conclude that live transport of Yellow Perch and Nile Tilapia at higher loading densities resulted in high survival regardless of the AQUI‐S 20E concentrations we tested.