Kim T. Fredricks

Effects of carbon dioxide on juveniles of the freshwater mussel (Lampsilis siliquoidea [Unionidae])

Carbon dioxide (CO2 ) 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 CO2 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 CO2 concentrations >160 mg/L for more than 2 wk or >100 mg/L CO2 for more than 30 d. Mean shell growth was significantly lower for mussels that survived CO2 treatments. Growth during the postexposure period did not differ among treatments, indicating recovery of the mussels. Also, CO2 caused shell pitting and erosion. Behavioral effects of CO2 included movement of mussels to the substrate surface and narcotization at the highest concentrations. Mussels in the 110 mg/L mean CO2 treatment had the most movements in the first 3 d of exposure. If CO2 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.

Determine the effect of 35% PEROX-AID® (hydrogen peroxide), administered to control mortality from saprolegniasis, on the nitrogen oxidation efficiency of the biofilters of in recirculating aquaculture systems (RAS) for freshwater finfish

These data were collected to determine how bacterial nitrification in recirculating aquaculture systems changes when exposed to hydrogen peroxide. Hydrogen peroxide is an approved aquaculture therapeutic drug, but not yet approved for use in RAS. These data will help support data already accepted by the U.S. Food and Drug Administration (FDA) that demonstrated the effectiveness of 35% PEROX-AID® (hydrogen peroxide) to (1) control mortality in freshwater-reared finfish eggs due to saprolegniasis, (2) in freshwater-reared salmonids due to bacterial gill disease, (3) in freshwater-reared coolwater finfish and channel catfish due to external columnaris disease, (4) in freshwater-reared finfish due to saprolegniasis and (5) reduce infestation density in freshwater-reared salmonids due to Gyrodactylus sp. The use of 35% PEROX-AID® for these label claims is designated by the FDA Office of Minor Use Minor Species (MUMS). This research supports expansion of the approved label of 35% PEROX-AID® (hydrogen peroxide), a MUMS-designated drug, to control the aforementioned pathogens of freshwater finfish in RAS.

Feeding response of sport fish after electrical immobilization, chemical sedation, or both

Abstract Fishery managers frequently capture wild fish for a variety of fishery management activities. Though some activities can be accomplished without immobilizing the fish, others are accomplished more readily, humanely, and safely (for both the handler and the fish) when fish are immobilized by physical (e.g., electrical immobilization) or chemical sedation. A concern regarding the use of chemical sedatives is that chemical residues may remain in the fillet tissue after the fish recovers from sedation. If those residues are harmful to humans, there is some risk that a postsedated fish released to public waters may be caught and consumed by an angler. To characterize this risk, a series of four trials were conducted. Three trials assessed feeding activity after hatchery-reared fish were electrically immobilized, chemically sedated, or both, and one trial assessed the likelihood of an angler catching a wild fish that had been electrically immobilized and chemically sedated. Results from the first trial...