Michael A. Boogaard

Acute Toxicity of TFM and a TFM/Niclosamide Mixture to Selected Species of Fish, Including Lake Sturgeon (Acipenser fulvescens) and Mudpuppies (Necturus maculosus), in Laboratory and Field Exposures

The toxicity of the lampricides 3-trifluoromethyl-4-nitrophenol (TFM) and 2′,5-dichloro-4′-nitrosalicylanilide (niclosamide) to non-target fishes has been a major point of concern since their use to control larval sea lamprey (Petromyzon marinus) populations began in the early 1960s. The toxicity of TFM to several non-target fish species has been demonstrated in previous studies. However, little information is available on the toxicity of the TFM/1% niclosamide mixture. One species of particular concern is the lake sturgeon (Acipenser fulvescens). Juvenile lake sturgeon of several size ranges were exposed to determine potential effects of the lampricides to individuals present in treatment streams. Sac fry were most resistant to the lampricides followed by fingerlings in the 200 to 225 mm size range. Swim-up fry and fingerlings less than 100 mm were the most sensitive. Concentrations that produced 50% mortality (LC50 s) in juvenile lake sturgeon of these smaller size ranges were at or near the minimum lethal concentrations (MLCs) required for effective control of larval sea lampreys. The mudpuppy (Necturus maculosus), an amphibian native to several tributaries of the Great Lakes, have also become a species of interest in recent years. Laboratory tests conducted with TFM and a TFM/1% niclosamide mixture on adult mudpuppies indicate that although the amphibian is sensitive to the lampricides, an adequate margin of safety exists for adult mudpuppies to survive when exposed during stream treatments. Fifteen other fish species native to streams treated with lampricides were investigated in the laboratory to determine their sensitivity to the lampricides. Centrarchids, bluegill (Lepomis macrochirus) and green sunfish (Lepomis cyanellus) were the least sensitive to TFM, while ictalurids, black bullhead (Ictalurus melas), channel catfish (Ictalurus punctatus), and tadpole madtom (Notorus gyrinus) were the most sensitive. On-site bioassays conducted before lampricide treatments also revealed that lake sturgeon, channel catfish, and whitefish (Coregonus clupeaformis) were sensitive to the lampricides although considerably less sensitive compared to sea lamprey.

Development of a pH/alkalinity treatment model for applications of the lampricide TFM to streams tributary to the Great Lakes

Abstract It has long been known that the toxicity of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) is influenced by chemical and physical properties of water. As the pH, conductivity, and alkalinity of water increase, greater concentrations of TFM are required to kill sea lamprey ( Petromyzon marinus ) larvae. Consequently, the concentration of TFM required for effective treatment varies among streams. Brown trout ( Salmo trutta ) and sea lamprey larvae were exposed to a series of TFM concentrations in a continuous-flow diluter for 12 h. Twenty five exposures were conducted at various water alkalinities and pHs that treatment personnel encounter during lampricide treatments. Survival/mortality data were analyzed for lampricide concentrations that produced 50 and 99.9% mortality (LC 50 and LC 99.9 ) for sea lamprey larvae and 25 and 50% mortality (LC 25 and LC 50 ) for brown trout. Linear regression analyses were performed for each set of tests for each selected alkalinity by comparing the 12-h post exposure LC 99.9 sea lamprey data and LC 25 brown trout data at each pH. Mortality data from on-site toxicity tests conducted by lampricide control personnel were compared to predicted values from the pH/alkalinity prediction model. Of the 31 tests examined, 27 resulted in the LC 100 s (lowest TFM concentration where 100% mortality of sea lamprey was observed after 12 h of exposure) falling within 0.2 mg/L of the predicted sea lamprey minimum lethal (LC 99.9 ) range. The pH/alkalinity prediction model provides managers with an operational tool that reduces the amount of TFM required for effective treatment while minimizing the impact on non-target organisms.

Toxicity of Rotenone and Antimycin to Silver Carp and Bighead Carp

Abstract The general public, natural resource managers, and government agencies have become increasingly concerned about the continued spread of silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis in the Mississippi River basin and their potential spread into the Great Lakes. An integrated approach of chemical, biological, and physical measures is needed to reduce Asian carp populations in these waters. Rotenone and antimycin are the only general piscicides that are registered with the U.S. Environmental Protection Agency for controlling fish populations. Considerable information is available regarding the toxicity of these chemicals to numerous fish species. However, there is little available toxicity information indicating the potential for these chemicals to control Asian carp. In this study, Prenfish (5% rotenone) and antimycin (90% antimycin-A) toxicities to silver carp and bighead carp were assessed in acute toxicity and effective contact time tests. Each acute toxicity test consiste...

Effects of Lampricide Exposure on the Survival, Growth, and Behavior of the Unionid Mussels Elliptio complanata and Pyganadon cataracta

The effects of a 12-h exposure to the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) and a combination of TFM and 1% niclosamide (active ingredient in Bayluscide 70% wettable powder) on the short and long-term ( 10 mo post exposure) survival and behavior of two unionid freshwater mussel species Elliptio complanata and Pyganadon cataracta were measured. Growth of juvenile E. complanata mussels 10 months after exposure was also compared. Toxicity was determined after 12 h exposures at maximum concentrations from 2- to 2.5- fold higher than the LC99 for sea lamprey larvae. A logistic model was used to estimate the probability of survival among treatments, trials, species, and sizes. Mortality was minimal in all test concentrations of TFM alone and the TFM/1% niclosamide combination. Estimated survival decreased 6% for each unit increase in the relative toxicity of TFM. Survival was greater for E. complanata than for P. cataracta, and for adults relative to juveniles. Lampricide treatment caused narcotization of both mussels (defined as having gaped shells and an extended foot) in concentrations ≥ LC99 for sea lamprey larvae and narcotization ranged from 0–50% among treatments. Recovery from narcosis was apparent by 12 h post-exposure and complete by 36 h post-exposure. The rate of growth of E. complanata over the 10-month post-exposure period did not vary among treatments.

Avoidance Behavior of Ruffe Exposed to Selected Formulations of Piscicides

Abstract Ruffe were introduced into Duluth Harbor, Minnesota in the early 1980s, probably by release of ballast water from sea-going freighters. Since then, it has become the most abundant species in the fish community. The sensitivity of ruffe to a number of piscicides has been demonstrated, however, the feasibility of using piscicides to control populations depends on whether ruffe can detect piscicides and move to untreated water. We used a two-choice preference testing system to evaluate avoidance or attraction reactions of ruffe during exposures to the lampricides TFM and bayluscide and the general fish toxicants rotenone and antimycin. We used a second testing system to evaluate the potential for benthic ruffe to move vertically in the water column to avoid piscicides dissolving from experimental bottom-release formulations of bayluscide and antimycin. Near-lethal concentrations of TFM and rotenone tended to repel ruffe. Antimycin and bayluscide did not seem to repel ruffe in the avoidance chamber, but bottom-release formulations (antimycin granules—0.25% a.i. and bayluscide granules—3.2% a.i.) did cause increased swimming and surfacing activity among ruffe in column tests. We conclude that TFM and rotenone could be used to treat entire bodies of water, while bottom-release formulations of antimycin and bayluscide may have more application for treating localized concentrations of ruffe.

Evaluation of the short term 12 hour toxicity of 3‐trifluoromethyl‐4‐nitrophenol (TFM) to multiple life stages of Venustaconcha ellipsiformis and Epioblasma triquetra and its host fish (Percina caprodes)

The present study evaluated the risk of 12-h exposures of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) to multiple life stages of the federally endangered snuffbox (Epioblasma triquetra) and its primary host fish the common logperch (Percina caprodes) as well as a surrogate to the snuffbox, the ellipse (Venustaconcha ellipsiformis). Life stages examined included free glochidia, 1-wk juveniles, and adults of the ellipse; free glochidia, glochidia on host fish, and 1-wk juveniles of the snuffbox; and adult logperch. Larval sea lampreys were also tested alongside adult ellipse and logperch for direct comparison. Survival exceeded 82% among all life stages in both mussel species at levels up to 1.8 times what would be applied during treatments, suggesting that routine sea lamprey control operations would not adversely affect mussels. However, substantial mortality of adult logperch was observed at TFM concentrations typically applied to streams, and loss of host fish could adversely affect snuffbox reproduction. In addition, TFM had no significant effect on the number of glochidia that metamorphosed on adult logperch. Although the snuffbox is not likely to be acutely affected from sea lamprey control operations, mitigation efforts to minimize impacts to the host fish should be considered.

Uptake, Metabolism, and Elimination of Niclosamide by Fish

The lampricide 2’,5-dichloro-4’-nitrosalicylanilide (niclosamide) formulated as the 2-aminoethanol salt (Bayluscide) has been used in combination with 3-trifluoromethyl4-nitrophenol (TFM) to control sea lampreys (Petromyzon marinus) in streams tributary to the Great Lakes for over 30 years. In addition, a bottom release formulation of Bayluscide has been used extensively to assess populations of larval lampreys in lenitic areas. The nature and magnitude of niclosamide residues in rainbow trout (Onchorhynchus mykiss) tissues and rates of elimination have been evaluated under laboratory and field exposure conditions. The uptake of niclosamide from water by rainbow trout is rapid, and residues reach equilibrium after 3 days of exposure. Only about 9% of total body niclosamide residues are found in edible fillet tissues after 24 hours of exposure. Metabolism of niclosamide by hydrolysis, reduction, or conjugation with glucuronic acid has been reported in fish, rats, cestodes, nematodes, midge larvae, mouse and sheep liver homogenates, and aerobic and anaerobic pond sediments. Rainbow trout exposed to niclosamide recently have been reported to have residues of the glucuronide conjugate and the sulfate ester in muscle fillet tissue. Fish transferred to niclosamide-free water after 24 hours of exposure to 0.02 mg/L of the chemical eliminated residues to below the limit of detection within 2–3 days.

An automated approach to Litchfield and Wilcoxon's evaluation of dose-effect experiments using the R package LW1949.

The authors developed a package, LW1949, for use with the statistical software R to automatically carry out the manual steps of Litchfield and Wilcoxons method of evaluating dose-effect experiments. The LW1949 package consistently finds the best fitting dose-effect relation by minimizing the chi-squared statistic of the observed and expected number of affected individuals and substantially speeds up the line-fitting process and other calculations that Litchfield and Wilcoxon originally carried out by hand. Environ Toxicol Chem 2016;35:3058-3061. 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.

Multilevel empirical Bayes modeling for improved estimation of toxicant formulations to suppress parasitic sea lamprey in the upper Great Lakes.

Estimation of extreme quantal-response statistics, such as the concentration required to kill 99.9% of test subjects (LC99.9), remains a challenge in the presence of multiple covariates and complex study designs. Accurate and precise estimates of the LC99.9 for mixtures of toxicants are critical to ongoing control of a parasitic invasive species, the sea lamprey, in the Laurentian Great Lakes of North America. The toxicity of those chemicals is affected by local and temporal variations in water chemistry, which must be incorporated into the modeling. We develop multilevel empirical Bayes models for data from multiple laboratory studies. Our approach yields more accurate and precise estimation of the LC99.9 compared to alternative models considered. This study demonstrates that properly incorporating hierarchical structure in laboratory data yields better estimates of LC99.9 stream treatment values that are critical to larvae control in the field. In addition, out-of-sample prediction of the results of in situ tests reveals the presence of a latent seasonal effect not manifest in the laboratory studies, suggesting avenues for future study and illustrating the importance of dual consideration of both experimental and observational data.