Geology topics

J.J. Rach

Publications and source records attributed to J.J. Rach.

At least 19 recordsLinked to original sources

USGS2011

Effects of handling and aerial exposure on the survival of unionid mussels

We conducted a relocation study of unionid mussels in Navigation Pool 7 of the upper Mississippi River (river mile 713.2) to evaluate survival after handling and aerial exposure. Two separate studies were conducted to compare seasonal differences in mussel survival; the first was initiated in June and the second in October. Amblema plicata plicata (subfamily Ambleminae) and Obliquaria reflexa (subfamily Lampsilinae) were studied. Mussels were marked, held out of water for either 0, 1, 4, or 8 h, and then placed into a 3 × 3 m grid (divided into nine 1-m 2 units). The mussels were re-examined after four-five months to measure mortality in the control and treatment groups. Mussels of both species had >90% survival after aerial exposure up to 4 h in both studies. However, survival (number recaptured live/number recaptured live and dead) of mussels showed a decreasing trend with duration of exposure in the first study, but not in the second study. The overall recovery of marked mussels (number recaptured/number marked) was 91% in the first study and 87% in the second study. However, only 37% of O. reflexa mussels in the 8-h treatment were recovered in the first study; the adjusted survival (number live recaptured/number marked) of this treatment group was significantly (p < 0.05) lower (35%) than all other treatments.

Journal of Freshwater Ecology↗

USGS2008

Efficacy of oxytetracycline hydrochloride bath immersion to control external columnaris disease on walleye and channel catfish fingerlings

The efficacy of oxytetracycline hydrochloride (OTC-HCl) in controlling external columnaris disease caused by Flavobacterium columnare on fingerling walleyes Sander vitreus and channel catfish Ictalurus punctatus was evaluated in two on-site hatchery trials. Microscopic examination of skin scrapings before treatment confirmed the presence of bacteria with characteristics indicative of F. columnare.in separate trials, walleyes (4.4 g) and channel catfish (1.5 g) were exposed to 60-min static bath treatments of OTC-HCl at 0, 10, and 20 mg/L (walleyes) or 0, 10, 20, and 40 mg/L (channel catfish) on three consecutive days. Each treatment regimen was tested in triplicate, and each replicate contained either 30 walleyes or 55 channel catfish. Posttreatment presumptive disease diagnosis indicated that F. columnare was the disease agent causing the mortality in both species of fish. Walleye survival at 10 d posttreatment was greater in the 10- and 20-mg/L treatment groups than in the control group; however, only the 10-mg/L treatment significantly (P < 0.05) increased walleye survival in comparison with controls. In the channel catfish trial, survival at 10 d posttreatment was significantly (P < 0.05) greater for all OTC-HCl treatment groups relative to controls. Results from these trials indicated that OTC-HCl treatments effectively reduced mortality in walleyes (10 mg/L only) and channel catfish infected with F. columnare. ?? Copyright by the American Fisheries Society 2008.

North American Journal of Aquaculture↗

USGS2006

Safety of fish therapeutants to glochidia of the plain pocketbook mussel during encystment on largemouth bass

Mussel biologists and fisheries managers have developed propagation techniques to duplicate the natural glochidia infestation on host fish. However, in intensive culture situations, fish diseases may threaten the survival of both fish and their attached glochidia and chemical treatments may be required to control a disease epizootic. Five therapeutants were evaluated for their safety to largemouth bass Micropterus salmoides encysted with mussel glochidia by comparing the number of sloughed glochidia in the chemical treatment groups with that of an untreated control group. Largemouth bass were infested with glochidia from the plain pocketbook mussel Lampsilis cardium and treated with 20 mg chloramine-T/L, 2 mg Cutrine/L, or 200 mg formalin/L (trial 1) and 200 mg formalin/L, 100 mg hydrogen peroxide/L, or 20,000 mg sodium chloride/L (trial 2). Chemicals were applied for 60 min (15 min in the case of sodium chloride in trial 2) once every other day, for a total of three treatments (six in the case of formalin in trial 2). After the first treatment, aquaria were siphoned each weekday to determine the number of sloughed glochidia or transformed juveniles. In trial 1, the initial mean number of glochidia per fish ranged from 257 to 294, and approximately 94% of the glochidia transformed to juveniles. In trial 2, the initial mean number of glochidia per fish ranged from 97 to 115, and approximately 91% of the glochidia transformed to juveniles. The mean percent of sloughed glochidia varied by less than 2% among all test groups in each trial. There were no significant differences (P < 0.05) in the number of sloughed glochidia or transformed juveniles among control or treatment groups in either trial. Therapeutic treatment of diseased fish with chloramine-T, Cutrine, formalin, hydrogen peroxide, or sodium chloride at the treatment regimens evaluated are viable options for enhancing the survival of fish encysted with glochidia.

North American Journal of Aquaculture↗

USGS2005

Efficacy of hydrogen peroxide versus formalin treatments to control mortality associated with saprolegniasis on lake trout eggs

We compared the efficacy of hydrogen peroxide versus formalin treatments to control fungal infections on eggs of lake trout Salvelinus namaycush incubated at a hatchery in Wisconsin. Four strains of lake trout eggs were incubated in six vertical-flow Heath incubators; three replicate incubators for each chemical. Each incubator had 13 trays containing approximately 25,000-30,000 eggs/tray. Formalin (1,667 mg/L) or hydrogen peroxide (1,000 mg/L) treatments were administered once daily for 15 min up to the development of visible eye spots in the eggs (eyed egg stage). Eyed and dead eggs were separated using a photoelectric egg sorter, and the number of live and dead eggs was determined volumetrically. In the hydrogen peroxide test group, the bottom trays of each incubator had fungus present on the eggs, whereas no fungus was observed on eggs treated with formalin. The mean percentage of eyed eggs for an incubator treated with formalin (75%) was significantly greater than an incubator treated with hydrogen peroxide (70%). Formalin was the most efficacious therapeutant; however, both therapeutants were effective in increasing lake trout egg survival up to the eyed egg stage. ?? Copyright by the American Fisheries Society 2005.

North American Journal of Aquaculture↗

USGS2004

Efficacy of hydrogen peroxide to control saprolegniasis on channel catfish (Ictalurus punctatus) eggs

The efficacy of hydrogen peroxide to control mortality associated with saprolegniasis in channel catfish ( Ictalurus punctatus ) eggs was evaluated at the Lost Valley State Fish Hatchery (Warsaw, MO). Two efficacy trials were conducted. In Trial 1, channel catfish eggs in their natural gelatinous matrix were treated with hydrogen peroxide at 0, 500, and 750 mg l(-1). Channel catfish eggs in Trial 2 had the gelatinous matrix removed before treatment with hydrogen peroxide at 0 and 500 mg l(-1). Each treatment regimen was tested in triplicate and each egg jar contained similar to 17,400 eggs. Hydrogen peroxide was administered as a 15-min flow-through treatment applied once daily for a total of six applications. Control jars were similarly treated with culture water. Samples of exposure water were collected during each treatment and analyzed to verify actual treatment concentrations. Hydrogen peroxide treatment efficacy was assessed by comparing the percent egg hatch in the treatment group to the untreated control group in each trial. Mean percent hatch in Trial I was 44% (control), 54% (500 mg l(-1)), and 69% (750 mg l(-1)). Hydrogen peroxide treatment at either 500 or 750 mg l(-1) significantly (P<0.01) increased the percent hatch compared to the untreated control group. In Trial 2, hydrogen peroxide treatment at 500 mg l(-1) significantly (P<0.01) increased the percent egg hatch (67%) relative to the untreated controls (57%). Hydrogen peroxide treatment reduced egg mortality and increased the percent hatch of channel catfish eggs regardless of whether eggs were incubated in the gelatinous matrix or without the matrix in comparison to the untreated control.

Missouri↗

USGS2003

Efficacy of hydrogen peroxide in controlling mortality associated with saprolegniasis on walleye, white sucker, and paddlefish eggs

The efficacy of hydrogen peroxide in controlling saprolegniasis on eggs of walleye Stizostedion vitreum, white sucker Catostomus commersoni, and paddlefish Polyodon spathula was evaluated at four private, state, and federal production hatcheries participating in an Investigational New Animal Drug efficacy study (experiment 1; walleyes) and in a laboratory-based miniature egg jar incubation system (experiment 2; walleyes, white suckers, and paddlefish). Naturally occurring fungal infestations (saprolegniasis) were observed on eggs in both experiments. Confirmatory diagnosis of infested eggs from one hatchery in experiment 1 identified the pathogen as Saprolegnia parasitica. During experiment 1, eggs were treated daily for 15 min with either 0, 500, or 750 mg/L of hydrogen peroxide, and one trial compared a 500-mg/L hydrogen peroxide treatment with a formalin treatment at 1,667 mg/L. Saprolegniasis infestation was observed in control egg jars, whereas treatment with either formalin or hydrogen peroxide virtually eliminated the infestation. Hydrogen peroxide treatments of 500 mg/L either increased egg hatch or were as effective as physical removal of infested eggs in controlling mortality. Although treatment with formalin at 1,667 mg/L significantly increased the percent eye-up of walleye eggs compared with that of those treated with hydrogen peroxide at 500 mg/L, the difference was only 1.9-2.6%. In experiment 2, noneyed eggs were treated for 15 min every other day with 0, 283, 565, or 1,130 mg/L of hydrogen peroxide until the viable eggs hatched. Saprolegniasis infestation engulfed most control eggs, whereas infestation of treated eggs was either reduced or not visible. Hydrogen peroxide significantly increased egg hatch for all three species tested in experiment 2. Although hydrogen peroxide treatments as low as 283 mg/L significantly increased walleye and white sucker hatch, treatments between 500 and 1,000 mg/L are more likely to be effective in production egg incubation systems.

North American Journal of Aquaculture↗

USGS2003

Efficacy of Hydrogen Peroxide in Controlling Mortality Associated with External Columnaris on Walleye and Channel Catfish Fingerlings

The efficacy of hydrogen peroxide in controlling mortality associated with external columnaris infections on walleye Sander vitreus (formerly Stizostedion vitreum) and channel catfish Ictalurus punctatus fingerlings was evaluated in two on-site trials. Microscopic examination of skin scrapes before treatment confirmed the presence of bacteria indicative of columnaris disease. In separate trials, walleyes (12 g) and channel catfish (2.3 g) were exposed to a total of three every-other-day hydrogen peroxide treatments of 0, 50, 75, or 100 mg/L for 60 min. Each treatment regimen was tested in triplicate, and each replicate contained 13 walleyes or 26 channel catfish. Hydrogen peroxide exposures of 50 mg/L for 60 min significantly increased walleye survival relative to that at other treatment concentrations, including the controls. Exposures of 50, 75, or 100 mg/L of hydrogen peroxide for 60 min significantly increased channel catfish survival in comparison with that of controls. These trials indicated that hydrogen peroxide treatments effectively reduce mortality in walleyes and channel catfish infected with external columnaris.

North American Journal of Aquaculture↗

USGS2000

Analytical verification of waterborne chemical treatment regimens in hatchery raceways

Chemical therapy for control and prevention of fish diseases is a necessary and common practice in aquaculture. Many factors affect the accuracy of a chemical treatment application, such as the functioning of the chemical delivery system, calculation of chemical quantities to be delivered, water temperature, geometry of the culture unit, inlet-outlet structure, the influence of aerators, wind movement, and measurement of water volumes and flow rates. Three separate trials were conducted at the Osceola Fish Hatchery, a facility of the Wisconsin Department of Natural Resources, evaluating the accuracy of flow-through hydrogen peroxide treatments applied to 1, 3, or 9 raceways that were connected in series. Raceways were treated with 50 or 75 ??L/L of hydrogen peroxide for 30 min. Chemical concentrations were determined titrimetrically. The target treatment regimen was not realized in any of the applications. Chemical concentrations dropped and exposure times increased with each additional raceway treated in series. Single introduction of a therapeutant to more than three raceways in series is not recommended. Factors that interfered with the accuracy of the treatments were culture unit configuration, aeration, and flow rates. Several treatment modifications were identified that would result in more accurate chemical treatments.

North American Journal of Aquaculture↗

USGS2000

Efficacy of hydrogen peroxide to control mortalities associated with bacterial gill disease infections on hatchery-reared salmonids

The efficacy of hydrogen peroxide to control mortalities associated with bacterial gill disease (BGD) was evaluated in three trials conducted at two Wisconsin Department of Natural Resources hatcheries. Microscopic examination of the fish gills before treatment revealed gill damage and the presence of bacteria indicative of BGD. In separate trials, brown trout Salmo trutta , chinook salmon Oncorhynchus tshawytscha , and rainbow trout O. mykiss were exposed to hydrogen peroxide concentrations of 0, 56, 110, or 230 mg/L for 30 or 60 min every other day. In all three trials, at least one of the hydrogen peroxide treatment regimens reduced cumulative fish mortality in comparison with the controls. Exposures of 230 mg/L for 60 min increased the risk of mortality in brown trout and chinook salmon relative to that at other treatment concentrations. Exposures of up to 230 mg/L for 30 min decreased the risk of mortality in rainbow trout. Posttreatment qualitative gill examination indicated that gills of the treated fish appeared normal, whereas the gills of control fish exhibited pale coloration, clubbing of filaments, and lamellar fusion. On the basis of the efficacy data, two static bath treatment regimens were effective in the control of BGD: hydrogen peroxide administered at concentrations of 56–110 mg/L as a 60-min exposure or hydrogen peroxide administered at concentrations of 56–230 mg/L as a 30-min exposure.

Journal of Aquatic Animal Health↗

USGS1999

Acute toxicity of hydrogen peroxide treatments to selected lifestages of cold-, cool-, and warmwater fish

Hatchery personnel depend on therapeutant treatments to control diseases. Currently, hatchery managers in the United States are limited to one approved therapeutant (formalin) and three compounds of Low Regulatory Priority (sodium chloride, hydrogen peroxide, and acetic acid) to control external diseases of cultured fish. Hydrogen peroxide has been used to effectively control external columnaris and bacterial gill disease in rainbow trout, however, definitive safe treatment concentrations for hydrogen peroxide are lacking for a variety of species. We report the acute toxicity of hydrogen peroxide treatments to 11 species of fry and 13 species of fingerling freshwater fish. Most mortality occurred within the first 30 h after the first exposure to hydrogen peroxide with little change in the overall shape of survival curves over time. Our data predict that in an actual therapeutic application of hydrogen peroxide, most treatment-related mortalities would be observed shortly after the initial exposure. Coolwater species were more sensitive than coldwater species but were generally similar to warmwater species tested. Based on our mortality data, coldwater species and largemouth bass may be treated for 60 min at concentrations of ??? 150 ??l/l without harmful effects; all muskellunge, walleye, bluegill, channel catfish, yellow perch, pallid sturgeon fingerlings, fathead minnow fingerlings, white sucker fingerlings, and northern pike fry may be treated for 60 min at ??? 100 ??l/l; and northern pike fingerlings and white sucker, yellow perch and fathead minnow fry may be treated for 60 min at ??? 50 ??l/l.

Aquaculture↗

USGS1999

Behavioral responses to disturbance in freshwater mussels with implications for conservation and management

Knowledge about the ability of freshwater unionid mussels to recover from physical disturbance is important to their conservation and management. Threatened species may be disturbed by relocation to refugia as a conservation measure, and some species are disturbed by size- and species-selective harvesting of shells for use in the production of cultured pearls. The activity of freshwater unionid mussels generally decreases with water temperature, but intra- and interspecific differences in the frequency and distribution of recovery behaviors following disturbances at specific water temperatures have not been previously quantified. We observed righting, moving, and burrowing behavior of 4 mussel species, Amblema plicata plicata, Potamilus alatus, Fusconaia flava, and Lampsilis cardium, at 3 water temperatures (7, 14, and 21°C). The temporal frequency (intensity) and times-to-1st-event of behaviors were analyzed using proportional hazards models. Righting events and consecutive movements occurred at different intensities among temperatures and species. For righting, intensity increased by 8%/°C within the range of 7-21°C. Subsequent movements increased in intensity by 10%/°C. Amblema plicata was the slowest to respond, and had an intensity of turning upright only 27% of that for P. alatus. The intensities of movements for A. plicata and F. flava were 16% of those for P. alatus. Lampsilis cardium righted themselves most quickly, and had an intensity of righting 124% of that for P. alatus. The distribution of the 3 behaviors among treatment groups at 1 wk was analyzed with a proportional odds model. The distribution of righting, moving, and burrowing 1 wk after disturbance was described entirely by high-order interactions in our proportional odds model. Therefore, that model revealed little interpretable pattern in the endpoint data and it was less sensitive than our analysis of time-to-event data for measuring the effects of disturbance. We attributed the difference in sensitivity between the 2 models to the greater information content of time-until-event data. For similar studies of occurrences of key events, times to events should be recorded and interpreted whenever feasible and consistent with study objectives. Our results suggest that water temperature has an important effect on the outcome of mussel conservation projects and commercial harvesting activities. Our modeling approach, applied to other species, could help guide decisions about which species can safely be disturbed and the optimal seasonal timing of those disturbances.

Journal of the North American Benthological Societ↗

USGS1998

Method for inducing saprolegniasis in channel catfish

A method was developed to uniformly and systematically induce saprolegniasis in channel catfish Ictalurus punctatus. Three different methods for inducing saprolegniasis were evaluated in waters containing known zoospore concentrations of Saprolegnia parasitica : (1) low-temperature shock to induce immunosuppression; (2) physical abrasion stress; and (3) a combination of both low temperature shock and abrasion stress. Low-temperature shock or abrasion stress alone were not effective for inducing saprolegniasis. Only 10% of fish stressed by low-temperature shock alone became infected. No fish receiving abrasion stress treatments alone became infected even though these fish were subject to significant abrasion and dewatering stress. A combination of low-temperature and abrasion stress, however, was sufficient to induce saprolegniasis in 100% of fish tested and resulted in 90% mortality. No fish became infected in the positive control group (exposed to zoospores of S. parasitica without stress) or in the negative control group. The combined-stress method should enable researchers to induce saprolegniasis in channel catfish at will to study its pathogenesis or to test the efficacy of candidate antifungal treatments. In conducting efficacy studies, therapeutic treatments must begin immediately when the first signs of saprolegniasis are observed because the disease progresses quickly and is deadly.

Journal of Aquatic Animal Health↗

USGS1998

Toxicity of hydrogen peroxide treatments to rainbow trout eggs

Hydrogen peroxide treatments of 0, 500, 1,000, and 3,000 I?L/L, concentrations that were multiples of the Low Regulatory Priority limit of 500 I?L/L, were administered for 15 min every weekday (Mondaya??Friday) to eggs of rainbow trout Oncorhynchus mykiss and steelhead (anadromous rainbow trout) to determine the margin of safety existing for standard egg treatments. All untreated and treated eggs remained free of fungal infection throughout incubation. Hydrogen peroxide treatment reduced the mean percent hatch of rainbow trout eggs by 1.4a??5.9% among those treated at 500 I?L/L, 6.8a??15.4% among those treated at 1,000 I?L/L, and 13.2a??25.3% among those treated at 3,000 I?L/L. Mean percent hatch of rainbow trout eggs treated at 1,000 I?L H2O2/L was 7% lower than that for eggs treated at 500 I?L H2O2/L. Mean percent hatch of Skamania strain steelhead was significantly reduced by hydrogen peroxide treatment, whereas the mean percent hatch of Ganaraska strain steelhead was similar to the mean percent hatch of rainbow trout eggs. Daily percent mortality of rainbow trout eggs increased significantly from day 6 to day 10 (78a??135 daily temperature units, DTUsA?C) of incubation. Discontinuing hydrogen peroxide treatments to Skamania strain steelhead eggs from day 7 to day 11 (78a??105 DTUsA?C) of incubation significantly increased the probability of eggs reaching the eyed egg stage. The mean percent hatch of rainbow trout eggs treated with hydrogen peroxide at concentrations up to 1,000 I?L/L may be increased if no treatments are administered between 70 and 140 DTUsA?C. Mortality of sac fry was not observed at hydrogen peroxide concentrations of 1,000 I?L/L or lower. Fish culturists should be aware that other species or strains may be more sensitive than rainbow trout. Other species and strains should be initially treated with hydrogen peroxide at 500 I?L/L until monitoring of egg mortality identifies the presence or absence of a sensitive period.

Journal of Aquatic Animal Health↗

USGS1997

Effect of species, life stage, and water temperature on the toxicity of hydrogen peroxide to fish

Hydrogen peroxide is a drug of low regulatory priority status that is effective in treating fish and fish eggs infected by fungi. However, only limited information is available to guide fish culturists in administering hydrogen peroxide to diseased fish. Laboratory tests were conducted to determine (1) the sensitivity of brown trout Salmo trutta , lake trout Salvelinus namaycush , fathead minnow Pimephales promelas , walleye Stizostedion vitreum , channel catfish Ictalurus punctatus , and bluegill Lepomis machrochirus to hydrogen peroxide treatments; (2) the sensitivity of various life stages of rainbow trout Oncorhynchus mykiss to hydrogen peroxide treatments; and (3) the effect of water temperature on the acute toxicity of hydrogen peroxide to three fish species. Fish were exposed to hydrogen peroxide concentrations ranging from 100 to 5,000 μL/L (ppm) for 15‐min or 45‐min treatments every other day for four consecutive treatments to determine the sensitivity of various species and life stages of fish. Except for walleye, most species of fish tested (≤2 g) tolerated hydrogen peroxide of 1,000 μL/L or greater. Walleyes were sensitive to hydrogen peroxide concentrations as low as 100 μL/L. A correlation was found between the toxicity of hydrogen peroxide and the life stages of rainbow trout; larger fish were more sensitive. Generally, the toxicity of hydrogen peroxide increased for all species as water temperature increased. The results of these experiments demonstrate that it is important to consider the effects of species, life stage, and water temperature when conducting hydrogen peroxide treatments.

Progressive Fish-Culturist↗

USGS1997

Importance of analytically verifying chemical treatments

Hydrogen peroxide is considered a low regμLatory priority compound by the U.S. Food and Drug Administration. It is used to control fungal infections on fish eggs. We studied the treatment profiles of hydrogen peroxide in Heath, McDonald egg jar, and Clark–Williamson incubators during treatments intended to deliver an effective regimen of at least 500 μL hydrogen peroxide/L (i.e., treatments of 500 and 1,000 μL/L) for 15 min. Hydrogen peroxide concentrations decreased with increasing distance from the influent water in both Heath and Clark–Williamson incubators. The top treatment tray (tray 2) of the Heath incubator received more than 90% of the intended regimen during the 500 μL/L treatment, whereas at 1,000 μL/L, all trays had hydrogen peroxide concentrations at or above 500 μL/L for 15 min. None of the compartments in the Clark–Williamson incubator received the intended therapeutic regimen when treated at 500 μL/L. The McDonald egg jar system distributed the intended concentration for the designated treatment period in all jars, except those located directly below the influent water. Our results indicate that dilution of therapeutants applied through certain egg incubation systems significantly decreases the efficacy of treatments and may render them ineffective, The dilution characteristics of egg incubation systems should be assessed in order to ensure proper delivery of all intended chemical concentrations and exposure regimens. Suggestions for maintaining the minimum effective concentrations in evaluated incubators are included.

Progressive Fish-Culturist↗

USGS1994

Effects of water temperature and pH on toxicity of terbufos, trichlorfon, 4-nitrophenol and 2,4-dinitrophenol to the amphipod Gammarus pseudolimnaeus and rainbow trout (Oncorhynchus mykiss)

Acute toxicity tests were conducted to determine (a) the individual and interactive effects of water temperature (7, 12, 17°C), pH (6 5, 7 5, 8 5, 9 5), and time on the toxicity of terbufos, trichlorfon, 4 nitrophenol, and 2,4-dinitrophenol to rainbow trout ( Oncorhynchus mykiss ) and the amphipod Gammarus pseudohmnaeus , and (b) the individual and interactive effects of water temperature and pH on chemical bioconcentration during acute tests with rainbow trout and Gammarus exposed to terbufos, 4 nitrophenol, and 2,4 dinitrophenol The toxicity of all four chemicals was significantly affected by pH in all tests, except for Gammarus exposed to terbufos The toxicity of terbufos to rainbow trout and Gammarus was less at pH 7 5 than at higher or lower pH The toxicity of both nitrophenols decreased as pH increased, whereas the toxicity of trichlorfon increased with pH The effect of pH on trichlorfon toxicity decreased with temperature Temperature significantly affected the toxicity of all four chemicals to both species Toxicity increased with temperature in all tests, except for rainbow trout exposed to nitrophenols, toxicity decreased as temperature increased for rainbow trout Chemical bioconcentration was also significantly af fected by temperature and pH and was directly related to toxicity in most tests Significant interactive effects between toxicity modifying factors were also frequently observed Temperature and pH effects on chemical toxicity need to be consid ered in chemical hazard assessment to ensure adequate protection of aquatic organisms

Environmental Toxicology and Chemistry↗

USGS1994

Development of an antimycin-impregnated bait for controlling common carp

The common carp Cyprinus carpio is a major problem for fisheries and wildlife managers because its feeding behavior causes degradation of valuable fish and waterfowl habitat. This study was designed to evaluate the effectiveness of an antimycin‐impregnated bait for control of common carp. The toxic bait contained fish meal, a binder, antimycin, and water. The ingredients were mixed together and made into pellets. This bait was force‐fed to common carp or administered in a pond environment, where fish voluntarily fed on the bait. The lowest lethal dose in the force‐feeding study was 0.346 mg antimycin/kg of fish and doses that exceeded 0.811 mg antimycin/kg were toxic to all fish. On three occasions, adult common carp held in 0.004‐ha concrete ponds were offered 10 g of toxic bait containing 5.0, 7.5, and 10 mg antimycin/g of bait and the mean mortalities 96 h later were 21, 35, and 51%, respectively. Three tests were conducted in 0.04‐ha earthen ponds each containing 100 adult common carp; these fish were offered 50 g of the toxic bait that contained 10 mg antimycin/g, and the mean mortalities (96 h) were 19, 32, and 74%. Toxic baits should be used in conjunction with other management techniques, and only when common carp are congregated and actively feeding, and when few nontarget bottom‐feeding species are present.

North American Journal of Fisheries Management↗

USGS1994

Hydrogen peroxide as a fungicide for fish culture

Antifungal agents are needed to maintain healthy stocks of fish in the intensive culture systems currently employed in fish hatcheries. Malachite green has been the most widely used antifungal agent; however, its potential for producing teratology in animals and fish precludes further use in fish culture. Preliminary studies at the National Fisheries Research Center, La Crosse, WI, USA (La Crosse Center) indicate that hydrogen peroxide is effective for control of Saprolegnia sp. fungus on incubating eggs of rainbow trout. It is also effective against a wide variety of other organisms such as bacteria, yeasts, viruses, and spores, and has been proposed as a treatment for sea lice on salmon. Hydrogen peroxide and its primary decomposition products, oxygen and water, are not systemic poisons and are considered environmentally compatible. In response to a petition from the La Crosse Center, the U.S. Food and Drug Administration (FDA) recently classified hydrogen peroxide as a 'low regulatory priority' when used for control of fungus on fish and fish eggs. Preliminary tests conducted at the La Crosse Center suggest that prophylactic treatments of 250 to 500 ppm (based on 100% active ingredient) for 15 minutes every other day will inhibit fungal infections on healthy rainbow trout (Oncorhynchus mykiss) eggs. This treatment regime also seems to inhibit fungal development and increase hatching success among infected eggs. Efficacy and safety of hydrogen peroxide as a fungicide for fish are currently being evaluated.

Bulletin of the Aquaculture Association of Canada↗