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This range-finding study determined the optimum concentration of copper sulfate (CuSO4) for fungus control on eggs of channel catfish Ictalurus punctatus. The study consisted of five CuSO4 concentrations (2.5, 5, 10, 20, and 40 mg/L) and an untreated control in a flow-through system. A single spawn was used for each replication (N=4). Eggs were treated daily until the embryos reached the eyed stage. When hatching was complete for all viable eggs, fry were counted to determine the percent survival in each treatment. Fungal growth was severe in the untreated controls; survival of hatched fry in the control group was approximately 2%. The optimum CuSO4 treatment, as determined by percent survival of hatched fry, was 10 mg/L daily (69% survival); survival for this treatment group was significantly different from that for the controls. Very little fungus was present in treatments receiving 10-mg/L CuSO4 or higher except in one replication that had approximately 40% unfertilized eggs. The average survival rates in the 0-, 2.5-, 5-, 10-, 20-, and 40-mg/L CuSO4 treatments were 2, 34, 50, 69, 59, and 51%, respectively.

Theronts from 2 different strains of Ichthyophthirius multifiliis (AR1 and AR5) were exposed to copper sulfate (CuSO4) in waters of different total alkalinities and observed for 4 h to determine relative toxicity and kinetics of parasite mortality. Consistent with the known solubility properties of the metal, Cu was significantly more toxic to cells maintained under low (48 mg l(-1)) compared with high (243 mg l(-1)) total alkaliniity conditions. This was reflected in both the median lethal concentration (LC50) values and rates of mortality for both parasite strains; strain differences were also observed. The AR1 strain was significantly more resistant to copper toxicity than the AR5 strain in both high and low alkalinity waters. In general, these strain differences were more evident under conditions of low stress (i.e. low CuSO4 concentration and high alkalinity), and suggest that genetic factors are overridden under high stress conditions. The present study establishes a role for alkalinity in the effectiveness of CuSO4 treatment of ichthyophthiriasis and reveals differences in the susceptibility of parasite populations that are clearly important for control programs.

Objective: An experiment was conducted to evaluate the effects of repeated copper sulfate (CuSO4) treatments on the growth and survival of juvenile Walleye Sander vitreus. Methods: Culture tanks were treated with 0 or 0.76 mg/L CuSO4 every other day for five exposures, then were not treated for 14 consecutive days; this regimen was repeated for a total of 10 exposures over the course of 50 days. Copper sulfate treatments had a half‐life of about 60 min. The study was conducted in flow‐through well water at ≈1.5 L/m and 23.8°C. Result: The resulting survival data for CuSO4 treated and nontreated fish was 96% and 85% survival, respectively, and not statically different. There was no difference in weight, with treated weighing 25.3 g compared to 25.2 g for nontreated control fish. Both groups had weight increases of over 400% during the study. Neither group differed in length, with treated fish reaching a mean length of 14.6 cm and nontreated reaching a mean length of 14.5 cm. Conclusion: The results indicate that repeated CuSO4 treatments had no effect on Walleye growth or survival. Impact statementCopper sulfate has a long history of use in aquaculture. While it is no secret that copper toxicity or other deleterious effects can happen, if used appropriately copper sulfate can be one of the most useful chemicals in aquaculture. [ABSTRACT FROM AUTHOR]

The use of copper sulfate pentahydrate (herein, designated CuSO4) for fungus control on fish embryos is extremely effective and economical for farmers in waters with moderate or high alkalinity/hardness; however, fry toxicity in low alkalinity/hardness waters is a concern. The present study determined the acute toxicity of CuSO4 to Largemouth Bass Micropterus salmoides in naturally soft water (42 mg/L alkalinity [as CaCO3], 41 mg/L hardness [as CaCO3]). Median lethal concentration (LC50) values at 24 h were 3.97 mg/L CuSO4 for yolk‐sac fry and 5.24 mg/L CuSO4 for swim‐up fry. Most importantly for farmers, the no observed effect concentration (NOEC; the highest concentration tested to not cause fry mortality) was 0.625 mg/L CuSO4 for both stages of fry. Regarding the safe use of CuSO4 for fungus control on Largemouth Bass embryos, this research was done to demonstrate CuSO4 toxicity to Largemouth Bass fry in soft water. [ABSTRACT FROM AUTHOR]

This study determined the effectiveness of copper sulfate (CuSO4) to inhibit fungal growth (caused by Saprolegnia spp.) on largemouth bass (LMB) eggs spawned on/in fiber mats in very high‐alkalinity/‐hardness waters; experiments also determined the toxicity of CuSO4 to LMB fry and juveniles. An untreated control and three CuSO4 concentrations (10, 20, and 40 mg/L) were tested under a flow‐through scenario in the effectiveness experiment. Eggs were treated daily until hatching began. Fungal load at the time of hatch had a total area > 3.0 cm2 in the untreated controls, total area 1.0 to <2.0 cm2 in the 10 and 20 mg/L CuSO4 treatments, and total area > 1.0 cm2 in the 40 mg/L CuSO4 treatments. Fungus samples were identified as Saprolegnia australis. The 24‐hr median lethal concentration (LC50) values on the LMB yolk‐sac and swim‐up fry were 32.0 and 4.6 mg/L CuSO4, respectively; the No Observed Effect Concentrations (NOEC) were 16.0 and 0.125 mg/L CuSO4, respectively. Juvenile LMB were extremely tolerant to CuSO4, and their 24‐hr LC50 value was 185.5 mg/L; the NOEC was 64 mg/L. This study indicates that CuSO4 can be an important resource for hatcheries to control egg fungus, especially in high‐alkalinity/‐hardness waters. [ABSTRACT FROM AUTHOR]

Columnaris disease is an important bacterial disease of commercially grown channel catfish, Ictalurus punctatus. Copper sulphate (CuSO4) has been shown to be therapeutic and prophylactic as a water treatment for columnaris disease. Copper is an essential dietary component in animal feeds and CuSO4 is typically included in base diets; a study was conducted to evaluate whether fish feed supplemented with additional CuSO4 at 0, 40 and 80 mg kg−1 of diet and fed at a daily rate of 3% body weight would affect survival to columnaris disease. Results indicate fish fed the copper-supplemented diet for 2 weeks significantly increased survival following F. columnare challenge. This increase appeared to be dose-dependent. The mean per cent survival (±SEM) for fish fed the base diet (unsupplemented) for 2 weeks and then challenged was 2.0% ± 1.1. Fish fed the base plus 40 mg CuSO4 kg−1 had a mean survival of 22.0% ± 11.0. Fish fed the base plus 80 mg CuSO4 kg−1 had a mean survival of 29.3% ± 13.4. The mean per cent survival for fish fed the base diet for 4 weeks and then challenged was 28.3% ± 9.0. Fish fed the base plus 40 mg CuSO4 kg−1 for 4 weeks had a mean survival of 12.5% ± 6.3. Fish fed the base plus 80 mg CuSO4 kg−1 for 4 weeks had a mean survival of 40.5% ± 8.1. There was a significant effect after 4 weeks with fish fed the base plus 80 mg CuSO4 kg−1 mg not with 40 mg kg−1. [ABSTRACT FROM AUTHOR]

An obstacle to the larval production of sunshine bass (female White BassMorone chrysops× male Striped BassM. saxatilis) is fungal growth on the eggs caused by the water mold,Saprolegniaspp. Copper sulfate (CuSO4) is commonly used for fungus control in troughs at catfish hatcheries, but the effectiveness in other fish-egg hatching systems is unknown. Because sunshine bass eggs begin hatching after 48 h, CuSO4treatments (0, 10, 20, and 40 mg/L) began the afternoon of spawning with a 10-min, aerated, static bath and were repeated the morning and afternoon of day 2; eggs were not treated after hatching began. An in vitro assay was developed for this treatment regimen that indicated maximum fungal inhibition was achieved with 20 mg/L CuSO4. In the effectiveness experiment in McDonald hatching jars (n= 3), fungus was severe in the untreated controls (27.7% survival), but very little fungus was present in treatments receiving 10 mg/L CuSO4(31.4% survival) or higher. The control was not significantly different from the 10-mg/L treatment. The highest survival was at 40 mg/L CuSO4(50.5% survival); however, the survival from the 20-mg/L CuSO4treatment (45.8%) was not significantly different from that in the 40-mg/L treatment and thus allows for a greater margin of safety. Fungus samples were identified asSaprolegnia feraxthrough genetic sequencing. Toxicity experiments on sunshine bass larvae indicated the 24- and 48-h LC50 values were 5.4 and 3.9 mg/L CuSO4, respectively; the no observed effect concentrations were 0.5 and 0.25 mg/L CuSO4, respectively. This study confirms that CuSO4can be an economical and valuable resource in hatchery management for the control of saprolegniasis on sunshine bass eggs in McDonald jars. Received September 25, 2015; accepted January 20, 2016 Published online June 15, 2016 [ABSTRACT FROM PUBLISHER]

Four studies were conducted to compare the effects of copper sulfate (CuSO4), when delivered in either a flow-through or a static system, on the survival of Golden ShinersNotemigonus crysoleucasand Fathead MinnowsPimephales promelasinfected withFlavobacterium columnare. The treatment regimens were administered to fish in well water and were based on the recommended treatment rate (1% of alkalinity). Golden Shiners (experiments 1 and 3) and Fathead Minnows (experiments 2 and 4) were treated separately. In experiments 1 and 2, the treatment rate was 2.0 mg/L CuSO4applied to a flow-through system daily for five consecutive days; control fish were untreated. Study durations were 7 d with the majority of the mortalities occurring in the first 5 d. Survival rates in the flow-through system were 77% and 69% for CuSO4-treated Golden Shiners and Fathead Minnows, respectively. Survival in both species was significantly different from that in their untreated control fish, which was 33% for Golden Shiners and 41% for Fathead Minnows. Static applications of CuSO4were investigated in experiments 3 and 4. Treatment doses were 0, 0.5, 1, 2, and 4 mg/L (approximately 0.0, 0.25, 0.5, 1, and 2 times the recommended rate). Survival of Fathead Minnows in this experiment was 10, 28, 52, 47, and 35% in the 0, 0.5, 1, 2, and 4 mg/L CuSO4treatments, respectively. The corresponding survival of Golden Shiners was 49, 50, 65, 75, and 60% in the 0, 0.5, 1, 2, and 4 mg/L CuSO4treatments, respectively. Received March 28, 2014; accepted August 2, 2014 [ABSTRACT FROM PUBLISHER]

A study was conducted to compare the effects of two chemical therapeutants on channel catfish (CCF)Ictalurus punctatusconcurrently infected withFlavobacterium columnareandIchthyobodo necator. Copper sulfate (CuSO4) and potassium permanganate (KMnO4) were investigated for their ability to reduce the bacterial load, parasite load, and subsequent mortality.Treatment rates of CuSO4or KMnO4were 2.1 mg/L and 3.0 mg/L, respectively, and were applied at 24 h intervals on three consecutive days and control fish were untreated. Fin and gill samples were taken on day 4 (24 h after the final treatment) and day 10 (one week after the final treatment) for quantification of parasite and bacterial load. The survival rate of CuSO4-treated fish (73.0 %) was significantly different from the untreated control fish (41.5%). KMnO4-treated fish was (53.6%) and not significantly different from untreated control or CuSO4-treated fish.I. necatorloads were significantly reduced by both CuSO4and KMnO4,but only CuSO4significantly reduced theF. columnareload. [ABSTRACT FROM PUBLISHER]

I chthyobodo necator is a single-celled biflagellate parasite, which in high density can cause significant mortality in young fish. Copper sulphate ( CuSO4), potassium permanganate ( KMnO4) and peracetic acid ( PAA) were evaluated for effectiveness against ichthyobodosis. Treatments were: untreated control, 2.1 mg L−1CuSO4, 3.0 mg L−1 KMnO4, 1.5 mg L−1 PAA and 3.0 mg L−1 PAA, and were applied to flow-through tanks on three consecutive days. The study was designed to simulate the flow-through systems utilized in the commercial rearing of juvenile channel catfish ( I ctalurus punctatus). Mortality was monitored daily to compare survival rate among treatments. Parasite intensity was assessed pre chemical exposure and 20-24 h after the third application to determine effectiveness of the treatment. An assessment was also done 7 days post application to investigate possible reoccurrence. Copper sulphate, KMnO4 and PAA (3.0 mg L−1) significantly reduced the infestation rate of I . necator. Copper sulphate significantly improved the survival of I . necator infested channel catfish after three flow-through applications compared with the untreated control. The 3.0 mg L−1 PAA resulted in significantly lower survival than the untreated control, the 1.5 mg L−1 PAA and the KMnO4 were not statistically different from the untreated control. [ABSTRACT FROM AUTHOR]

The article focuses on a study which examined the effectiveness of bath treatments of formalin and copper sulfate on cultured white bass or Morone chrysops infected by Onchocleidus mimus and Ichthyphthirius multifiliis. The researchers conducted a statistical analysis using one-way analysis of variance (ANOVA) to analyze infection intensity and treatment effect after each exposure. It noes the percentage effectiveness (P. E.) and prevalence of Onchocleidus mimus in gill of white bass.

Columnaris disease is one of the most important bacterial diseases affecting Channel Catfish Ictalurus punctatus commercially grown in the USA. This disease can greatly diminish the profitability of aquaculture operations by large-scale mortality events, particularly in the fingerling production phase. Three experiments were conducted to evaluate the susceptibility of Channel Catfish fingerlings to columnaris disease when they were preexposed to copper sulfate (CuSO4). In experiment 1, fish were exposed for 24 h to 0, 1, 2, or 4 mg/L CuSO4 and were challenged immediately with Flavobacterium columnare, the etiological agent of columnaris disease. The resulting survival data indicated that fish preexposed to CuSO4 and then challenged exhibited significantly lower survival than did fish not exposed and then challenged. Experiment 2 was designed as above, except after the 24-h static exposure to CuSO4, fish were subjected to an additional 24 h in flow-through water prior to the challenge with F. columnare. In contrast to experiment 1, fish preexposed to CuSO4 and allowed an additional 24 h in flow-through water had a significantly higher survival rate than fish not exposed and then challenged. Experiment 3 evaluated the longevity of resistance to columnaris disease afforded by preexposure to CuSO4; in this experiment the remaining fish from experiment 2 were challenged 9 d after exposure to CuSO4. The increased survival rate of fish preexposed to CuSO4 was still significantly different, indicating the incurred resistance to F. columnare lasts for at least a week after exposure to CuSO4. [ABSTRACT FROM PUBLISHER]

Copper sulfate (CuSO4) and potassium permanganate (KMnO4) were evaluated for their effectiveness to curtail mortality and decrease bacterial load in fish tissues and water in channel catfish Ictalurus punctatus infected with Flavobacterium columnare, the causative agent of columnaris. Fish (average size, 16.6 g and 13.7 cm) were obtained from a single culture tank undergoing an epizootic of columnaris and were stocked at a density of 30 fish per tank in each of 12 tanks. The study consisted of three treatments (n = 4 replicates per treatment): an untreated control group, a CuSO4-treated group, and a KMnO4-treated group. Treatment rates were 2.1 mg/L CuSO4 and 3.0 mg/L KMnO4 and were applied on three consecutive days at 24-h intervals. Caudal fin, gill, and liver samples were taken from one fish of each replication 24 h after the last treatment for analysis by quantitative real time PCR. A significant improvement in survival was noted among fish treated with CuSO4 (72.7%) compared with the control fish (38.5%) and the KMnO4-treated fish (52.2%). Survival of the KMnO4-treated fish was not significantly different from the control. Quantitative PCR indicated a significant reduction of bacteria in the water after the first and second treatments of both therapeutants; no difference was detected in fish tissues. Histological analysis of gill samples 24 h after the last treatment indicated that CuSO4-treated fish exhibited significantly less gill damage than untreated controls and there was no difference in KMnO4-treated fish. Copper sulfate therapy significantly improved survival, reduced the number of bacteria in the water, and reduced gill pathologies associated with F. columnare infection in channel catfish. Received August 23, 2011; accepted November 22, 2011 [ABSTRACT FROM AUTHOR]

The efficacy of copper sulphate (CuSO4) against the early stages of an experimental acute infection of Flavobacterium columnare in channel catfish ( Ictalurus punctatus) was evaluated. Fish were challenged, by waterborne exposure to F. columnare in an ultra-low flow-through water delivery system, and treated with CuSO4 at 4.2 and 2.1 mg L−1 at 5.5 h post challenge for 4 h. Bacterial challenged non-treated fish acted as a positive control and non-challenged non-treated fish acted as a negative control. Fish challenged with F. columnare and treated with CuSO4 at 4.2 and 2.1 mg L−1 post challenge had mortalities of 6.4% and 18.3%, respectively, compared with the positive control, which had 90.2% mortality. The mortality of challenged fish treated with CuSO4 at 4.2 and 2.1 mg L−1 was significantly different from the positive control. There was no significant difference between the mortalities of the 4.2 and 2.1 mg L−1 treatments. The results suggest that CuSO4 has clear therapeutic value against columnaris infections. [ABSTRACT FROM AUTHOR]

Copper sulfate (CuSO4) is used in the catfish industry to control saprolegniasis (caused by the watermolds Achlya spp. or Saprolegnia spp.) on eggs. This study was designed to establish the margin of safety of CuSO4 at 10, 30, and 50 mg/L when applied for three times the normal treatment duration to hatching troughs containing channel catfish Ictalurus punctatus eggs in 26°C, flow-through well water. The safety of CuSO4 was indicated by the percentage of fry that hatched from the eggs. Eggs were treated daily until the embryos reached the eyed stage. The least-squares means ± SE of hatch rates were 40.8 ± 9.1, 80.9 ± 6.4, 64.2 ± 8.6, and 80.3 ± 6.6% for the 0-, 10-, 30-, and 50-mg/L CuSO4 treatments, respectively. The hatch rate for the 0-mg/L CuSO4 treatment was significantly different from that of all other CuSO4 treatments. Treating channel catfish eggs with five times the recommended dose of 10-mg/L CuSO4 for three times the recommended duration did not adversely affect the hatch rates in this study. There appears to be an adequate margin of safety above the therapeutic dose of 10 mg/L for channel catfish eggs; therefore, CuSO4 should be considered a safe treatment to alleviate egg losses caused by saprolegniasis. Received May 18, 2011; accepted May 23, 2011 [ABSTRACT FROM AUTHOR]

Catfish hatcheries use copper sulphate pentahydrate (CuSO4·5H2O) as an economical control for saprolegniasis on eggs. This study determines hatch rate of channel catfish, Ictalurus punctatus (Rafinesque 1818), eggs in hatching troughs containing 23.8 °C flow-through well water when treated with 100 mg L−1 CuSO4·5H2O (10 times the proposed therapeutic dose). Eggs were treated daily until the embryos reached the eyed stage. Fry survival in the control and 100 mg L−1 CuSO4·5H2O treatments was significantly different (15% and 71% respectively). This study demonstrates that there is a considerable margin of safety in using CuSO4·5H2O as a catfish egg treatment to control saprolegniasis. [ABSTRACT FROM AUTHOR]

Reduced survival of fish eggs is often a result of infestation with fungi Saprolegnia spp. However, timely chemical treatments often limit these infestations and increase survival. The effect of copper sulfate pentahydrate (CSP; 10 mg of CSP/L of water), diquat bromide (25 mg of diquat cation/L), formalin (433 mg/L), and hydrogen peroxide (H2O2; 250 mg/L) on percent hatch and fungal infestation in eggs of channel catfish Ictalurus punctatus was compared in two identical trials (five replicates for each chemical treatment per trial). The percent hatch in all chemical treatments was significantly better than percent hatch of the controls. The amount of fungal coverage on egg masses treated with CSP, formalin, and H2O2 was significantly less than that observed on the controls. Although not statistically different from the other treatments, H2O2 at 250 mg/L exhibited the highest average percent hatch (64%; control hatch = 34%), the lowest fungal coverage (1.5 cm; control coverage = 7.2 cm), and the lowest occurrence of fungi (50%; control occurrence = 100%) among the treatments. [ABSTRACT FROM AUTHOR]

Two dose confirmation studies are required by the U.S. Food and Drug Administration to verify the effectiveness of a candidate before approval as a new animal drug is awarded; the two studies provide independent substantiation of the results. This laboratory study was designed to compare an untreated control and a 10-mg/L copper sulfate (CuSO4) treatment to control fungus (Saprolegnia spp.) on eggs of channel catfish lctalurus punctatus at 23.5°C in a flow-through system. The eggs were treated once daily until the embryos reached the eyed stage (rive treatments). When hatching was complete for all viable eggs (day 10), the fry were counted to determine the percent survival in each treatment. Infestation by a fungus identified morphologically and by polymerase chain reaction as Saprolegnia spp. was severe in the control fish, resulting in 8% survival. The mean percent survival of fry hatched from the CuSO4-treated eggs was significantly higher (mean, 55%; range, 27-71%). [ABSTRACT FROM AUTHOR]

Yolk sac and swim-up fry from five separate spawns of channel catfish Ictalurus punctatus were exposed to dissolved copper sulfate (CuSO4) in a series of static toxicity bioassays to observe age sensitivity at 24 and 48 h in waters with two different chemistries at a temperature of 23.1 ± 0.47°C (mean ± SD). The two waters were (1) well water with a total alkalinity (as CaCO3) of 217 mg/L and a total hardness of 126 mg/L and (2) a 1:1 mixture of well water and deionized (WDI) water with a total alkalinity of 112 mg/ L and a total hardness of 66 mg/L. Probit median lethal concentration (LC50) values were estimated with PoloPlus using the nominal CuSO4 concentrations. The mean 24-h LC50 values for the yolk sac fry were 62.8 ± 37.1 mg of CuSO4/L in the well water and 10.2 ± 3.4 mg/L in the WDI water; the 24-h LC50 values for the swim-up fry were 13.5 ± 11.5 mg/L in well water and 4.3 ± 4.4 mg/L in WDI water. The mean 48-h LC50 values for the yolk sac fry were 14.9 ± 5.0 mg/L in well water and 3.9 ± 1.6 mg/L in WDI water; the 48-h LC50 values for the swim-up fry were 3.5 ± 1.8 mg/L in well water and 1.5 ± 0.3 mg/L in WDI water. The yolk sac fry were about 4.6 times more tolerant of CuSO4 than the swim-up fry at 24 h and 4.3 times more tolerant at 48 h. Fry were about 4.7 times (at 24 h) and 3.3 times (at 48 h) more sensitive to CuSO4 in water with low alkalinity and hardness (WDI ,water) than in water with high alkalinity and hardness (well water). The differences in LC50 values between the different spawns of each fry type and time within a water type are attributed to natural variation and channel catfish strain. [ABSTRACT FROM AUTHOR]

Channel catfish, Ictalurus punctatus (Rafinesque 1818), and sunshine bass, female white bass Morone chrysops (Rafinesque 1820) X male striped bass M. saxatilis (Walbaum 1792), juveniles (10 and 12 g, respectively) were exposed to copper sulfate (CuSO4)in a series of static toxicity tests to observe species sensitivity. The water used in this study was 18.9°C filtered well water with initial pH of 8.71, and total alkalinity and total hardness of 224 and 110 mg/L, respectively. Estimates of mean 96-hour median lethal concentration (LC50) values were 1.75 mg/L Cu (6.89 mg/L CuSO4) for channel catfish and 0.85 mg/ L Cu (3.35 mg/L CuSO4) ) for sunshine bass; LC50 values were calculated using nominal CuSO4) concentrations. These values differed significantly. This study demonstrates that sunshine bass juveniles are less tolerant of CuSO4 than channel catfish fingerlings when exposed concurrently in waters from the same source. [ABSTRACT FROM PUBLISHER]

Channel catfish, Ictalurus punctatus (Rafinesque 1818), and sunshine bass, female white bass Morone chrysops (Rafinesque 1820) X male striped bass M. saxatilis (Walbaum 1792), juveniles (10 and 12 g, respectively) were exposed to copper sulfate (CuSO4)in a series of static toxicity tests to observe species sensitivity. The water used in this study was 18.9°C filtered well water with initial pH of 8.71, and total alkalinity and total hardness of 224 and 110 mg/L, respectively. Estimates of mean 96-hour median lethal concentration (LC50) values were 1.75 mg/L Cu (6.89 mg/L CuSO4) for channel catfish and 0.85 mg/ L Cu (3.35 mg/L CuSO4) ) for sunshine bass; LC50 values were calculated using nominal CuSO4) concentrations. These values differed significantly. This study demonstrates that sunshine bass juveniles are less tolerant of CuSO4 than channel catfish fingerlings when exposed concurrently in waters from the same source. [ABSTRACT FROM PUBLISHER]