Safety of Copper Sulfate to Channel Catfish Eggs

Abstract

Copper sulfate (CuSO 4 ) 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 CuSO 4 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 CuSO 4 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 CuSO 4 treatments, respectively. The hatch rate for the 0-mg/L CuSO 4 treatment was significantly different from that of all other CuSO 4 treatments. Treating channel catfish eggs with five times the recommended dose of 10-mg/L CuSO 4 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, CuSO 4 should be considered a safe treatment to alleviate egg losses caused by saprolegniasis.

Inhibiting fungus on largemouth bass eggs with copper sulfate and its toxicity to fry and juveniles

“…Research from our lab has focused on the use of copper sulfate pentahydrate (denoted CuSO 4 ) to control egg fungus on two commercially important species: channel catfish, Ictalurus punctatus , (Mitchell, Straus, Farmer, & Carter, ; Straus, Mitchell, Carter, McEntire, & Steeby, ; Straus, Mitchell, Carter, & Steeby, ; Straus, Mitchell, Carter, & Steeby, ; Straus, Mitchell, Carter, & Steeby, ; Straus, Mitchell, Radomski, Carter, & Steeby, ), and sunshine bass, female White Bass Morone chrysops × male striped Bass Morone saxatilis , (Straus et al, ) [Correction added on 11 July 2019 after first online publication: the male striped Bass “ Micropterus saxatillis ” has been corrected to “ Morone saxatilis ”]. Copper sulfate has been given deferred regulatory status for use in aquaculture (USFDA, ) by the FDA and can be used for the control of mortality caused by external bacteria, external parasites, and fungus on finfish and finfish eggs (Investigational New Animal Drugs file #9101, #10046 and #11401; Bowker, Trushenski, Gaikowski, & Straus, ).…”

“…It is well known that CuSO 4 is extremely toxic to fish and other aquatic organisms and that this toxicity decreases with increasing pH and total alkalinity concentrations (Boyd & McNevin, ). Alkalinity has not been shown to be an issue when treating eggs with CuSO 4 for fungus control (Mitchell et al, ; Straus et al, ; Straus et al, ; Straus, Mitchell, Carter, McEntire, & Steeby, ; Straus, Mitchell, Carter, & Steeby, ; Straus, Mitchell, Carter, & Steeby, ; Straus, Mitchell, Radomski, et al, ).…”

Effects of transgenic sterilization constructs and their repressor compounds on hatch, developmental rate and early survival of electroporated channel catfish embryos and fry

“…The knockout targets were primordial germ cell marker genes, such as the dead end (DND), vasa and nanos genes, which are important genes for the migration, differentiation, specification and survival of primordial germ cell lineage (Yoon et al 1997;Köprunner et al 2001;Weidinger et al 2003;Slanchev et al 2005;Saito et al 2006;Richardson and Lehmann 2010) and may have pleiotropic effects during various life stages of the fish; thus, their knockout could have a variety of negative or positive effects. Repressors such as salt and copper sulfate were considered in the current study because salt and copper sulfate are inexpensive and widely used to treat fungus in catfish hatcheries (Phelps and Walser 1993;Steeby and Avery 2005;Straus et al 2012;Su et al 2013a). Transferrin (TF) also was chosen as a promoter system as it is strongly down-regulated by cadmium chloride in fish (Carginale et al 2002).…”

“…Percentage hatch of channel catfish continuously exposed to 24 lg/l copper in soft water (36 mg/l CaCO 3 ) was 92 % compared to 74 % for the control, while percent hatch was 23.5 % at 66 lg/l compared to 64.5 % for controls in hard water (186 mg/l CaCO 3 ) (Sauter et al 1976). The least-squares means for percent hatch of channel catfish eggs treated a few minutes per day with 0, 10, 30, and 50 mg/l of CuSO 4 at 26°C were 41, 81, 64 and 80 %, respectively (Straus et al 2012).…”

Toxicity of Copper Sulfate to Largemouth Bass Fry in Naturally Soft Water

“…Fungus control with CuSO 4 on embryos of Channel Catfish Ictalurus punctatus, sunshine bass (female White Bass Morone chrysops × male Striped Bass M. saxatilis), and LMB is extremely effective and economical for farmers in waters with moderate-or high-alkalinity/hardness (Straus et al 2009a(Straus et al , 2009b(Straus et al , 2011(Straus et al , 2012a(Straus et al , 2012b(Straus et al , 2016(Straus et al , 2020Mitchell et al 2010). It is well known that the toxicity of CuSO 4 decreases as pH and the concentrations of alkalinity, calcium hardness, and dissolved/particulate organic matter increase (Boyd and Tucker 2014).…”