Evaluation of the Natural Product SeaKleen for Controlling the Musty‐Odor‐Producing Cyanobacterium Oscillatoria perornata in Catfish Ponds

Abstract

The cyanobacterium (blue‐green alga) Oscillatoria perornata is the major cause of musty off‐flavor in farm‐raised channel catfish Ictalurus punctatus in western Mississippi. Currently, the only federally approved compounds for use as selective algicides in catfish aquaculture ponds in the southeastern United States are the herbicide diuron and copper‐based products (e.g., copper sulfate). Due to environmental issues and the broad‐spectrum toxicity of these synthetic algicides to nontarget organisms, there is a need for environmentally safe algicides for controlling O. perornata in catfish ponds. Laboratory bioassay screening of the natural product SeaKleen, a quinone‐based biocide used to treat the ballast water from ships, found that it is selectively toxic towards O. perornata compared with the green alga Selenastrum capricornutum. Subsequently, efficacy testing of SeaKleen was performed using limnocorrals placed in catfish aquaculture ponds containing O. perornata blooms. Two studies were performed: a dose–response study and a single‐effective‐concentration study. For both studies, water samples were removed from inside the limnocorrals before and after the application of SeaKleen. These water samples were monitored for levels of the musty off‐flavor compound 2‐methylisoborneol (MIB), chlorophyll‐a levels, and phytoplankton community structure. Results from both studies found that approximately 1.3 mg/L SeaKleen was effective in significantly reducing the levels of chlorophyll a and MIB compared with controls. In addition, the abundance of O. perornata and other predominant species of filamentous cyanobacteria were significantly reduced compared with controls. Green algae and diatoms were not significantly affected. Additional studies are needed to determine the potential of SeaKleen as a selective algicide in commercial catfish aquaculture.

Off‐flavors in pond‐grown ictalurid catfish: Causes and management options

“…The quinone‐based commercial biocide SeaKleen®—a water‐soluble derivative of menadione (also known as vitamin K 3 or 2‐methyl‐1,4‐naphthoquinone)—was also found to be effective against P. perornata in laboratory and pond studies (Schrader, Rimando, et al, ). However, higher concentrations of SeaKleen (1.3 mg/L) were required to reduce abundance of P. perornata compared to 9,10‐anthraquinone.…”

Bloom Dynamics of Cyanobacteria and Their Toxins: Environmental Health Impacts and Mitigation Strategies

“…The herbicide diuron together with copper sulfate as well as other copper-based compounds have been approved by the United States Environmental Protection Agency (USEPA) for use as algicides in fish production ponds ( Schrader et al, 2004 ). Moreover, the use of synthetic compounds for bloom control has their own limitations, and therefore, a range of natural chemicals (e.g., anthraquinone, nostocarboline, and stilbenes) from diverse organisms have been derived as potent substituents of synthetic algicides ( Schrader et al, 2003 , 2004 ; Becher et al, 2005 ; Mizuno et al, 2008 ; Table 2 ). Recently, Jančula and Maršálek (2011) reviewed the availability of different chemical compounds for prevention and management of cyanobacterial blooms.…”

Natural Toxins for Use in Pest Management

“…SeaKleen ® , a commercial biocide used to treat the ballast water of ships to prevent the spread of pest organisms such as algae [ 61 ], is another quinone-related natural compound determined to be effective in reducing the abundance of odor-producing cyanobacteria at application rates of 1.3 mg/L [ 62 ]. SeaKleen ® consists of menadione sodium bisulfite, a water-soluble form of menadione that is also known as vitamin K 3 or 2-methyl-1,4-naphthoquinone ( Figure 12 ).…”