Effect of solid and liquid algicides on the growth of and antioxidant capacity of Cladophora

Abstract

Cladophora outbreaks in Chinese mitten crab Eriocheir sinensis culture ponds deplete the nutrients in the water and affect the growth of crabs. Thus, the scientific management of these outbreaks is particularly important. Herein, we investigate the killing effect of different algicides on Cladophora. Cladophora were put into six different concentrations (0, 0.01, 0.1, 1, 10, and 20 mg/L) of 4 solid algicides (Algaecide-A, B, C and CuSO4) and 3 liquid algicides (Algaecide-D, E and F). The results showed that: (1) all treatments had a significant effect on dissolved oxygen (DO) in water; (2) under the experimental conditions, the effects of CuSO4, Algaecide-D, E, and F on algae inhibition were significant, with CuSO4 having the strongest inhibition effect, while Algaecide-C had the weakest effect (with its lowest concentration promoting growth); (3) with the increase in concentration and time, the toxicity of CuSO4, Algaecide-D, and E to Cladophora increased, and the activity of superoxide dismutase (SOD) and peroxidase (POD) first increased, and then it decreased; Algaecide-D had the most obvious effect on the antioxidant capacity of Cladophora; and (4) the content of malondialdehyde (MDA) was low overall, and there were no significant differences among types, concentrations, or duration of action of the algicides. In summary, all 7 types of algicides, to a certain extent, had a killing effect on Cladophora. However, CuSO4, Algaecide-D, and E were more effective at controlling algal damage in crab cultures.

Keywords

• Cladophora
• Algicide
• Dissolved oxygen
• Inhibition rate
• Oxidation resistance