Redox potential in freshwater and seawater culture ponds: determination methodology behavior

Abstract

Little is known about the behavior of oxidation-reduction potential in aquaculture ponds and its relation with yields. Such information may be useful in managing ponds by avoiding the production of reduced and potentially toxic substances. Difficulty in collecting a sample that allows the reading of the redox potential value within the desired range is a constraint. This study proposes a methodology that uses a sample collector adjusted to the needs of this type of work. The device was built with available materials, is easy to build and can be operated by a single person. The method allows the viewing of the sample for the introduction of the electrode in the desired range. The study was carried out in two properties in Santa Catarina state: a pond in a catfish farm and another in a marine shrimp farm. Redox potential behavior was observed for 50 days during a production cycle, when ponds were sampled in twelve sites. In both ponds, redox potential presented different behavior and distinct management may have influenced it. In the catfish pond, redox potential was stable, although negative, whereas in the shrimp pond, values were very low and tended to stabilize after 20 days of observation.