Biological monitoring for detection of toxic chemicals in water by the swimming behavior of small freshwater fish

Abstract

We conducted exposure tests using three small fish species, medaka (Oryzias latipes), guppy (Poecilia reticulata), and white cloud mountain minnow (Tanichthys albonubes). The fish were exposed to nominal concentrations of test chemicals (potassium cyanide [KCN; 1 and 5mg/L], sodium cyanide [NaCN; 1 and 5 mg/L], and aldicarb [5 mg/L]) for one hour. We used two cameras for tracking the fish behavior in three dimensional (3D) data. Then the 3D data were analyzed for fish behavior such as, swimming speed and surfacing behavior. Swimming speed and position of the three fish species were affected by KCN, NaCN, and aldicarb exposure test. Three fish species showed the different behavioral patterns after the exposure of test chemicals. Although the patterns of effect on behavioral parameters differed among the test species and toxic chemicals, we could find the significant effects on both the frequency of high swimming speed and duration time of surfacing behavior in test fish. We concluded that three fish species are useful species for monitoring the water quality by their behavioral changes.