A new method for analysis of alarm reaction of fishes is proposed by the study of "Schreckreaktion" from Mimagoniates lateralis (Nichols, 1913) and Mimagoniates microlepis (Steindachner, 1876), which results were discussed on species ecology context. The method is based on Cartesian interpretation of the behaviour, where three distinct experimental series are analyzed in segmented way on horizontal and vertical axes. Data were analyzed by non-parametric statistics and longitudinal data analysis, which allow the time series graphic analyses, and interpreted together the crowding states of the schools by use of indexes. The conjugated analysis of all factors allowed a less subjective measurement of the reaction intensity. The results obtained from the horizontal axis weren't conclusive and the vertical axis demonstrated significant behavioural differences between series and species. Mimagoniates lateralis (Nichols, 1913) showed more stressed and crowded individuals, with schools trending to bottom, while M. microlepis showed more fitness to experimental conditions. Both species exhibited clear alarm reaction, and M. lateralis showed it three times more intense, presenting larger cohesion of the schools and larger period and amplitude of reaction, what is coherent with its status of endemic and threatened species.
Alarm intensity; behaviour; ecology; fishes; methodology; schreckreaktion
