Changes in aggresive behavior of rainbouw trout after 3-month exposure to 0.05 and 0.1 mg/l copper concentrations

摘要

Aggressive behaviour of rainbow trout Oncorhynchus mykiss was investigated after 3-month exposure to 0.05 and 0.1 mg/l copper concentrations (that consisted 0.08 and 0.16 of of 96 h LC50 value, respectively). Aggressive encounters were recorded in the newly formed social groups of two individuals during the first hour of hierarchy formation. Aggressiveness of fish exposed to 0.05 mg/l copper concentration was increased: aggressive encounters between pairs of fish began earlier, number of aggressive acts was higher, and hierarchy was formed earlier than in control groups. Moreover, only in fish treated with 0.05 mg/l copper concentration there was observed the highly aggressive elements of behaviour - fighting. Aggressiveness of fish treated with 0.1 mg/l copper concentration was reduced: aggressive encounters appeared later, number of aggressive acts was lower, and hierarchy was formed later than in control groups.