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This study examined the effects of an acoustic stimulus on the haemolymph and agonistic behaviour of the red swamp crayfish, Procambarus clarkii. The experiment was conducted in a tank equipped with a video recording system using six groups (three control and three test groups) of five adult crayfish (30 specimens in total). After 1 h of habituation, the behaviour of the crayfish was monitored for 2h. During the second hour, the animals in the test groups were exposed to a linear sweep (frequency range 0.1-25kHz; peak amplitude l48dBrmsre. 1 μPa at 12kHz) acoustic stimulus for 30mm. Exposure to the noise produced significant variations in haemato-immunological parameters as well as a reduction in agonistic behaviour. Key words: acoustic stress. aaonistic behaviour. ohvsioloaical resoonse. red swamo crayfish [ABSTRACT FROM AUTHOR]

This study describes the underwater acoustic behavior of the red swamp crayfish Procambarus clarkii. The study was conducted both in a tank and in the natural environment. The tank was equipped with video and acoustic recording systems. Observations were conducted to identify the underwater acoustic signals produced and their association with behavioral events and the movement status of the animals. In a lake in a natural reserve, a remote acoustic recording station was used to study the circadian underwater acoustic activity of the crayfish and to assess the acoustic features of the signals. The red swamp crayfish produces irregular trains of wide-band pulses (duration 0.4 ms, SPLPK 128 dB re 1 μPa, peak frequency 28 kHz, bandwidthRMS 20 kHz). The production of signals is positively related to intraspecific interactions (encounter/approach, fighting and successive Tail Flips). In the natural environment, acoustic activity is almost absent during the day, increases abruptly at sunset and continues until dawn. This study reveals the previously unknown underwater acoustic signals of Procambarus clarkii and the potential of passive acoustic methods to monitor the presence, the abundance and the behavioral activities of this invasive species. [ABSTRACT FROM AUTHOR]