Browsing by Subject "bighead carp"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Behavior and Bioacoustics of Invasive Silver and Bighead Carp
    (2016-05) Vetter, Brooke
    Invasive silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp (collectively bigheaded carp) dominate the Mississippi River Drainage, outcompete native species, and continue to expand northward. Silver carp demonstrate an unusual jumping behavior to boat traffic. Understanding this response is important from a behavioral standpoint and critical to developing effective control methods. Experiments in outdoor concrete ponds (10 x 5 x 2 m), investigated the impact of pure tones (500 – 2000 Hz) and a recording from an outboard motor (0.06 – 10 kHz) on bigheaded carp swimming. Speakers broadcasting the sound stimuli were placed at either end of the concrete pond and bigheaded carp behavior was assessed using overhead cameras. Silver carp were consistently directed away (mean: 11.8 ± 1.3 consecutive responses) from the broadband sound (outboard motor recording) and the bighead carp were more responsive, exhibiting a median of 20.0 consecutive responses (1st Q: 12.0, 3rd Q: 23.0). However, both species were less reactive and habituated quickly to pure tones (after 1-2 trials). Field observations of silver carp jumping frequency, orientation, and direction in response to fast moving (16 – 40 km/hr) boats suggest that jumping is non-random, as the fish primarily move away from (79.8%) and behind the boat (> 90%), avoiding the area directly astern (< 4 m) in the most turbulent part of the wake. Finally, broadband sound (> 150 dB) stimulated wild silver carp to jump in a small tributary of the Illinois River. The fish demonstrated a different pattern than those reacting to the fast moving boats, with carp jumping all around the slow moving boat. This research suggests that sound can be used to alter the behavior of bigheaded carp with implications for deterrent barriers or other uses (e.g., herding fish to increase harvest).
  • Thumbnail Image
    Item
    Hearing Thresholds and the Impact of Anthropogenic Noise in Four Invasive Fishes: Silver (Hypophthalmichthys molitrix), Bighead (H. nobilis), Black (Mylopharyngodon piceus), and Grass (Ctenopharyngodon idella) Carp
    (2018-10) Nissen, Andrew
    Due to extensive ecological impacts, aggressive range expansion, and their potential to enter the Laurentian Great Lakes, silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp are primary targets for fisheries management. One promising measure to prevent their further dispersal is the use of acoustic deterrents because carp exhibit negative responses to sound. However, for an acoustic deterrent to be effective the sound level emitted needs to be above the hearing sensitivity for any target species, yet not too high to be detrimental to fish hearing. In this study, auditory evoked potentials (AEPs) were used to determine the impacts of exposure to high intensity sound on the hearing of silver and bighead carp. Auditory temporary threshold shifts (TTS) of up to 32 dB re 1 μPa SPLrms following sound exposure were observed between 0.2 – 2 kHz for both silver and bighead carp and sensitivity to some frequencies remained elevated up to 96-hrs following exposure. As there is often overlap of detectable frequency ranges among different species, there is the potential for acoustic deterrent signals to effectively target multiple fishes. Therefore, auditory thresholds were also determined for the invasive grass (Ctenopharyngodon idella) and black (Mylopharyngodon piceus) carp. Auditory thresholds were measured from 0.2 - 4 kHz with the greatest sensitivity between 0.3 - 0.4 kHz for both species. This study indicates that acoustic deterrents could impact carp hearing and that such deterrents may also be detectable by other invasive fishes in the area, such as grass and black carp. These findings will be used to increase the long-term efficacy of acoustic deterrents aimed at preventing the range expansion of invasive carps.