Use and Evaluation of Stimuli for Herding Bigheaded Carps to Increase their Capture Efficiency

Science Center Objects

Mass removal of silver carp Hypophthalmichthys molitrix and bighead carp Hypophthalmichthys nobilis, hereafter referred to as bigheaded carps, is a primary management action to contain the population growth and reduce upstream dispersal. Given their evasive behavior and gear avoidance, catching bigheaded carps efficiently has been difficult. Techniques that can allow managers to more efficiently harvest bigheaded carps are needed, and the USGS is working to develop and evaluate such methods.

Boat-mounted speakers

Boat-mounted speakers used for herding bigheaded carps with sound.

(Public domain.)

The Issue: The USGS is part of the Asian Carp Regional Coordinating Committee (ACRCC) and is focused on the research and development of techniques that could help managers better control Asian Carp populations. Techniques are needed to move aggregations into areas where they can be more efficiently harvested.

 

Addressing the Issue: Preliminary work in 2016 and 2017 showed that playback of a broadband acoustic stimulus from boat-mounted speakers, and electricity both led to higher catches compared to nets that were fished without behavioral manipulation. In 2018, three different acoustic stimuli were tested and the sound that provoked the greatest movement was selected for herding trials. Several electrofisher anode configurations were also evaluated using voltage gradient mapping and the one with the optimal voltage gradient and performance was selected for further testing in herding trials. Herding trials conducted in 2018 more rigorously test the ability of various techniques including sound and electrofishing to move bigheaded carps downstream. The most effective technique(s) could then be used in future Unified Method events, and to drive fish into trap nets for more efficient capture.

block net

Downstream block net used in 2018 trials to funnel carp downstream through a narrow opening so that they can be enumerated using sonar.

(Public domain.)

 

Next Steps/Future Steps/Results: Following the comparative performance of a variety of herding techniques, the most effective technique will be further tested to identify its ability to enhance capture efficiency. Novel trap nets are currently in development and preliminary trials to herd bigheaded carp into trap nets will be conducted.

 

 

 

 

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