Testing whether carp can be located using Judas fish: a new behavioral tool to locate aggregating invasive fish so they might be tracked and/or removed

Project manager: Peter Sorensen

Phase I Description: This project will develop techniques to locate aggregating carp using sterile, sexually active Judas fish to determine if sterilized carp can be rendered sexually active with hormone implants, and then perform proof-of-concept work in ponds, and the apply in the field. New sensory tools (e.g. sound playback) will be developed as needed to control the behavior and distribution of adults.

To remove highly mobile and invasive fish such as carp, we must know where they are. The Judas fish technique (tracking a few individual animals to find other members of their group) will be developed as a means to locate low numbers of Asian carp in Minnesota waters. This technique has been used with great success in other locations. The first step will be developing means to sterilize carp in collaboration with a veterinarian. Later, we will develop means to track them using radio-transmitters in rivers. Common carp will be our primary model but we will include work on Asian carp in the laboratory. After initial research, it was determined that this technique would not work well with males competing in the wild. Research is now focused on conducting experiments to determine how to fully feminize sterile fish instead.

Project start date: 2012

Estimated project end date: 2016, Phase 2 to continue through 2018

Updates and progress:

Invasive Bighead and Silver Carps Form Different Sized Shoals that Readily Intermix (Published paper)

Male-typical courtship, spawning behavior, and olfactory sensitivity are induced to different extents by androgens in the goldfish suggesting they are controlled by different neuroendocrine mechanisms (Published paper)

Promising new developments with Judas fish technology (MAISRC newsletter)

Judas Fish technique closer to use with Asian carp (MAISRC newsletter)

Researchers use 'Judas fish' to battle invasive carp (MAISRC in the news)

'Judas' fish could help wipe out Asian carp (MAISRC in the news)

Phase II: Attracting carp so their presence can be accurately assessed

Project manager: Peter Sorensen

Description: MAISRC researchers are currently working to prevent adult bigheaded (Asian) carp from migrating upstream from the lower Mississippi River using acoustic deterrents and modifying gate operations. Because this needs to be very strategic and efficient, MAISRC must have extremely accurate information on the abundance of adult invasive carp in the area.

This project aims to remedy the deficiencies currently associated with eDNA by developing new techniques to cause predictable aggregations of adult invasive carps. This will facilitate their accurate measurement using eDNA and pheromones or alternately their being trapped and removed.

This research will examine the possibility of causing aggregations using both sexual and feeding cues.

In order to develop reliable and practical ways of using sexual stimuli to find carp, researchers will artificially induce female sexual behavior and sex pheromone release using hormone implants. They will then determine if they can track these aggregations using eDNA measurements and sex pheromone concentrations. They will also test the possibility that a Judas fish (a sterilized fish equipped with a tracking device) could be used both to drive an aggregation and/or track it. Additionally, researchers will test whether food or a synthesized compound could drive aggregations of carp.

Project start date: 2015

Estimated project end date: 2018

Updates and progress:

Following data collection in 2015, it was found that food was able to drive large aggregations of common carp which we successfully measured using eDNA and pheromones. This baiting scheme has now been perfected and in some cases, a third of the population of mature common carp were able to be attracted using food, all while measuring abundance with a new level of sensitivity, precision, and accuracy. Pheromone-releasing Judas fish were also evaluated for their ability to attract other carp. This research has now informed a pilot study of attracting Silver carp in Illinois using both methods.