Events

More webinars coming soon

The Threat of Invasive Crayfish on Crayfish of Greatest Conservation Need In Illinois: Habitat Associations and Conservation Implications (recorded on 3/14/24, 56 minutes)

Illinois has seven crayfish species on the IL Species of Greatest Conservation Need (SGCN) list, four of which are considered state-threatened or endangered. Currently, invasive crayfish species do not occur in the aquatic systems that support these SGCN species. Since 1995, invasive species ranges have been broadening in Illinois and spreading south toward these unique systems while displacing native species. Dusty Swedberg from the Illinois Natural History Survey discusses the habitat associations of these SGCN species and uses data collected in Illinois to show the adverse effects that introduced crayfish species can have on native crayfish—discussing a link to why invasive species are one of the most significant threats to SGCN crayfish species in Illinois.

What do you mean I need a permit? Lessons learned-Michigan pond chemical treatments for invasive red swamp crayfish (recorded on 1/24/24, 59 minutes)

Resource managers are increasing awareness of the significant impact of invasive crayfish on native crayfish and ecosystems; however, many agencies lack integrative pest management plans to control invasive crayfish populations. Chemical control is potentially an effective tool; however, resource managers may not be familiar with the regulations governing the use of pesticides. Annie Allert from the U.S. Geological Survey summarizes key regulations governing pond treatments for invasive crayfish, specifically the invasive red swamp crayfish (Procambarus clarkii), the collaborative approach for permitting used in Michigan, and examples of permitting documents, treatment equipment and staffing requirements.

Managing for Native Burrowing Crayfish in Illinois (recorded on 1/17/24, 52 minutes)

Illinois is home to 7 species of burrowing crayfish. These cryptic organisms spend their lives hidden in underground burrows, garnering less attention than their stream or lake-dwelling counterparts. Consequently, there is a paucity of distributional, ecological, and life history data for many of these species. Dr. Caitlin Bloomer from the Illinois Natural History Survey discusses conservation land management for these species, considerations for distributional modeling, and the development of the American Crayfish Atlas.

Case Studies of Applying Environmental DNA to Monitor Invasive Crayfishes (recorded on 1/9/24, 63 minutes)

Environmental DNA (eDNA) has been applied to the surveillance of invasive crayfish populations with mixed results, with some researchers suggesting that crayfish may be less detectable than organisms like fish due to their exoskeleton and benthic habitat use. Dr. Eric Larson from the University of Illinois Urbana-Champaign reviews recent studies from his lab and collaborators on eDNA applications to invasive crayfish surveillance, including laboratory tests of the role of the exoskeleton in affecting crayfish eDNA detectability (i.e., pre- and post-molt) and comparisons of crayfish eDNA detectability to other taxa from field studies. Results of these studies suggest that crayfish eDNA detectability is minimally affected by the exoskeleton, but rather crayfish eDNA is likely derived from metabolic wastes and is most detectable at times of high activity (i.e., warmer water temperatures in late summer and early autumn).

Production of neofemales to increase available tools for suppressing invasive crayfish populations (recorded on 12/8/23, 55 minutes)

A variety of techniques have been employed to suppress or eradicate populations of invasive crayfish, including chemical control agents and baited trapping and removal. However, there is growing desire to develop species-specific control measures that limit effects to off-target organisms, which can be used to augment existing eradication techniques. PhD student Katie Eaton from Auburn University discusses one emerging method that involves a simple manipulation to the sex determination system. Juvenile male crayfish can be sex-reversed in the lab using a technique called RNA interference. These “neofemale” crayfish, when mated with normal males, will produce broods that are 100% male. By introducing neofemales into invasive populations on a regular basis, managers can, over time, skew the sex ratio of these non-native populations, eventually leading to complete or near-complete eradication.

An Overview of Michigan’s Invasive Red Swamp Crayfish Response (recorded on 11/13/23, 64 minutes)

Red Swamp Crayfish (RSC) were first detected in Michigan waters in the summer of 2017. Since then, they have been found in eight distinct population complexes. Following the initial detection, Michigan Department of Natural Resources, Michigan State University, and other partners have trapped and removed close to 200,000 RSC and have conducted innovative pesticide treatments. Monitoring data were collected to evaluate the effectiveness of treatment strategies. Dr. Brian Roth from MSU and Kathleen Quebedeaux from MDNR gives an overview of Michigan’s control and monitoring strategies and will evaluate the impact of their efforts.

Development of Multiple Control Techniques for Red Swamp Crayfish in Surface Waters and Burrows (recorded on 10/25/23, 63 minutes)

In collaboration with a multi-agency research team funded by the Great Lakes Restoration Initiative, researchers at Auburn University have used laboratory and pond studies to develop and evaluate potential control techniques for Red Swamp Crayfish in surface waters and burrows. Control approaches range from carbon dioxide to physical blockers to plain old hot water. In this webinar, Dr. Jim Stoeckel and his graduate student Nick Barnes from Auburn University present results of previous and ongoing studies and discuss strengths and weaknesses of each approach.

Food Web Impacts of Invasive Red Swamp (Procambarus clarkii) and Rusty (Faxonius rusticus) Crayfishes in the Chicago River and Lake Michigan (recorded on 10/12/23, 64 minutes)

Invasive crayfish can disrupt the natural balance of aquatic ecosystems, often by outcompeting native species and altering trophic relationships. Dr. Reuben Keller from Loyola University Chicago shares his work on the food web impacts of two invasive crayfish species in the Chicago River and Lake Michigan, the red swamp (Procambarus clarkii) and rusty (Faxonius rusticus) crayfishes.