“Grass carp, a plant-eating species of the invasive Asian carp family, have also been found spawning in Lake Erie and its many tributaries…Though fears over invading Asian carp have largely centered on bighead and silver carp — which gulp down large amounts of plankton, the all-important food-source foundation for a healthy aquatic ecosystem — the new study suggests conservationists should pay attention to grass carp too.Grasses are also an important nutritional source for native fish species, and as its name suggests, grass carp could prove detrimental in that department.The U.S. government has already spent upwards of $200 million trying to slow the encroachment of Asian carp into the Great Lakes. Many worry their growing presence will turn the Great Lakes into one giant carp pond — ruining ecological diversity and the multi-billion dollar fishing industry in the region. Regional authorities remain in discussion with federal agencies over further mitigation efforts.”
Recent News
- Freshwater jellyfish may increase in numbers as Illinois and Indiana waters continue to warm
- Tomas Höök signing off as Illinois-Indiana Sea Grant director this summer
- Illinois-Indiana Sea Grant welcomes Stuart Carlton as the program’s new director
- Four Illinois and Indiana educators will set sail on Lake Michigan aboard EPA’s research ship
- Join IISG as a new pollution prevention outreach assistant
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Who says “Back to School” means back indoors? While the weather is still warm, take your students on an outdoor science adventure by exploring crayfish in your local waterways.
The Invasive Crayfish Collaborative invites grades 2-12 educators to take part in a hands-on participatory science activity. By catching, identifying, and reporting crayfish species in your area, students contribute valuable data that helps scientists better understand where native and invasive crayfish live.
Check out what other educators have found and get involved: inaturalist.org/projects/great-lakes-crayfish

Come round up some rusty crayfish and help remove this #invasivespecies from the Fox River at the 7th Annual Rusty Rodeo. Join us at this FREE event and help collect, identify, and remove rusty crayfish from the river using aquatic nets and buckets. Prizes are given to the participant who collects the most, the largest, and the smallest rusty crayfish. Learn more about native and invasive aquatic species at educational pop-
up exhibits.
Participants will need to provide their own supplies. We suggest bringing an aquatic net, a bucket, and clothes and shoes you don’t mind getting dirty. This is a partnership program with: Forest Preserve District of Kane County, St. Charles Parks & Recreation Department, Fox Valley Park District, and Friends of the Fox River. No registration required.
More info: https://kaneforest.com/upload/2025RustyRodeoFull-pageFlyer.pdf
#CrayWeek #Crayfish #InvasiveSpecies #RustyCrayfish #FoxRive

Illinois and Indiana are home to many native crayfish species, but invasive crayfish are putting that diversity at risk. The red swamp crayfish (photo 1) and rusty crayfish (photo 2) can outcompete native species for food and habitat, degrade water quality, and reduce amphibian, fish, mollusk, and plant populations. Once established, they’re incredibly costly and difficult to remove, making prevention our most effective tool.
Another invasive to keep an eye on is the marbled crayfish (photo 3). Unlike most crayfish, they are all female and reproduce asexually, meaning one individual can quickly turn into one hundred in no time. Fortunately, they haven’t been found in Illinois or Indiana yet!
If you think you’ve found a suspected invasive crayfish, take multiple high-res photos and report it to your state’s natural resource agency.
#CrayWeek #InvasiveSpecies #RedSwampCrayfish #RustyCrayfish #MarbledCrayfish

Illinois and Indiana are home to approximately 24 crayfish species each, all holding significant ecological value in their freshwater habitats as vital prey, predators, and ecological engineers, directly enhancing habitat quality and resource availability for other organisms. One method by which crayfish can accomplish this is through their burrowing behavior (photo 1). These burrowing abilities allow them to modify and create habitats that can be utilized by other organisms. One particular species that has directly benefited from these burrows is the federally endangered Hine’s emerald dragonfly!
However, these native crayfish populations face significant pressure. In Illinois, seven crayfish species are classified as Species of Greatest Conservation Need, and four are listed as threatened or endangered, including the Bigclaw crayfish (photo 2).
Photo 1: Devil crayfish (Lacunicambaurus diogenes) leaving its burrow
Photo 2: Illinois-endangered bigclaw crayfish (Faxonius placidus)
Photo 3: Two depression crayfish (Cambarus rusticiformis) interacting
Photo 4: Paintedhand mudbug (Lacunicambarus polychromatus)
Photo Credit: Zack Graham, flickr.com/photos/196391561@N03
#CrayWeek #Crayfish #NativeSpecies #Conservation #Burrows
