The Great Lakes Almanac to Invasive Crayfish is an educational resource developed to aid in the identification of invasive crayfish species primarily found in the pet trade. It highlights four invasive species—rusty crayfish, red swamp crayfish, marbled crayfish, and Australian crayfish—providing detailed descriptions and illustrations for accurate identification. The guide emphasizes that releasing aquarium crayfish into waterways can harm ecosystems and it offers steps for proper handling and reporting. Retailers, hobbyists, and educators are encouraged to use this resource if they interact with crayfish.

This resource was developed for the aquarium retail community – however, teachers are a known vector of aquatic invasive species (AIS) introduction, especially of crayfish. All state natural resource agencies in the Great Lakes basin approved the messaging of this product.

Developed in English, this resource was also translated available into Hmong, simplified Chinese, and Spanish. Find all of these resources (all are ADA accessible) on the Great Lakes Invasive Crayfish Collaborative website.

Resource Citation: Filice, P., W. Budnick, R. Feagley, B. Roth, and L. Nathan. 2024. Great Lakes Almanac to Invasive Crayfish: Identification and Reporting. URL: invasivecrayfish.org/almanac.