Specimens with a carapace length (CL) of fewer than 15 mm were classified as juveniles.
The range of include the Ohio River basin in Ohio, Kentucky, Indiana, West Virginia, and Tennessee, but it has extended its range to most of the Midwestern United States and Canada .It was introduced widely by anglers through bait bucket release into lakes and streams where the species has outcompeted native crayfish species, especially in Wisconsin and Minnesota .Relationships found for each sexual form can offer conclusions for sexual dimorphism between male form I, form II, and female.The relationship of chelae length (Ch L) to chelae width (Ch W) is important for describing factors of aggressive behavior and competitive outcomes in rusty crayfish .Comparison of growth data from other tertiary burrowing crayfish species was compiled to evaluate patterns in growth.
Study area The study area included portions of the native and introduced range of the rusty crayfish in the Midwestern United States.
Individuals were sampled from a range of counties (See supplemental materials) including introduced areas such as Hendricks, Shelby, Lake, La Grange, Jay, Delaware, Franklin, Carroll, Grant, and Decatur, while native counties included Ripley and Madison.
Sample collection and analysis Specimens (n=343) were measured for carapace length and weight based on gender.
The invasive nature of the rusty crayfish, is known as an aggressive invader and displaces many native species of crayfish [1,4], destroys macrophyte beds , competes with fish for invertebrate prey, and decreases recruitment rates of sport fishes by eating eggs and removing macrophyte habitat [6-8].
The species was originally described from streams near Cincinnati in Hamilton County, Ohio, from the Ohio River basin, as well as the Whitewater and Maumee rivers in Indiana .
The chelae are used in antagonistic competition displays and in reproduction during amplexus [10,13-16].