'Crayfish' USA

   

Cambarus

   

Message from the web-master Dave;

I have had the good fortune of making the acquaintance of Roger F. Thoma from the Ohio State University in the USA. He has supplied these wonderful images of his local buddies from central USA. Unlike me Roger cannot be considered a layman and his knowledge on crayfish is unbelievable ( hope to get to meet him one day). His images are first class and like me records only live specimens. Roger can be contacted here for further information on his crayfish. As you can see I was so impressed I decided to change the format from 'Downunder' to 'Upover'. I'll still be updating this site on Roger's behalf. Who know's where this will go, with cray's on most continents this could be the beginnings of a truly International site. We also now have a European section.


All images ( here and elsewhere on the site ) have been reduced for speed of loading and to save on space. Larger images can be sent by request via e-mail.

Text and photos by Roger F. Thoma, additional photographs Christian Lukhaup.

 Big River Crayfish

Cambarus robustus. This crayfish is a widely distributed species that can be found in the larger rivers of North America from "Ontario and New York to Illinois, and southward to Tennessee, North Carolina and Virginia." (Hobbs Jr., 1989) and in the deeper waters of Lakes Erie and Ontario. It prefers to burrow under large rocks, usually flat and about 10 to 15cm. thick. The bigger the rock the bigger the crayfish! This specimen is a large first form male (mating form). It is one of our larger crayfish species here in N. America with this individual being about 25 cm. long (total length). I photographed this one in Conneaut Creek of Ohio (April 1999). 

CAMBARIDAE

 

The New River Crayfish

Cambarus sciotensis This is a species of crayfish found in one of the oldest continuously flowing rivers in the world. The New River has it's origin in North Carolina, flows through Virginia and into West Virginia where it is then called the Kanawa River. It debauches into the Ohio River. Historically it was the preglacial Teays River that drained much of what is now called "the Midwest". It is known to be an ancient river because it cuts through the backbone of the Appalachian Mountains, flowing from east to west. This species is much like
the Big River Crayfish
(Cambarus robustus) in life history. Where the two species are found together the New River Crayfish tends to inhabit the smaller cooler stream sections. The two species are easy to tell apart by their chela structure, C. sciotensis has a smooth hand and C. robustus has numerous enlarged tubercles and rough areas.

Editor note; Both images are displayed to show how colour can vary with light source. The top photograph is in shaded natural light in the stream and the bottom in direct sunlight. Direct comparisons can be made between this crayfish and C robustus.


The Rock Crawfish (proposed common name)


Cambarus carinirostris. This picture was taken at the southern edge of the rock crawfish's range in a tributary of the New River (1978). Note the clarity of the water and the large number of snails on the surrounding rocks. This crayfish species (and the snails) favor very clean waters with little or no turbidity. These types of streams are harder and harder to find in the States these days. Stream channelization, mining activities, destruction of riparian trees and intense farming activities are all contributing to the decline of the rock crawfish and more significantly Pleurocerid snails. This crayfish burrows under rocks and is found primarily in the foothills of the Appalachian Mountains on the
western side.

 

The same photograph showing the snails on the surounding rocks. 

Cambarus brachydactylus

More information on this crayfish soon. 

 

Cambarus deweesae

More information on this crayfish soon.

Cambarus diogenes

More information on this crayfish soon.

 

 

Cambarus grayson

More information on this crayfish soon.

  

Cambarus ortmanni

More information on this crayfish soon.

 

for more USA and other crayfish continue here