Cambarus and Freshwater shrimp.

Photos and text by Roger Thoma

   
Cambarus jezerinaci
Ray's Mountain Crayfish (proposed common name) Cambarus (Jugicambarus) jezerinaci

This is a species I recently described (November, 2000) in the Proceeding of the Biological Society of Washington. I named it after my old crayfish
collecting buddy Ray Jezerinac. Ray taught me a great deal about crayfish, aquatic ecology, and scientific research. He also named a species after me. This species lives in the heart of the Appalachian Mountains in Virginia and Tennessee. It comes in two color phases, red and blue. They are very small,
this one is on a stick covered with lichens.


This is me and my son, Zachary, collecting Ray's Mountain crayfish (Cambarus jezerinaci) at the type locality in 1986. The type locality is in Lee County, Virginia. It's a mountain stream, very high gradient, very clean, cold water in a heavily wooded area. Zach is now 22 years old and I'm 49

Cambarus bartonii cavatus

Blue phase C. b. cavatus
Here's a picture of this form that I collected in the Grand River basin of Northeast Ohio. This population lives at the very northeast edge of the species' range. Many populations of animals and plants exhibit unusual variations at distributional edges. This may be due to lower genetic variability and less genetic communication with the main population. These factors can lead to recessive genes being expressed possibly like this blue coloration seen here.
Palaemonetes kadiakensis

The Mississippi Grass Shrimp Palaemonetes kadiakensis. This is the only native freshwater shrimp presently found in Ohio. At one time there were two but the Ohio Shrimp (Macrobrachium ohione) has been extirpated from the state. The Mississippi grass shrimp prefers to live in low gradient streams and wetlands with abundant aquatic vegetation and clear water. As you can see they are see through and when caught in the net they look more like splashes of water than an animal. The distribution and abundance of this species has been greatly reduced in Ohio due to high turbidity levels and wetland draining. They can still be found in the Ohio River near clean tributary mouths, and clean tributaries of Lake Erie.
Populations also exist around the Bass Islands of Lake Erie in sheltered bays.