1 reply to this topic

[MichaelAngelo]

These two fish were caught in a creek near Alexandria, VA.  

 

I've read that one way to tell these two species apart is on the partial or full pigmentation of the dorsal fin membranes, but there can be some overlap in breeding male spotfin shiners which display pigmentation similar to satinfin.  It's spring time so I can see this being an issue.

 

Another way I've read is based on an anal ray count.  However, I'm not sure how to do this correctly and which rays I should and should not count.

 

Fish 1:

 

 P5083287.JPG   112.78KB   1 downloads

 

 P5083300.JPG   101.8KB   1 downloads

 

Fish 2:

 

 P5083305.JPG   106.19KB   1 downloads

 

 P5083305.JPG   67.74KB   1 downloads

 

 

 

Edited by MichaelAngelo, 09 May 2016 - 01:19 PM.

[gerald]

For shiners, count the first full-length anal ray as #1 (ignoring the very short ray in front, if present).  The LAST ray often branches very close to the body, but it is still counted as ONE ray.  It can be tricky to determine if the last two apparent rays are actually one ray - look close with a good hand-lens where the rays disappear under the skin.  I think this fish #1 above has 9 anal rays (not certain).  Fish #2 photos are not clear enough.