Javascript Disabled Detected

You currently have javascript disabled. Several functions may not work. Please re-enable javascript to access full functionality.

Scartomyzon sp differentiation

Started by Guest_UncleWillie_* , Apr 26 2010 07:30 PM

Please log in to reply

9 replies to this topic

#1 Guest_UncleWillie_*

Guests

Posted 26 April 2010 - 07:30 PM

I have yet to purchase the SC book, but was hoping that if anyone familiar with Scartomyzon could aid me in differentiating between brassy and striped. I have been told that brassy have very distinct stripes while striped have less of the striped appearance. My project takes me to the Ocmulgee River, GA where both species are present. While I have never seen any adult jumprocks until Sunday, I am fairly certain I only caught one species of jumprock. I was wondering if anyone could shed some light on the subject, and could give some helpful hints or tips for distinguishing the two.

Below are pictures of the Scartomyzon from my outing yesterday.

Female:
Posted Image

Male:

The breeding males are particularly colorful with a nearly copper color with a teal glow. We captured nearly around 18 of these. Thanks in advance for any help!

Back to top

#2 Guest_mzokan_*

Guests

Posted 27 April 2010 - 09:14 AM

I have zero experience with this fish, but I am the proud owner of "Fishes of South Carolina". Based on what I've read there, if the pale spaces between stripes are wider than the dark stripes, then you should have a brassy jumprock -- if the opposite is true then its likely a striped jumprock. Based on that yours look like brassy to me, but if you really want to nail it down then count dorsal rays (usually 10-11 for striped, usually 12 for brassy) and gillrakers (23-26 for striped and 28-34 for brassy).

by the way there is a book preview of the SC fishes book on google which lets you see the account for striped jumprock at least
follow this link:
http://books.google....xostoma&f=false

Just out of curiosity, what kind of habitat did you get these in?

Marcus

Back to top

#3 Guest_UncleWillie_*

Guests

Posted 27 April 2010 - 11:35 AM

Thanks for the information. Next time I go out, I will likely have to take a voucher specimen or two. I had been calling them striped b/c of the previous info in my previous post. Like you said, coloration hints at brassy, but ray count points to striped. As I learn more, I will post updates. Again, anyone with other useful tips, please feel free to chime in. Thanks!

Back to top

#4 Michael Wolfe

Board of Directors

North Georgia, Oconee River Drainage

Posted 28 April 2010 - 06:18 AM

Thanks for the information. Next time I go out, I will likely have to take a voucher specimen or two. I had been calling them striped b/c of the previous info in my previous post. Like you said, coloration hints at brassy, but ray count points to striped. As I learn more, I will post updates. Again, anyone with other useful tips, please feel free to chime in. Thanks!

Hey Uncle,

I have the book and was looking at dorsal fin ray count also in your pick and I counted 11... but it was just a picture, and the book did include a little bit of variation in that ray count (some numbers in paranthesis and such... plus they said "ususally"). Also from zooming the picture I would say that the striping pattern (light versus dark and the relative width of those striped inthe lateral line area) point to brassy.

There was also a couple of other characteristics regarding the width vs depth of the head (couldn't tell from the picture) and one about the depth of the head at a certain point and how many times it goes into the predorsal length). While I didnt actually measure that one, just comparing the two pictures in Fishes of SC, it seems that your photos look like the predorsal length is somewhat shorter... again pointing to brassy.

MW

Either write something worth reading or do something worth writing. - Benjamin Franklin

Back to top

#5 Guest_gerald_*

Guests

Posted 28 April 2010 - 11:30 AM

Brassy, based on previous comments and size. Max TL for striped jumprock is 11 inches. Your fish are 14 to 16 inches.

Back to top

#6 Guest_UncleWillie_*

Guests

Posted 29 April 2010 - 05:42 PM

Thanks for all the great info! This helps out a ton. I will be out and about again next weekend (and the next). I will try to take pictures if I am not too terribly pushed for time. Hopefully I will see some striped jumprocks in the flesh and be able to distinguish the two. Everyone keep your fingers crossed that I get a ton of robust redhorse next week. I also have access now to the SC book until I can purchase my own copy. (I wonder if my assistantship will pay for it.. :rolleyes:

) Again thanks everyone. If I get some striped, I will also post them here for anyone else looking to compare the two.

Back to top

#7 Guest_UncleWillie_*

Guests

Posted 05 July 2010 - 10:36 AM

Update:
So my spring season went fairly smoothly and I finished all of my sites within the study reach completed by the end of May. I had encountered many more brassy jumprocks (above), but none in breeding condition. I did, however, started to catch smaller fish as the season went on - catching more juveniles of mostly spotted suckers, with the occasional brassy jumprock. Finally, in a fast-flowing shoal area with gravel substrate, I encountered a group of smaller suckers mingling with large Hybopsis They looked a bit different from the brassy jumprocks.
I called them striped jumprocks (Scartomyzon rupestris)
The most obvious characteristic was the appearance of saddles..
Posted Image

Here are the lateral views of the same two fish.
Posted Image

Edited by UncleWillie, 05 July 2010 - 10:42 AM.

Back to top

#8 Guest_UncleWillie_*

Guests

Posted 05 July 2010 - 10:45 AM

I started my summer season last week and found one more fish that had similar characteristics as the above fish, but not nearly as prominent - getting shocked can do that..
Posted Image

Oh, here are some beastly Brassy jumprocks. You can see the inch increments in blue and white... Big 'uns:
Posted Image

Edited by UncleWillie, 05 July 2010 - 10:46 AM.

Back to top

#9 Guest_gerald_*

Guests

Posted 05 July 2010 - 01:59 PM

I agree on the striped jumprocks. BTW, the species name is Scartomyzon rupiscartes, not rupestris.

Back to top

#10 Guest_UncleWillie_*

Guests

Posted 05 July 2010 - 02:37 PM

Thanks for the second opinion. And thank you for correcting me. I should know better, but have been using species codes all year (e.g. robust redhorse = MoRub) I have been just using ScRup for the striped jumprocks.