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Crayfish ID

Started by Guest_IsaacSzabo_* , May 24 2012 01:32 AM

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16 replies to this topic

#1 Guest_IsaacSzabo_*

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Posted 24 May 2012 - 01:32 AM

Can anyone help with the identification of this crayfish? It is from the Buffalo River in Northwest Arkansas. I am a beginner at identifying crayfish, but 2 possibilities I came up with are Northern Crayfish (Orconectes virilis) and Golden Crayfish (Orconectes luteus). Thanks!

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#2 Guest_Casper_*

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Posted 24 May 2012 - 09:01 AM

Nice pic, handsome cray. I like all the little bits of color and the way the focus is on the head. The Buffalo is a great river to snorkel. A friend is doing a week canoe float on it in early June. I am envious.
Cant help you with the cray but Brian Wagner of AR fish and game could surely advise. He would be a good guy to get to know in your part of NA.
There is also the crayfish book from AR or MO.

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#3 Guest_farmertodd_*

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Posted 24 May 2012 - 11:36 AM

Fantastic photos as always Issac! My guess (and let me highlight the word guess) is that it's a golden crayfish. Northern do not have that little nubbin (orange on this specimen) there at the pincher joint.

Todd

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#4 Guest_centrarchid_*

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Posted 24 May 2012 - 02:25 PM

Golden crayfish. I work with it. It is part of what is mistakenly called the rusty crayfish in parts of Iowa and Minnesota.

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#5 Guest_davidjh2_*

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Posted 24 May 2012 - 07:14 PM

I want one!

And it definitely isn't a Virilis so I'd go with Centrarchid's id since he's seen both species and I've only come across Virilis

Edited by davidjh2, 24 May 2012 - 07:16 PM.

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#6 Guest_IsaacSzabo_*

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Posted 25 May 2012 - 01:12 AM

Thanks Casper. I will have to remember to try Brian Wagner for stuff like this in the future. I ordered the Crayfishes of Missouri book. I was really missing some kind of guide to help me with crayfish IDs.

Hopefully we will get some rain before your friend’s June canoe trip. The Buffalo is extremely low right now and unfloatable in the upper and middle sections. One local canoe rental claims it is the lowest they’ve seen it in their 35 years of operation.

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#7 Guest_IsaacSzabo_*

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Posted 25 May 2012 - 01:30 AM

Thanks for the identification help guys. In what way to you work with the Golden Crayfish Centrarchid?

Since that one went so well, I'll try one more. To me, this one looks similar to pictures of the Ozark Crayfish (Orconectes ozarkae). Can anyone confirm?

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#8 Guest_centrarchid_*

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Posted 25 May 2012 - 06:06 AM

Taxonomy. The golden has a considerably larger range than most texts indicate and when it occurs outside of Missouri it is confused with either invasives like the rusty crayfish Orconectes rusticus, relatively rare species like O. placidus, or species not until recently describedsuch as O. pardalotus.

Teaching. It is the most abundant species in most streams here and can be found along side either O. virilis or O. punctimanus. These species make for good training using the ID techniques and are abundant enough to demonstrate life history.

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#9 Guest_centrarchid_*

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Posted 25 May 2012 - 06:09 AM

Thanks for the identification help guys. In what way to you work with the Golden Crayfish Centrarchid?

Since that one went so well, I'll try one more. To me, this one looks similar to pictures of the Ozark Crayfish (Orconectes ozarkae). Can anyone confirm?

Looks like male that just undergone molt. Coloration and overall appearance typical of Ozark crayfish. Need to see reproductive parts for conformation.

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#10 Guest_davidjh2_*

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Posted 25 May 2012 - 08:49 AM

Again what an amazing picture. What kind of camera are you using? the detail is exquisite.

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#11 Guest_IsaacSzabo_*

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Posted 25 May 2012 - 07:28 PM

Thanks again Centrarchid. I guess that is probably as close to an ID as I can get without a picture of the underside. I will try to remember to do that in the future.

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#12 Guest_IsaacSzabo_*

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Posted 25 May 2012 - 07:28 PM

Thanks David! These pictures were taken with a Nikon D90. I'm currently using a Nikon D7000.

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#13 Guest_Casper_*

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Posted 25 May 2012 - 09:35 PM

Beautiful pic, you can almost feel the texture. The canoe trip is about June 9. Season has been dry here to but we did get an inch of rain the other day. Today was way hot... i hope not a tease for a long summer. Another good reason to snorkel in the cool, clear swimming hole.

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#14 Guest_IsaacSzabo_*

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Posted 11 September 2012 - 03:51 PM

Well, to follow up on this thread, I now have the Crayfishes of Missouri book and have used it to confidently key out a few crayfish (thanks Casper). However, I still had some doubts since I was not sure whether the Missouri book covered all of the species present in the Buffalo River that I frequent in Arkansas. So, as Casper suggested, I contacted Brian Wagner, the AGFC Nongame Aquatics Biologist. I found out that he has spent a good amount of time surveying crayfish in the Buffalo River, and he was able to provide a list of crayfish species know to occur there (very helpful).

He also provided his thoughts on the IDs of the two crayfish in this thread. He said that there are only two records (both before 1954) of O. luteus (Golden Crayfish) in Arkansas, and that he doubts their validity. He said that O. ozarkae (Ozark Crayfish) is highly variable in color and pattern and that my first crayfish looks similar to ozarkae he has seen in the Buffalo. He said my second crayfish looks more like O. meeki meeki (Meek's Crayfish).

Anyway, I now realize that it is unrealistic to expect a definite ID on most crayfish species from photos like the ones above. I now try to capture the crayfish I encounter and take photos of the key ID features. I have learned a lot about crayfish since starting this thread, and I appreciate everyone's help!

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#15 Guest_centrarchid_*

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Posted 11 September 2012 - 04:00 PM

One of my favorite arguements to deal with concerns color variation in crayfish, that they are two variable for coloration to be of value taxonomically. So much of that color variation is due to taxonomic differences. I am familiar with both species and first crayfish is outside range of variation for O. ozarkae occuring in Missouri but consistent with O. luteus. It is time to collect a few more and look at pecker parts in addition to coloration.

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#16 Guest_IsaacSzabo_*

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Posted 12 September 2012 - 02:05 PM

I agree that in many ways, based on the photos in Crayfishes of Missouri, the coloration of the first crayfish looks more like O. luteus than O. ozarkae. However, according to that book, O. luteus has a "nearly uniform background color - no dark mottling or spots," while O. ozarkae has "many small black specks on pincers." My crayfish seems to have dark specks on the pincers. I agree that what I really need to do is catch some more at the same spot and get some better ID photos (including the gonopods).

Edited by IsaacSzabo, 12 September 2012 - 02:06 PM.