6 replies to this topic

[Michael Wolfe]

So both of these individuals were caught on the same day in the same creek (in the Chattahoochee watershed) north of Atlanta this Saturday.  I cannot get over the difference.  I know this is supposed to be a highly variable species, but really?  One has flecks and markings on almost all the fins and the other one has almost none.  The one with no markings on the fins looked almost bluish when it first came out of the water (both of these fish were in a bucket for 30 minutes or so), and the other one was always a brownish overall color.  The more plain one was also a bit larger, but it really makes me wonder about these fish.  We have seen these "bluish looking blackbandeds" before, but this was the first time I saw such a contract in one location.

 

 

[Dustin]

I think this is due to sexual variation.  My assumption is that the top fish is female and the bottom is male.  I completely agree with you regarding variation across it's range though, which I suppose should be expected from such a widespread species.  It seems like there was talk of splitting them into at least two species with the Edisto and maybe Savannah being one species and those west being a separate species over to the Halloween territory.

[gerald]

More fin speckles and body mottling in females seems to be a trend with other Percina spp too, and some Etheostoma.  Also, pattern differences may be temporary depending on social status, mood, health, hunger, ... who knows what else.  I have caught fantail darters with a wide range of patterns (barred, blotched, striped, light, dark) at one site, but after a few days in captivity they all look the same.

[Betta132]

Could some of it also vary due to the color of the river bottom? I've seen what I think are orangethroated darters float out onto a patch of white sand and go almost completely white in order to hide. 

[gerald]

Could some of it also vary due to the color of the river bottom? I've seen what I think are orangethroated darters float out onto a patch of white sand and go almost completely white in order to hide. 

Yup definitely that too, as anyone who's carried fish in a light-colored bucket over to their field-photo setup can confirm.

[Michael Wolfe]

Could be in theory but not in this case. These fish came out looking different and were held in the same bucket prior to photo.

I'm going back to the same spot this weekend and will look again for this difference and see if it is size based and maybe gender based.

[smbass]

I agree appears to be gender based. My very similar species in Ohio is p. sciera and they show the same differences. Males a little more dusky and solid colored fins and females have all sorts of spots on the body and fins. I have always thought Dusky's were just the blackbanded in the rest of country, very similar fish so I'm not surprised at all that they would show similar sexual dimorphism.