does anybody have any idea about thermal tolerance of E. parvipinne? The reason I ask is that the fish seems to be primarily a spring/spring run species in Florida, but not so in other states.

any thoughts?

I don't know about that. They're commonly associated with springs and first order streams in West Tennessee. They may just be more closely associated with springs in Florida simply because there are more springs available to them there than elsewhere in their range.

My labmate is working on phylogeography of E. parvipinne. We've collected them throughout their range over the past three years. It looks like their life history is variable, regardless of geography. Where springs are present, they are occupied year round and the fish have an extended breeding season. Where springs are unavailable, they occupy rootwads in sandy or muddy streams, but move up into seeps and flooded grassy areas to spawn en masse in spring time.

In the Oakmulgee forest of central Alabama, we found 1.5" juveniles in a trickle of water; all the way up to the source of the seep. We caught them easily by hand, to give you an idea how much water the fish were using. The water slowly flowed along a roadcut on a sandy hillside, and the fish were about 300 yards from (and at least 50 feet above) the stream channel.

In February, in the lower Chattahoochee watershed, I found a few flooded grassy areas filled with them, and their larvae. Interestingly, the larvae are not benthic, but hover and forage in the water column (<6"). There is little chance of this working well in the stream channel, so it makes sense that the stream populations move up into seeps and swampy areas to spawn.

Regarding thermal tolerance, I'd guess they must be tolerant to slightly warmer conditions, and probably lower O2 levels than most Etheostoma species. Since the shallow backwaters become unavoidably warmer and less oxygenated, there must be some selection pressure for individuals who can withstand occasional temperature spikes and/or hypoxic episodes.

Edited by Elassoman, 25 May 2009 - 03:02 PM.

Hmmm,
while the fish does typically inhabit tiny creeks in NW Florida, I did collect them from Econfina Creek (the one near Panama city) at SR 20. While this location is by no means a huge creek, I had to fish it with a boat (to give you an idea about size). The creek is in management district hands so the riparian zone is intact. One way or the other I will have to give this topic more thought. thanks for the responses