Estill Fork Had Higher Water, Interesting Darters

Of course, we went to Estill Fork to find darters and we did. After some rain earlier in the week the river was at a normal level, or even more so, with some water running over the low bridge. So we modified our sampling technique from September. We made eight transects instead of sixteen, each of about 15 meters, and took depth and flow measurements at 1 meter intervals from bank to bank. Most of the flow measurements were well over the zeros we found last time, and as a measure of that much of the emergent vegetation was scoured out.

We didn't net any blotchside logperch this time, but we did find greensides in the deeper, faster flows where you'd expect them and nowhere else. The new species this time was blueside darters, Etheostoma jessiae, found in greenside habitat as might be expected. Both fantails and stripetails were more common this time, too. The tennessee snubnoses are the generalist in this assemblage. We found them pretty much everywhere along transects, from deep, still water to shallow, flowing water and variations in between. Rainbows, the other common species, tended to be in shallow, flowing water.

On question I have is why there aren't banded darters at this site. They're present several miles downstream at the Baptist church site, but I've never, ever seen one at our study site. The major difference between the two sites is that the downstream site is rockier, and the upstream site substrate is largely sand and gravel. And that might be it.

Here's a view of the stretch of stream we were working, with Brian and Jeremy looking at a data sheet.
Here's a broader view of the same scene, with the whole crew: Robert, Alex, Brian and Jeremy.

And finally, Jeremy, Robert and Brian poking around in a seine haul trying to pick out darters while I'm holding the other end of the seine and taking a picture.

Estill Fork On Saturday

We'll spend much of the day on Saturday at Estill Fork. It will be our second survey of flow, depth and substrate measurements along with netting darters along at least many of the same transects we followed in September. I'm hoping that the rain we've had lately is enough to raise stream flow above the pitiful levels of the last several months.

The Dactylogyrus manuscript is almost ready to go to Freshwater Biology. I have to figure out the best way to send the 4 figures, created in Excel and currently copied into a Word file. They should be sent as .tiff files, or in a PDF or EPS format. I think that PDF is looking better and better for sheer simplicity.

And, Maybe On To Panama In May?

UAH is trying to establish some kind of university presence in Panama as some form of international campus, which is fine with me in general. To support this they've made some money available for faculty to visit Panama and work on establishing funded research projects. Naturally I stood up and said, "Sure! I can do that!". And it's true. I've proposed visiting the Smithsonian Tropical Research Institute (STRI) in May for two weeks to meet staff scientists and hopefully start a research project. The project would be examining populations of a local livebearer fish, Brachyraphis episcopi, for trematode gill parasites and relating that to reproductive function. A surprising amount of research has been done with this species that shows that different populations respond to the presence or absence of a larger predatory fish in a stream. I'm curious if parasite load varies with such predatory pressure. Plus, as far as I can tell, no one has ever described such parasites from Panamanian freshwater fishes, so there's an unknown swathe of biodiversity to be described. The chances look good that the university will give me a reasonable amount of money to cover airfare and expenses at STRI. At least my passport is current.

Dactylogyrus / Notropis telescopus manuscript almost ready to go

I think I've finally polished our manuscript on the patterns of Dactylogyrus spatulus gill parasite infections of telescope shiners, Notropis telescopus. It's relatively short, with 4 figures (2 could be combined as 1, really). If both co-authors, Brittany and Andrew, like it as is I'll go back and format it specifically for submission to the journal Freshwater Biology (Brittany told me she thought it was OK). Here's the current version of the abstract:

ABSTRACT: Dactylogyrus is a holarctic genus of trematode flatworms that infect the gills of cyprinid fishes. Dactylogyrus species are usually highly host specific, and little is known about their life history in North America. The purpose of this study was twofold: to determine whether Dactylogyrus exhibits seasonality in its life cycle, and if there is any effect upon reproductive effort of the host as a result of Dactylogyrus infection. We examined 383 Telescope Shiners, Notropis telescopus, collected from Hurricane Creek and Estill Fork in the upper Paint Rock River system in Jackson County, northeastern Alabama, USA, from February to September, 2007, and October, 2008 to January, 2009. A total of 967 Dactylogyrus spatulus were found on the gill arches of fish collected. Parasite counts yielded a peak in the average number of parasites present per fish in May, a significant relationship between host length and infection, and a negative correlation between higher parasite load and gonadosomatic index (GSI). Parasites per fish averaged about 1.5 from August to February, with an average high of just under 6 per fish in May. Chi square tests of the assumptions that parasites are evenly distributed among individual host fish and in each month groups lead to the rejection of both assumptions, with the months of March through July as a prevalence peak for Dactylogyrus infection. These months are the time of gonadal development and reproduction in Telescope Shiners. Both male and female fish with higher parasite infections had significantly lower GSI than fish with lower parasite infections.

The Florida Panhandle Fundulus Might Become A Project

I received more information from Charlie today about these unusual Fundulus populations in the Florida panhandle. Their distribution is better known than I had realized, and we might be on to something for either a new species or, more probably, an intergrade between F. escambiae to the west and F. lineolatus to the east. Either way it's interesting because it's not just a single creek, but sites spread among three different rivers. This might be the focus of a spring trip in March...

A Gel Of Mostly Fundulus bifax DNA, PCR amplified

I received the image below from Lance at IXG who is working to amplify and sequence a batch of samples I gave him of mostly Fundulus bifax DNA (and some F. diaphanus). I usually shy away from showing these images because it can get really tedious, but Lance was so excited that all 15 samples yielded very solid bands that you can see, which are all concentrated mitochondrial DNA, the cyt-b gene in particular. He told me I was a really good primer designer, which are short chunks of DNA used to begin amplifications. All I did was find what others have used, and give Lance the information. Anyway, I hope to receive sequences in the near future.

Two Days At The Flint River, AL

We went out Friday afternoon to the Flint to run driftnets, and back today to do transects for flow, depth, substrate and darters. It's finally cold, certainly when we get there at 9 a.m. We found a blotched chub, Erimystax insignis, today that's a rare species in Alabama streams. It likes fast riffle water over boulder and cobble, exactly where we found it. The Nature Conservancy rates the species as S2 in the state, so we certainly released the one we netted.

Here are Jeremy, Robert and Brian standing around a driftnet yesterday at the Flint. Both nets collected a large number of drifting leaves, not surprisingly.

This is a photo I took while holding one end of our transect tape measure line. Brian is handling the flow meter while Brittany records data. Jeremy is peeking in from the far bank, holding the other end of the tape. We make readings of depth and flow at one meter intervals, with the river being about 30 meters wide.

The Florida Fundulus From Tony

I received a package of preserved fishes from Tony, finally delivered to me through campus mail on Tuesday. The one individual from the apparent intergrade creek really does look exactly intermediate between the F. lineolatus and F. escambiae also in the package, variously from SC and FL. The specific locale is just to the east of the Appalachicola River which is a famous biogeographic boundary between very similar species to the east and west, so the fact that this intergrade killifish population seems to exist is no real surprise. But we still have to get decent DNA sequences from it, so we'll see.

Always Work In Progress

This weekend we'll do a Flint River extravaganza. On Friday afternoon we'll go out just to run the drift nets. And on Saturday we'll go back to do the flow measurement, seining and substrate ID'ing. In principle we could do both on the same day, but some people can do one or the other day so we'll spread everyone around some.

Hopefully I'll receive a package from Tony T. today with some preserved Fundulus fish from the deep southeast. We'll attempt to get good sequences from some lineolatus, escambiae and an apparent species intergrade from a creek in the Florida panhandle near Tallahassee. My aim is to amplify several mitochondrial and nuclear genes following the method of Whitehead in his recent Evolution paper on this genus' phylogenetics. I suppose it's possible that this is a previously overlooked new species of starhead topminnow, but that would be too easy(!). But ya never know.