Monday, November 27, 2006

My Scarlet Shiners

I've posted this picture to the NANFA Forum, but I thought I'd put it here too. It's hard to photograph scarlet shiners in my tank since they're always in motion, and I was lazy and left the camera on automatic settings... but I hope you get the idea. They're coloring up and growing out, so I'm happy to have raised about 20 of these fish to maturity, the first time I've ever really kept them. The acid test would be spawning them and raising them to maturity, we'll see.

Wednesday, November 22, 2006

The New NANFA Forum

There's a new on-line Forum operated by NANFA, the North American Native Fishes Association. You can visit it at Registration is free, and makes it much more interesting. A variety of topics are running simultaneously, such as Fish Collecting Trip Reports, or Shiners and Suckers.

Speaking of shiners, I've got to get a decent photo of my display tank in one of our teaching labs. The ~20 scarlet shiners who are most of the inhabitants are looking better and better. I've been feeding them two cubes of frozen brine shrimp every other day for two weeks and it's had a noticeable effect on pumping up their color and making them sleek, plump fish which of course is a good thing....

My next big fish expedition will hopefully be on Saturday, February 3, to Hurricane Creek at the Walls of Jericho primarily to collect adult telescope shiners. I'm already scheming and hoping on getting at least one 4WD truck for the trip, besides maybe enticing Nick to help drive in again. I'll pursue various (polite) options to get this in gear. I have about 5 students signed up to do research for credit with me next semester, so I hope this'll work.

Sunday, November 19, 2006

More Fish Brain Data, Male vs Female, For Scarlet Shiners

Enrique and Leigh have now removed the brains from all of the scarlet shiners we had available from this summer's collections, for a grand total of 85. My arbitary goal had been 100, but this'll work. With this expanded data set, the trends that were apparent after only 45 were still there: male brain size is more variable than female brain size, as described by a linear regression of brain mass as a dependent variable against body mass as the independent variable. The R-squared for male brains is 0.29, the R-squared for females is 0.69. For your viewing pleasure I have posted the two graphs below. If you double click them you can view them so they're legible, I hope.

Our next step is to measure the volume of three key brain areas in a representative sample of males and females so that we can try to explain the basis for the wider spread in male brain size. We'll be looking at the telencephalon, the optic tectum and the cerebellum, which are pretty much the three biggest regions in a scarlet shiner brain. The optic tectum in particular is large. This structure processes visual information which is important if you're a scarlet shiner living in a shallow pool of clear water, their preferred habitat. It's my bet (hypothesis, really) that this turns out to be the variable area, which would mean that some male fish have better vision than others. We'll see.

Wednesday, November 15, 2006

A Trend In Our Gill Parasite Data, And Fundulus Bifax Distribution

Christian showed me an interesting graphical representation of her work on Dactylogyrus gill parasites yesterday. Her raw data show little difference between the two creeks we've studied in terms of parasite load per fish, and little difference between scarlet shiners and striped shiners in parasite load. Christian restated our results as a time line of what was the maximum number of parasites we found in any one fish, beginning with fish from a year ago. What her trend line shows is that in Limestone Creek in the winter and spring we never found fish with more than two parasites in a gill, and by the end of the summer we were finding fish with four. The other creek, Swan Creek, had a steady rate of three parasites per fish as a maximum. This might not sound like much, but it would be consistent with fish growing over the summer and being a better target for larval parasites to find. This may actually also show that Limestone Creek could be considered a healthier creek, with a cyclicity of parasite infestation. I've got to flesh out that thought and come up with a fuller explanation but I'm excited at the thought (no, really!).

I also talked to Kevin today about our various mapping projects. It hit me that our project to map the known occurrences of the stippled studfish, Fundulus bifax, shows that the known range of this species is five counties in east-central Alabama, and most of these locations are not just in the Tallapoosa River drainage, but in eastern tributaries of the Tallapoosa especially in Randolph County. This could well be a sampling artifact. But it informs what could be a good survey in this region to determine the species' status. The species seems to have disappeared from Georgia, and the Alabama range is better thought of as three counties since two of the occurrences are in counties within 3 km of an adjoining county with more known sites. I suspect that it would be easy to make a case for this species to receive protection under the Endangered Species Act. I don't think it will happen, but it should. You heard it here first.

Saturday, November 11, 2006

Work In Progress: The First Two Paragraphs Of My Flame Chub Article

I've finally found what I think is the right journal for submission of my flame chub survey work: Endangered Species Research. So I've started to write an article today. Below is my work of the last hour or so writing the Introduction; I'm going home, maybe to work on more this evening or tomorrow. It's always easier for me to write this kind of stuff after a manuscript has started, everything else can then fall in to place. So I've started!


The status of many freshwater fish species in the species-rich southeastern United States is surprisingly poorly known. Attempts to characterize the status of some rare river species such as the snail darter, Percina tanasi or the Alabama sturgeon, Scaphirhyncus suttkusi, have sparked political controversy and drawn media attention even as exploratory field work goes on for years. Both of these species have suffered from the alteration of river habitat by dam construction.

Vulnerable fish species found in smaller streams in the same region have not received the same level of attention from either the popular media or government agencies. One example is the Alabama Pygmy Sunfish, Elassoma alabamae, considered extinct for 35 years after several springs were drowned in 1938 by Pickwick Pool on the Tennessee River until another isolated spring population was discovered (Boschung & Mayden, 1999). Another example is the federally Threatened slackwater darter, Etheostoma boschungi, with now disjunct populations in two stream systems as more and more of their habitat is lost to changing land use (McGregor & Shepard, 1995; Boschung & Mayden, 1999).

Wednesday, November 08, 2006

Pombo Lost Re-Election, Mummichog DNA Analysis

An interesting outcome of yesterday's elections was that Representative Richard Pombo of California lost his bid for re-election. Pombo spent his time in Congress trying to gut the Endangered Species Act, which luckily never quite succeeded. The next Congress will be improved simply by not including this clown.

Various research projects are moving ahead in my lab. Enrique and Leigh have now removed the brains of 85 scarlet shiners, so we'll double our data set for brain mass vs. somatic mass. I still haven't processed that data though. Once they remove the last few brains from the remaining preserved fish, they'll move on to examining variation in the size of specific brain regions such as the telencephalon, optic tectum and cerebellum. In principle, larger, more dominant males should show enhanced size in one or more of these structures. But if I knew the answer it wouldn't be research, would it?

Kris has made a lot of progress massaging and lining up the cytochrome-b mtDNA sequences from the mummichogs. That work has been a lot harder than I'd thought it would be, although now we've completed the learning curve part of the project and the remaining sequence work goes faster. It appears that we'll have homologous sequences of roughly 700 base pairs from most if not all of the 33 fish for which we apparently have sequences. The bad news is that the worst of these sequences is the single sequence I have from Martha's Vineyard. Without that we still have 32 fish from 6 locations, Boston south to Charleston, SC. After working on this project off and on for 11 years I'm excited at the prospect of being able to present a phylogeny based on this gene.

Friday, November 03, 2006

Aquarium Observations Of Scarlet Shiners

I heard from Phil Kukulski in Michigan about his scarlet shiners the other day. He was able to induce spawning in a small group of them when he raised the water temperature to 78 deg. F. But newly hatched fry all quickly died at that temperature. I guess I'm not surprised, in local streams they probably breed at about 68-70 deg. F in the late spring and early summer, so newly hatched fry would probably prefer that temperature. But that's all conjecture on my part. Phil's the first person I've heard from who has spawned them in captivity, although I'm sure others have. I just noticed that my own colony of about 20 scarlets collected last May as subadults that are in an aquarium in one of our teaching labs can now be sexed; the males have distinctive red bands on their fins, especially the dorsal. I guess they've grown up. They've been at room temperature of around 22-23 deg. C in this lab which seems to be just fine.

Below is a photo Phil K. sent me of his spawning male. He's definitely all pumped up, with the distinctive metallic spanglings dorsally: