Perfecting Our Scarlet Shiner Photography... I Think!

I spent two hours today with Jennifer photographing scarlet shiners. She has picked up floodlights with almost daylight spectral characteristics, two panes of low glare glass, and some sheet of dull matte light gray paper. This means we could set up our photo table with less glare, and more accurate color. The joke on us was that when we went to net fish out of my scarlet shiner tank, all of the large adults were female; I thought we still had at least one male. But none of them was tuberculated or vividly colored. So, we went ahead and sacrificed the two largest females with MS-222 and photographed them. We have to do this anyway so that we can compare their colors to the alpha males.

I wish I could post one of the photos but I don't have any at the moment... What we found was that adult females in breeding condition are also distinctly colored, just not vividly. Both fish had dark bluish bodies, with rusty brown-red swathes of color on their fins and a diminished orangish bar on the operculum. Maybe they're best described as handsome, rather than eyepopping like the alpha males. Our photo technique was to stretch out the freshly euthanized fish on the low-glare glass, using a centimeter ruler to hold out the very tip of the dorsal fin. The other fins we could spread out, and the moisture held them in place against the glass. We experimented with various exposures, finding that a very slight underexposure according to the automatic settings gave the best color with almost no glare (at one eightieth of a second, F3.5, with indirect reflected lighting). Jennifer has begun to fool around with the dental school image analysis software, so now she has two high quality images to work with (at least I HOPE they're high quality!). Next, we move on to working out the details of bleeding the fish to obtain 50-100 microliters of blood for testosterone assays. One of Jennifer's former co-workers who does mouse bleeding for a local biotech company has put together a small collection of articles for us that describe different approaches to bleeding small animals, and also pointed out that there's a website dedicated to zebrafish research techniques. Away we go!

On Friday, the flame chub trip will continue along the southern edge of the Tennessee divide in Alabama. We'll visit two historic sites in the southwest corner of Morgan County, along Crowdabout Creek, and two sites not far to the west in Lawrence County at the edge of the Bankhead National Forest. These are geologically interesting sites, sitting on top of a formation called the Hartselle Sandstone. They're on the edge of a low range of mountains that are ancient barrier beach islands from 220 million years ago when this area was a shallow sea, positioned much closer to the equator than now. The creeks we'll visit flow off this ancient mountain chain. As always I have faith that it'll be interesting......