Nothing But Shiners Yesterday

I went out collecting with Jennifer and Christian to Limestone and Swan Creeks. This was Jennifer's first trip, looking for male scarlet shiners for her project assaying breeding color intensity. Christian was out for both scarlets and striped shiners as part of looking for gill parasites.

It has rained off and on over the last several days, and Limestone Creek looked awful when we arrived. The water looked like coffee & cream, loaded with clay silt like we haven't seen. But the water wasn't high or fast, and we were able to collect lots of striped shiners with a few scarlets, just the opposite of our May 1 visit. We found no darters, since we were working deeper runs rather than the shallow riffles. The pH was depressed at 7.2, and total dissolved solids was at 52 ppm.

Swan Creek in Athens, AL, was clear and lower than our last visit on May 1, with similar water chemistry to Limestone Creek. After tossing out the empty 4 liter jug of Cossack vodka we netted lots of both scarlet and striped shiners. We also found black darters, one of whom was still in relatively bright breeding coloration. The scarlets were in full coloration, with tuberculated males feeling like sandpaper.

It's not quite an hour back to my lab aquaria, so I was hoping that all of the fish we caught at both creeks would make it back alive. Unfortunately we kept more fish at Swan Creek than I realized, and we got back with about 25 live fish and 17 dead. I've got to finally get a battery powered air pump, and at least one more bucket. It's not a total loss, since Christian can use the dead ones for parasite examination.

The good news is that several alpha male scarlets survived in good shape so Jennifer can start working with them this week. Her task for the summer is to figure out the best way to photograph the colored-up parts of the males so that we can quantify how colored up they are using a software package that can analyze images. This might involve focusing on the caudal and dorsal fins and the operculum which has a vivid orange streak in most males. The capstone will be analyzing males for circulating levels of testosterone, which we might do next spring in conjunction with image analysis.

By coincidence, yesterday morning there was an interview on NPR with the Swedish biologist who came up with ELISA, the anitbody assay method for testing for various molecules. We'll use an ELISA test for testosterone in male (and female, too) scarlet shiners. I'd forgotten that pregnancy test kits use a simple form of ELISA, obviously a yes or no response. So next time you hear the Aerosmith song "Sweet Emotion", when Stevie Tyler sings "You can't catch me, the rabbit done died" it's about a negative ELISA assay (lucky for him, the girl wasn't pregnant).