This blog originates on the banks of the Atchafalaya River, in Louisiana. It proposes to share the things that happen on and by the river as the seasons progress. As the river changes from quiet, warm, slow flow to rises of eighteen feet or more, there are changes in the lives of the birds, fish, amphibians and reptiles that use the river. And the mood of the river changes with the seasons. I propose to note and comment on these things.

My Photo
Location: Butte La Rose, Louisiana, United States

I transitioned a few years ago from a career as a water-pollution control biologist. I want to do this blog to stay in touch with a world outside my everyday surroundings, whatever they may be. I like open-minded company and the discussion of ideas. Photo by Brad Moon.

Friday, July 14, 2006

The Shrimp are Back

Sunset today on the river.

Yes, they are, the shrimp are back. I first noticed the nighttime migration of juvenile river shrimp last year, and it turned out that the observation is sort of a new thing. Not that it wasn’t observed before, it was, but not by very many people and not publicized in scientific circles. Now the scientists are aware and interested and we all were anxiously waiting to see if the shrimp would return this summer. They have, by the millions, and ON THE SAME NIGHT that I first saw them last year. It certainly could be a coincidence, but maybe not? Another returnee in the last couple days is the annual upriver movement of salt water shad (pogies and threadfin). I see them every year when the water gets low and warm, sometimes in immense schools swimming on the surface. They come from the estuaries along the Gulf, and so do the shrimp probably. Do both of these things happen because environmental conditions at this time of year have a similar effect on the fish and the crustaceans? Probably so, but we will have to see what answers research brings. Pretty exciting stuff, if you’re a biologist, and maybe even if you’re not. The shrimp are less than one inch long as they swim upriver, as the ruler shows. Notice that they are all swimming from right to left, upriver, and against the slow current (click on the picture to see the red eyes). It’s one thing to see a few shrimp in the water or in a trap, it’s quite another to watch billions (not an exaggeration) of them swim by night after night until sometime later in the annual low-water cycle. Consider how much food this provides for everything in the river. Awesome.

I was fishing for the cats this afternoon, using some of the same shrimp (but grown up) for bait. I caught seven or eight bream, one catfish, one mullet and two turtles. It is always a surprise to me to catch mullet on a baited hook. The assumption was always made previously that they consumed algae and such and would not take bait. Wrong. This was also confirmed during the last two weeks as the deceased alligator melted away into the river. It was in shallow water and it was easy to see the schools of mullet tearing away at the tenderized gator meat. They looked like the proverbial piranha in the rivers to our south. If they had sharp teeth, you might imagine someone in a Louisiana river someday yelling for the kids to get out of the river because the mullets were coming. And jumping like they do, they could even snatch a mouthful out of a passing boater. I can just see Academy advertising the newest thing in water safety when boating: mullet armor.

I also mentioned catching a couple of turtles today. One was a stinkpot (Sternotherus odoratus) and the other was a large red-eared slider (Trachemys scripta). I wasn’t too sure of the latter when I saw it because the shell was so full of green algae that I couldn’t see the pattern on the back, and the area on the head that is usually red showed only a line of faded dark orange. In order to try to be sure of the identification, I brought it up to the house and tried to clean the shell with a fiber brush. No luck, it just combed the algae so that it lay down nice and pretty. Next I tried one of those green scrub pads that works well to scrub pots and will take the cutting edge off of a sharp knife if you’re not careful. It didn’t remove the algae either, just mashed it down. By now I’m developing more respect for the tenacity of the turtle’s green coat. But, the turtle and me, we’re in my shop and I’m surrounded by man tools. I mean stuff you have to sweat to use. Surely something I have will remove the algae, surely. So next in line on this escalation was a very stiff wire brush and I’m pleased to say that it worked. Good thing, I was going to go for the orbital sander if it didn’t. And then on to…what? Maybe a bench grinder wheel with a wire brush attached? But, now the turtle was naked, and I could see that the reason I didn’t recognize it at first was because it was a very old member of the species. The shell had those black squares outlining the scutes on the back, a trait only acquired after many years, and the faded orange on the head confirmed it. In honor of its age, it went back into the river instead of becoming a resident in my osteological collection. So did the stinkpot, I have the skeleton of one of them already.

The river is at 2.7 feet on the Butte La Rose gauge, going to 2.4 by Sunday. The upper Mississippi is kind of up a little and down a little, but the Ohio is showing some very healthy rises of 3.0 feet at Paducah, which makes it interesting to watch.

Rise and Shine, Jim


Post a Comment

<< Home