Sunday, April 21, 2013

More stoneflies for the Arkansas.

    Whether or not the weather cooperates, field season is upon us. We've already completed our first little project of the year, which was to get another batch of Pteronarcys stoneflies from the Colorado River to transplant over to the Arkansas. These bugs were native to the Arkansas before acid mine drainage wiped them out. The Arkansas has been cleaned up enough in modern times that it looks like they could survive there again. So last year my friend and counterpart in Salida, Greg Policky, came up with the idea of making these transplants.
     In 2012 we collected about 37,000 nymphs from the Colorado to transport to the Arkansas. This year, over two days of collection we managed to gather about 50,000 nymphs. Greg transplanted all these nymphs to four specific riffles with good habitat on the Arkansas. He did observe adults hatching last year. So now it's just a question of whether or not there are enough adults to find each other once they do hatch and look for mates. 
     Here are some photos of this year's collection efforts. They were taken by Mike Kline, who is working with me as a field technician this spring.

     Here we are trying to become enthusiastic about getting in the river on a less-than-pleasant day.

     Any day in the field is better than any day in the office, though, right? Sometimes we have to remind ourselves of that repeatedly.
     Here's the collection process. It's just a matter of rolling rocks in the places with just the right depth and velocity. You quickly get a feel for finding the "sweet spots" that hold a lot of nymphs.

     When you roll a good rock, your net looks like this.

     High-quality trout food.

     As field season progresses, my approach to these posts is going to change a bit. My year basically runs in two modes: data collection mode and data analysis mode. What you've been seeing up to this point is the result of the data analysis part of my year. Now that field season is here, I don't do a lot of data analysis. So these posts are going to become more of a journal of what my weeks entail, and what interesting things we ran across. Keep posting questions - this is going to be a much better resource for everyone if there is two-way communication here. So I appreciate that and it helps guide me as far as what topics are of interest to people.
    On tap for the next two weeks is eight days of spring raft electrofishing surveys on the Colorado. We're surveying four, two-mile reaches that are roughly evenly spaced between Pumphouse and Dotsero. Here's hoping that the weather doesn't treat us too miserably.



  1. Very cool on the Stonefly nymph transplants.

    Are there other rivers in the state where this has been tried? If successful on the Arkansas, are there other rivers that are candidates for this type of transplant? Clear creek seems like a place that has stonefly habitat and a history of acid mine drainage that is similar to the Arkansas.

    1. Dan (and Bennett), I believe this is the first time that this has been tried in Colorado. If it is successful, I'm sure other biologists around the state will consider trying it too. The thing about the Arkansas, though, is that we know this species is native to that river. It's an entirely different deal to talk about introducing a species that has never historically occurred in a particular water (possibly Clear Creek - I don't actually know if Pc were native there or not). That tends to give biologists the heebie-jeebies. There are so many examples throughout history of species introductions that went horribly wrong and had unintended negative consequences. From my limited knowledge of Clear Creek, I'm under the impression that it hasn't been cleaned up very much and still has a lot of problems with metals. I could be wrong about that though. Likewise, I'm nut sure about the Poudre - that would be a good question for Kurt Davies.

  2. Dan you beat me to the question! I was wondering if a river like the Poudre River could be a candidate since the fire has impacted it with silt/ash?

    Bennett Colvin

  3. Back in March you discussed sculpins on the Fraser River. From what I've been able to read, sculpins are only in the San Juan, Animas, Yampa, White, Colorado, Gunnison, and Dolores river basins. What about the Eastern rivers (South Platte, Arkansas, etc)? When they are present, how much of a trout's diet is made up of sculpins? I'm sure it depends on the size of the fish and species. Thanks.

    1. James, sculpin are definitely a west-slope species. The east slope rivers have longnose dace, but no sculpin that I'm aware of. As far as how much of a trout's diet consists of sculpin, I would have to go back and look at some of Barry Nehring's diet analysis he did with brown trout on the Colorado back in the '80's. The only problem is, he conducted that study in an area where there are not sculpin now - I don't know if there were sculpin there then. I'm not aware of a thorough trout diet study that has been done in a place that has a high density of sculpin. It's a great question. We make the assumption that they are important trout food, but don't necessarily have direct data to support that. It would be a good thing to have and we may be pursuing that over the next couple of years. One thing I can point out, though, is that for the size of the stream (which is relatively small), brown trout larger than 14" are much more common in the Fraser than in many similar-sized streams that do not have sculpin. I consider that to be INDIRECT evidence that the presence of sculpin constitutes an important component to the forage base.

  4. I remember in Browns Canyon last year in September having a huge stone fly landing all over us at the Hecla Junction camp ground, not much of a flyer those things. I had no idea they had been wiped out on the Ark and introduced that year until I read one of your previous posts on it.