On September 24 & 27, we ran our annual raft electrofishing survey of the Parshall-Sunset reach, AKA the Kemp-Breeze State Wildlife Area. I always consider this to be probably the single most important data set that I collect every year, for the simple reason that it is one of the longest-running big river trout population data sets that exists in the state. Our researcher Barry Nehring was the first biologist in Colorado to start running raft electrofishing surveys, in the late '70's. He had gone up to Montana, where they had figured out how to do it. 1981 was the first year that he surveyed the Parshall-Sunset reach, so as of this year that data set is 32 years old. It's been done the same way, at the same time of year all those years.
Speaking of Barry Nehring, I often like to say that I owe my career to a series of phenomenal mentors. I did not arrive in this job by the traditional route of attending graduate school in fisheries. Instead, three years out of college when I was trying to figure out my next move, I stumbled into my first permanent job as a wildlife officer for our agency. After five years I transferred into the biologist job. My goal was always to work as a fisheries biologist; I just arrived here via a slightly different route than most. It's not unprecedented - I've got coworkers who took the same route. But what I was getting at, is that I am constantly thankful for the series of spectacular mentors that I have worked with in the fisheries field. These are guys that I feel so lucky for every day that I have worked side-by-side with. It's the knowledge that I was able to glean off of them that got me where I am today. Barry is one of those guys. It seems that quality mentorship may be slowly fading away in the professional world, and if that's truly the case it's a sad, sad thing.
Anyway, I digress. I haven't worked up the data yet from the Parshall reach, but thought I would share a couple of things. First of all, it looks like the density for large fish (>14") is as low as it has ever been, and at this point may be flirting with dropping below the gold medal standard of at least 12 fish per surface acre greater than 14 inches. That is really bad news, for a reach of river that not very long ago supported densities in the neighborhood of 100 or more per acre. Numbers of rainbows in that size category are up, which is good news, but browns are way down. I don't have a precise explanation for it at the moment, but we can get into that over the winter.
But here is the really sensational tidbit that I wanted to share for now. On our first day, the mark run on the 24th, I was working fish out of the tank and picked up this little 3-inch silvery thing. I immediately said "kokanee" because every once in a while we pick up the occasional small kokanee that got flushed out of one of the reservoirs. However, as soon as I said it, I realized that was not what I was looking at. I said, "Wait--" and the other guys on the boat looked, and three of us said in unison, "MOUNTAIN WHITEFISH !?!?"
We have NEVER captured a mountain whitefish anywhere upstream of Gore Canyon. Thirty years of one of the most intensively studied trout rivers in this state, and not a SINGLE record of a mountain whitefish. Not just in the Colorado, but not in any tributary, any lake or reservoir, nowhere in the Blue River watershed. In the entire time I've been here, I've taken it for granted that Gore Canyon is the natural upstream barrier of whitefish on the Colorado. There are a lot of them below, and there are none above. That is simply the way that it is and what we have observed in the entire historical record. But here was this little three-inch fish in my hand that was very definitely a mountain whitefish, no question about it.
The weird thing about it is, this is not a species that people move around. When a new species pops up in an unexpected place, it is almost always the result of either deliberate or accidental introduction by people. But I just can't see someone willfully moving mountain whitefish from a lower section of the Colorado to the upper section, and I have a hard time picturing how it would happen on accident. I didn't know what to make of it, and chalked it up to just one of those crazy anomalies that keeps us humble. A one-time occurrence that I probably would never run across again.
Three days later, on the 27th, we ran our recap run on the same reach. You'll never guess what we picked up right in the Parshall Hole. Not one - not two - but THREE young-of-the-year mountain whitefish. Three of them. I was just flabbergasted, and remain so today.
So here is my theory for the moment. We just came through two extremely unusual years flow-wise. 2011 was an insanely high-water year, and 2012 was an insanely low-water year. I think that if whitefish were to make it through Gore Canyon, it would be more likely to happen during high water than low water. I'm thinking that maybe a few adults managed to find their way through in 2011. We have never run across the adults, but now we have found their offspring.
There is a good lesson in humility for me in this. At some point over the past year, I was talking with someone who told me that their friend caught what he was sure was a mountain whitefish somewhere above Gore Canyon. I don't remember who it was or exactly where the person was fishing. But it was a secondhand report that came to me. Secondhand reports are never very reliable, and I basically brushed it off because there are many examples of incorrect species identification by anglers. I can't tell you how many times I've talked to people who don't know the difference between a whitefish and a white sucker. So, whoever it was that told me that, if you're reading this please drop me a line so I can get those details again, and you can watch me eat a little crow.
If whitefish proliferate in the upper Colorado, it could change the ecology of the river significantly. There would be some benefits to the sport fishery and some potential drawbacks. It will be fascinating to see if they manage to get a foothold here. If they do, 2013 will be a milestone marking the end of the "pre-whitefish" era and the beginning of the "post-whitefish" era.
Thursday, October 24, 2013
Tuesday, October 15, 2013
Kokanee season
I'm fully immersed in chasing kokanee eggs at the moment. Things are not looking quite as rosy this year statewide, and we have a good chance of coming up a bit short. By this date last year, Blue Mesa had produced 2.5 million already; prior to today, they were sitting at right about half of that, at 1.2 million. I think it's safe to say that they're not going to have another record-breaking year. Hopefully I'm wrong about that.
Up here, things are looking decidedly worse. As for Williams Fork, all our indicators tell us that whatever run takes place will be very weak. My best estimation is that we would get about half the eggs we got in 2011 - which would be approximately 300K. That's the best-case scenario. That operation is extremely labor-intensive. If you've never seen it, I have to build an electric barrier in the river to stop upstream migration, which means that I have to hire a dedicated person to live in a camper there and monitor the thing around the clock. 300,000 eggs is not worth that much expense and manpower. So, we're not putting the trap in at WF this year. The buoy line is in and the fishing closure is in effect, but the purpose of that is to allow us to get our disease sample. We have to keep a disease history current to continue to use it as an egg source in the future. That involves getting ovarian fluids and a couple other biopsies from 60 females. Once we have that, we'll pull the buoy line. Hopefully that will happen by the 25th. We haven't seen a fish running there yet. My first year here, 2007, we took 4.5 million eggs from Williams Fork. Crazy how times change.
Granby is not looking much better. Last year, we scraped and scraped for 800,000 eggs. That was the first time in over a decade that Granby did not provide enough eggs for itself - we need 1.2 million there to break even. Our projections for this year suggest a continued decline, and I will feel lucky if we get half a million there.
It's also a weird year for Granby with the water regime. When the floods started happening around September 11, the water entities immediately stopped taking water through the tunnels to the east slope. There hasn't been any water going through the Adams, Moffat, or Roberts tunnels since the floods. Because of that, all of a sudden we've got a lot more water in certain places where there is never water this time of year. One of those places is below Shadow Mountain dam. It's sitting at 200 CFS right now, when normally at this time of year they're releasing 40. The only control they have on the elevations of Grand and Shadow right now is releases out of Shadow Mountain dam. Normally there is a lot of water going through the Adams Tunnel this time of year. At one brief point in September, Shadow dam was spilling 1600 CFS. Our whole kokanee trap system there is designed to handle 40 CFS, and it's always a very controlled, steady situation, except for this year. We're way late on getting a trap in the river there. So, tomorrow they're going to cut releases for us for a few hours while we jump in the river and get a trap built that can handle 200-300 CFS. When we're done they'll crank it back up and we'll stand there with our fingers crossed hoping that it holds. It's a good problem to have; I shouldn't complain.
The one bright spot in this neighborhood is Wolford. We have every reason to believe that I'll take just as many eggs there this year as I did last year - 1.9 million. Over the past year we built a new and improved Merwin trap which corrected some of the design flaws of the original one that we used. We set it yesterday, and this morning there were 100 or so kokes in it. That's a good sign. We'll start taking eggs there on Monday, and we'll be taking every egg we can get out of Wolford. Our biggest day there last year was November 20, so we'll be sticking with it for a while, and in fact Wolford will probably be the lake that saves our bacon for kokanee up here.
Here is the disturbing trend for kokanee in Colorado: fewer and fewer lakes are able to support them. My mantra for kokanee the past few years has been "Competitors, Predators, and Parasites." That is, I'm not aware of a single lake in the state with a viable kokanee population that has all three of those things. In my time here, I've seen both Williams Fork and Green Mountain go from one to two, and the kokanee populations at both those lakes have taken a major hit. The only lake I've got left with none of those three things is Wolford - assuming we can stay on top of the pike population there. If the pike take off, or gill lice were to get into Wolford, I'm afraid we'd be done with kokanee in this area. We keep turning away from problem reservoirs as egg sources, and it feels an awful lot like we're backed into a corner now.
Up here, things are looking decidedly worse. As for Williams Fork, all our indicators tell us that whatever run takes place will be very weak. My best estimation is that we would get about half the eggs we got in 2011 - which would be approximately 300K. That's the best-case scenario. That operation is extremely labor-intensive. If you've never seen it, I have to build an electric barrier in the river to stop upstream migration, which means that I have to hire a dedicated person to live in a camper there and monitor the thing around the clock. 300,000 eggs is not worth that much expense and manpower. So, we're not putting the trap in at WF this year. The buoy line is in and the fishing closure is in effect, but the purpose of that is to allow us to get our disease sample. We have to keep a disease history current to continue to use it as an egg source in the future. That involves getting ovarian fluids and a couple other biopsies from 60 females. Once we have that, we'll pull the buoy line. Hopefully that will happen by the 25th. We haven't seen a fish running there yet. My first year here, 2007, we took 4.5 million eggs from Williams Fork. Crazy how times change.
Granby is not looking much better. Last year, we scraped and scraped for 800,000 eggs. That was the first time in over a decade that Granby did not provide enough eggs for itself - we need 1.2 million there to break even. Our projections for this year suggest a continued decline, and I will feel lucky if we get half a million there.
It's also a weird year for Granby with the water regime. When the floods started happening around September 11, the water entities immediately stopped taking water through the tunnels to the east slope. There hasn't been any water going through the Adams, Moffat, or Roberts tunnels since the floods. Because of that, all of a sudden we've got a lot more water in certain places where there is never water this time of year. One of those places is below Shadow Mountain dam. It's sitting at 200 CFS right now, when normally at this time of year they're releasing 40. The only control they have on the elevations of Grand and Shadow right now is releases out of Shadow Mountain dam. Normally there is a lot of water going through the Adams Tunnel this time of year. At one brief point in September, Shadow dam was spilling 1600 CFS. Our whole kokanee trap system there is designed to handle 40 CFS, and it's always a very controlled, steady situation, except for this year. We're way late on getting a trap in the river there. So, tomorrow they're going to cut releases for us for a few hours while we jump in the river and get a trap built that can handle 200-300 CFS. When we're done they'll crank it back up and we'll stand there with our fingers crossed hoping that it holds. It's a good problem to have; I shouldn't complain.
The one bright spot in this neighborhood is Wolford. We have every reason to believe that I'll take just as many eggs there this year as I did last year - 1.9 million. Over the past year we built a new and improved Merwin trap which corrected some of the design flaws of the original one that we used. We set it yesterday, and this morning there were 100 or so kokes in it. That's a good sign. We'll start taking eggs there on Monday, and we'll be taking every egg we can get out of Wolford. Our biggest day there last year was November 20, so we'll be sticking with it for a while, and in fact Wolford will probably be the lake that saves our bacon for kokanee up here.
Here is the disturbing trend for kokanee in Colorado: fewer and fewer lakes are able to support them. My mantra for kokanee the past few years has been "Competitors, Predators, and Parasites." That is, I'm not aware of a single lake in the state with a viable kokanee population that has all three of those things. In my time here, I've seen both Williams Fork and Green Mountain go from one to two, and the kokanee populations at both those lakes have taken a major hit. The only lake I've got left with none of those three things is Wolford - assuming we can stay on top of the pike population there. If the pike take off, or gill lice were to get into Wolford, I'm afraid we'd be done with kokanee in this area. We keep turning away from problem reservoirs as egg sources, and it feels an awful lot like we're backed into a corner now.
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