So that was the good news. Now the bad news. We've got problems at Green Mountain. They had already started by the time I got here in 2007, with an explosion of the gill lice parasite in the kokanee salmon population. From that time onward, the reliability of the kokanee run took a nosedive and has never recovered. Green Mountain used to produce a good spawning run in the Blue River as well as reliable ice fishing for silver kokes. Those opportunities disappeared after the gill lice showed up. As far as I can tell, a few folks still get into some fish by snagging during the spawn or ice fishing for silvers, but it's extremely spotty and unpredictable.
Because they originated in the Pacific, the gill lice that we have infect both kokanee and rainbows (also from the Pacific). They do not infect browns or lake trout. The rainbows at Green Mountain are also heavily infected and have been for years, with no reduction in infection apparent over time. There is no known mechanism of control of gill lice in a water body this size. Except for one.
This is an obligate parasite - meaning, it won't survive if it can't find its specific host species, in this case rainbows and kokanee. The only known biological way to reduce prevalence of the parasite is to deprive it of its host. This is one of the three reasons that, for the first time in the history of the reservoir, we are not stocking Green Mountain with any fish in 2016.
The other problem we've got at Green Mountain is an illegal introduction of northern pike. I received some word-of-mouth reports of pike being caught beginning in '08 or so, but no confirmation with photos or any carcasses. I finally picked one up in my standard gillnet surveys in 2012. Then I got four in 2013, one more in 2014, and in 2015 I picked up 17. That's not quite as bad as it sounds, because in 2015 I increased my gillnet effort from 24 net sets to 40. So in terms of gillnet hours, pike capture went from 0.01 fish per hour to 0.07 fish per hour. So still a low catch rate indicating a small population, but they were all the same size (22-25 inches), indicating that they are all from the same year class, born in the lake around 2012.
When Green Mountain spills, the volume of water going over the spillway can be big. 2015 wasn't a particularly big water year, and it spilled for 15 days at an average of 513 CFS. In 2011, which was a huge water year, it spilled for 27 days at an average of 1,141 CFS. So if pike take off in GM, we've got a huge risk of the lake dumping a lot of them into the Blue and Colorado Rivers. We do a lot of survey work downstream of GM, and we have not seen pike establish themselves at this point.
What's so frustrating about this is that whoever takes it upon themselves to spread fish around is probably unaware of the implications of tying these waters to the Endangered Fish Recovery Program. We have a great luxury here at the head of the basin in that we can manage these waters with recreational opportunity as the top priority. This is a luxury that we should never, ever take for granted. If the species that are problematic to the Recovery Program - northern pike, yellow perch, walleye, smallmouth - continue to turn up in these waters, it is probably only a matter of time before it is proven that fish from one or more of these reservoirs are finding their way all the way down to Rifle and causing problems in the recovery area. At that point, managing these fisheries to maximize recreational opportunity immediately becomes the second priority, and that luxury that we've enjoyed all this time disappears indefinitely, possibly permanently. All options are on the table then, including rotenone treatment of large reservoirs and closing large bodies of water to fishing.
I know I'm preaching to the choir here. I've communicated this message before many times, and no one who would bucket stock fish would ever take the time to read this. So this is the second reason we're not stocking any fish into Green Mountain this year. We're not going to turn that lake into yet another pike feedlot. We've got plenty of them around, and it's a ridiculously expensive way to manage a fishery.
Here's the little bit of good news within this piece of bad news: we're implementing a northern pike angler harvest incentive of $20 at GM. If you catch a pike there, you can take it to Heeney Marina and they'll give you a twenty dollar bill. We have got to get on top of this as quickly as we can, and enlisting the help of anglers is the best way to do it. So I'm hoping that whatever angler traffic is lost due to the lack of stocking, is replaced by folks going after pike.
The third reason we're not stocking fish is that we've got some production issues in the hatchery system. I rely heavily on our Glenwood Springs hatchery for a lot of my plants, and last year Glenwood came down with a disease called Bacterial Kidney Disease. It's a long story, but the point is that we can't stock fish that have been exposed to this disease, and Glenwood had to be completely depopulated and disinfected last year. So there is a general shortage of fish on the west slope as the other hatcheries try to make up for the fish that Glenwood will not have in 2016. One of the results is that I have a smaller allocation of rainbows than normal. If I cut one major reservoir (Green Mountain) out of my schedule, I am able to maintain catchable numbers at the other large waters in my area.
One benefit taking a timeout from stocking is that this will serve as a large-scale lake trout management experiment. A couple messages that I get on a regular basis from the lake trout angling community are an almost universal lack of support for kokanee in Colorado, and and the assertion that we can have perfectly good trophy lake trout fisheries based on a sucker prey base alone. These two positions are totally misguided - and quite possibly tragic for the future of trophy lakers in this state - but we've seen over and over again that it doesn't matter how many times we try to communicate this. Here is our golden opportunity to test these theories. The proof will be in the pudding, and we'll see how this trophy lake trout fishery fares when both kokanee and rainbows disappear from the prey base.
When Green Mountain spills, the volume of water going over the spillway can be big. 2015 wasn't a particularly big water year, and it spilled for 15 days at an average of 513 CFS. In 2011, which was a huge water year, it spilled for 27 days at an average of 1,141 CFS. So if pike take off in GM, we've got a huge risk of the lake dumping a lot of them into the Blue and Colorado Rivers. We do a lot of survey work downstream of GM, and we have not seen pike establish themselves at this point.
What's so frustrating about this is that whoever takes it upon themselves to spread fish around is probably unaware of the implications of tying these waters to the Endangered Fish Recovery Program. We have a great luxury here at the head of the basin in that we can manage these waters with recreational opportunity as the top priority. This is a luxury that we should never, ever take for granted. If the species that are problematic to the Recovery Program - northern pike, yellow perch, walleye, smallmouth - continue to turn up in these waters, it is probably only a matter of time before it is proven that fish from one or more of these reservoirs are finding their way all the way down to Rifle and causing problems in the recovery area. At that point, managing these fisheries to maximize recreational opportunity immediately becomes the second priority, and that luxury that we've enjoyed all this time disappears indefinitely, possibly permanently. All options are on the table then, including rotenone treatment of large reservoirs and closing large bodies of water to fishing.
I know I'm preaching to the choir here. I've communicated this message before many times, and no one who would bucket stock fish would ever take the time to read this. So this is the second reason we're not stocking any fish into Green Mountain this year. We're not going to turn that lake into yet another pike feedlot. We've got plenty of them around, and it's a ridiculously expensive way to manage a fishery.
Here's the little bit of good news within this piece of bad news: we're implementing a northern pike angler harvest incentive of $20 at GM. If you catch a pike there, you can take it to Heeney Marina and they'll give you a twenty dollar bill. We have got to get on top of this as quickly as we can, and enlisting the help of anglers is the best way to do it. So I'm hoping that whatever angler traffic is lost due to the lack of stocking, is replaced by folks going after pike.
The third reason we're not stocking fish is that we've got some production issues in the hatchery system. I rely heavily on our Glenwood Springs hatchery for a lot of my plants, and last year Glenwood came down with a disease called Bacterial Kidney Disease. It's a long story, but the point is that we can't stock fish that have been exposed to this disease, and Glenwood had to be completely depopulated and disinfected last year. So there is a general shortage of fish on the west slope as the other hatcheries try to make up for the fish that Glenwood will not have in 2016. One of the results is that I have a smaller allocation of rainbows than normal. If I cut one major reservoir (Green Mountain) out of my schedule, I am able to maintain catchable numbers at the other large waters in my area.
One benefit taking a timeout from stocking is that this will serve as a large-scale lake trout management experiment. A couple messages that I get on a regular basis from the lake trout angling community are an almost universal lack of support for kokanee in Colorado, and and the assertion that we can have perfectly good trophy lake trout fisheries based on a sucker prey base alone. These two positions are totally misguided - and quite possibly tragic for the future of trophy lakers in this state - but we've seen over and over again that it doesn't matter how many times we try to communicate this. Here is our golden opportunity to test these theories. The proof will be in the pudding, and we'll see how this trophy lake trout fishery fares when both kokanee and rainbows disappear from the prey base.
