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Adopt-A-Fish Update: May 6, 2004 with bigger river flows Montana Fish, Wildlife and Parks As we expected, the increased flows out of Fort Peck Reservoir have triggered movements of some of our Adopt-A-Fish up the Missouri River. That's what we figured would happen with our radio-implanted fish in Missouri River Adopt-A-Fish. Paddlefish No. 4 and Pallid Sturgeon No. 4 have made significant movements up the Missouri River this past week. In fact, we're seeing quite a few paddlefish up the Missouri and none in the Yellowstone River yet. So is this a good thing? Migration up a river is only a small part in having a successful spawn with young of the year recruited into a population. Successful recruitment depends on many factors. First - there are spawning cues, which are a combination of higher flows (most important), increased water temperature, and increased turbidity (muddy water). These are what trigger the fish to start moving toward spawning areas. With the Yellowstone River being barely a trickle at the moment, many fish are choosing to go up the higher flows of the Missouri River instead. The second step - reproduction, requires a preferred substrate - the right kind of river bottom - and the right water temperatures. Most of our native Missouri fish prefer gravel substrate and warmer temperatures. This is where the problems start to arise. Most of the gravely areas in the mighty Mo. are above Wolf Point which also have colder temperatures due to water releases out of Fort Peck Reservoir. This colder water results in a delay in the spawning process. This has a direct effect on the final step - recruitment into the population. These fish that hatch later in the season just don't have enough time to grow in our short Montana summer before winter arrives. A small fish will have less chance of survival through the winter than a larger fish. I'm not implying that we're not going to have any fish from this year growing to be adults and that we're going to have a totally missing year class of fish. It's just that you can't count your chickens (or fish) before they hatch (and grow). |
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