What's Up With Our Water and Streamflow Situation?

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What's Up With Our Water and Streamflow Situation?

Proper handling of fish will increase survival rates, especially during warm water years.


There is no debate as to whether or not Montana is seeing unusually high temperatures and is in various stages of drought just like the rest of the West.  The western part of the state has already gone to "hoot owl" fishing regulations and some rivers in Southwest Montana are on the verge.  "In many areas we're seeing stream flows fall below average for this time of year, and some that are the lowest ever recorded," said Stephen Begley, a water conservation specialist for FWP in Helena.


While this sounds like a doomsday report, there is hope. Big Sky is lucky to have both high elevations, cold creeks and canyon walls to help keep the water temperatures on the Gallatin lower than other nearby rivers. Nighttime temps the next few days are going to drop below 50 in Big Sky and daytime temps are going to be in the low 70's. This should allow water temps to drop, giving the fish a much needed break from the heat.  


Besides fishing with a thermometer and taking temperatures throughout the day our friends at TU, FOAM and FWP have promoted "Warm, Low Water Ethics"  with the basics outlined below.  More detailed info can be found here http://foam-montana.org/drought_guidelines.php

  • Use cooler stretches or start earlier to avoid rising water temperatures.
  • Limit the number of fish you catch and release. If appropriate, use slightly heavier gear and tackle to land fish quickly. Land and release fish quickly.
  • In general, salmonids prefer temperatures in the range of 54° F. to 63° F.
  • Dissolved oxygen can be reduced  when water temperatures rise. Depending on water temperatures, ideal dissolved oxygen concentrations for active fish can be around 10 parts per million (ppm) or higher. When levels of dissolved oxygen drop below 6 parts per million, trout become stressed. Feeding, predator avoidance and sustained swimming becomes difficult. Below 4 ppm, trout can die.
  • In general, depending on species, once temperatures rise above the mid–60's F., trout can start feeling the adverse effects of high temperatures. Feeding will be reduced. Sustained swimming becomes more laborious. The ability to compete with other species for common food sources is reduced once temperatures approach the 70's. Higher temperatures can affect equilibrium. Lethal temperatures, depending on species, range from 74° F to 79° F. However, it's possible for trout to survive at these temperatures if they locate cool thermal refuges, or if these high temperatures are moderated by drops in temperature at night.


While we as a fly shop make our living out of people fishing, we also rely on the incredibly healthy fisheries surrounding us.  While we aren't saying not to fish, we are preparing for a few weeks of making adjustments to the norm. Find a cold stream, a lake or cold canyon water.  Enjoy the sunrise and start your fishing day as early as possible, take water temperatures, and if the water is around 70 degrees, crack a cold soda, beer, or water and go swimming.  

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Gallatin River Guides

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