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Restore the Gore

  • 23 May 2016

What’s Bugging Gore Creek

Over the past 10 years there has been a noticeable decline in the aquatic bug community of Gore Creek. These bugs, called macroinvertebretes, include insects, crustaceans, mollusks, arachnids (spiders), and annelids (worms). Because aquatic bugs spend most all of their life in the water, water quality is essential to their survival. They are very sensitive to different chemical and physical conditions of the water and require cold, clean, and well oxygenated water to survive. If there is a change in the water quality, perhaps because of a pollutant entering the water, or a change in the flow from runoff or drought then the bug community may be negatively altered. Therefore, the diversity and quantity of the bugs in Gore Creek can be used as an indicator of overall creek health.



Why are bugs so important?

Bugs are a main food source and significant within the food-chain to larger animals like trout and birds. The structure of the bug community determines what is ‘on the menu’ and what isn’t. Trout are opportunistic feeders and will eat whatever is presently being ‘served’ but prefer a wide variety of choices. If there is less variety and certain bugs are not present, the trout population will be undernourished.

The Colorado Department of Public Health and Environment recently listed Gore Creek on the Clean Water Act’s 303(d) List as “provisionally impaired for aquatic life”. This means there is a lack of bug diversity, but the cause of impairment is not yet known. The State and the Town have 10 years to find out what the problem is. Though Gore creek is still considered a Gold Medal Water from Red Sandstone Creek to the junction with the Eagle River, the impairment includes all of Gore Creek through the Town of Vail.

Available Documents

The Gore Creek Water Quality Improvement Plan is complete! Download the full plan here.

Gore Creek Bug Buffet The Diners

There are five different types of fish that inhabit Gore Creek. Four of them are trout species and one is called a mottled sculpin. All these fish require cold, clean, and well oxygenated water to survive. Gore Creek is an ideal habitat for them to live.


troutCutthroat Trout

This is the only trout species native to Gore Creek. They are easily distinguishable by the red slash on their throat hence the name Cutthroat. Unfortunately they’ve been out-competed by other species of introduced trout and at one point they were close to extinction from habitat degradation and over fishing.  There is however a small population of Cutthroat trout still living in Gore Creek.  


Brook Trout

Brook TroutNative to the eastern part of the United States, Canada, and the Great Lakes, Brook Trout are the most prolific species of trout and have inhabited small creeks and high mountain lakes in Colorado since being introduced in 1872.



Rainbow Trout

Rainbow TroutIntroduced to Colorado in the late 1880’s, Rainbow Trout are native to the western coast of North America. They are recognizable by their pinkish/red stripe across the length of their body. Now the primary fish stocked in Colorado they are often a favorite of anglers due to their acrobatic fighting and tasty meat.


Brown Trout

Brown TroutIntroduced to Colorado in the 1890’s Brown Trout are originally from Europe and parts of Asia. Brown trout now thrive in Colorado’s rivers and lakes and have naturally sustaining populations. Gore Creek in particular is full of large browns.



Mottled Sculpin- The Daily Special

SculpinSculpin are native throughout North America and inhabit waters that are cold, clean and well oxygenated.  These fish are part of the menu because large trout will often prey on them for a big meal. They belong to the same order of fish species as the saltwater lionfish. Though they are typically under 6 inches, they have a very large mouth for eating aquatic bugs when hunting at night.



MidgesMidges are a diverse group of insects that are sometimes called gnats or true flies. Due to their small size lots of them must be consumed to satisfy a fish.
Often confused with mosquito's because of their similar appearance, midges don’t have the ability to bite, but can be a nuisance. They spend the majority of their life underwater and have adapted to live in many different types of environments. In their immature state they are often called bloodworms due to their worm like appearance and red coloration from hemoglobin like substance that allows them to breathe oxygen by absorbing it through their skin. This helps them survive in a wide variety of water conditions.  Once certain environmental conditions are met, they will emerge from their worm-like case and rise in the water column until they are at the surface. Then they will begin to swarm together and mate. Once they’ve completed mating they will lay their eggs back in the water and quickly die. Midges hatch year round and often make up a large portion of a trout diet.


Dragonflies/Damselflies - Weekly Special

DragonfliesThese predator insects can maneuver like a helicopter and have been estimated to be able to fly 30-60 miles per hour! They spend the first year or two of life underwater as predators of other aquatic insects.

Over that time they can shed their skin up to 15 times until they are ready to become adults. Once they are in their adult form they have a few weeks to live and in that time they keep busy by eating other flying insects like mosquito's , gnats, mayflies, caddis flies, and flying ants. Once they mate they return to the water to lay their eggs and sometimes end up as trout food.


Terrestrials- Late Summer Special

TerrestrialsTerrestrials are composed of a broad range of insects that originate and grow-up on the land, not the water. They are the late summer special because that is when they are most prevalent. 
Since they live on land and not in the creek, water quality does not affect their survival. Some common terrestrials are ants, beetles, grasshoppers, spiders, and moths. All can end up in the creek from storm runoff or blowing wind and end up in the stomach of a hungry trout.


Worms- Dessert

WormFrom earthworms to leeches, flatworms and sludge worms, worms are the staple bait for spin fisherman and a common food source for almost any kind of fish. (Learn more) Large populations of worms are often a sign of excess organic matter in a water body. They get their oxygen in a way similar to midge larvae by absorbing oxygen through their skin and can live in a wide variety of environments because of this.      


Mayfly- The Local’s Favorite

MayflyA staple food of trout and birds, mayflies spend almost all of their life as larva underwater clinging to bare rocks. They require cold, clean, and fast moving oxygenated water to survive.

In their larval state they breathe oxygen using external gills on their abdomen. During their time as larva, from a couple months to a year or two, they shed their skin multiple times until certain environmental conditions such as water or air temperature are met. Then they will rise up to the waters surface and molt again into their pre-adult form. Mayflies are the only insect to molt as a winged adult into their mature adult form. Thought to have the shortest adult lifespan of only a few hours to a day or two, mayfly adults only job is to mate and lack mouth parts and a digestive system, so they cannot eat as adults. They mate in the air above the water in large swarms, then they fly back to the surface of the water or actually dive under it to lay their eggs and die.


Stonefly-Monthly Special

StoneflyStoneflies are one of the largest aquatic bugs, some up to 2 inches, found in Gore Creek. They also hatch year around in all four seasons.
A stonefly larva is similar to a mayfly larva but can live up to 3 years underwater. It also has external gills but they are located in the thoracic part of the bug not the abdomen. Stoneflies shed their skin multiple times and once they are ready will crawl out of the water onto a rock or plant and shed a final time into their adult form. Stoneflies then will live as adults for a few weeks and in this time they will eat vegetation and other smaller insect. After they mate the females return to the water to lay their eggs and often get eaten in the process.


Caddis fly- Not being served

CaddisCaddis flies are a very unique aquatic bug that are similar to moths and butterflies in that they build a shell like cocoon out of twigs, pebbles, or leaves and will live in it for most of their life. Also some are similar to spiders and spin webs from rock to rock and traverse fast moving water. Cold, clean, and well oxygenated water is essential to their survival. (Learn More) Caddis larva can live under water for a year or two and once they are almost ready to become adults they will seal themselves into their shell and start the developing process. Once adults, they will rise to the surface of the water and fly into the nearby plants to eat and find a mate. Caddis usually hatch into their adult form in early summer and are a very important food source for the trout. Unfortunately Gore Creek’s caddis populations have been in decline over the past 10 years and are not found in the numbers that they need to be. 

Possible causes of problem

  1. Loss of riparian habitat
    The Riparian Habitat and is the land and plants along side the banks of a creek or river that provides critical functions related to habitat and water quality. These plants stabilize the stream bank, filter sediment, and provide food, cover and reproductive habitat for a variety of birds, insects and other animals.
  2.  Stream habitat disturbances
    Channelization (straightening) of rivers leads to faster water with higher erosive power. When natural flooding in the spring runoff occurs there are not enough curves in the stream to slow down the water and filter pollutants.
  3. Non-point sources
    Non-point source means the pollutant origin is not from one determinable source, but from many undeterminable sources across a large area. Storm water discharge of paved areas like streets, parking garages, and driveways pick up trash, motor oil, coolant, traction sand, etc. that will end up directly in the creek untreated.
  4.  Use of pesticides/herbicides/fertilizers
    Pesticides are engineered to kill bugs. When sprayed in windy conditions or close to the creek they end up in the creek, killing aquatic bugs. Herbicides are engineered to kill weeds. When used inappropriately, they end up in the creek, killing aquatic vegetation. Fertilizers are meant to give extra food to our lawns or gardens to encourage growth. When we use fertilizers on our lawn and it rains, extra fertilizers run off into the creek and fertilize the algae, making it grow in excess, which can be very bad!
  5. Didymo algae or “Rock Snot”
    An Invasive, slimy species of algae, Didymo takes up oxygen and coats rocks that bugs live on, causing the aquatic bug community structure to be altered. Due to their ability to breath through their skin, smaller bugs such as midges and worms adapt to the algae environment, but the favorites of trout; caddisflies, stoneflies and mayflies aren’t able to survive. The algae prevents the flies from gripping the rocks and blocks their gills from taking up oxygen.

What you can do to help save our creek

  1. Be aware of your input into the land and the creek and ask questions if you think something may impact the creek negatively.
  2. Save water and save money!
  3. Keep pollution out of the storm drains! All lead directly to the creek!
  • Use earth friendly landscaping.  Fertilize with natural fertilizers like compost, bone meal and kelp. 
  • Don’t spray pesticides or herbicides when its windy, and keep 50 feet back from the creek’s edge.
  • Keep your car properly maintained,  check your emissions regularly. 
  • Wash your car at a commercial car wash where water is treated and recycled.
  • Clean up after your pet! Bacteria like E. coli can end up in the stream if not picked up and disposed of properly.
    3) Carpool, walk, bike to places when possible. Sign up for the Sole Power Challenge at

To get your free Protect Gore Creek Packet, or for more information email, or call 970-477-3455 with questions. 

  • Documents to download

Documents to download