Difference between revisions of "Brown Trout"

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! style="width=50%; background:#cedff2;" | [[File:RainbowTrout1.jpg]]<br> [http://www.azgfd.gov/h_f/fish_rainbow_trout.shtml Rainbow Trout]
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! style="width=50%; background:#cedff2;" | [[File:BrownTrout1.jpg*]]<br> [http://www.azgfd.gov/h_f/fish_brown_trout.shtml Brown Trout]
 
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Revision as of 09:45, 7 November 2016

BrownTrout LCR NO 2013.JPG Brown trout caught at the LCR during the 2013 summer Natal Origins trip

Brown Trout

Brown trout are native to Europe and were introduce to tributaries in the Grand Canyon in the 1920s. They are capable of withstanding slightly higher temperature than other trout. Unlike most other trout species, brown trout spawn in the late fall. Their spawning behavior, however, is similar to other trout species. Like rainbow trout, young brown trout feed on aquatic and terrestrial insects and invertebrates but brown trout are more apt to switch to eating other fish as they get bigger. The rainbow trout found in Grand Canyon are more likely to continue to eat mostly insects and invertebrates even as adults. Many studies have shown that rainbow trout and native fish like humpback chub often have a difficult time persisting with large populations of brown trout.[1]

Desired Future Condition for the Lees Ferry Trout Fishery

A high quality trout fishery in GCNRA, as further described in the Recreation DFC that does not adversely affect the native aquatic community in GCNP.
• Minimize emigration of non-native fish from the Lees Ferry reach in Glen Canyon National Recreation Area to downstream locations.
• Minimize emigration of non-native warm water fish to the mainstem Colorado River.

File:RainbowTrout1.jpg*
Rainbow Trout 		File:BrownTrout1.jpg*
Brown Trout

Updates

BrownTrouSizetLeesFerry USGS2016.jpg
BrownTroutLeesFerry USGS2016.jpg
BrownTroutLeesFerry.jpg
BrownTroutLeesFerry2.jpg

Brown trout numbers during AZGFD monitoring in the Lees Ferry reach.

RBT BT piscivory.jpg

Brown trout are much more likely to eat other fish (piscivory) but since there are many more rainbow trout in the Colorado River between Glen and Marble Canyons, rainbow trout probably eat more fish numerically than brown trout.

An increasing brown trout population could, however, pose a problem for both the rainbow trout fishery in Glen Canyon and native fish in Grand Canyon because brown trout eat both rainbow trout and native fish alike.

BrownTrout FGD2016.jpg

A brown trout collected during 2016 trout monitoring below Flaming Gorge dam that had eaten a 10" stocked rainbow trout.

Information and Links

Questions

  • Why are brown trout increasing in the Lees Ferry reach?
  • When do brown trout spawn in Lees Ferry? Ans: Nov-Dec
  • Could delaying a fall HFE to late November be effective in disrupting the brown trout spawn?
  • Do fall HFEs bring more brown trout upstream into the Lees Ferry reach to spawn?
  • Has the decrease in the rainbow trout population allowed for increased brown trout spawning in the Lees Ferry reach because of decreased competition for spawning area and decreased egg predation?

Presentations and Papers

2016

2013

2011

Other Stuff

Brown trout tend to grow faster and be more aggressive than rainbow and brook trout, so they outcompete the rainbows and the brooks for limited resources. When they get big enough, brown trout are known to prey directly on smaller trout... [2]

"The divergent responses of brown trout and rainbow trout populations to the summer flood could be explained by competitive interactions. Brown trout are autumn spawners, whereas rainbow trout are spring spawners, and thus, YOY brown trout emerge earlier, are larger and may outcompete YOY rainbow trout (Gatz, Sale & Loar, 1987; Strange et al., 1992 ). Conversely , the autumn spawning of brown trout increases the risk of egg loss if autumn or winter floods occur. Several investigations showed that YOY brown trout or brook trout were generally more numerous than YOY rainbow trout except during years when floods scoured the eggs of the autumn spawners (Seegrist & Gard, 1972; Strange et al., 1992; Warren et al., 2009 ). " [3]

Spearfish Creek offers some of the best fishing in the Black Hills. Well known for its ample brown, rainbow and even brook trout, the stream, with its clear, cool waters is the destination of many anglers year-round. But with 2,000 to 4,000 fish per mile, the size of the fish may not be as large as in other area creeks. So, the South Dakota Game, Fish and Parks removed approximately 3,000 brown trout this summer in hopes of enhancing the size of the fish... Davis said the rainbow trout population is also ample, but sizes also are smaller than in other streams. He said he hopes removing some of the brown trout will give the rainbows a boost in size as well. Davis said brown trout are generally more aggressive and will outcompete a rainbow population. [4]

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