Difference between revisions of "Brown Trout"

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[[File:BrownTrout LCR NO 2013.JPG]] Brown trout caught at the LCR during the [https://goo.gl/photos/zRQzx2eLdFB6ZsWp8 2013 summer Natal Origins trip ]
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[[File:BrownTrout LCR NO 2013.JPG|center|500px]] Brown trout caught at the LCR during the [https://goo.gl/photos/zRQzx2eLdFB6ZsWp8 2013 summer Natal Origins trip ]
 
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[http://web.b.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=17986540&AN=97363287&h=a4WVC6zWlS7kfpE47mLeQaiZ8uWspeW63uKCHkuB8CkvQ3%2bFuE9%2b%2ba3hTiNYXRqSiD0l3Mjh7Spx84R7APtC1g%3d%3d&crl=c&resultNs=AdminWebAuth&resultLocal=ErrCrlNotAuth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d17986540%26AN%3d97363287 Hasegawa, K., N. Ishiyama, H. Kawai. 2014. Replacement of nonnative rainbow trout by nonnative brown trout in the Chitose River system, Hokkaido, northern Japan. Aquatic Invasions. Vol. 9 Issue 2, p221-226. 6p.]
+
A telemetry study aimed to document the mobility of brown trout in the River Ourthe sub-basin (tributary of the River Meuse) during summer and autumn, and to analyse the environmental factors which trigger spawning migration or limit their extension. Both in the River Ourthe and in the Aisne stream, '''all migrations started within less than three weeks (early October) and were found to be triggered by the combination of three environmental factors: high variations of water temperature and water level between consecutive days, within a thermal range of 10–12 °C.''' From the trout point’s of view, these may be signs that the environment becomes unpredictable, as its variability increases within a thermal range which no longer enables them to achieve high growth rates. These results are discussed within the context of foraging strategies, life history strategies and management of trout population. M. Ovidio, E. Baras, D. Goffaux, C. Birtles, J. C. Philippart [https://link.springer.com/chapter/10.1007%2F978-94-011-5090-3_30 Environmental unpredictability rules the autumn migration of brown trout (Salmo trutta L.) in the Belgian Ardennes] Advances in Invertebrates and Fish Telemetry, Volume 130 of the series Developments in Hydrobiology pp 263-274
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[http://web.b.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=17986540&AN=97363287&h=a4WVC6zWlS7kfpE47mLeQaiZ8uWspeW63uKCHkuB8CkvQ3%2bFuE9%2b%2ba3hTiNYXRqSiD0l3Mjh7Spx84R7APtC1g%3d%3d&crl=c&resultNs=AdminWebAuth&resultLocal=ErrCrlNotAuth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d17986540%26AN%3d97363287 Hasegawa, K., N. Ishiyama, H. Kawai. 2014. '''Replacement of nonnative rainbow trout by nonnative brown trout''' in the Chitose River system, Hokkaido, northern Japan. Aquatic Invasions. Vol. 9 Issue 2, p221-226. 6p.]
 
   
 
   
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Study showing that late summer floods may be advantageous for brown trout recruitment. [https://www.researchgate.net/publication/291522945_Effects_of_extreme_floods_on_trout_populations_and_fish_communities_in_a_Catskill_Mountain_river S.D. George, B.P. Baldigo, A.J. Smith, and G.R. Robinson. 2016. Effects of extreme floods on trout populations and fish communities in a Catskill Mountain river. Freshwater Biology.]  
+
Study showing that '''late summer floods may be advantageous for brown trout recruitment.''' [https://www.researchgate.net/publication/291522945_Effects_of_extreme_floods_on_trout_populations_and_fish_communities_in_a_Catskill_Mountain_river S.D. George, B.P. Baldigo, A.J. Smith, and G.R. Robinson. 2016. Effects of extreme floods on trout populations and fish communities in a Catskill Mountain river. Freshwater Biology.]  
  
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"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 ). " [https://www.researchgate.net/publication/291522945_Effects_of_extreme_floods_on_trout_populations_and_fish_communities_in_a_Catskill_Mountain_river]
+
"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 ). " [https://www.researchgate.net/publication/291522945_Effects_of_extreme_floods_on_trout_populations_and_fish_communities_in_a_Catskill_Mountain_river]
  
 
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Revision as of 10:22, 21 March 2017

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 introduced to tributaries in the Grand Canyon in the 1920s. They are capable of withstanding slightly higher temperature than rainbow 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. [1] (2) Studies have shown that rainbow trout and native fish like humpback chub often have a difficult time persisting in the presence of a large population of brown trout. [2] [3] [4]

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

Action requested. Proposed draft motion AMWG meeting 2/15/17:

The AMWG believes that before moving forward with any new actions to manage brown trout (BT) in the Lees Ferry reach of the Colorado River, it would be beneficial to work to develop a plan based on the most up to date information and that has involvement from interested members of the AMWG. Accordingly, the AMWG requests that the Secretary of the Interior direct the National Park Service, and request the Arizona Game and Fish Department, to organize and facilitate a workshop among scientists, managers, tribes, and interested stakeholders to address:

  1. The root causes of the increases in BT,
  2. The risks associated with an expanding BT population to a quality rainbow trout fishery in Lees Ferry and the recovery/conservation of humpback chub and other native fish down river,
  3. The pros and cons of different management options to address those risks, and
  4. The research needs to support more informed decisions moving forward.

The workshop should also review the efficacy of the current High Flow Experiment protocol in light of new scientific information and how it could be modified to allow for more frequent Spring HFEs to conserve sediment and enhance biological resources in the Colorado River below Glen Canyon dam. Results from the workshop, and any recommended actions based on them, should be reported to the TWG for consideration in development of the Triennial Work Plan and presented to the AMWG at the August 2017 meeting.

BrownTrouSizetLeesFerry USGS2016.jpg
[5]
BrownTroutLeesFerry USGS2016.jpg
[6]
BrownTroutLeesFerry.jpg
[7]
BrownTroutLeesFerry2.jpg
[8]
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.[9]

BrownTrout FGD2016.jpg

An increasing brown trout population in Glen Canyon could pose a problem for both the Lees Ferry rainbow trout fishery and native fish in Grand Canyon because brown trout eat both rainbow trout and native fish alike. Above is a photo of a brown trout collected during 2016 trout monitoring below Flaming Gorge dam that had just eaten a 10" stocked rainbow trout.

Information and Links

Stakeholder Concerns

  1. the root causes of the increases in BT,
  2. the risks associated with an expanding BT population to a quality RBT fishery in Lees Ferry and the recovery/conservation of humpback chub and other native fish down river,
  3. the pros and cons of different management options to address those risks, and
  4. the research needs to support more informed decisions moving forward.

Questions

  • Why are brown trout increasing in the Lees Ferry reach?
  • Has the recent (winter 2014-15) 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/or decreased egg predation by rainbow trout? If so, what caused the decrease in the rainbow trout population and what can be done in the future to avoid this from happening?
  • Are increased numbers of brown trout in Lees Ferry a product of higher release temperatures?
  • Do fall HFEs clean spawning substrate in the Lees Ferry reach leading to increased the spawning success of brown trout during their fall spawning season?
  • Do fall HFEs increase the upstream migration of brown trout from other parts of the canyon resulting in more brown trout spawning in the Lees Ferry reach?
  • Could delaying a fall HFE to late November be effective in disrupting the brown trout spawn? When do brown trout spawn in Lees Ferry? Ans: Nov-Dec
  • Irregardless of the cause, what should we do about the increasing brown trout population currently found in the Lees Ferry reach?

Presentations and Papers

2017

2016

2014

2013

2011

Other Stuff

A telemetry study aimed to document the mobility of brown trout in the River Ourthe sub-basin (tributary of the River Meuse) during summer and autumn, and to analyse the environmental factors which trigger spawning migration or limit their extension. Both in the River Ourthe and in the Aisne stream, all migrations started within less than three weeks (early October) and were found to be triggered by the combination of three environmental factors: high variations of water temperature and water level between consecutive days, within a thermal range of 10–12 °C. From the trout point’s of view, these may be signs that the environment becomes unpredictable, as its variability increases within a thermal range which no longer enables them to achieve high growth rates. These results are discussed within the context of foraging strategies, life history strategies and management of trout population. M. Ovidio, E. Baras, D. Goffaux, C. Birtles, J. C. Philippart Environmental unpredictability rules the autumn migration of brown trout (Salmo trutta L.) in the Belgian Ardennes Advances in Invertebrates and Fish Telemetry, Volume 130 of the series Developments in Hydrobiology pp 263-274


Hasegawa, K., N. Ishiyama, H. Kawai. 2014. Replacement of nonnative rainbow trout by nonnative brown trout in the Chitose River system, Hokkaido, northern Japan. Aquatic Invasions. Vol. 9 Issue 2, p221-226. 6p.

Study showing that late summer floods may be advantageous for brown trout recruitment. S.D. George, B.P. Baldigo, A.J. Smith, and G.R. Robinson. 2016. Effects of extreme floods on trout populations and fish communities in a Catskill Mountain river. Freshwater Biology.

"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 ). " [10]

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