Difference between revisions of "FISHERY"

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! <h2 style="margin:0; background:#cedff2; font-size:120%; font-weight:bold; border:1px solid #a3b0bf; text-align:left; color:#000; padding:0.2em 0.4em;"> [[Media:Appendix D Final Chub Triggers 2017.pdf| LTEMP BiOp Triggers for Trout Removals at the LCR (LTEMP BA Appendix D)]] </h2>
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=== '''Tier 1 Trigger – Early Intervention Through Conservation Actions:''' ===
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*1a. If the combined point estimate for adult HBC (adults defined ≥200 mm) in the Colorado River mainstem LCR aggregation; RM 57-65.9) and Little Colorado River (LCR) falls below 9,000 as estimated by the currently accepted HBC population model (e.g., ASMR, multi-state).
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-OR-
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*1b. If recruitment of sub-adult HBC (150-199mm) does not equal or exceed estimated adult mortality such that:
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# Sub-adult abundance falls below a three-year running average of 1,250 fish in the spring LCR population estimates, or
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# Sub-adult abundance falls below a three-year running average of 810 fish in the mainstem Juvenile Chub Monitoring reach (JCM annual fall population estimate; RM 63.45-65.2).
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Tier 1 Trigger Response:
 +
*Tier 1 conservation actions listed below will be immediately implemented either in the LCR or in the adjacent mainstem. Conservation actions will focus on increasing growth, survival and distribution of HBC in the LCR & LCR mainstem aggregation area.
 +
 +
=== '''Tier 2 Trigger - Reduce threat using mechanical removal if conservation actions in Tier 1 are insufficient to arrest a population decline:''' ===
 +
Mechanical removal of nonnative aquatic predator will ensue:
 +
*If the point abundance estimate of adult HBC decline to <7,000, as estimated by the currently accepted HBC population model.
 +
 +
Mechanical removal will terminate if:
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*Predator index (described below) is depleted to less than 60 RBT/km for at least two years in the JCM reach and immigration rate is low (the long term feasibility of using immigration rates as a metric still needs to be assessed),
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-OR-
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*Adult HBC population estimates exceed 7,500 and recruitment of sub-adult chub exceed adult mortality for at least two years.
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[[File:PredatorIndexTable.jpg|center|500px]]
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If immigration rate of predators into JCM reach is high, mechanical removal may need to continue. These triggers are intended to be adaptive based on ongoing and future research (e.g., Lees Ferry recruitment and emigration dynamics, effects of trout suppression flows, effects of Paria River turbidity inputs on predator survival and immigration rates, interactions between humpback chub and rainbow trout, other predation studies).
  
 
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Revision as of 13:31, 21 March 2017

GlenCanyonTrout.jpg

The Lees Ferry Rainbow Trout Fishery

In 1964, the Lees Ferry tailrace on the Colorado River was given birth by the completion of Glen Canyon Dam, which impounded Lake Powell. Subsequent water releases from the bottom of Lake Powell changed the once highly turbid, warm waters of the Colorado River into a constant cold (46-50°F), clear flowing river. Shortly after completion of the dam, the Arizona Game and Fish Department stocked rainbow trout (Oncorhynchus mykiss) in the 15-mile Lees Ferry reach and, in 1981, began to manage this section of river as a Blue Ribbon rainbow trout fishery. The trout began to flourish in the Lees Ferry reach from 1970-1985 when catches of rainbow trout above 10-pounds were not uncommon, and angler pressure was relatively low. In 1991, however, the Bureau of Reclamation implemented the Record of Decision flow regime, which consisted of higher minimum and more stable flows and allowed for increased trout reproduction and survival. Under these conditions, a huge population of trout developed causing individual fish growth rates to decline. Quite simply, there was a large number of fish competing for limited space and food items, resulting in a fishery where trout less than 14-in were dominant.

In 2000, the Arizona Game and Fish Department began a long-term monitoring program sponsored by Grand Canyon Monitoring and Research Center to determine the effects of Glen Canyon Dam operation on the trout fishery at Lees Ferry and to make recommendations for improving this fishery. Since 2000, our data collection has shown an increase in the general health of all trout age classes (especially since 2002). This increase in fish health is usually associated with an increase in growth rates. There has been a marked increase in catch rates of young-of-the-year fish in recent years. With successful spawning and recruitment continuing to occur, fishing conditions in Lees Ferry are improving. [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

RT cpue 2016.jpg
[2]
RTjuvi cpue 2016b.jpg
[3]
RTjuvi cpue 2016.jpg
[4]
RT LFreq 2016.jpg
[5]
RT condition 2016.jpg
[6]
RT Anglercpue 2016.jpg
[7]
RT AnglerSat 2016.jpg
[8]
RT AnglerUse 2016.jpg
[9]
NO TroutAbundances2016.jpg
[10]


TroutFlows.jpg


RBT BT piscivory.jpg


TroutRemoval.jpg

Links and Information

Presentations and Papers

2017

2016

2015

2014

2013

2011

Lees Ferry Fishing Report

The river is a living creature. Just because you caught fish in a certain spot in years past, don’t think that you are going to experience the same success this year. Fishing is changing daily. It is our goal and desire that everyone have a great trip to the Ferry. Be sure to stop by the shop to see the flies that are currently working. The flies change on a daily basis and every day LFA guides let everyone at the shop know the top producing flies and how to use them. We are anxious to share this knowledge with you – even where to fish!

There is an ongoing aquatic food base study that has taken place over the past couple of years. The purpose of this study is multifaceted and is studying the relationship of flows on food production, taking inventories of and monitoring populations of aquatic insects and invertebrates that live in the river and other very important aspects of the aquatic food base. I believe that this is by far the most important study that has ever been conducted on this river. Previously, hundreds of millions of dollars have been spent studying sediment while ignoring the aquatic food base and resource. Common sense dictates that fish, birds and animals do not live off of dirt or sand. The aquatic food base and habitat are the foundation for all that lives in the Colorado River. One of the long term goals of the food base study is to determine how to enhance the populations and production of aquatic insects in the river which will benefit native fish, trout, and migratory bird populations. This is a study and a goal that we can all embrace!

Quagga mussels have become established in Lake Powell and we are now seeing some in the river below the dam. Their arrival in the river happened sooner than I expected. So far, there has not been a major infestation and there is some thought by experts that they will not become very well established in the river due to the current. Be aware and remember to dry waders and boots before using them in any other body of water. Also, all private boats should drain all water from the boat and live-wells as soon as you exit the river. We all need to do our part to limit the transport of this and all invasive species.

LTEMP BiOp Triggers for Trout Removals at the LCR (LTEMP BA Appendix D)

Tier 1 Trigger – Early Intervention Through Conservation Actions:

  • 1a. If the combined point estimate for adult HBC (adults defined ≥200 mm) in the Colorado River mainstem LCR aggregation; RM 57-65.9) and Little Colorado River (LCR) falls below 9,000 as estimated by the currently accepted HBC population model (e.g., ASMR, multi-state).

-OR-

  • 1b. If recruitment of sub-adult HBC (150-199mm) does not equal or exceed estimated adult mortality such that:
  1. Sub-adult abundance falls below a three-year running average of 1,250 fish in the spring LCR population estimates, or
  2. Sub-adult abundance falls below a three-year running average of 810 fish in the mainstem Juvenile Chub Monitoring reach (JCM annual fall population estimate; RM 63.45-65.2).

Tier 1 Trigger Response:

  • Tier 1 conservation actions listed below will be immediately implemented either in the LCR or in the adjacent mainstem. Conservation actions will focus on increasing growth, survival and distribution of HBC in the LCR & LCR mainstem aggregation area.

Tier 2 Trigger - Reduce threat using mechanical removal if conservation actions in Tier 1 are insufficient to arrest a population decline:

Mechanical removal of nonnative aquatic predator will ensue:

  • If the point abundance estimate of adult HBC decline to <7,000, as estimated by the currently accepted HBC population model.

Mechanical removal will terminate if:

  • Predator index (described below) is depleted to less than 60 RBT/km for at least two years in the JCM reach and immigration rate is low (the long term feasibility of using immigration rates as a metric still needs to be assessed),

-OR-

  • Adult HBC population estimates exceed 7,500 and recruitment of sub-adult chub exceed adult mortality for at least two years.
PredatorIndexTable.jpg

If immigration rate of predators into JCM reach is high, mechanical removal may need to continue. These triggers are intended to be adaptive based on ongoing and future research (e.g., Lees Ferry recruitment and emigration dynamics, effects of trout suppression flows, effects of Paria River turbidity inputs on predator survival and immigration rates, interactions between humpback chub and rainbow trout, other predation studies).

Other Stuff

Vermillion Video- Fishing.jpg

Vermillion: Highlights the passion the fishing community has for the Glen Canyon fishery and their love of not only the fishing experience but for the TOTAL experience. VIDEO LINK
040513 AZGF- Fishing Pic.jpg
Arizona Game and Fish Wildlife Views Article titled "Tight Lines at Lees Ferry". Published February 2012




Quick Facts

Visitor Use and Experience

  • Visitor Experience as it relates to fisheries, include opportunities to fish for rainbow trout in GCNRA's Glen Canyon Reach, which has been referred to as Blue Ribbon by the State of Arizona, and to fish for rainbow and brown trout and a variety of non-native introduced fish species in the main stem Colrado River and some tributaries in GCNP. Most angling in GCNP occurs in or near Bright Angle Creek and Phantom Ranch, particularly in fall and spring (NPS 2006c)

HISTORY

  • In 1991 the Arizona Game and Fish stocked large trout instead of fingerling trout to maintain the Lees Ferry trout sport fishery (090711_Minority Report to TWG_FFF_Mark Steffen)


Additional Links



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