Difference between revisions of "FISHERY"

Data from a large-scale mark-recapture study was used in an open population model to determine the cause for long-term trends in growth and abundance of a Rainbow Trout Oncorhynchus mykiss population in the tailwater of Glen Canyon Dam, AZ. Reduced growth affected multiple life stages and processes causing negative feedbacks that regulated the abundance of the population, including: higher mortality of larger fish; lower rates of recruitment (young of year) in years when growth was reduced; and lower rates of sexual maturation the following year. High and steady flows during spring and summer of 2011 resulted in very large recruitment event. The population declined 10-fold by 2016 due a combination of lower recruitment and reduced survival of larger trout. Survival rates for trout ≥ 225 mm in 2014, 2015, and 2016 were 11%, 21%, and 22% lower than average survival rates between 2012 and 2013, respectively. Abundance at the end of the study would have been three- to five-fold higher had survival rates for larger trout remained at the elevated levels estimated for 2012 and 2013. Growth declined between 2012 and 2014 owing to reduced prey availability, which led to very poor fish condition by fall of 2014 (~0.9-0.95). Poor condition in turn resulted in low survival rates of larger fish during fall of 2014 and winter of 2015, which contributed to the population collapse. In Glen Canyon, large recruitment events driven by high flows can lead to increases in the population that cannot be sustained due to limitations in prey supply. In the absence of being able to regulate prey supply, flows which reduce the probability of large recruitment events can be used to avoid boom-and-bust population cycles. Our study demonstrates that mark-recapture is a very informative approach for understanding the dynamics of tailwater trout populations. [2]

• 2019 National Park Service Expanded Non-native Aquatic Species Management Plan
• 2016 Fish Protocol Evaluation Panel (PEP)
• 2015 State of Arizona Lees Ferry Fish Management Plan
• 2013 National Park Service Comprehensive Fisheries Management Plan
• GCMRC Annual Reports page
• Lees Ferry Anglers / Cliff Dwellers Lodge
• A local perspective on the Lees Ferry trout fishery by Terry Gunn, owner of Lees Ferry Anglers and Cliff Dwellers Lodge
• Lees Ferry Fishing Report
• AZGFD: Managing for Blue Ribbon Rainbow Trout at Lee's Ferry
• GCDAMP: Lees Ferry Recreational Trout Fishery Management Recommendations

• The Trout Ad Hoc Group Page
• Brown Trout Page
• Whirling Disease Page
• Humpback Chub Page
• Aquatic Foodbase Page
• Water Quality Page
• Nutrients Page

• Trout Management Flows (TMFs)
• Trout Reproductive and Growth Demographics (TRGD)
• Natal Origins Project (NO)
• Spring and Fall Lees Ferry Trout Monitoring and CREEL surveys
• Rainbow Trout Early Life Stage Study (RTELSS)
• Rainbow trout / humpback chub predation studies
• Trout Reduction Efforts
• Trout Stocking: Nov 2018 500 triploids stocked at the walk-in
• Bioenergetics Studies
• Rainbow Trout Individual Based Modeling (IBM)

• Status of the Lees Ferry Rainbow Trout Fishery 2017 Annual Report
• Status of the Lees Ferry Rainbow Trout Fishery 2014 Annual Report
• Status of the Lees Ferry Rainbow Trout Fishery 2010 Annual Report

2023

• Effects of the 2023 Spring HFE and Balancing Flows on Rainbow and Brown Trout in Glen Canyon
• Korman et al. 2023. Drought-related changes in water quality surpass effects of experimental flows on trout growth downstream of Lake Powell reservoir. Can. J. Fish. Aquat. Sci
• Yard et al., 2023, Declines in prey production during the collapse of a tailwater rainbow trout population are associated with changing reservoir conditions: Transactions of the American Fisheries Society
• Part I: Update on Rainbow and Brown Trout Growth, Abundance, and Recruitment in Glen Canyon (TRGD)
• Grand Canyon National Park Fisheries Program Updates, FY 2022

2022

• Rainbow/Brown Trout Growth Abundance Recruitment
• Lees Ferry Rainbow Trout Fishery-Status Update and Discussion of Threats
• Effects of Bug Flows, Fall HFEs, Competition, and Water Quality on Growth Rates of Rainbow Trout in Glen Canyon
• Fisheries review: Annual Reporting FY2021
• AZGFD Lees Ferry Monitoring Spring 2022 Update
• Reproductive structure of Rainbow and Brown Trout in Glen Canyon and advancing methods to assess spawning capability
• Population Dynamics of Rainbow (Oncorhynchus mykiss) and Brown (Salmo trutta) Trout in Glen Canyon
• Lees Ferry fishery

2021

• Lees Ferry Monitoring Update
• Dodrill et al. 2021, As the prey thickens—Rainbow trout select prey based upon width not length: Canadian Journal of Fisheries and Aquatic Sciences.
• Arizona Game & Fish – Lees Ferry Spring Monitoring – Trip Report
• GCDAMP Annual Reporting Meeting Update: Fishes
• Fish Populations and Aquatic Ecosystems in Lees Ferry through the Little Colorado River

2020

• Trout Recruitment, Growth and Population Dynamics
• GCMRC 2019 Annual Reporting Meeting Overview – Part 2a
• TRGD: Trout Recruitment, Growth and Population Dynamics

2019

• Long-term Monitoring

2018

• Biological Opinion for the Intra-Service Section 7 consultation to fund Lees Ferry rainbow trout stocking conducted by the Arizona Game and Fish Department
• Grand Canyon flood fattened fish, but it's not all good news on the Colorado River
• Dibble et al., 2018, Warm water temperatures and shifts in seasonality increase trout recruitment but only moderately decrease adult size in western North American tailwaters: Environmental Biology of Fishes
• Compliance Status for Stocking in Glen Canyon PPT
• Letter from Governor Val Panteah, Sr.'s Statement on Proposed Stocking of Rainbow Trout at Lees Ferry by Arizona Game and Fish Department to the AMWG dated February 14, 2018
• Turbidity as a management tool to constrain Rainbow Trout downstream of the Paria River PPT
• AGFD Lees Ferry long term monitoring
• Effects of HFEs on Growth and Population Dynamics of Rainbow Trout in Glen Canyon and Mable Canyon PPT

2017

• Korman et al., 2017, Trends in Rainbow Trout Recruitment, Abundance, Survival, and Growth during a Boom-and-Bust Cycle in a Tailwater Fishery, TAFS
• Dzul et al., 2017, Estimating disperser abundance using open population models that incorporate data from continuous detection PIT arrays, CJFAS
• Korman et al. 2017. Effects of environmental covariates and density on the catchability of fish populations and interpretation of catch per unit effort trends: Fisheries Research
• Lees Ferry Trout Fishery Status and PPT
• Lees Ferry Long Term Monitoring PPT
• Boom-and-Bust Cycles in the Population of Rainbow Trout in Glen Canyon and Effect of Fall High Flow Experiments PPT

2016

• Grand Canyon Monitoring and Research Center Science Updates (BO Compliance, Trout Updates, Green Sunfish, Fisheries PEP, Partners in Science)
• Bair et al. 2016 Economic Value of Angling on the Colorado River at Lees Ferry: Using Secondary Data to Estimate the Influence of Seasonality: North American Journal of Fisheries Management, no. 6, vo. 36, p. 1229-1239,
• Current Status of the Lees Ferry Fishery - Spring 2016
• Lees Ferry Recreational Trout Fishery Management Recommendations: The Voice of Lees Ferry Recreational Anglers, Guides, and Businesses
• Memo from Scott VanderKooi to TWG Chair Dated 12/9/15, Subject: Technical Review of the Lees Ferry Recreational Trout Fishery Management recommendations
• Long-Term Monitoring of the Lees Ferry Fishery: Update
• Economic value of angling on the Colorado River at Lees Ferry: Using secondary data to estimate the influence of seasonality

2015

• Korman et al. 2015. Factors Controlling the Abundance of Rainbow Trout in the Colorado River in Grand Canyon in a Reach Utilized by Endangered Humpback Chub. Canadian Journal of Fisheries and Aquatic Sciences
• Dibble et al. 2015. Flow management and fish density regulate salmonid recruitment and adult size in tailwaters across western North America
• Lees Ferry Recreational Trout Fishery Management Recommendations: The Voice of Lees Ferry Recreational Anglers, Guides, and Businesses
• GCMRC review of the Lees Ferry Anglers Trout Fishery Recommendations
• Management Prescription
• Mercury in Grand Canyon Trout
• GCMRC Science Update - Trout
• Potential Application of an Individual-Based Model to the Glen Canyon”
• Native and Nonnative Interactions; Factors Influencing Predation and Competition
• Glen Canyon Tailwater Fishery “Integrating Fish and Channel Mapping
• State of the Fishery Lees Ferry and Lees Ferry and Marble Canyon Rainbow Trout Update
• Lees Ferry Recreational Trout Fishery
• Lees Ferry Management Plan Update and handout

2014

• Modeling Long Term Effects of HFEs on Trout and HBC
• Context and Comparison: Status of Tailwater Fisheries in the Western United States

2013

• GCMRC Update - Status of Resources and Sediment Conditions
• Science Update: Fisheries
• GCMRC Science Update on Sediment and Fisheries
• Grand Canyon Rainbow Trout 2012 Monitoring Results
• Effects of Recent Flow Events on the Juvenile Rainbow Trout Population in Lees Ferry

2012

• Grand Canyon Monitoring and Research Updates
• GCMRC Updates and Sediment Update PPT
• Update on Native and Non-Native Fish Populations PPT
• GCMRC Updates and PPT
• Grand Canyon National Park Fishery Management Process and PPT
• 2011 Annual Report - Lees Ferry, Creel, and Mainstem Monitoring
• Salmonid Status and Trends. USGS Scientific Investigations Report 2011–5015
• SSQ-1-4

2011

• The Effects of Glen Canyon Dam Operations on Early Life Stages of Rainbow Trout in the Colorado River. USGS Fact Sheet
• Status and Trends of the Rainbow Trout Population in the Lees Ferry Reach of the Colorado River downstream from Glen Canyon Dam, Arizona, 1991–2009

2010

• Effects of High-Flow Experiments from Glen Canyon Dam on Abundance, Growth, and Survival Rates of Early Life Stages of Rainbow Trout in the Lees Ferry Reach of the Colorado River. USGS Open–File Report 2010–1034
• Rainbow Trout Abundance in the LCR Reach

2009

• AIF: Grand Canyon Monitoring and Research Center (GCMRC) Update
• AIF: Lees Ferry Trout Fishery Group Update
• Grand Canyon Monitoring and Research Center updates by Program Managers
• Preliminary data update on AGFD Mainstem Colorado River fish monitoring
• Effects of Hydropeaking on Nearshore Habitat Use and Growth of Age-0 Rainbow Trout in a Large Regulated River written by Josh Korman and Steve Campana
• Effects of Fish Size, Habitat, Flow, and Density on Capture Probabilities of Age-0 Rainbow Trout Estimated from Electrofishing at Discrete Sites in a Large River written by Josh Korman, et. al

2008

• The Natal Origins of Rainbow Trout in The Natal Origins of Rainbow Trout in Grand Canyon: Grand Canyon: A Lines of Evidence Review A Lines of Evidence Review

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.

In Bishop et al. (1987; on page 410 of the 30 page report: “Grand Canyon Recreation and Glen Canyon Dam Operations: An Economic Evaluation) fluctuating flows are defined as any operation where the daily flow fluctuation was equal to or more than 10,000 cfs/day. Bishop treated daily flow fluctuations of less than 10,000 cfs/day as “constant flow releases.” Bishop identified that this “10,000 cfs threshold was determined to be the point at which fluctuations begin to be perceptible to recreationists.”

Additionally, Stewart et al.’s (2000) follow-up of the Bishop et al. (1987) study found that angler’s did not identify river level fluctuations, at least under the MLFF operating regime, as an issue. Based on information from Stewart et al (2000) and Bishop et al. (1987), any flow fluctuation below 10,000 cfs/day should be treated the same as a steady flow release.

• The Stewart Report: Preferences of Recreation User Groups of the Colorado River in Grand Canyon. 2000
• The Bishop Study: Grand Canyon Recreation and Glen Canyon Dam Operations: An Economic Evaluation. 1987. pg 407-436
• File:1987 Bishop GCDam releases downstream rec analysis user pref.pdf

Nutrients released from GCD and trout competition appear to have a bigger effect on growth than fall HFEs [3]

The interaction of fish, foodbase, and temperature

Fish occupying warmer water have higher metabolic demands than individuals in cooler water, and if these demands increase concurrently with a seasonal decline in prey availability, then growth rates may be reduced. [4]

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  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.

• Arizona Game and Fish Wildlife Views article titled "Tight Lines at Lees Ferry". Published February 2012