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 Glen Canyon Dam Technical Work Group 

Agenda Item Information 

October 28-29, 2014 

Agenda Item 

New Information on Razorback Sucker in Western Grand Canyon and Lake Powell 

Action Requested 

Information item only 

Presenter 

Glen Knowles, Bureau of Reclamation (Reclamation) 

Previous Action Taken 

n/a 

Relevant Science 

Current efforts build on prior science in the GCDAMP, the Lower Colorado River Multi-Species 

Conservation Program, and the San Juan River and Upper Colorado River Recovery Programs. 

In the fall of 2010, Reclamation convened a science panel and conducted a comprehensive 

evaluation of razorback sucker habitat primarily to assess the suitability of habitat in lower Grand 

Canyon and the Lake Mead inflow. This undertaking was in collaboration with the USFWS, 

GCDAMP, Lower Colorado River Multi-Species Conservation Program (MSCP), NPS, GCMRC, 

Nevada Department of Wildlife (NDOW), and the Hualapai Tribe. A razorback sucker 

augmentation plan was completed in 2011 as a result of the science panel evaluation. 

Science and research completed since the GCDMP was established will be used in the development 

of the EIS and assessment of impacts. 

Background Information 

Lower Grand Canyon: A newly initiated contract was executed early in 2014 with BioWest and 

ASIR, funded by Reclamation and administered by NPS, and with the cooperation of the U.S. Fish 

and Wildlife Service, Lower Colorado River Multi-Species Conservation Program, Nevada 

Department of Wildlife, Arizona Game and Fish Department, and the Hualapai Tribe. This work, a 

component of the Grand Canyon National Park’s Comprehensive Fisheries Management Plan, has 

already yielded surprising findings regarding the razorback sucker. The study area is from Lava Falls 

Rapid downstream to the Lake Mead inflow area, and 2-3 miles out into the lake. In Lake Mead, 

current efforts continue on studies initiated in 1996. Lake Mead has been known to have recruiting 

populations in 4 areas, and the first larvae were found in 2000. Work upstream to Lava Falls began 

in March 2014, and initial fish collections began in April 2014. The April samples yielded more than 

350 larval razorback suckers at 21 of 47 sites sampled. Samples from May through July are yet to be 

fully analyzed, but initial reports showed a dramatic increase in larvae in June and July. 

Lake Powell: Work in Lake Powell began in 2011 at the San Juan River inflow, and in 2014, a 

second study area at the Colorado River inflow was established. In 2011 and 2012, despite large 

stocking programs for the razorback sucker upstream in both the San Juan and Colorado Rivers, 

36% of captures at the San Juan arm were without PIT tags, and their ages ranged from 4 to 19 
RBS, continued 

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years. These captures were in the lake proper, and 8 fish were observed to move upstream during a 

two week period in 2012. One larval fish was also collected. 

During the high water year of 2011, the San Juan River waterfall was inundated for two weeks, 

during which time 10% of marked fish moved upstream into the river. Some moved over 150 miles 

upstream. In 2014, 241 individual razorbacks were captured between the Colorado River inflow 

area and Good Hope Bay, and many fish were in reproductive condition. Percentage of PIT-tagged 

fish was about 8%, lower than the San Juan Arm. 
RAZORBACK SUCKER IN LAKE M

LOWER GRAND CANYON AND 

POWELL—WHAT’S NEW
1) Background on razorback sucker

2) Overview of work in Lake Mead an

Powell—Bio-West, ASIR, USFWS, DWR

3) Findings in Lower Grand Canyon4) Findings in Lake Powell5) Questions and discussion—5-10 m

Outline
Overview Razorback Sucke

• Listed ESA 1991• Critical Habitat

designated 1994

• Recovery plan 1998

• Recovery goals 2002

• Recovery Goals req

populations in upp

(Green River and U

Colorado River OR 

River), and two poin the lower Basin specified where)
Study Areas

Lower Grand Canyonand Lake Mead Inflow

Co

Lak

San Lak
Review of Biological Opinions for R

Grand Canyon

• 1995 BiOp (Reclamation, Operation of Glen Ca

Dam)— “sponsor a workshop, develop a mana

plan for RBS in Grand Canyon.”

• 2006 BiOp (NPS‐Colorado River Management P

“...conduct surveys in the Lower Gorge‐Lake M

interface for spawning razorback suckers...”

• 2008 BiOp (Reclamation, Shortages and Coordi

Reservoir Operations)—“...examine the potent

habitat in the lower Grand Canyon for RBS 

institute an augmentation program in collabora

with FWS, if appropriate.”
What is Lower Grand Canyo

Lava Falls (RM 179.5)

South Cove*

*

Current inflow area (~RM 293)

W

Diamond C

Full Pool Lake Mead (~RM 240)

Pearce Ferry (RM 280) *

Quartermaster (RM 260) *

Spencer Crk. (RM 246) *
Lake Mead

Study Area

CIn
Overview of RBS in Lake M

• 18 years of study (1996-2014)• 108 sonic-tagged individuals in Lake Mead • 1,317 total individuals captured • 860 unique individuals • 4 areas of known, established reproduction in 

Mead (Las Vegas Bay, Echo Bay, Overton ArColorado River Inflow)

• 492 individuals aged, 2-36 years old• 2014 Lake-wide population estimate 590 (CI 

873) 

• Only documented population of recruiting fis

Colorado River Basin

Data courtesy Brandon Albrecht and Ron Kegerries, Bio-West
RBS Records From Colorado Ri

Inflow Area of Lake Mead 2000‐

• 2000 and 2001—larvae found• 2008—adult in Gregg Basin (near CRI)

• 2010—3 untagged (wild) adults captured, 

• 2011—7 untagged (wild) adults, 8 recaps, 

larvae

• 2012—13 untagged (wild) adults, 13 recap

Larvae, 2 fish moved upstream to Quarteor beyond, 3 fish moved up past Pearce Fewild fish (male, ripe) captured at Spencer 

Data courtesy Brandon Albrecht and Ron Kegerries, Bio-West
Current Work—2014>

• Study area is downstream of Lava Falls/W

Wash to Colorado River Inflow area

• Larval and small-bodied fish sampling

– Larval fish community (what is spawning?)

• composition, timing, abundance, location, period

– Small-bodied fish community

• composition, relative numbers, habitats

• Sonic telemetry (captive adult fish-’Judas• Trammel netting• Continued monitoring at Colorado River 

area
Results (so far) of sampling in Lo

Grand Canyon

• All sonic sensors installed by March 2014; Monthly s

larval fish started in April.

• Nine sonic‐tagged fish released @ Lava Falls March 1

• April sampling = > 350 larval razorback suckers ident

of 47 sites sampled, river miles 191 to 279 (widely diSamples from May to September still need to be com

• Sonic‐tagged fish detected from Lava Falls downstrea

multiple locations and include fish from 2010 tagging

• 75 unmarked, juvenile humpback chub from river m

275, and larval HBC

• LOTS of native sucker larvae, Larval fish increased dr

June and July

Data courtesy Brandon Albrecht and Ron Kegerries, Bio-West; Howard Brandenburg, Judith Barkstedt , ASIR
Lake Powell Study Areas 2011‐

Colorado RiverInflow

San Juan RiverInflow

Sw

Inflow area
• San Juan River Inflow 2011-2012

– Large stocking program for RBS upstream in both Sa

Colorado rivers, BUT 53/148 (36%) captured withou2011-2012 in San Juan inflow (Recruitment??)

– One RBS Larvae (Reproduction)– Age of fish 4 to19 years old– RBS captured in Lake portion of inflow– 8 fish moved upstream (up to 200 miles) of waterfall 

week period in 2012

– Fish movement from Farmington, NM to Grand Valle

(through Lake Powell)

– 25 Colorado pikeminnow (usually poor condition)

• Colorado River Inflow 2014

– > 250 individual razorbacks captured– Four (4) bonytail-1 spawning– Two Colorado pikeminnow (poor condition)

Key Findings Lake Powell
Lake Powell Habitat
San Juan River Waterfall 2008 vs 

8 fish (of 4tagged in moved in 

a two wee

upstream waterfall, 

200 miles 
Acknowledgements

Lake