Long-Term Experimental and Management 

Plan (LTEMP) Biological Opinion 

Conservation Measures Update 

Technical Work Group Meeting

January 22, 2021

Mike Moran and Scott VanderKooi

Southwest Biological Science Center

Grand Canyon Monitoring and 

Research Center

Kerri Pedersen

Bureau of Reclamation

Upper Colorado Basin
Incidental Take Parameters –

Tier 1 Action Initiation Triggers

TIER 1 – Early Intervention TRIGGER 2018 2019 2020 3-year 

average

1A. Combined adult (≥200 mm) humpback Chub 

(HBC) in the mainstem Little Colorado River (LCR) 

aggregation and LCR

≤ 9,000 15,000 12,000 11,000

OR

1B. Recruitment of sub-adult HBC (150-199 mm) 

does not equal or exceed estimated adult mortality

1) Sub-adult population estimate in LCR in spring* ≤ 1,250 for 

3 years 1,800 2,600 1,000* 1,800

OR

2) Sub-adult population estimates in mainstem in 

Juvenile Chub Monitoring (JCM) Reach in fall

≤ 810 for 3 

years

1,100 500 200 600

Model estimates for adults are rounded to the nearest 1,000 and to the nearest 100 for sub-adults.

*No estimate was obtained for sub-adults in LCR in spring 2020 due to COVID-19 restrictions. The 2020 

number was estimated by using data collected and abundance estimated from fall 2019.

Preliminary data, subject to revision, do not cite
Incidental Take Parameters –

Tier 2 Action Triggers

Tier 2 – Action Triggers TRIGGER 2018 2019 2020

Mechanical Removal implemented

If adult HBC (≥200 mm) as estimated by the 

HBC population model <7,000 N/A N/A N/A

Terminate Mechanical Removal 

If predator index is <60 rainbow trout/km 

in JCM reach - - -

and immigration rate is Low (to be determined) - - -

OR

HBC population estimates > 7,500 - - -

and survival rates of sub-adult chub exceeds adult mortality 

for at least 2 years - - -

Preliminary data, subject to revision, do not cite
Two-Tier Approach

 Tier 1 - emphasize conservation 

actions that take place during 

adult or sub-adult population 

declines.

 Tier 2 - predator removal if 

conservation actions unsuccessful.
Humpback Chub – Tier 1 Action Triggers

 If the combined point estimate for adult HBC (≥200 

mm) in the Colorado River mainstem-Little Colorado 

River (LCR) aggregation) and LCR <9,000

OR

 If recruitment of sub-adult HBC (150-199mm) ≤ 

estimated adult mortality such that:

 a) Sub-adult abundance <1,250 fish (3-yr average) in the 

spring LCR population estimates.

OR

 b) Sub-adult abundance <810 fish (3-yr average) in the fall 

mainstem Juvenile Chub Monitoring reach.
LTEMP -Tier 1 Trigger Response

1. LCR - Expand translocation actions in the LCR by collecting an additional 300-

600 young of the year (YOY) HBC and move to above Chute Falls in October.

2. LCR - Assess efficacy of transporting larval HBC (April/May) into Big Canyon 

and above Blue Springs in the LCR system. Evaluate growth and survival of 

these transplants.

3. Mainstem LCR Aggregation - Larval fish will be removed from LCR 

(April/May) and head-started at SNARRC. Once fish reach 150-200 mm they 

will be translocated to the mainstem LCR reach the following year (currently 

grow-out space at SNARRC is limited to 750 HBC, use of fish for this purpose 

would reduce numbers available for other actions, e.g. Havasu, Shinumo.);

4. Additional conservation actions as identified and evaluated.
Trigger Response & Next Steps

 Trigger met does not mean take was 

exceeded 

 Conservation actions implemented in 

the LCR or adjacent mainstem

 Next Steps

 Initial conversations with FWS

 Small group to discuss triggers & response

 5-year review of action triggers
Conservation Measures

Described in the 2016 LTEMP ROD and Biological Opinion

Resource Conservation Measures

Humpback chub

Translocations

Monitoring

Non-native fish removal

Refuge support

Disease & parasite monitoring

Razorback sucker Monitoring

All native aquatic species

Evaluate non-native fish management

Evaluate temperature control

Evaluate fish passage

Southwestern willow flycatcher Monitor every 2 years

Yuma Ridgway’s rail Monitor every 3 years
Humpback Chub

Conservation 

Measures

2020 Updates

Translocations 415 translocated to Bright Angel Creek

Monitoring 2 trips to Shinumo Creek (July, September)

1 trip to Havasu Creek (October)

Non-native fish removal 312 brown trout & 1,001 rainbow trout (electrofishing)

4 brown trout & 7 rainbow trout (weir)

Refuge Support Collections scheduled for spring 2020 cancelled 

HBC translocated fish to Bright Angel in June were reared 

by SNARRC (originally collected in LCR in 2019)

Disease & parasite 

monitoring

Monitoring for Asian fish tapeworm did not occur in 2020 

due to restricted access to the Little Colorado River on 

Navajo Nation lands 
Razorback Sucker

Conservation Measure 2020 Updates

Monitoring • Monitoring Trips in March (larval only), June, July (2), 

August, September (small-bodied only)

• No small-bodied razorback suckers

• 0 larval razorback suckers (but typically identified in 

April & May)

Other Species Identified on Monitoring Trips

Species # of 

Juveniles

# of 

Larvae

Bluehead Sucker 507 3,632

Flannelmouth 

Sucker

4,499 7,992

Humpback Chub 313 177

YOY Sucker 574 2,427

Bluegill 12 0

Brown Trout 1 0

Common Carp 1 0

Species # of 

Juveniles

# of 

Larvae

Fathead Minnow 425 459

Plains Killifish 347 3

Green Sunfish 33 17

Western 

Mosquitofish

49 28

Red Shiner 77 256

Rainbow Trout 33 15

Preliminary data, subject to revision, do not cite
All Native Aquatic Species

Conservation Measures 2020 Updates 

(Research & Development Office – Denver)

Evaluate fish passage Reclamation partnered with DOE Water-Power Technologies 

Office to launch fish protection prize.

1. Deal with the Devil Fish: Biometric Screen

2. Fish Diversion Materials & Inspection Improvement Coating

3. The Center Sender

https://americanmadechallenges.org/fishprotection/pitch.html

Evaluate temperature control (https://www.usbr.gov/tsc/techreferences/hydraulics_lab/pub

s/PAP/PAP-1184.pdf) 

Reclamation partnered with yet2 to complete a technology 

search to explore innovative water temperature control devices.

https://www.yet2.com/active-projects/exploring-watertemperature-control-devices/
Avian Surveys

Resource 2020 Updates

Southwestern Willow 

Flycatcher

No surveys planned or conducted 

– next survey planned for May & June 2021

Yuma Ridgway’s Rail No surveys planned or conducted 

– next survey planned for 2022
Questions?