Brown Trout telemetry at Lees 

Ferry and Grand Canyon, Arizona

Robert Schelly1, Brian Healy1, Clay Nelson2, 

Benjamin Vaage2, David Ward2, Brandon Albrecht3, 

Ron Kegerries3, Harrison Mohn3, Jan Boyer4

1 National Park Service, US Department of the Interior, Grand Canyon National Park, Flagstaff, AZ

2 U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, Flagstaff, AZ

3 Bio-West, Logan, Utah

4 Arizona Game and Fish Department, Research Branch, Flagstaff, AZ
Funded by Reclamation,

NPS, and GCA

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Grand 

Canyon 

Association 
• Brown Trout introduced as eyed eggs into Shinumo, Garden, and 

Bright Angel Creeks between 1926-34

• Glen Canyon Dam completed 1963, providing cold, clear tailwater

and downstream habitat suitable for trout

• Greater predation threat from Brown Trout than Rainbow Trout

• In recent decades, highest main-channel Brown Trout captures 

have centered on Bright Angel Creek

Joseph R. Tomelleri

AZGFD Monitoring, Speas et al. 2003

BAC, RM 88.3

2001 BNT catch 

rates, GRCA

History of Brown Trout in Grand Canyon:
AZGFD Monitoring, Rogowski et al. 2017

BNT

6 seasons of Bright Angel Creek trout removals: electrofishing and weir
Bright Angel Creek weir Brown Trout recaptures -

Movement

• small percentage of PIT tagged fish moved up to 92 mi 

0

2

4

6

8

10

12

14

16

18

20

Frequency of recaptured BNT

100

908070605040302010

0

102030405060 708090

100

Bright Angel

Creek

LCR Lees Ferry

DOWNSTREAM UPSTREAM

Movements of tagged BNT – 2002-2017, n=47

Miles from BAC

Source: PIT tag #’s cross-checked against GCMRC Master Database for original tagging information
Bright Angel Creek

RM 88.3

Little Colorado River

RM 61.7

Lees Ferry

RM 0
AZGFD preliminary results, prepared by Jan Boyer 

Recent increased captures of Brown 

Trout and observations of spawning

2017

Lees Ferry
Brown Trout telemetry project objectives:

• Gather data on movements and habitat preferences, both daily 

and seasonally, and better identify spawning period

• Identify periods of vulnerability and invulnerability to 

electrofishing (shallow nearshore vs. deep habitats)

• Improve understanding of rates of adult migration downstream 

from Lees Ferry

• Potentially identify new spawning aggregations
SUR (Submersible ultrasonic receiver)

passive tracking

Sonic tag

Towable

hydrophone

Manual tracking unit
• 10 Brown Trout implanted with dual sonic / RF tags on Feb 1, 2017 

at -4 mi bar (9 males, 1 female)

• 2 active telemetry passes/day for 1st week (boat with towable 

hydrophone from Glen Canyon Dam to Lees Ferry)

• Weekly passes for first month

• Monthly passes through present

Lees Ferry Brown Trout Telemetry Pilot Study

Expanded in winter 2017-2018

• 12/19/2017 – additional 14 Brown Trout tagged (4 males, 9 

females, 1 unknown)

• 1/9/2018 – additional 15 Brown Trout tagged (11 males, 4 females)

• Grand total of 39 fish tagged over 3 tagging events
Expanding SUR network: Lees Ferry, Marble Canyon, and Grand Canyon

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River Mila, 
Scan for PIT tag (fish with 

adipose clips might have just a 

PIT tag, or both a PIT tag and 

sonic tag. Surgery scars from 

February 2017 had healed) 
CO2 used to 

anesthetize fish
Incision
Stuff in sonic tag and

PIT tag
Suture, clip adipose

fin, and release
Results after year of tracking 10 fish:

• In the 2-3 months following Feb tagging, most contacts remained 

within ~1 mi up or downstream of -4 mi bar

• Utility of day / night telemetry passes reconsidered; hydrophone 

too imprecise to identify small movements

• Diminishing contacts through time

• Of initial 10 fish, 3 tags were found to have stopped transmitting 

upon recapture this season

• 2 fish were angled, and tags returned 

• 2 or 3 individuals spent summer months in deep, electrofishing 

invulnerable eddy at -2.5 mi (including the 1 female tagged in Feb)

• 2 outmigrations from Ferry, with detections again next season
Bright Angel Creek

RM 88.3

Little Colorado River

RM 61.7

Lees Ferry

RM 0

-4 mi spawning bar

Lees Ferry

0 mi
BNT 3148

Male
BNT 3148: Tagged 2/1/2017 Motionless from 2/5 Not dead! Contacted at Moved downstream 2/5 – 9/17, suspected mortality -4.2 mi on November 6 2017 – 2/9/2017
BNT 3148: Back downstream through Lees Ferry gate, 12:49 Next day, 12/3/2017, upstream through gate 06:53 Contacted at -4.3 mi again on 1/19/2018 -15:10 on 12/2/2017 -07:26
BNT 3085

Male
BNT 3085: Tagged 2/1/2017 Downstream migration past Ferry 2/6/2017

?

Upstream return past Ferry on 10/14/2017; contact at -4.2 mi on 11/6/2017
BNT 3085: Downstream past Ferry at 20:12 on 11/11/2017

?

?

Downstream past Ferry 20:38 Returned upstream 07:30 Upstream return between 02:47 -09:03 on 1/2/2018 -02:38 on 12/19 -03:05 on 11/12/2017 -20, 2017
BNT 3091

Male
BNT 3091: Downstream past Ferry at 19:37-21:00 on 2/22/2017

?

?

Upstream return at 20:32-20:53 on 10/12/2017
(very) Preliminary results of winter 2017-18 tagging:

• Many contacts still in vicinity of -4 mi bar (some signal 

interference), with 3 contacts further upstream, as far as -11.9 mi 

(unique #’s not obtained)

• 3 unique newly tagged fish detected on Lees Ferry SURs in late 

December – early January, all possible outmigration downstream

• Tagging events in December and early January fell earlier in 

spawning period, captured a more balanced female:male ratio

• Continuous expansion of Marble Canyon SUR network should help 

to precisely describe distance and timing of downstream 

movements
Questions?