Glen Canyon Reach – 

Glen Canyon NRA

Update

• Electrofishing

• Netting

• Water

Temperatures
Glen Canyon Reach – Glen Canyon NRA 

Lees Ferry 

Glen Canyon Dam 

Slough 
Electrofishing Effort - 2023 

Reach 2 Reach 1 

Reach 3 
Electrofishing – Post HFE (May 1-5) 

Reach 1 

Segment 

A 

B 

GSF BGS WAL 

Count 35 3 2 

0 

5 

10 

15 

20 

25 

30 

35 

40 

Number of Fish 

May 1, 2023 

GSF BGS WAL BNT RBT 

Count 4 5 0 8 3 

0 

5 

10 

15 

20 

25 

30 

35 

40 

Number of Fish 

May 2, 2030 

GSF BGS WAL 

Count 20 12 1 

0 

5 

10 

15 

20 

25 

30 

35 

40 

Number of Fish 

May 3, 2023 

GSF BGS WAL BNT RBT SMB 

Count 68 15 1 24 25 3 

0 

10 

20 

30 

40 

50 

60 

70 

80 

Number of Fish 

May 4, 2023 

GSF BGS WAL BNT RBT SMB 

Count 68 17 1 6 0 6 

0 

10 

20 

30 

40 

50 

60 

70 

80 

Number of Fish 

May 5, 2023 

Segment 
GSF BGS WAL SMB 

Count 52 13 2 4 

0 

10 

20 

30 

40 

50 

60 

Number of Fish 

May 31, 2023 - 8 Sites (250 m each) 

Segments A and B 

Slough – 4 Sites (250 m each) 

12 

10 

8 

6 

4 

2 

0 

Number of Fish 

GSF BGS LMB 

Count 10 2 

Electrofishing – May 31, 2023 
Lower and Upper Slough ( -12 mile) 

Upper Slough 

Blue-Large Fyke Nets; Green-Small Fyke Nets; Yellow-Temperature Logger Locations 
90 

Upper Slough - Mini-Fyke Net 

 May 10 23-May 13-Jun 

GSF 46 15 84 

BGS 4 3 22 

0 

10 

20 

30 

40 

50 

60 

70 

80 

GSF BGS 

Fyke Nets – Upper Slough 
Fyke Nets – Lower Slough

0

1

2

3

4

5

6

7

8

9

 May 10 23-May 13-Jun

Number of Fish

Mini-Fyke Nets Total

GSF BGS BNT RBT CRP

0

5

10

15

20

25

30

 May 10 23-May 13-Jun

Large Fyke Nets Total

GSF BGS BNT RBT CRP FMS
Water Temperature (oC) 

6 

8 

10 

12 

14 

16 

18 

20 

22 

1-Ja n 6-Ja n 

11-Ja n 16-Ja n 21-Ja n 26-Ja n 31-Ja n 

5-Feb 

10-Feb 15-Feb 20-Feb 25-Feb 

2-Ma r 7-Ma r 

12-Ma r 17-Ma r 22-Ma r 27-Ma r 

1-Apr 6-Apr 

11-Apr 16-Apr 21-Apr 26-Apr 

1-Ma y 6-Ma y 

11-Ma y 16-Ma y 21-Ma y 26-Ma y 31-Ma y

5-Jun 

10-Jun 15-Jun 20-Jun 25-Jun 30-Jun 

5-Jul 

10-Jul 15-Jul 20-Jul 25-Jul 30-Jul 4-Aug 9-Aug 

14-Aug 19-Aug 24-Aug 29-Aug 

3-Sep 8-Sep 

13-Sep 18-Sep 23-Sep 28-Sep 

3-Oct 8-Oct 

13-Oct 18-Oct 23-Oct 28-Oct 

2-Nov 7-Nov 

12-Nov 17-Nov 22-Nov 27-Nov 

2-Dec 7-Dec 

12-Dec 17-Dec 22-Dec 27-Dec 

Daily Average Water Temperature of Colorado River at Lees Ferry, AZ - 09380000 

2010 2015 2021 2022 2023 

Historic and Current Water Temperature 

Lees Ferry 
Current Water Temperature 

Lower Slough 
12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

Lower Slough Water Temperature (C) 

6/1/2023 12:00... 6/1/2023 17:00... 6/1/2023 22:00... 

6/2/2023 3:00... 6/2/2023 8:00... 

6/2/2023 13:00... 6/2/2023 18:00... 6/2/2023 23:00... 

6/3/2023 4:00... 6/3/2023 9:00... 

6/3/2023 14:00... 6/3/2023 19:00... 

6/4/2023 0:00... 6/4/2023 5:00... 

6/4/2023 10:00... 6/4/2023 15:00... 6/4/2023 20:00... 

6/5/2023 1:00... 6/5/2023 6:00... 

6/5/2023 11:00... 6/5/2023 16:00... 6/5/2023 21:00... 

6/6/2023 2:00... 6/6/2023 7:00... 

6/6/2023 12:00... 6/6/2023 17:00... 6/6/2023 22:00... 

6/7/2023 3:00... 6/7/2023 8:00... 

6/7/2023 13:00... 6/7/2023 18:00... 6/7/2023 23:00... 

6/8/2023 4:00... 6/8/2023 9:00... 

6/8/2023 14:00... 6/8/2023 19:00... 

6/9/2023 0:00... 6/9/2023 5:00... 

6/9/2023 10:00... 6/9/2023 15:00... 6/9/2023 20:00... 6/10/2023 1:00... 6/10/2023 6:00... 

6/10/2023 11:00... 6/10/2023 16:00... 6/10/2023 21:00... 

6/11/2023 2:00... 6/11/2023 7:00... 

6/11/2023 12:00... 6/11/2023 17:00... 6/11/2023 22:00... 

6/12/2023 3:00... 6/12/2023 8:00... 

6/12/2023 13:00... 6/12/2023 18:00... 6/12/2023 23:00... 

6/13/2023 4:00... 6/13/2023 9:00... 

Current Water Temperature 

Lower Slough 
Questions?