Washington Department of Fish and WildlifeWDFW Region 3 - South Central Washington

Leech Lake Stock Assessment
2003

Leech Lake triploid rainbow trout about 17 inches in length.
Male Leech Lake eastern brook; 12.5 inches in length.
Washington Department of Fish and Wildlife stocked 1,670 large (1.7 lb. Ave.) triploid rainbow into Leech Lake for the first time in 2002. WDFW biologists set four fyke nets in Leech Lake recently for 8 days as a means to evaluate the triploid planting program. We also captured several fish by hook and line (fly fishing). Captured fish were marked with a hole punch (upper caudal) and released unharmed. We will collect additional data this summer (creel census).

We trapped 40 triploids (8 by hook & line) and 106 eastern brook > 20.0 cm. No recaptures and no population estimate was made because gear efficiency was low and declined over time. Still, we determined that there was significant carryover of triploids...enough to provide fishing opportunity prior to this years triploid stocking (scheduled for June 17 @ 1,070 fish). We contacted a number of anglers who were catching and releasing both triploids and eastern brook.

We measured 37 triploid rainbows that averaged 43.1 cm (17.0") total length (range: 37.5 cm (14.8") to 48.5 cm (19.1")). We also weighed 11 triploids that averaged 775 grams (1.7 lbs.) and ranged from 437 gm (1.0 lbs) to 1125 gm (2.5 lbs). Since the fish ranged from 15" - 17" and 1.7 lbs ave. weight at release on 6/19/02, it appears that ave. length has increased about 1 inch and ave. weight gain is negligible, although our sample size is small. The largest individual fish sampled may have grown up to 2 inches and put on 1 lbs. of weight gain (maybe a brook trout predator?). Generally speaking, the condition of the fish looked to be average....not too fat, but not too "snakey" either....just nice fish.

We measured 106 brook trout >= 20.0 cm that averaged 24.6 cm (9.7") with the largest brookie at 33.3 cm (13.1"). We weighed 49 EB's that averaged 149 grams (.33 lbs) and ranged from 83 gm (.2 lbs) to 352 gm (.8 lbs). The brook trout population appears to be very healthy with a fair number of 10 - 13" fish and numerous 6 - 10" fish. Brook trout fry had emerged and were feeding in the shallows.

Based on this information, we will plan on continuing the "quality" triploid trout program in "drive-to high lakes" including Leech (elev. 4412) and Dog (elev. 4207) ...and possibly Lost L. in Kittitas Co. next year (145 acres, elev. 3089)...assuming the agency has funds to purchase triploids next year. Because we added Dog L. (60 acres) to our triploid stocking list this year, stocking density has dropped to 27 fish/acre for all waters in 2003. This resulted in a 600 fish reduction for 40 acre Leech L. (1,670 —->1,070). Based on what we saw in terms of growth and condition factor, a reduction is probably warranted. The lake's aquatic invertebrate production may not be able to adequately support a sizeable natural brook trout population and 1,670 triploid rainbows (42/acre; 1 acre = 235' dia. circle). We did not sample stomach contents and do not know if any RB's have started preying on juvenile brook trout. If a percentage of rainbows became piscivorous, higher densities and better growth could be supported. If we are allocated 5,500 triploids again in 2004 and add Lost L. to the stocking list, ave. stocking density will decline further to 16 fish/acre and Leech L. would only receive 640 triploids....perhaps more sustainable on an annual basis.

We are going to utilize our Naches R. trout creel census technician to perform spot creel census at Leech L. and Dog L. this season in addition to his duties down on the river. The objective will be to interview anglers only to determine CPUE....no estimates of total effort, catch or harvest will be made. We will collect CPUE data before and after the triploid release at Leech L. on 6/17 to compare catch rates.

John Easterbrooks, 6/6/03
Jim Cummins, Editor - 6/10/03

Leech Lake Stock Assessment
May/June 2003

Leech Lake Schnabel Multiple Census Population Estimate
5/28/03 to 6/4/03
Date - Day #
Number Caught - "C"
Recaptures - "R"
Number Marked*
Marked at Large - "M"
C x M
Comments
RB
EB
RB
EB
RB
EB
RB
EB
RB
EB
5/28 - Day 1
4
3
0
0
4
3
0
0
0
0
 4 fyke nets set in a.m.;
hook & lined in p.m. to capture fish to mark
5/29 - Day 2
7
46
0
0
7
46
4
3
28
138
 1 RB hook & line, 6 RB in nets
5/30 - Day 3
6
33
0
0
6
33
11
49
66
1617
  
5/31 - Day 4
10
7
0
0
10
7
17
82
170
574
 includes 3 RB's by hook & line
6/1 - Day 5
2
1
0
0
1
1
27
89
54
89
 1 RB injured; not counted as marked
6/2 - Day 6
4
4
0
0
3
3
28
90
112
360
 1 RB, 1 EB gilled & poor condition;
not counted as marked
6/3 - Day 7
5
7
0
0
5
7
31
93
155
651
  
6/4 - Day 8
2
5
0
0
2
5
36
100
72
500
  
 
38
105
  
Totals =
40
106
0
0
38
105
657
3929
  

All fish batch marked with 1/4" hole punched in upper lobe of caudal fin
only EB >= 20.0 cm marked for pop. est.
* less removals for injured fish
Nets pulled on 6/4/03; low net efficiency resulted in declining catches and no recaptures; unable to generate a population size estimate 

 

Leech Lake Trout Biological Data
5/28 -6/4/03
Triploid RB's
EB
Length (cm)
Weight (grams)
Length (cm)
Weight (grams)
45.0
41.1
920
32.4
29.5
20.8
337
89
47.4
46.1
1080
23.1
21.5
30.1
150
160
41.9
45.0
686
19.9
26.0
21.0
83
142
44.0
40.9
800
22.0
22.0
23.2
103
235
44.5
42.7
702
23.5
21.5
24.6
118
117
37.5
42.5
437
23.2
23.2
21.7
123
146
48.5
45.0
1125
22.3
29.0
22.6
112
97
43.8
41.0
782
22.4
21.5
20.8
111
225
41.0
45.2
696
25.7
21.2
30.1
160
104
43.8
38.0
750
25.2
22.5
25.0
145
103
39.0
42.5
550
31.0
20.4
22.4
280
91
40.5
44.5
 11= n
775= mean weight
437= min
1125= max
23.5
24.2
30.9
135
182
45.5
44.0
23.6
20.2
32.5
130
163
43.6
42.5
22.2
20.2
29.5
96
141
44.0
43.0
30.0
22.5
21.9
245
98
39.0
43.5
25.5
20.0
24.6
166
270
41.2
47.0
29.0
22.5
33.3
187
99
43.7
44.2
24.3
20.5
30.1
130
125
43.3
22.0
20.0
28.0
102
249
37= n
43.1= mean length
37.5= min
48.5= max
32.5
27.5
30.0
352
94
28.5
21.6
31.5
229
186
22.4
21.2
23.0
101
98
22.6
20.3
30.0
109
93
21.5
22.5
28.0
93
116
22.0
22.5
24.5
98
22.0
26.0
24.0
49= n
149= mean weight
83= min
352= max
25.4
20.5
20.0
24.5
27.0
25.0
27.2
29.0
29.0
26.5
23.2
28.5
25.2
21.0
22.0
20.5
23.2
21.2
30.5
24.6
32.3
21.5
21.7
21.3
23.0
22.6
24.3
106= n
24.6= mean length
19.9= min
33.3= max
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