g.g.oliver and associates environmental...

G.G.Oliver and Associates Environmental Science

• Watershed Restoration • Aquatic Science • Fisheries Research

•

Kootenay Region Small Lakes Stocking

Assessment: 2003

Prepared for

Ministry of Water, Land and Air Protection

205 Industrial Rd. G

Cranbrook, B.C. V1C 7G5

Prepared by

G. G. Oliver, M.Sc., R.P.Bio.

GG Oliver and Associates

Environmental Science

2291 1st Ave S.

Cranbrook, B.C. V1C 6Y3

February 2004

Kootenay Region Small Lakes Stocking Assessment: 2003

February 2004 ii

EXECUTIVE SUMMARY

Twelve small lakes in the Kootenay Region were investigated September through

October 2003 to assess the performance of rainbow trout stocks outplanted in

monoculture systems or lakes having a coarsefish presence. Gillnet surveys were

completed at Box, Cameron and Rosebud lakes in the West Kootenay and Aid,

Alces, Comfort, Halfway, Help, Rockbluff, Rocky Point, Solar and Three Island lakes

in the East Kootenay. Length-at-age and length-weight relationships were

determined and evaluated against current stocking rates and management regimes.

Measurements of total dissolved solids (TDS) and pH were also collected to update

current water chemistry conditions. Isometric growth coefficients ranged from a low

of 2.62 to a high of 3.00. The lowest value was determined for rainbow trout in

Comfort Lake where coarsefish numbers have dramatically increased since the mid-

1980’s; the highest values were obtained at Alces Lake and may be coincidental with

present levels of angling effort that maintain an appropriate population structure

relative to lake productivity. Of the rainbow trout stocks monitored across the 12

study lakes, Tunkwa and Pennask-Premier stocks were most characteristic of early

maturation at a smaller size, particularly among males. The size and age structure

of individual populations was variable among study lakes and survival of rainbow

trout to adulthood was believed to be affected by early maturation or competitive

interactions between rainbow and other species, where present. At Rosebud Lake,

survival may have been influenced by prevailing environmental conditions leading to

physiological stress associated with high pH. Recommendations are provided

relative to changes in stock selection, stocking density and fisheries management

alternatives.


February 2004 iii

ACKNOWLEDGEMENTS

The following people are gratefully acknowledged for contributions of information and

assistance during this study:

Ministry of Water, Land and Air Protection

W.T. Westover, Fisheries Biologist, Cranbrook, B.C.

Jeff Burrows, Sr. Fisheries Biologist, Nelson, B.C.

J. Bell, Fisheries Fisheries Biologist, Nelson, B.C.

Herb Tepper, Fisheries Biologist, Cranbrook, B.C.

Kevin Heidt, Fisheries Technician, Cranbrook, B.C.

Peter Brown, Fish Culturist, Wardner, B.C.

Doug Crowley, Fish Culturist, Wardner, B.C.

Kevin Franck and Associates

Kevin Franck, Draftsman, Cranbrook, B.C.

Kevin Heidt, Herb Tepper, Jeff Burrows and John Bell assisted with netting surveys and

provided sources of information necessary in the completion of the report. Bill Westover

and Kevin Heidt provided information on angler use in the East Kootenay. Peter Brown

and Doug Crowley provided background on rearing practices for individual stocks at

Kootenay Trout Hatchery and information on fish size at time of release. Kevin Franck

provided drafting services during report preparation. My sincere thanks to all

participants.


February 2004 iv

TABLE OF CONTENTS

EXECUTIVE SUMMARY .................................................................................................. II

ACKNOWLEDGEMENTS................................................................................................ III

TABLE OF CONTENTS ..................................................................................................IV

LIST OF TABLES............................................................................................................VI

LIST OF FIGURES .........................................................................................................VII

1.0 INTRODUCTION....................................................................................................1

1.1 BACKGROUND ......................................................................................................1

2.0 METHODS .............................................................................................................2

2.1 WATER CHEMISTRY ..............................................................................................2

2.2 FISH SAMPLING.....................................................................................................4

2.3 ANALYTICAL PROCEDURES....................................................................................4

3.0 RESULTS...............................................................................................................5

3.1 PHYSICAL AND CHEMICAL CHARACTERISTICS .........................................................5

3.2 BIOLOGICAL CHARACTERISTICS.............................................................................5

3.2.1 Aid Lake ..........................................................................................................5

3.2.2 Alces Lake.....................................................................................................10

3.2.3 Box Lake .......................................................................................................13

3.2.4 Cameron Lake...............................................................................................17

3.2.5 Comfort Lake.................................................................................................23

3.2.6 Halfway Lake.................................................................................................29

3.2.7 Help Lake......................................................................................................32

3.2.8 Rockbluff Lake ..............................................................................................38

3.2.9 Rocky Point Lake ..........................................................................................41

3.2.10 Rosebud Lake ...........................................................................................45

3.2.11 Solar Lake .................................................................................................48

3.2.12 Three Island Lake......................................................................................53

3.3 GROWTH, STOCKING DENSITY AND ANGLER USE ..................................................56


February 2004 v

4.0 DISCUSSION.......................................................................................................58

5.0 LITERATURE CITED...........................................................................................62

APPENDIX 1...................................................................................................................63

BATHYMETRIC MAPS FOR SELECTED LAKES.........................................................63

APPENDIX 2...................................................................................................................74

BIOLOGICAL DATA.......................................................................................................74

APPENDIX 3...................................................................................................................92

PHOTOGRAPHIC PLATES............................................................................................92


February 2004 vi

LIST OF TABLES

TABLE 1. PHYSICAL AND CHEMICAL CHARACTERISTICS OF SMALL LAKES IN THE STUDY AREA.6

TABLE 2. BACK-CALCULATED LENGTHS AT SUCCESSIVE ANNULI FOR RAINBOW TROUT IN AID

LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS. ..........................................7

TABLE 3. BACK-CALCULATED LENGTHS AT SUCCESSIVE ANNULI FOR RAINBOW TROUT IN

ALCES LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS. .............................12

TABLE 4. BACK-CALCULATED LENGTHS AT SUCCESSIVE ANNULI FOR RAINBOW TROUT IN BOX

LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS. ........................................15


CAMERON LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS.........................20


CAMERON LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS.........................24


HALFWAY LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS..........................30

TABLE 8. BACK-CALCULATED LENGTHS AT SUCCESSIVE ANNULI FOR RAINBOW TROUT IN HELP

LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS. ........................................33


ROCKBLUFF LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS. .....................39


ROCKY POINT LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS. ..................44

TABLE 11. BACK-CALCULATED LENGTHS AT SUCCESSIVE ANNULI FOR DOMESTIC RAINBOW

TROUT IN ROSEBUD LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS...........47


SOLAR LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS. .............................50


THREE ISLAND LAKE. 95% CONFIDENCE LIMITS ARE SHOWN IN BRACKETS. .................55


February 2004 vii

LIST OF FIGURES

FIGURE 1. LOCATION OF STUDY AREA. ................................................................................3

FIGURE 2. RAINBOW TROUT STOCK SELECTION AND STOCKING RATE AT AID LAKE FROM 1998

TO 2003. .....................................................................................................................8

FIGURE 3. LENGTH FREQUENCY DISTRIBUTION OF RAINBOW TROUT SAMPLED IN AID LAKE ON

SEPTEMBER, 2003. .....................................................................................................8

FIGURE 4. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN AID LAKE............................9

FIGURE 5. LENGTH FREQUENCY DISTRIBUTION OF FINESCALE SUCKER SAMPLED IN AID LAKE

ON SEPTEMBER, 2003. ................................................................................................9

FIGURE 6. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN AID LAKE ON

SEPTEMBER 30, 2003................................................................................................10

FIGURE 7. RAINBOW TROUT STOCK SELECTION AND STOCKING RATE IN ALCES LAKE FROM

1999 TO 2003. ..........................................................................................................11

FIGURE 8. LENGTH FREQUENCY DISTRIBUTION OF RAINBOW TROUT SAMPLED IN ALCES LAKE

ON OCTOBER 17, 2003. .............................................................................................11

FIGURE 9. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN ALCES LAKE. ....................12

FIGURE 10. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN ALCES LAKE

ON OCTOBER 17, 2003. .............................................................................................13

FIGURE 11. LENGTH FREQUENCY DISTRIBUTION OF RAINBOW TROUT SAMPLED IN BOX LAKE

ON OCTOBER 7, 2003. ...............................................................................................14

FIGURE 12. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN BOX LAKE. .....................15

FIGURE 13. RAINBOW TROUT STOCK SELECTION AND STOCKING RATE AT BOX LAKE FROM

1993 TO 2003. ..........................................................................................................16

FIGURE 14. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN BOX LAKE ON

OCTOBER 7, 2003. ....................................................................................................16

FIGURE 15. LENGTH FREQUENCY DISTRIBUTION OF EASTERN BROOK TROUT SAMPLED IN BOX

LAKE ON OCTOBER 7, 2003. ......................................................................................17

FIGURE 16. LENGTH-WEIGHT RELATIONSHIP FOR EASTERN BROOK TROUT SAMPLED IN BOX

LAKE ON OCTOBER 7, 2003. ......................................................................................18

FIGURE 17. RAINBOW TROUT AND EASTERN BROOK TROUT STOCK SELECTION AND STOCKING

RATE AT CAMERON LAKE FROM 1998 TO 2003. ..........................................................18

FIGURE 18. LENGTH FREQUENCY DISTRIBUTION OF RAINBOW TROUT SAMPLED IN CAMERON

LAKE ON OCTOBER 7, 2003. ......................................................................................19


February 2004 viii

FIGURE 19. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN CAMERON LAKE..............20

FIGURE 20. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN CAMERON

LAKE ON OCTOBER 7, 2003. ......................................................................................21

FIGURE 21. LENGTH FREQUENCY DISTRIBUTION OF EASTERN BROOK TROUT SAMPLED IN

CAMERON LAKE ON OCTOBER 7, 2003. ......................................................................21

FIGURE 22. LENGTH-WEIGHT RELATIONSHIP FOR EASTERN BROOK TROUT IN CAMERON LAKE

ON OCTOBER 7, 2003. ...............................................................................................22

FIGURE 23. LENGTH FREQUENCY DISTRIBUTION OF RAINBOW TROUT SAMPLED IN COMFORT

LAKE ON SEPTEMBER 30, 2003..................................................................................23

FIGURE 24. RAINBOW TROUT STOCK SELECTION AND STOCKING RATE AT COMFORT LAKE

FROM 1998 TO 2003..................................................................................................24

FIGURE 25. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN COMFORT LAKE..............25

FIGURE 26. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN COMFORT


FIGURE 27. LENGTH FREQUENCY DISTRIBUTION OF FINESCALE SUCKER SAMPLED IN

COMFORT LAKE ON SEPTEMBER 30, 2003..................................................................27

FIGURE 28. LENGTH-WEIGHT RELATIONSHIP FOR FINESCALE SUCKER SAMPLED IN COMFORT


FIGURE 29. RAINBOW TROUT STOCK SELECTION AND STOCKING RATE AT HALFWAY LAKE

FROM 1998 TO 2003..................................................................................................29

FIGURE 30. LENGTH FREQUENCY DISTRIBUTION OF RAINBOW TROUT SAMPLED IN HALFWAY

LAKE ON OCTOBER 1, 2003. ......................................................................................30

FIGURE 31. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN HALFWAY LAKE. .............31

FIGURE 32. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN HALFWAY

LAKE ON OCTOBER 1, 2003. ......................................................................................32

FIGURE 33. RAINBOW TROUT STOCK SELECTION AND STOCKING RATE AT HELP LAKE FROM

1998 TO 2003. ..........................................................................................................33

FIGURE 34. LENGTH FREQUENCY DISTRIBUTION OF RAINBOW TROUT SAMPLED IN HELP LAKE

ON SEPTEMBER 30, 2003. .........................................................................................33

FIGURE 35. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN HELP LAKE. ....................34

FIGURE 36. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN HELP LAKE ON

OCTOBER 1, 2003. ....................................................................................................35

FIGURE 37. LENGTH FREQUENCY DISTRIBUTION OF FINESCALE SUCKER SAMPLED IN HELP

LAKE ON OCTOBER 1, 2003. ......................................................................................36


February 2004 ix

FIGURE 38. LENGTH-WEIGHT RELATIONSHIP FOR FINESCALE SUCKER SAMPLED IN HELP LAKE

ON OCTOBER 1, 2003. ...............................................................................................36

FIGURE 39. LENGTH FREQUENCY DISTRIBUTION OF EASTERN BROOK TROUT SAMPLED IN

HELP LAKE ON OCTOBER 1, 2003. .............................................................................37

FIGURE 40. LENGTH-WEIGHT RELATIONSHIP FOR EASTERN BROOK TROUT SAMPLED IN HELP

LAKE ON OCTOBER 1, 2003. ......................................................................................37

FIGURE 41. RAINBOW TROUT STOCK SELECTION AND STOCKING RATE AT ROCKBLUFF LAKE

FROM 1998 TO 2003..................................................................................................38

FIGURE 42. LENGTH FREQUENCY DISTRIBUTION OF RAINBOW TROUT SAMPLED IN ROCKBLUFF

LAKE ON OCTOBER 17, 2003. ....................................................................................39

FIGURE 43. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN ROCKBLUFF LAKE...........40

FIGURE 44. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN ROCKBLUFF

LAKE ON OCTOBER 17, 2003. ....................................................................................41

FIGURE 45. RAINBOW TROUT STOCK SELECTION AND STOCKING RATE AT ROCKY POINT LAKE

FROM 1999 TO 2003..................................................................................................42

FIGURE 46. LENGTH FREQUENCY DISTRIBUTION OF RAINBOW TROUT SAMPLED IN ROCKY

POINT LAKE ON OCTOBER 2, 2003. ............................................................................43

FIGURE 47. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN ROCKY POINT LAKE. .......43

FIGURE 48. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN ROCKY POINT

LAKE ON OCTOBER 2, 2003. ......................................................................................45

FIGURE 49. RAINBOW TROUT STOCK SELECTION AND STOCKING RATE AT ROSEBUD LAKE

FROM 1996 TO 2002..................................................................................................46

FIGURE 50. LENGTH FREQUENCY DISTRIBUTION OF RAINBOW TROUT SAMPLED IN ROSEBUD

LAKE ON OCTOBER 8, 2003. ......................................................................................46

FIGURE 51. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN ROSEBUD LAKE. .............48

FIGURE 52. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN ROSEBUD

LAKE ON OCTOBER 8, 2003. ......................................................................................49

FIGURE 53. RAINBOW TROUT STOCK SELECTION AND STOCKING RATE AT SOLAR LAKE FROM

1998 TO 2003. ..........................................................................................................49

FIGURE 55. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN SOLAR LAKE...................52

FIGURE 56. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN SOLAR LAKE

ON OCTOBER16, 2003...............................................................................................53

FIGURE 57. RAINBOW TROUT STOCK SELECTION AND STOCKING RATE AT THREE ISLAND LAKE

FROM 1999 TO 2003..................................................................................................54


February 2004 x

FIGURE 58. LENGTH FREQUENCY DISTRIBUTION OF RAINBOW TROUT SAMPLED IN THREE

ISLAND LAKE ON OCTOBER 2, 2003............................................................................54

FIGURE 59. BODY:SCALE RELATIONSHIP FOR RAINBOW TROUT IN THREE ISLAND LAKE. ......55

FIGURE 60. LENGTH-WEIGHT RELATIONSHIP FOR RAINBOW TROUT SAMPLED IN THREE ISLAND

LAKE ON OCTOBER 2, 2003. ......................................................................................56

FIGURE 61. A COMPARISON OF RAINBOW TROUT LENGTH-WEIGHT RELATIONSHIPS AMONG

REPRESENTATIVE STUDY LAKES. ................................................................................57

FIGURE 62. A COMPARISON OF ANGLER USE AT SELECTED LAKES BASED ON AVAILABLE SLIM

DATA. DATA SUMMARIZED FOR INDIVIDUAL YEARS. .....................................................58


February 2004 1

1.0 Introduction

Over the past twenty years, the small lakes management program in the Kootenay

Region has included a variety of activities to improve the size and survival of

hatchery-maintained rainbow trout fisheries and to expand the quality of local angling

opportunities. Earlier management activities focused on special regulations,

chemical rehabilitation and lake aeration at several small lakes in the East and West

Kootenay. More recently, however, management activities have centered on special

stock introductions into selected small lakes to off-set growth impairment due to early

maturity issues or coarsefish interactions. To this end, the most appropriate stocks

that best maximize rainbow trout production have been considered to improve

angling quality within small lakes in the Kootenay Region. The present report

outlines rainbow trout age and growth characteristics as part of an ongoing program

in its second year. The small lakes assessment program is designed to evaluate the

performance of individual stocks in selected lakes and provide recommendations for

future management options.

1.1 Background

Special stocks employed in the present evaluation include rainbow trout of either

Premier, Pennask, Tunkwa, Tunkwa/Badger, Gerrard or Fraser Valley origin.

Pennask stock was introduced into Premier Lake (Kootenay Trout Hatchery’s egg

collection station) in the mid-1980’s owing to a chronic problem of early maturity in

the original Premier stock that plagued growth and survival of out-planted yearlings

in stocking-dependent small lakes throughout the region. Selection for early maturity

was artificially hastened by earlier hatchery operations that utilized two year old

males as a donor source for fertilization purposes. Introduction of Pennask stock,

known for its later maturity, into Premier Lake has helped to correct the problem and

shifted the average age of first maturity to 3 and 4 years for male and female fish,

respectively. For present purposes, Premier and Pennask stocks obtained from

Premier Lake are distinguished by previous marks (clips) applied to Pennask stock;

unmarked fish are assumed to represent Premier stock. In a single stocking

example, Fraser Valley rainbow trout eggs were manipulated by heat shock

treatment to enhance sterility (i.e., triploidy). As a consequence of their sterile


February 2004 2

condition, growth efficiencies are directed at somatic development allowing individual

fish to achieve a larger overall size. With the exception of the Gerrard stock, raised

at Selkirk College (as part of an embryology program in the present curriculum), all

other stocks were cultured at Kootenay Trout Hatchery (Wardner, B.C.). All fish

were released as either yearlings or fingerlings.

The present evaluation includes 3 lakes in the West Kootenay (Rosebud, Box and

Cameron lakes) and 9 lakes in the East Kootenay (Aid, Comfort, Help, Rocky Point,

Three Island, Halfway, Alces, Rockbluff, and Solar lakes; Fig. 1). Rocky Point, Three

Island, Halfway, Alces, Rockbluff lakes are managed as rainbow trout monoculture

systems. Historically, Cameron and Box lakes have been managed for both rainbow

and eastern brook trout. Aid, Comfort and Help lakes support multiple fish species

that also include coarsefish.

The purpose of the present study is to evaluate rainbow trout stocks across variable

stocking densities and assess rainbow trout growth relative to physical, chemical and

biological (single/multiple species) conditions. Stock evaluations examine age and

growth and length-weight relationships across lake environments and management

regimes. Updates in chemical lake conditions are also assessed through

measurements of pH and total dissolved solids (TDS). Recommendations to

changes in current management strategies are included where current stocks or

stocking densities have not met expectations.

2.0 Methods

2.1 Water chemistry

Total dissolved solids (TDS) and pH were measured at each selected lake during the

period of assessment from late September through mid-October 2003. A 500 ml

water sample was collected from the surface near the lake margin where depths

exceeded 0.5 m and analyzed. TDS was measured with an Oakton TDS Testr 1

while pH was measured with an Oakton pH Testr 2; individual meters were calibrated

with reference samples prior to use at each lake to assess precision and maintain

accuracy. Further adjustments to the TDS meter beyond factory settings were not

required over the duration of the study.


February 2004 3

Figure 1. Location of study area.


February 2004 4

2.2 Fish sampling

Fish collections were completed by gillnet surveys employing floating and sinking

nets; use of a floating net was restricted to Aid Lake whereas all other study lakes

were sampled by sinking net only. Ninety-two meter standard experimental gangs

consisting of 6, 15 X 2.5 m variable mesh panels (ordered as 25, 76, 51, 89, 38 and

64 mm mesh sizes shoreward to lakeward) were deployed in littoral habitats and

each set was placed perpendicular to the shoreline. Individual nets were anchored

shoreward and lakeward; the lakeward end of the each net was supported with a

buoy to mark the endpoint and assist with retrieval. Overnight sets were completed

from 14:30 to 12:00 hours with an average soak time of 19.4 hours. All sets were

made from a 4 m aluminum boat.

Individual fish were collected as a composite sample from all panels and catch per

unit effort (CPUE) was reported as fish per hour by species. Fork lengths were

obtained with a measuring board to the nearest millimeter and weights were

measured to the nearest gram with an Ohaus Model CS 5000 (0-5 kg) electronic

balance; each fish was supported in a plastic cradle that required taring prior to each

measurement. A representative number of scales across the size range of the

rainbow trout sample were removed within 3-5 rows of the lateral line immediately

posterior to the dorsal fin and stored in individual scale envelopes.

2.3 Analytical procedures

Rainbow trout scales were cleaned, mounted on a glass slide and read with a 3MTM

800 Microfiche reader at 60X magnification. Measurements of scale radius and

distance from nucleus to each annulus were marked on a paper strip, body:scale

relationship (mm) determined by regression analysis and lengths at successive

annuli back-calculated using Lea’s formula (Bagenal 1978). Ages were then

assigned to length frequency distributions assembled for each rainbow trout sample.

Length-weight data were transformed by natural logarithm; coefficients for each fish

sample were generated by regression analysis to explain the length-weight

relationship. Proportionality was used to compare deviations from isometric growth

among sample populations from each lake relative to present stocking densities and

corresponding lake productivity. For each regression calculated, a plot of residuals

was inspected for equality of variance among individual samples. Theoretical


February 2004 5

stocking rate was calculated using the formula: Number of yearlings = TDS * ((2.47

shoal area) + (0.247 surface area)); for fall fry determinations: two fall fry were

considered equivalent to one yearling.

3.0 Results

3.1 Physical and chemical characteristics

A summary of the physical and chemical characteristics of selected lakes in the

study area are provided in Table 1. Four of the lakes are considered high elevation

lakes and lie above 1000m while the remainder are considered low elevation lakes

lying below 1000 m. The majority of candidate lakes have inlets and/or outlets while

remaining waterbodies are considered small kettle lakes; water level fluctuation

occurs primarily through direct surface run-off during snowmelt or natural upwelling

springs. The extent of natural recruitment to lakes with a surface supply is unknown

but considered marginal. The mean surface area of the study lakes is ~22 ha; Box

Lake has the largest surface area at 71 ha. The majority of lakes are also

considered shallow with maximum depths ranging from 2.5 to 34 m and mean depths

ranging from 1- 10 m. Accordingly, the amount of shoal area is considered moderate

with an average of 63% littoral area estimated across all lakes. pH ranges from 8.1

to 9 yet the majority of lakes lie within an acceptable limit for fish production. Total

dissolved solids are highly variable ranging from 40 to 430 ppm. Across the range of

candidate lakes, a comparison of MEI (Ryder et al. 1974), an index of lake

productivity, suggests a production capability that ranges from low to moderate. A

summary of lake bathymetry, for candidate lakes with completed physical surveys, is

provided in Appendix 1; all biological data is in Appendix 2.

3.2 Biological characteristics

3.2.1 Aid Lake

Previous gillnet surveys conducted in 1984 identified rainbow trout and largescale

sucker as local species (FISS database, Victoria, B.C.); closer inspection of suckers


February 2004 6

Table 1. Physical and chemical characteristics of small lakes in the study area.

Lake Watershed Latitude Longitude Elevation Surface Maximum Mean Shoal area pH TDS MEI1

code (m) area (ha) depth (m) depth (m) (ha) (ppm)

Aid 300-871400 51:39:38 117:27:05 985 13.18 5 2.4 13.18 8.1 150 7.91Alces 349-666200-32000 50:07:14 115:32:21 1210 30.1 14.8 6.7 14.50 8.3 180 5.18Box 300-706100 50:12:32 117:42:57 593 70.82 7.3 4.5 8.9 90 4.47Cameron 300-697000-74600 50:18:51 117:59:59 930 35.37 12.5 4.2 23.80 8.6 40 3.09Comfort 300-871400 51:38:49 117:25:48 997 9.11 5.5 3.3 9.11 8.5 150 6.74Halfway 300-968400-25600 50:45:57 116:22:08 1103 5.5 13.4 3.8 1.20 8.9 270 8.43

42200-5960Help 300-871400 51:39:09 117:26:15 994 11.97 2.4 1.2 11.97 8.5 150 11.18Rockbluff 349-491000-78400 49:53:32 115:38:34 940 19.83 25.6 9.1 7.00 8.8 350 6.20Rocky Point 390-359600 51:00:55 116:46:12 1426 27.64 14.6 4.6 18.50 8.5 90 4.42Rosebud 330-092600-11000 49:02:52 117:16:03 808 13.36 14.9 7 8.9 130 4.31Solar 349-434900-13700 49:45:39 115:49:18 930 3.26 10 8.9 430

77200-7880Three Island 390-137600-40800 51:00:43 116:47:04 1518 23.7 34.3 10.7 6.97 9 70 2.561MEI = morpho-edaphic index


February 2004 7

in the present survey suggests that these fish are likely finescale owing to the nature

of their extended bulbous snout, a ventral mouth that protrudes behind the tip of the

snout and small cycloid scales. The catch composition on September 30, 2003

consisted of 84% rainbow trout (CPUE=2.09) and 16% finescale sucker (longnose;

CPUE=0.39). Rainbow trout have been planted consistently at a 1500 yearlings per

annum over the last several years utilizing either Premier and Pennask stock or their

crosses (Fig. 2). The rainbow trout sample ranged from 122 – 260 mm (mean =

190.3 Fig. 3) and included individuals up to age-group 3+. Size-at-age from scale

interpretations are provided in Table 2; back-calculated lengths for each age class

were estimated from the body:scale relationship depicted in Figure 4. Low

incremental growth during their second and third years may be related to a condition

of early maturity in combination with low lake productivity (TDS=150); all fish >200

mm FL were developing gonads and would have spawned during the spring of 2004.

Finescale sucker ranged in size from 103 – 210 mm (mean = 144.6; Fig. 5) with

corresponding weights from 14 - 110 g.

The length-weight relationship for rainbow trout indicates that growth is less than

proportional (Fig. 6). Accordingly, the lack of proportionality over the range of fish

size sampled suggests that individuals are in slightly poorer condition than expected

if growth was isometric (Plate 1 (Appendix 3)). Their present condition may be

related to competitive interactions with coarsefish for a limited food supply. The

slightly lower slope coefficient is not believed to be related to stocking density since

the lake is currently managed at ~28% of theoretical stocking capacity.

Table 2. Back-calculated lengths at successive annuli for rainbow trout in Aid Lake. 95%

confidence limits are shown in brackets.

Age-group nI II III

1+ 4 67.7(11.67)

2+ 7 64.1 136.1(6.89) (13.53)

3+ 7 73.8 138.3 200.7(8.10) (12.36) (11.55)

Grand Average 68.5 137.2 200.7

Age Class


February 2004 8

0

200

400

600

800

1000

1200

1400

1600

1998 1999 2000 2001 2002 2003

Num

ber o

f fis

h re

leas

ed

Pennask-PremierPennask-PremierPremier PremierPennask Pennask

Figure 2. Rainbow trout stock selection and stocking rate at Aid Lake from 1998 to 2003.

0

2

4

6

8

10

12

14

16

18

120 130 140 150 160 170 180 190 200 210 220 230 240 250 260

Size category (mm)

Perc

ent o

ccur

renc

e

n=48

1+

2+

3+

Figure 3. Length frequency distribution of rainbow trout sampled in Aid Lake on

September, 2003.


February 2004 9

0

50

100

150

200

250

300

0 10 20 30 40 50 60 70 80 90

Scale radius ( X60 mm)

Fork

leng

th (m

m)

Fork length (mm) = 20.1793 + 3.1590 (Scale radius); r2 = 0.78; n = 18

Figure 4. Body:scale relationship for rainbow trout in Aid Lake.

0

5

10

15

20

25

30

35

100 110 120 130 140 150 160 170 180 190 200 210Size category (mm)

Perc

ent o

ccur

renc

e

n=9

Figure 5. Length frequency distribution of finescale sucker sampled in Aid Lake

on September, 2003.


February 2004 10

3

3.5

4

4.5

5

5.5

4.7 4.8 4.9 5 5.1 5.2 5.3 5.4 5.5 5.6

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -10.7639 + 2.8736 Ln (FL); r2= 0.98; n=48

Figure 6. Length-weight relationship for rainbow trout sampled in Aid Lake on September 30, 2003.

3.2.2 Alces Lake

Composition of the catch from a single sinking gillnet retrieved on October 17, 2003

consisted entirely of rainbow trout (CPUE=2.51; Premier or Premier-Pennask stock;

Fig. 7). A review of the stocking records indicates a consistent outplanting of 2000

fish per year over the last five years. The size distribution (n=49) of trout ranged from

140 – 400 mm (mean = 333.6) with age-groups ranging from 1+ - 5+ (Fig. 8). Of this

total, 4 fish were immature, 2 were in kelted condition, 1 female was egg-bound and

the remainder were maturing. Size-at-age information is provided in Table 3 based

on the body-scale relation shown in Figure 9; considerable scatter was observed

about the regression line for the given scale subsample size. Incremental growth

begins to slow after the 3rd year and may be related to maturity and low to moderate

lake productivity. Weight is proportional to body length in this sample and an

average slope coefficient is apparent (Fig. 10; Plate 2). Present stocking levels

occur at ~26% of theoretical stocking capacity in consideration of


February 2004 11

0

500

1000

1500

2000

2500

1999 2000 2001 2002 2003

Num

ber o

f fis

h re

leas

edPennask Premier Premier Pennask-Premier Pennask-Premier

Figure 7. Rainbow trout stock selection and stocking rate in Alces Lake from 1999 to 2003.

0

2

4

6

8

10

12

14

16

140

150

160

170

180

190

200

210

220

230

240

250

260

270

280

290

300

310

320

330

340

350

360

370

380

390

400

Size category (mm)

Perc

ent o

ccur

renc

e

n=49

1+

2+

3+

4+

5+

Figure 8. Length frequency distribution of rainbow trout sampled in Alces Lake

on October 17, 2003.


February 2004 12

Table 3. Back-calculated lengths at successive annuli for rainbow trout in Alces Lake. 95%


Age-group nI II III IV V

1+ 1 121.5

2+ 5 132.7 192.2(3.81) (13.00)

3+ 6 137.2 202.3 269.9(4.76) (18.15) (25.73)

4+ 2 132.6 181.5 251.7 316.9(0.95) (2.87) (30.81) (11.53)

5+ 5 135.0 179.6 236.9 296.9 343.7(2.30) (6.03) (21.92) (10.13) (10.32)

Grand Average 131.0 192.0 260.8 316.9 343.7

Age Class

0

50

100

150

200

250

300

350

400

450

0 20 40 60 80 100 120 140 160 180

Scale radius (mm X60)

Fork

leng

th (m

m)

Fork length (mm) = 99.0354 + 1.9614 (Scale radius); r2=0.77; n=19

Figure 9. Body:scale relationship for rainbow trout in Alces Lake.


February 2004 13

ambient lake productivity.

3

3.5

4

4.5

5

5.5

6

6.5

7

4 4.5 5 5.5 6 6.5Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -11.4846 + 3.0081 Ln (FL); r2=0.95; n=49

Figure 10. Length-weight relationship for rainbow trout sampled in Alces Lake on October 17, 2003.

3.2.3 Box Lake

Rainbow trout (10%; CPUE=1.38) and eastern brook trout (90%; CPUE=12.19) were

captured in an overnight sinking gillnet set on October 7, 2003. Rainbow trout size

distribution varied from 114 – 391 mm (mean = 205.1) and ages were assigned from

1+ - 4+ (Fig. 11). The frequency distribution was highly skewed to younger fish

suggesting low survival of adults and all fish >190 mm were maturing. Size-at-age

from scale interpretations are provided in Table 4; lengths were estimated from the

body:scale relationship shown in Figure 12. On average, the largest incremental

growth was observed during the second and third year (refer to Table 2). Pennask

and Premier rainbow stocks have been used in Box Lake since 1999 while the

Pennask-Premier cross has been utilized over the last two years (Fig. 13; the

stocking rate was reduced by 50% in 2003 and remains at 2500 fish per year. A

review of the length-weight relationship indicates isometric growth (Fig. 14); overall,

the fish are in average condition (Plate 3). A mild infestation of black spot on


February 2004 14

rainbow trout was also evident.

0

2

4

6

8

10

12

14

16

18

20

120 140 160 180 200 220 240 260 280 300 320 340 360 380

Size category (mm)

Perc

ent o

ccur

renc

en=291+

2+ 3+ 4+

Figure 11. Length frequency distribution of rainbow trout sampled in Box Lake on October 7, 2003.


February 2004 15

Eastern brook trout grossly outnumbered rainbow trout (~9 fold) in the catch; a more

balanced frequency distribution, but without specific age confirmation, suggests up

Table 4. Back-calculated lengths at successive annuli for rainbow trout in Box Lake. 95% confidence limits are shown in brackets.

Age-group nI II III IV

1+ 9 86.86(7.00)

2+ 5 81.1 162(5.87) (16.1)

3+ 1 105.6 266.9 309.7

4+ 2 72.5 118.3 253.7 321.8(11.47) (20.4) (80.6) (55.0)

Grand Average 86.5 182.4 281.7 321.8

Age Class

0

50

100

150

200

250

300

350

400

450

0 20 40 60 80 100 120 140


Fork

leng

th (m

m)


Figure 12. Body:scale relationship for rainbow trout in Box Lake.


February 2004 16

0

1000

2000

3000

4000

5000

6000

1999 2000 2001 2002 2003

Num

ber o

f fis

h re

leas

edPennask Premier Premier

Pennask-Premier Pennask-Premier

Figure 13. Rainbow trout stock selection and stocking rate at Box Lake from 1993 to 2003.

3.5

4

4.5

5

5.5

6

6.5

7

4.5 5 5.5 6 6.5

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -11.1867 + 2.9663 Ln (FL); r2=0.99; n=29

Figure 14. Length-weight relationship for rainbow trout sampled in Box Lake on


February 2004 17

October 7, 2003.

to 5 age classes of this species were present in the sample (Fig. 15). The size

distribution for brook trout varied from 102 to 383 mm (mean = 236.8) and

corresponding fish weight varied from 14 to 620 g, respectively. Fish > 180 mm

were sexually mature and all specimens in the sample were heavily plagued by black

spot disease. As indicated in the regression equation in Figure 16, a coefficient of

3.06 indicates proportional growth for the population (i.e., average condition). A

review of the stocking information dating back to the early 1920’s shows no record of

Eastern brook trout introduction; it is assumed that the presence of brook trout is the

result of an unauthorized introduction.

3.2.4 Cameron Lake

The catch composition from a single sinking gillnet set on October 7, 2003 consisted

of near equal proportions of rainbow trout and Eastern brook trout (CPUE=3.2). Two

thousand sterile brook trout were planted in 1998 and 1999 whereas 2000 Pennask

stock rainbow have been introduced over the last four years (Fig. 17).

0

2

4

6

8

10

12

110 130 150 170 190 210 230 250 270 290 310 330 350 370Size category (mm)

Perc

ent o

ccur

renc

e

n=253

Figure 15. Length frequency distribution of Eastern brook trout sampled in Box Lake on October 7, 2003.


February 2004 18

2.5

3

3.5

4

4.5

5

5.5

6

6.5

7

4 4.5 5 5.5 6 6.5

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -11.6195 + 3.0605 Ln (FL); r2=0.99; n=198

Figure 16. Length-weight relationship for Eastern brook trout sampled in Box Lake on October 7, 2003.

0

500

1000

1500

2000

2500

1998 1999 2000 2001 2002 2003

Num

ber o

f fis

h re

leas

ed

EbtRbt

Aylmer 3N Aylmer AF3N Pennask Pennask Pennask Pennask

Figure 17. Rainbow trout and Eastern brook trout stock selection and stocking

rate at Cameron Lake from 1998 to 2003.


February 2004 19

The stocking rate currently remains at 74% of theoretical capacity. Notwithstanding,

there was a definite contrast in length frequency between species. The size

distribution of rainbow trout ranged from 164 – 358 mm (mean = 222.9) and included

age-groups 1+ - 3+ but the sample was largely dominated by over-yearling fish (Fig.

18). Size-at-age information for rainbow trout is provided in Table 5; incremental

growth during their second and third years was highly comparable. The body:scale

relationship, illustrated in Figure 19, was again used to back-calculate length at

successive ages. A review of the length-weight relationship suggests proportional

growth with an average condition factor expressed by the rainbow trout population

(Fig. 20; Plate 4). Early maturity was again evident but size-related differences were

noted between sexes; rainbow trout males were maturing as small as 180 mm

whereas females were maturing >240 mm.

The size distribution of Eastern brook trout was more evenly balanced; the sample

ranged from 188 – 445 mm (mean = 312.0) and corresponding weights ranged from

102 – 1480 g (Fig. 21). The frequency distribution suggests that individuals up to 6

0

5

10

15

20

25

160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360

Size category (mm)

Perc

ent o

ccur

renc

e

1+

2+ 3+

Figure 18. Length frequency distribution of rainbow trout sampled in Cameron Lake on October 7, 2003.


February 2004 20

Table 5. Back-calculated lengths at successive annuli for rainbow trout in Cameron Lake. 95% confidence limits are shown in brackets.

Age-group nI II III

1+ 16 107.2(6.23)

2+ 8 114.3 217.9(7.83) (15.22)

3+ 2 100.9 161.6 271.6(1.22) (18.08) (38.34)

Grand Average 107.5 189.8 271.6

Age Class

years of age were present but this remains unconfirmed since aging structures were

not collected. Brook trout displayed an average condition (Fig. 22; refer to Plate 4)

and all fish were mature. There was no evidence of any all-female triploids, from the

1999 planting, in the sample.

0

50

100

150

200

250

300

350

400

0 20 40 60 80 100 120 140


Fork

leng

th (m

m)


Figure 19. Body:scale relationship for rainbow trout in Cameron Lake.


February 2004 21

3.5

4

4.5

5

5.5

6

6.5

5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 6

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -11.2531 + 2.9801 Ln (FL); r2=0.99; n=57

Figure 20. Length-weight relationship for rainbow trout sampled in Cameron

Lake on October 7, 2003.

0

2

4

6

8

10

12

14

190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440

Size category (mm)

Perc

ent o

ccur

renc

e

Figure 21. Length frequency distribution of Eastern brook trout sampled in

Cameron Lake on October 7, 2003.


February 2004 22

4

4.5

5

5.5

6

6.5

7

7.5

5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 6 6.1 6.2

Ln Fork length (mm)

Ln w

eigh

t (g)

Ln (W) = -11.4567 + 3.0427 Ln (FL); r2=0.99; n=56

Figure 22. Length-weight relationship for Eastern brook trout in Cameron Lake on October 7, 2003.


February 2004 23

3.2.5 Comfort Lake

Rainbow trout (38%; CPUE=4.83), Eastern brook trout (2%; CPUE=0.22) and

finescale sucker (60%; CPUE=7.56) were collected during an overnight, sinking

gillnet set at Comfort Lake on September 30, 2003. The size distribution of rainbow

ranged from 20 – 264 mm (mean = 195.9) and included age-groups 1+ and 2+ (Fig.

23). The absence of older age-groups in the sample suggests poor adult survival.

Multiple stocks of rainbow trout have been utilized over the past 6 years; 2000

Pennask yearlings were planted from 1998-99, 2000 Premier yearlings were planted

from 2000-01 and 2000 Pennask-Premier yearlings were planted from 2002-03 (Fig.

24). Current stocking levels are managed at ~54% of theoretical stocking capacity.

Back-calculated ages are provided in Table 6 based on the body:scale relationship

illustrated in Figure 25. The low correlation coefficient (r2=0.35) is attributed to the

high degree of scatter about the trend line owing to large differences in observed

scale growth among individuals in the sample. Low incremental growth during the

0

5

10

15

20

25

30

130 140 150 160 170 180 190 200 210 220 230 240 250 260

Size category (mm)

Perc

ent o

ccur

renc

e

1+

2+n=87

Figure 23. Length frequency distribution of rainbow trout sampled in Comfort Lake on September 30, 2003.


February 2004 24

0

500

1000

1500

2000

2500

1998 1999 2000 2001 2002 2003

Num

ber o

f fis

h re

leas

edPennask Pennask Premier Premier Pennask-Premier Pennask-Premier

Figure 24. Rainbow trout stock selection and stocking rate at Comfort Lake from 1998 to 2003.

Table 6. Back-calculated lengths at successive annuli for rainbow trout in Cameron Lake. 95% confidence limits are shown in brackets.

Age-group nI II

1+ 1 116.3(5.39)

2+ 5 139.8 189.2(3.55) (7.74)

Grand Average 128.1 189.2

Age Class


February 2004 25

second year may be attributed to early maturity (the majority of fish >165 mm were

maturing); low lake productivity (TDS=150) and/or coarsefish interactions.

Consequently, rainbow trout growth was not proportional based on the length-weight

determinations and a low slope coefficient was observed among the sample (Fig. 26;

Plate 5).

0

50

100

150

200

250

300

0 10 20 30 40 50 60 70 80 90

Scale radius (mm x60)

Fork

leng

th (m

m)

Fork length (mm) = 107.58 + 1.70 Scale radius; r2=0.35; n=20

Figure 25. Body:scale relationship for rainbow trout in Comfort Lake.


February 2004 26

3

3.5

4

4.5

5

5.5

4.8 4.9 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -9.4038 + 2.6141 Ln (FL); r2=0.92; n=85

Figure 26. Length-weight relationship for rainbow trout sampled in Comfort Lake on September 30, 2003.


February 2004 27

The four Eastern brook trout collected in the gillnet set ranged from 142 – 446 mm

(mean = 250.8) with corresponding weights ranging from 34 – 1180 g. The largest

individual (a female) was mature. Further analysis has not been attempted due to

the low sample size.

Finescale sucker displayed an even size structure; the frequency distribution ranged

from 110 to 295 mm (mean = 185.8; Fig. 27) and body weight ranged from 16 to 310

g. The high slope coefficient for finescale sucker (Fig. 28) suggests that this species

is likely out-competing rainbow trout for the available food supply. This same aspect

may explain the apparent poor survival of the selected rainbow trout stock owing to

the truncated size distribution that was observed. Although exact aging of the

sample was unconfirmed, the frequency distribution for finescale indicates that

individuals may be represented up to five years of age.

0

2

4

6

8

10

12

14

16

18

110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290

Size category (mm)

Perc

ent o

ccur

renc

e

n=58

Figure 27. Length frequency distribution of finescale sucker sampled in Comfort Lake on September 30, 2003.


February 2004 28

2.5

3

3.5

4

4.5

5

5.5

6

4 4.5 5 5.5 6

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -11.5092 + 3.0333 Ln (FL); r2= 0.99; n=58

Figure 28. Length-weight relationship for finescale sucker sampled in Comfort Lake on September 30, 2003.


February 2004 29

3.2.6 Halfway Lake

Rainbow trout (n=64; CPUE=3.05 fish/hr) was the only species captured in a sinking

gillnet set on October 1, 2003. Pennask stock was introduced in 1998 and 1999,

changed to Premier stock in 2000 and 2001 and presently includes the Pennask-

Premier cross; all plantings have remained at a stocking rate of 1500 fish per year

(Fig. 29) or ~58% of theoretical stocking. Rainbow trout ranged from 156 – 370 mm

(mean = 234.5) and included age-groups 1+ - 3+ (Fig. 30). Back-calculated ages for

the Halfway sample is provided in Table 7; incremental growth increased from ~80 to

100 mm from age 2 to age 3, respectively. The body:scale relationship displayed a

reasonable fit resulting in a high correlation coefficient (Fig. 31). Similarly, the

length-weight relationship was well-correlated, although growth was slightly less than

proportional (Fig. 32). Accordingly, the slope coefficient is slightly below average,

yet the fish visually appear healthy (Plate 6). Consistent with other observations that

include this stock, individuals were maturing but maturation was generally observed

0

200

400

600

800

1000

1200

1400

1600

1998 1999 2000 2001 2002 2003

Num

ber o

f fis

h re

leas

ed

Pennask Pennask Premier Premier Pennask-Premier Pennask-Premier

Figure 29. Rainbow trout stock selection and stocking rate at Halfway Lake from 1998 to 2003.


February 2004 30

0

2

4

6

8

10

12

14

16

18

20

160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370Size category (mm)

Perc

ent o

ccur

renc

e

n=641+

2+

3+

Figure 30. Length frequency distribution of rainbow trout sampled in Halfway Lake on October 1, 2003.

among fish >250 mm.

Table 7. Back-calculated lengths at successive annuli for rainbow trout in Halfway Lake. 95% confidence limits are shown in brackets.

Age-group nI II III

1+ 5 96(7.71)

2+ 9 96.1 174.2(2.48) (10.88)

3+ 5 95.1 181.3 279.6(5.36) (18.56) (23.42)

Grand Average 95.7 177.8 279.6

Age Class


February 2004 31

0

50

100

150

200

250

300

350

400

450

0 20 40 60 80 100 120 140


Fork

leng

th (m

m)


Figure 31. Body:scale relationship for rainbow trout in Halfway Lake.

3.5

4

4.5

5

5.5

6

6.5

5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 6Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -10.5296 + 2.8428 Ln (FL); r2=0.99; n=64


February 2004 32

Figure 32. Length-weight relationship for rainbow trout sampled in Halfway Lake on October 1, 2003.

3.2.7 Help Lake

The catch composition (n=223) from a single sinking gillnet set on September 30,

2003 consisted of 50% rainbow trout (CPUE=5.29), 41% finescale sucker

(CPUE=4.38), 7% Eastern brook trout (CPUE=0.76) and 2% burbot (CPUE=0.19).

The same choice of rainbow trout stocks selected for Aid and Comfort lakes have

been planted in Help Lake at a stocking rate of 2000 fish per year (Fig. 33) or ~41%

of theoretical stocking capacity. Similarly, the timing of stock introductions has

followed the same pattern recorded for the other local lakes from 1998 to 2003.

There is no record of previous brook trout or burbot release to Help Lake; their

occurrence may be natural owing to the lakes connectivity to Succour Creek and

hence the Columbia River, or, an unauthorized introduction.

The size distribution of rainbow trout ranged from 112 – 286 mm (mean = 188.4) and

includes age-groups 1+ to 3+ (Fig. 34). Back-calculated size-at-age determinations

appear in Table 8, based on the body:scale relationship provided in Figure 35. The

lower correlation coefficient is again attributed to the high degree of

0

500

1000

1500

2000

2500

1998 1999 2000 2001 2002 2003

Num

ber o

f fis

h re

leas

ed

Pennask Pennask Premier Premier Pennask-Premier Pennask-Premier


February 2004 33

Figure 33. Rainbow trout stock selection and stocking rate at Help Lake from 1998 to 2003.

0

2

4

6

8

10

12

14

16

18

110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290

Size category (mm)

Perc

ent o

ccur

renc

e1+

2+

3+

4+

n=111

Figure 34. Length frequency distribution of rainbow trout sampled in Help Lake on September 30, 2003.

scatter about the regression line due to considerable variation in growth among

Table 8. Back-calculated lengths at successive annuli for rainbow trout in Help Lake. 95% confidence limits are shown in brackets.


1+ 5 68(8.61)

2+ 13 65.9 143.2(4.75) (7.28)

3+ 10 64.5 131.9 190.8(7.67) (13.92) (12.08)

4+ 1 66.9 120.8 207 257.3

Grand Average 66.1 132.0 198.9 257.3

Age Class


February 2004 34

0

50

100

150

200

250

300

350

0 10 20 30 40 50 60 70 80 90

Scale radius (x 60 mm)

Fork

leng

th (m

m)

Fork length (mm) = 36.6099 + 2.8328 Scale radius; r2 = 0.68; n = 29

Figure 35. Body:scale relationship for rainbow trout in Help Lake.

individual fish. Low lake productivity (TDS=150), early maturity (generally, for fish

>185 mm), and coarsefish interactions are again suspected as causative factors

governing the growth characteristics of this population. Near-equal incremental

rainbow growth from age 2 to age 4 and the greater size distribution of the catch

suggest that competitive interactions may not be as intense as that observed in

Comfort Lake given the apparent lower density of coarsefish (i.e., based on a lower

CPUE in the sample). The length-weight relationship for rainbow trout provides

further evidence where a slightly improved coefficient (e.g., 2.84 in Help vs 2.62 in

Comfort) was evident, albeit that growth remained less than proportional (Fig. 36).

Finescale sucker frequency distribution ranged from 117 – 225 mm (mean = 170.2;

Fig. 37) and corresponding weights ranged from 20 – 148 g. The length-weight

relationship for this population is provided in Figure 38 which suggests a slightly

above-average slope coefficient.

Eastern brook trout ranged in length from 124 – 335 mm (mean = 228.2) and

corresponding weights varied from 18 – 444 g (Fig. 39). Above average condition


February 2004 35

was again evident for the sample (Fig. 40). Growth characteristics favouring the

2.5

3

3.5

4

4.5

5

5.5

6

4.6 4.8 5 5.2 5.4 5.6 5.8

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -10.6184 + 2.8449 Ln (FL); r2=0.99; n=111

Figure 36. Length-weight relationship for rainbow trout sampled in Help Lake on October 1, 2003.

0

2

4

6

8

10

12

14

16

18

20

120 130 140 150 160 170 180 190 200 210 220

Size category (mm)

Perc

ent o

ccur

renc

e

n=34


February 2004 36

Figure 37. Length frequency distribution of finescale sucker sampled in Help Lake on October 1, 2003.

2.5

3

3.5

4

4.5

5

5.5

4.7 4.8 4.9 5 5.1 5.2 5.3 5.4 5.5

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -11.9648 + 3.1324 Ln (FL); r2=0.99; n=32

Figure 38. Length-weight relationship for finescale sucker sampled in Help Lake on October 1, 2003.


February 2004 37

0

2

4

6

8

10

12

14

16

18

20

120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330

Size category (mm)

Perc

ent o

ccur

renc

e

n=16

Figure 39. Length frequency distribution of Eastern brook trout sampled in Help Lake on October 1, 2003.

2.5

3

3.5

4

4.5

5

5.5

6

6.5

4 4.5 5 5.5 6 6.5

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -12.7921 + 3.2625 Ln (FL); r2=0.99; n=16

Figure 40. Length-weight relationship for Eastern brook trout sampled in Help Lake on October 1, 2003.


February 2004 38

highest slope coefficient among representative species may in part be due to a low

brook trout population density displaying a competitive advantage over the other

species.

Burbot ranged in length from 158 – 304 mm (mean = 230.3) and corresponding

weights varied from 24 – 150 g. Low sample size restricted further analysis.

Representative photos of the species complex are shown in Plate 7.

3.2.8 Rockbluff Lake

Rainbow trout (n=49; CPUE=2.58) were the only species encountered in a single

sinking gillnet set on October 17, 2003. Multiple stocks have been planted over the

past six years: Badger-Tunkwa stock was introduced from 1998 to 2000, Premier

stock was released in 2001 and switched to Tunkwa stock over the last two years

(Fig. 41). The stocking rate for Rockbluff (Quartz) Lake has remained at 3000

yearlings per year over the same duration and is currently held at 39% of theoretical

stocking capacity. The size distribution of rainbow trout ranged from 144 – 445 mm

0

500

1000

1500

2000

2500

3000

3500

1998 1999 2000 2001 2002 2003

Num

ber o

f fis

h re

leas

ed

Badger-Tunkwa Badger-Tunkwa Badger-Tunkwa Premier Tunkwa Tunkwa

Figure 41. Rainbow trout stock selection and stocking rate at Rockbluff Lake from 1998 to 2003.


February 2004 39

(mean = 270.1) and included age-groups 1+ - 4+ (Fig. 42). Back-calculated size-at-

age determinations are provided in Table 9 based on the body:scale relationship in

Figure 43. The latter relationship is highly significant (r2=0.93) in consideration of

0

2

4

6

8

10

12

140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440

Size category (mm)

Perc

ent o

ccur

renc

e

n=49

1+

2+

3+

4+

Figure 42. Length frequency distribution of rainbow trout sampled in Rockbluff Lake on October 17, 2003.

Table 9. Back-calculated lengths at successive annuli for rainbow trout in Rockbluff Lake. 95% confidence limits are shown in brackets.


1+ 5 121.6(4.19)

2+ 12 123.4 195.4(5.35) (18.35)

3+ 5 124.9 197.2 291.9(4.30) (10.08) (21.87)

4+ 2 127.5 207.3 278.3 367.7(7.74) (4.47) (42.94) (8.75)

Grand Average 124.4 200.0 285.1 367.7

Age Class


February 2004 40

0

50

100

150

200

250

300

350

400

450

500

0 20 40 60 80 100 120 140 160 180


Fork

leng

th (m

m)


Figure 43. Body:scale relationship for rainbow trout in Rockbluff Lake.


February 2004 41

limited scatter about the trend line. Incremental growth was constant from ages 2

through 4 (refer to Table 9) and the majority of fish >240 mm were maturing. Despite

the lakes moderate to high productivity (TDS=350), growth is slightly less than

proportional; early maturation may contribute to the lower coefficient observed (Fig.

44). This growth characteristic may also account for the larger overlap between age-

groups 2+ and 3+ where non-maturing individuals (generally females) were able to

achieve a larger size during their third summer (refer to Fig. 42). The size

distribution and average condition of representative individuals are shown in Plate 8.

3.2.9 Rocky Point Lake

Eighty-eight rainbow trout (CPUE=4.89) were captured in a single sinking gillnet set

on October 2, 2003. With the exception of Premier stock planted in 1999, Tunkwa

stock has since been planted in Rocky Point Lake at a stocking rate of 8000 fall fry

per year (Fig. 45). The size distribution ranged from 160 – 430 mm (mean = 281.2)

3.5

4

4.5

5

5.5

6

6.5

7

4.5 4.7 4.9 5.1 5.3 5.5 5.7 5.9 6.1 6.3 6.5

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -10.8296 + 2.8985 Ln (FL); r2=0.99; n=49

Figure 44. Length-weight relationship for rainbow trout sampled in Rockbluff Lake on October 17, 2003.


February 2004 42

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

1999 2000 2001 2002 2003

Num

ber o

f fis

h re

leas

ed

Premier Tunkwa Tunkwa Tunkwa Tunkwa

Figure 45. Rainbow trout stock selection and stocking rate at Rocky Point Lake from 1999 to 2003.

and included age-groups 1+ - 5+ (Fig. 46). Notwithstanding, the length frequency

distribution was skewed to the younger age-groups. Back-calculated ages are

based on a body:scale relationship that displays a high degree of scatter and hence,

a lower correlation value (r2=0.72; Fig. 47); average annual increments in growth

steadily decline beyond their second year (Table 10) and may be related to early

maturation in this stock (i.e., majority of fish maturing >250 mm) or low lake

productivity (TDS=90). The rather large increment in their first year suggests that

fish released in the fall, continue to feed actively until ice-up.

Growth was again less than proportional (b=2.75; Fig. 48) and fish were generally in

fair condition (Plate 9); two of the larger individuals captured in the sample had not

recovered from their kelted condition following spawning (i.e., despite rearing

another summer in the lake).


February 2004 43

0

2

4

6

8

10

12

14

16

160 180 200 220 240 260 280 300 320 340 360 380 400 420

Size category (mm)

Perc

ent o

ccur

renc

e

n=68

1+ 2+

3+

4+

5+

Figure 46. Length frequency distribution of rainbow trout sampled in Rocky Point Lake on October 2, 2003.

0

50

100

150

200

250

300

350

400

450

0 20 40 60 80 100 120 140 160

Scale radius ( X60 mm)

Fork

leng

th (m

m)


Figure 47. Body:scale relationship for rainbow trout in Rocky Point Lake.


February 2004 44

Table 10. Back-calculated lengths at successive annuli for rainbow trout in Rocky Point Lake. 95% confidence limits are shown in brackets.

Age-groupI II III IV V

1+ 111.1

2+ 123.1 176.2(6.40) (34.63)

3+ 124.3 198.6 261.2(1.95) (14.80) (15.82)

4+ 121.3 192 265 323(4.72) (19.15) (26.24) (11.75)

5+ 117.2 176.1 252.1 318.3 374.8

Grand Average 119.4 185.7 259.4 320.7 374.8

Age Class


February 2004 45

3.5

4

4.5

5

5.5

6

6.5

7

5 5.2 5.4 5.6 5.8 6 6.2

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -10.0424 + 2.7516 Ln (FL); r2=0.98; n=68

Figure 48. Length-weight relationship for rainbow trout sampled in Rocky Point Lake on October 2, 2003.

3.2.10 Rosebud Lake

Seventy rainbow trout (CPUE=4.24 fish/hr) were captured in a single sinking

gillnetset on October 8, 2003. Fraser Valley Trout Hatchery domestic stock has

been introduced since 1999 at a stocking rate of 3000 fingerlings per year; additional

stocks planted in 2003 include Gerrard rainbow (1000 yearlings) raised at Selkirk

College as part of their educational program (Fig. 49). The size distribution of

rainbow trout ranged from 153 – 433 mm (mean = 253.7) and includes age-groups

1+ - 4+ (Fig. 50). The length frequency distribution is highly skewed to yearling fish

that are largely represented by Gerrard stock judging by the even pattern of circuli

spacing on scales and recorded size at release (22.7 g). The missing age-group

(2+) and low representation of older age classes in the population suggests

extremely low survival of domestic rainbow in Rosebud Lake. Poor survival may be

related to seasonal metabolic processes that provide environmental extremes within

this shallow, hardwater basin. Back-calculated ages based on the body: scale


February 2004 46

0

500

1000

1500

2000

2500

3000

3500

1999 2000 2001 2002 2003 2003

Num

ber o

f fis

h re

leas

ed

Fraser Valley 3N Fraser Valley Fraser Valley Fraser Valley Fraser Valley

Gerrard

Figure 49. Rainbow trout stock selection and stocking rate at Rosebud Lake from 1996 to 2002.

0

5

10

15

20

25

30

150 170 190 210 230 250 270 290 310 330 350 370 390 410 430Size category (mm)

Wei

ght (

g)

1+

3+ 4+

n=70

Figure 50. Length frequency distribution of rainbow trout sampled in Rosebud Lake on October 8, 2003.


February 2004 47

relationship (Fig. 51) are provided in Table 11 but caution is advised due to the

limited number of domestic age-groups in the data set; size-at-age determinations

for the Gerrard stock have not been included to avoid confusion in growth rates

Table 11. Back-calculated lengths at successive annuli for domestic rainbow trout in Rosebud Lake. 95% confidence limits are shown in brackets.


1+ 3 55.3(20.52)

2+

3+ 6 73.3 167.9 265.6(14.5) (15.93) (12.82)

4+ 2 53.6 95.8 226 351.7(2.09) (49.0) (1.78)

Grand Average 60.7 131.9 245.8 351.7

Age Class


February 2004 48

0

50

100

150

200

250

300

350

400

450

500

0 20 40 60 80 100 120 140 160Scale radius (mm X60)

Fork

leng

th (m

m)


Figure 51. Body:scale relationship for rainbow trout in Rosebud Lake. between stocks. A review of the length-weight relationship indicates proportional

growth among individuals in the sample and an average condition prevails (Fig. 52;

Plate 10). For the purpose of this investigation, both stocks of rainbow trout have

been included to evaluate overall condition. From the available data for Fraser

Valley rainbow trout, a maturing condition was observed for fish >240 mm.

3.2.11 Solar Lake

Rainbow trout (n=33; CPUE=1.61 fish/hr) was the only species recorded in the catch

during a single sinking gillnet set on October 16, 2003. Solar Lake was a candidate

lake for winter aeration during the mid-1980’s since it was known to partially winter-

kill; the presence of relatively mild winters over the last decade has minimized the

extent of oxygen depletion under ice cover and stocking has continued in the

absence of further management intervention (i.e., aeration). Tunkwa stock was

planted into Solar Lake from 1998-99, changed to Premier stock in 2000-01 and

returned to Tunkwa stock over the last two years (Fig. 53). The size distribution of

the catch (Fig. 54) varied from 225 – 560 mm (mean = 292.6), included age-groups


February 2004 49

3.5

4

4.5

5

5.5

6

6.5

7

4.5 5 5.5 6 6.5

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -11.1415 + 2.9633 Ln (FL); r2=0.98; n=70

Figure 52. Length-weight relationship for rainbow trout sampled in Rosebud Lake on October 8, 2003.

0

200

400

600

800

1000

1200

1998 1999 2000 2001 2002 2003

Num

ber o

f fis

h re

leas

ed

Tunkwa Tunkwa Premier Premier Tunkwa Tunkwa

Figure 53. Rainbow trout stock selection and stocking rate at Solar Lake from 1998 to 2003.


February 2004 50

0

2

4

6

8

10

12

14

16

220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560

Size category (mm)

Perc

ent o

ccur

renc

e

2+

3+

4+ 5+

n=33

Figure 54. Length frequency distribution of rainbow trout sampled in Solar Lake on October 16, 2003.

(2+ - 5+ and was highly skewed to fish <300 mm. The lower percentage of large fish

in the sample would suggest poor survival to adulthood that may be linked to poor

over-winter survival due to ongoing low oxygen concentrations under ice cover.

Size-at-age determinations appear in Table 12 based on the body:scale relationship

(r2=0.96) provided in Figure 55. Owing to inherent high lake productivity, individuals,

on average, demonstrated sustained incremental growth up to year 4 (refer to Table

12) yet fish weight was not proportional to fish length (Fig. 56) suggesting that body

condition is below expected growth. Representative samples of the catch are shown

in Plate 11. Early maturation (for males >250 mm) was again characteristic of the

sample; this condition was more frequent in smaller males that dominated the catch,

whereas females displayed early maturation at a larger size (generally > 270 mm).

Table 12. Back-calculated lengths at successive annuli for rainbow trout in Solar Lake. 95%


February 2004 51


Age-group nI II III IV V

1+

2+ 13 84.5 166.9(3.57) (19.18)

3+ 1 81 128.5 252.5

4+ 1 94.5 171.6 309.9 377.60 0 0 0

5+ 2 87.4 176.1 271.6 411.9 456.8(9.10) (43.70) (38.86) (40.10) (51.20)

Grand Average 86.7 160.8 278.0 394.8 456.8

Age Class


February 2004 52

0

100

200

300

400

500

600

0 50 100 150 200 250


Fork

leng

th (m

m)

Fork length (mm)= 36.1974 + 2.5705 (Scale radius); r2=0.96; n=17

Figure 55. Body:scale relationship for rainbow trout in Solar Lake.


February 2004 53

4.5

5

5.5

6

6.5

7

7.5

8

5.2 5.4 5.6 5.8 6 6.2 6.4

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -10.0218 + 2.7712 Ln (FL); r2=0.98; n=33

Figure 56. Length-weight relationship for rainbow trout sampled in Solar Lake on October16, 2003.

3.2.12 Three Island Lake

Rainbow trout (n=39; CPUE=2.17 fish/hr) was the only species sampled in a single

sinking gillnet set on October 2, 2003. Three Island Lake has been consistently

planted with Tunkwa stock over the last five years at a rate of 5000 fall fry per year

(Fig. 57) or ~77% of theoretical stocking. Prior stocking with Premier stock was

undertaken in 1999. The size distribution of the catch ranged from 158 – 350 mm

(mean = 235.9) and included age-groups 1+ - 4+ (Fig. 58); a more even size

distribution was evident for the sample. The body: scale relation demonstrated

limited scatter (r2=0.92; Fig. 59) and annual increments displayed continued growth

up to 4 years of age (Table 13). Consistent with low lake productivity (TDS=70),

however, body weight of individual fish was not proportional to body length and the

majority of fish were observed in fair condition (Fig. 60; Plate 12). Further

examination of the body cavity indicated early maturity among smaller males (for

individuals >230 mm) and larger females (for individuals > 280 mm).


February 2004 54

0

1000

2000

3000

4000

5000

6000

1999 2000 2001 2002 2003

Num

ber o

f fis

h re

leas

edPremier Tunkwa Tunkwa Tunkwa Tunkwa

Figure 57. Rainbow trout stock selection and stocking rate at Three Island Lake from 1999 to 2003.

0

2

4

6

8

10

12

14

16

18

20

160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350

Size category (mm)

Perc

ent o

ccur

renc

e

1+

2+

3+

4+

n=39

Figure 58. Length frequency distribution of rainbow trout sampled in Three Island Lake on October 2, 2003.


February 2004 55

0

50

100

150

200

250

300

350

400

0 20 40 60 80 100 120 140 160

Scale radius (x60 mm)

Fork

leng

th (m

m)


Figure 59. Body:scale relationship for rainbow trout in Three Island Lake.

Table 13. Back-calculated lengths at successive annuli for rainbow trout in Three Island Lake. 95% confidence limits are shown in brackets.


1+ 4 104.5(3.78)

2+ 5 105.9 170.4(4.51) (9.02)

3+ 7 109.8 167.9 246.7(2.34) (7.49) (20.09)

4+ 5 109.3 154.1 208.1 314.4(2.33) (9.17) (13.00) (15.21)

Grand Average 107.4 164.1 227.4 314.4

Age Class


February 2004 56

3.5

4

4.5

5

5.5

6

6.5

5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9

Ln Fork length (mm)

Ln W

eigh

t (g)

Ln (W) = -10.4104 + 2.8191 Ln (FL); r2=0.99; n=39

Figure 60. Length-weight relationship for rainbow trout sampled in Three Island Lake on October 2, 2003.

3.3 Growth, stocking density and angler use

A comparison of rainbow trout growth characteristics across the 12 study lakes

suggests a wide range of deviation from proportionality (i.e., from 2.62 – 3.00 (mean

= 2.85); the highest value was determined for Alces and the lowest value was

observed at Comfort Lake (Fig. 61). The higher coefficients approaching isometric

growth were generally associated with monoculture fisheries with low stocking

density while the lower values were generally associated with lakes characteristic of

high stocking density and/or coarsefish populations. An absence of theoretical

stocking calculations exist for those lakes where shoal area has not yet been

completed.

With respect to the length-weight relationship of individual rainbow trout populations,

the importance of stocking density cannot be over-stated in consideration of density-

dependent growth coupled with lake productivity. Moreover, stocking densities in


February 2004 57

combination with the appropriate management regime are generally intended to

meet a specific management objective. The array of management regimes can vary

from high turnover put and take fisheries to low turnover quality fisheries; the latter

2.4

2.5

2.6

2.7

2.8

2.9

3

3.1

Comfor

t

Halfway

Rocky

Point

Solar

Three I

sland Help Aid

Rockb

luff

Roseb

ud Box

Camero

nAlce

s

Dev

iatio

n fr

om is

omet

ric g

row

th

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Perc

enta

ge o

f the

oret

ical

cap

acity

Slope coefficient% Theoretical

Figure 61. A comparison of rainbow trout length-weight relationships among representative study lakes.

option is generally associated with more restrictive regulations to meet quality

angling objectives. In the present context, the 12 study lakes are more

representative of put and take fisheries where minimum restriction is emphasized.

Stocking densities are purposely set below the theoretical stocking rates of individual

lakes to ensure that proportional growth is achieved. Further fine-tuning of stocking

rate is dependent upon the amount of angler use and corresponding returns to the

creel. In this instance, angler use at a few of the selected lakes, monitored from

aerial counts, is considered low and without any apparent increasing trend; SLIM

counts for 2003 have been purposely avoided due to lower than expected numbers

associated with forest closure/ fire hazard rating during the summer of 2003. The

higher coefficient observed for Alces Lake, may in part be due to both a higher catch

(Fig. 62) and lower stocking rate that reduces intra-specific competition. Low angler

use and high corresponding CPUE’s from gillnet surveys may explain the lower

coefficient of fish in lakes with a more balanced size structure (e.g., Three Island,


February 2004 58

Rocky Point, Rockbluff and to a lesser extent Halfway) and assumed higher

0

200

400

600

800

1000

1200

1400

1600

1800

Rocky Point Three Island Halfway Rockbluff Alces Solar

Num

ber o

f ang

ler d

ays

per y

ear

1996

2002

Figure 62. A comparison of angler use at selected lakes based on available SLIM data. Data summarized for individual years.

density of fish. There are no angler use statistics available for West Kootenay lakes

other than anecdotal information pertaining to relative use in which case Rosebud

likely receives the greatest amount of annual pressure from Trail and Castlegar

residents (J. Bell, Fisheries Technician, Nelson, B.C.; pers. comm.).

4.0 Discussion

The results of the 2003 small lakes assessment program are particularly interesting

in light of the nature of candidate lakes that are generally of low biological

productivity and characteristic of rainbow trout stocks of a non-special designation.

Only two water bodies are considered under special management status in regard to

special angling regulations (Alces Lake; no bait, artificial fly, winter closure) or

reduced harvest (Rosebud; 2 fish daily limit). Moreover, none of the selected lakes

are considered to support exceptional angler use due to an inherent, above-average


February 2004 59

quality of the fishery. Earlier stock assessments have been conducted on seven of

the selected lakes during the mid to late 1980’s (Rockbluff, Comfort, Help, Aid and

Solar; Ministry of Water, Land and Air Protection; file data) or early 1990’s (Three

Island and Halfway; RL&L Environmental Services Ltd.; 1991 and 1993, respectively)

and provide some insight on future management direction. As a preface to further

discussion on fisheries management goals, interpretations consider the

“representativeness” of each fish sample at selected lakes recognizing 1) the size

selectivity of the sampling gear and 2) end of season growth rates that are likely

typical of the slower growing individuals in the population, since the faster growing

members are often removed by the fishery.

A general trend of poor to fair isometric growth exists for most of the representative

samples among the lakes surveyed. This condition was particularly evident for those

lakes with coarsefish populations; a comparison of coarsefish catch rates between

years (Ministry of Water, Land and Air Protection; Cranbrook, B.C.; file data)

suggests a burgeoning increase in coarsefish numbers in Comfort Lake that is likely

responsible for the poorest growth among study lakes. A negative correlation seems

apparent between coarsefish density and proportionality for the three lakes in the

Succour Creek drainage; the highest coarsefish catch per unit was observed in

Comfort Lake (7.56 fish per hour) while the lowest CPUE was observed in Aid Lake

(0.39 fish per hour). In contrast, the highest isometric growth coefficient was

determined for Aid Lake while the lowest value was afforded to Comfort Lake

rainbow trout. Owing to the nature of surface water interconnectivity between these

lake basins and coarsefish dynamics, growth of rainbow trout populations in Help

and Aid lakes is expected to decline into the future. Moreover, the recent occurrence

of two other species in the lake chain (i.e., brook trout and burbot; whether natural or

unauthorized introduction) suggests that competitive interactions between species

and/or predation will likely exert certain pressures on future rainbow trout survival.

Annual releases at present stocking levels should continue for Help and Aid Lake in

the interest of diversifying angling opportunity in the area, however, future monitoring

will be required to determine when further stocking is unwarranted. Alternatively, if

suitable rainbow trout stocks compatible with coarsefish populations, become

available in the future, continued stocking of all three lakes is recommended.

Outplanting of Blackwater stock in Help and Aid lakes is not recommended at this

time owing to inherent behaviour that would likely result in their downstream

migration as evidenced in other small lakes, with outlet channels, in the Kootenay


February 2004 60

Region and B.C. southern interior (Oliver 2003).

For monoculture lakes with apparent low angling pressure (e.g., Halfway, Rockbluff,

Rocky Point, Three Island and Solar), early maturation in both males and females

may be problematic towards improved trout growth among selected lakes. Early

maturation seems more apparent for Tunkwa and Pennask-Premier stocks and may

require a shift towards the use of Pennask stock in combination with sterilization

techniques presently employed at Kootenay Trout Hatchery. In recognition of the

low isometric growth coefficient for fish at Halfway Lake, a shift to triploid Pennask

stock and a reduction in stocking rate to 1000 yearlings per year may help resolve

the present situation. Despite the highest coefficient among study lakes in 2003,

Alces Lake should also be considered as a candidate for triploid introduction due to

its connectivity to the Lussier drainage and the provincial fisheries mandate to

protect native wildstock in natural waters. The use of heat shock to Pennask eggs

may be a cost-effective means of achieving management objectives without the

increased expense of AF3N introduction.

The condition of rainbow trout under multiple stock fisheries (i.e., Box and Cameron

lakes) is particularly interesting. Despite appearances, both rainbow stocks have

achieved acceptable growth in the presence of a successful competitor but rainbow

populations are highly skewed to younger fish. Despite large differences in Eastern

brook trout numbers between lakes (based on large differences in CPUE between

lakes), the size structure of each population is more evenly balanced than that

observed for rainbow trout at either lake. The fewer number of rainbow trout display

a lower deviation from proportional growth, but survival to adulthood would appear

somewhat compromised as a consequence of competition or predation. Continued

stocking of rainbow trout at current levels is recommended to diversify angling

opportunities in the area, but, encouragement of a differential harvest limit for brook

trout at Box and Cameron lakes (i.e., a higher daily catch limit) may be beneficial in

controlling very large brook trout populations. Alternatively, it would be beneficial to

block spawning migrations to the outlet channel at Box Lake to reduce overall

recruitment to the system. The introduction of catchable rainbow trout at Box Lake is

currently being considered by fisheries management staff; the provision of catchable

trout may be an important measure to alter public perception towards black spot

disease that currently appears to restrict angler use at this lake. The response of

catchables within a mixed stocked fishery will require further monitoring to evaluate


February 2004 61

their performance, however, since the results of catchable introductions at Rosen

Lake, in the East Kootenay, were not particularly favourable (Oliver 2003).

Rosebud Lake provides an interesting contrast in survival between rainbow trout

stocks. The results of the 2003 survey demonstrated proportional growth among

individuals yet poor survival to adulthood. It is important to recognize that the

contribution of Gerrard stock largely overshadows the contribution of Fraser Valley

rainbow in the analysis, as well, a missing year class (two year olds) was evident for

the latter stock. Although further investigation into Fraser Valley trout survival is

warranted, ambient water quality over the last few years may provide some insight.

Rosebud Lake supports an abundant macrophyte community and local water

chemistry likely supports moderate phytoplankton populations. The high demand for

carbon to meet the photosynthetic requirements of both macrophyte and

phytoplankton communities may cause a shift in CO2 equilibrium during the summer

growing season that elevates pH to levels in excess of 9.0; this occurrence seems

plausible given the late season pH value of 8.9 at time of survey (i.e., end of the

growing season). Supporting lines of evidence were apparent by the high amount of

calcium carbonate precipitate on plants or submerged woody debris within the littoral

zone that normally occurs in calcareous hardwater lakes with high pH values (Wetzel

1975). Given the differences in the genetic make-up between Fraser Valley and

Gerrard stock, domestics may have a lower pH tolerance than interior stocks of

rainbow trout. A higher summer pH would explain the missing year class and overall

low survival during hot, dry summers that have been experienced in the recent past.

The cumulative effect of high pH and elevated surface temperature could place

undue physiological stress on Fraser Valley stocks (i.e., stress that hasn’t been

observed among other interior stocks evolving under naturally high pH regimes).

Notwithstanding these concerns, partial winter-kill cannot be ruled out owing to the

high macrophyte community present and previous anoxic conditions below 4.5 m,

measured in late spring (J. Bell, Fisheries Technician; pers. comm.). Further

examination of summer pH is warranted and investigations could extend to caged

experiments with Fraser Valley stock in surface waters to corroborate potential

mortality. Similarly, continued monitoring of late winter oxygen profiles would be

useful to confirm the effects of lake metabolism under ice cover relative to over-

winter rainbow trout survival. In the absence of further study, it may be desirable to

introduce alternative interior rainbow stocks at present stocking levels or consider

catchable introductions.


February 2004 62

As a final note, the introduction of Eastern brook trout into Comfort, Help and Box

lakes suggest the need for heightened public awareness to avoid both the ecological

and legal consequences of unauthorized introductions into provincial waterbodies.

Disregard for the importance of maintaining current management strategies can

severely compromise both management objectives and the long-term maintenance

of the native species complex. Future efforts/actions are warranted to dissuade the

public from further inter-basin transfers.

5.0 Literature Cited

Bagenal, T.B. and F.W. Tesch. Age and growth. Pages101-136 in T.B. Bagenal (ed.) Methods for assessment of fish production in fresh waters. Blackwell Scientific Publications Ltd., Oxford, England.

Ministry of Water, Land and Air Protection, Cranbrook, B.C.

Oliver, G.G. 2003. Kootenay Region small lakes stocking assessment: 2002. Prepared for Ministry of Water, Land and Air Protection, Cranbrook, B.C. Prepared by GG Oliver and Associates Environmental Science, Cranbrook, B.C. 51 p + appnds.

RL&L Environmental Services Ltd. 1991. A Fisheries Investigation of Three Island Lake. Prepared for Mica Fisheries, Technical Committee, Nelson, B.C. Prepared by RL&L Environmental Services Ltd, Edmonton, AB. 31 p + appnds.

RL&L Environmental Services Ltd. 1991. A Fisheries Investigation of Halfway Lake. Prepared for Mica Fisheries, Technical Committee, Nelson, B.C. Prepared by RL&L Environmental Services Ltd, Vancouver, B.C.. 26 p + appnds.

Ryder, R.A., S.R., Kerr, K.H. Loftus, and H.A. Regier. 1974. The morphoedaphic index, a fish yield estimator – a review and evaluation. Journal of the Fisheries Research Board of Canada 31:663-688.

Wetzel, R.G. 1975. Limnology. W.B.Saunders Co., Philadelphia.


February 2004 63

APPENDIX 1

Bathymetric maps for selected lakes

Gillnet locations are indicated with an arrow


February 2004 64


February 2004 65


February 2004 66


February 2004 67


February 2004 68


February 2004 69


February 2004 70


February 2004 71


February 2004 72


February 2004 73


February 2004 74

APPENDIX 2

Biological data

Maturity Classifications:

IM = Immature

M = Mature

MT = Maturing

K = Kelt


February 2004 75

Lake: Aid Date: 29-Sep-03 TDS (ppm): 150 pH: 8.1Species:

Gillnet Deployment Time (hrs): 23

Weight Length Sex Maturity Stomach Weight Length Sex Maturity Stomach(g) (mm) contents (g) (mm) contents

Rainbow trout 202 260 F MT 72 19224 129 104 208 F MT138 242 M MT 90 195 F MT150 242 F MT 70 185 M MT146 252 F MT 36 14930 138 22 12262 180 F IM 70 18680 200 66 18940 151 94 202 F MT108 208 F MT 68 185 F MT58 169 F IM 90 214 M MT100 205 M MT 96 201 M MT118 211 F MT 78 190 M MT178 251 F MT 34 150108 212 M MT 52 172 F IM52 164 86 192 M MT114 226 F MT 118 223 F MT114 223 F MT 84 200 F IM50 166 24 13072 188 F IM 64 18486 204 F IM 62 178 F IM30 138 88 202 F IM68 184 F MT 64 17646 159 86 205 M MT

Finescale sucker 110 21096 19380 18416 10358 17020 11514 10316 11216 111


February 2004 76

Lake: Alces Date: 16-Oct-03 TDS (ppm): 180 pH: 8.3Species:

Gillnet Deployment Time (hrs): 19.5

Weight Length Sex Maturity Stomach(g) (mm) contents

Rainbow trout 704 382 F M538 370 F M770 390 M M420 340 F M504 350388 345 M M532 360 F IM592 387 M M388 330 M M374 328 M M472 345 M M192 243508 361 F M376 350 M M282 300 M M394 341 F M486 352 F M390 338 M560 364 F MT332 324 F MT242 280350 317 M MT304 303 F IM280 302 F IM464 359 M MT496 346 F MT348 328 M MT200 262 M MT354 313 M MT532 355 F MT434 335 F MT318 311 M MT408 332 F MT472 370 M K660 400 F MT578 380 F MT572 364 F EGG BOUND710 394 M MT358 320 M MT364 314 F MT608 364 F MT298 297 F IM318 311 F IM418 340 M MT342 328 M MT458 354 F MT314 355 M K222 269 M MT30 145 IM


February 2004 77

Lake: Box Date: 6-Oct-03 TDS (ppm) 90 pH: 8.9Species:



Rainbow trout 674 391 F MT496 358 M MT442 336 F MT244 273 F MT182 250 F IM146 232 M MT256 284 F IM166 237 M MT78 193 IM82 193 M IM98 210 M IM86 190 M MT58 170 F IM22 128 IM48 16128 13318 11428 13638 14872 18364 17290 193 M MT76 191 M MT72 178 M MT82 200 M MT58 175 M MT60 163 M MT64 183 IM66 174 M MT

Black spot disease not as apparent on Rb as Ebt


February 2004 78


Eastern brook trout398 316 F M E 436 324 F IM480 322 M M snails 306 302 F M260 262 F M E 158 240 F M456 340 F M E 24 126 F M228 265 M M E 236 265 M M202 255 M M E 236 274 M M420 316 F M E 278 265 M M446 319 F M E 376 314 F M358 300 F M E 228 255 M M398 314 F M E 386 315 F M192 246 F M E 192 246 F M300 290 M M snails 310 290 F M392 296 M M E 122 214 IM206 255 M M E 380 310 F M220 260 M M E 242 273 F M220 267 M M E 184 242 F M282 274 F M E 184 246 F M394 324 F M 78 192 F M486 322 F M 104 208 F22 123 78 186 M M20 121 232 259 F M36 143 260 262 M M20 118 198 249 M M20 124 230 266 F M34 140 80 182 M M16 118 250 264 M M22 124 280 28316 114 152 224 M M20 117 184 24934 148 354 307 F M14 108 246 258 M M16 110 128 222 M M20 119 376 316 M M

388 307 202 250 F M244 272 M M 238 258 M M206 256 M M 78 189 F M500 336 M M 80 194 M M362 307 F M 62 169 M M220 265 F M 176 235 M M312 296 F M 126 228 M M246 277 F M 150 220 M M254 276 M M 54 168 F M196 257 M M 362 295 F M296 308 M M 156 226 M M322 300 F M 228 254 F M388 319 F M 304 275 F M20 118 F M 162 239 F M18 112 IM 56 160 F M

148 228 IM 224 260 IM178 243 IM 320 309 M M132 216 IM 410 331 IM326 303 M M 198 254 M M328 298 M M 194 245 M M276 290 M M 620 366 M M172 242 M M 366 302 M M122 212 F M 194 254 M M156 221 M M 482 335 M M224 257 M M 504 356 M M360 311 M M 148 222 F M36 140 F M 164 233 F M


February 2004 79


Eastern brook trout80 188 F M 210 265 F M82 184 M M 152 230 F M

160 243 162 236 M IM chironomid32 139 M M 110 198 M M20 118 M M 104 203 F M28 132 M M 100 201 M M14 102 M M 59 163 M IM chironomid24 125 44 159 M M22 116 220 253 M M20 116 382 322 M M20 119 274 278 F M20 117 82 202 M M

292 274 282 278 M M196 236 234 262 M M242 260 394 320 M M306 280 404 325 M M330 317 M M 92 211 IM244 264 M M 394 309 M M176 236 M M 250 252 M M26 133 M M 330 309 M M18 112 F M 238 275 IM

266 262 M M 194 246 M M18 116 M M 292 269 F M22 123 572 354 F M18 117 138 214 M M16 119 M M 78 184 IM

302 267 82 185 M M268 268 100 204 M M328 302 172 235 F M462 327 102 199 F M302 296 214 240 F M610 383 102 199 M M364 300 56 170 F M334 292 366 302 M M384 308 430 316 F M190 250 M M 380 306 M M174 245 F M 318 302 M M232 266 F M 376 328 M M402 315 M M 466 322 M M

plus 3 unmeasured; all fish heavy with black spot disease


February 2004 80

Lake: Cameron Date: 6-Oct-03 TDS (ppm) 40 pH: 8.6Species:



Rainbow trout 520 358 F MT chironomids 78 187356 310 F IM 114 218 IM400 326 M MT 72 186 IM122 222 90 197 IM136 230 IM 86 198 IM120 216 M MT 98 207 IM54 170 118 219 IM54 169 IM 90 193 IM322 303 M MT 76 194 IM318 306 F MT 106 213176 260 F IM 62 169 IM110 204 M MT 64 182 IM52 164 68 180 IM446 344 F MT 76 187 IM298 287 M MT 184 242 M MT132 225 M IM 96 203 IM172 244 F MT 556 358 F MT132 218 M MT 448 332 F IM158 244 F IM 98 208 IM114 215 M MT 72 188 IM100 200 Im 74 179 IM86 195 108 200 M MT88 199 IM 70 181 M MT104 204 88 194 IM78 193 IM 350 310 M MT80 189 IM 116 219 IM108 208 IM 62 171 IM92 200 IM 84 19198 196 M MT plus 2 more unsampled


February 2004 81


Eastern brook trout1480 445 F M 394 310 M M1026 426 F M 210 254 M M668 349 M M 582 349 F M404 306 M M 476 327 F M372 310 F M 290 268 M M664 362 F M 158 228 M M668 362 F M 238 280 M M878 397 M M 258 268 F M234 257 F M 222 266 F M870 420 M M 118 218 M M598 349 M M 176 237 M M758 385 F M 128 215 M M912 404 M M 142 220 M M808 395 M M 172 239 M M704 365 M M 102 188 M M242 262 M M 144 221 M M250 248 F M 110 197 M M948 403 F M 240 260 M M714 378 F M 504 327 M M428 314 M M 806 370 M M502 344 M M 780 395 M M972 408 M M 966 419 F M474 340 F M 778 398 F M462 328 M M 286 280 M M292 275 M M 278 273 F M272 267 M M 272 279 F M286 275 M M 138 220 F M526 334 F M 210 258 M M


February 2004 82

Lake: Comfort Date: Sept 29 2003 TDS (ppm) 150 pH: 8.5Species:



Rainbow trout 86 205 60 17594 201 86 20074 186 88 211 F MT leech78 187 74 193 M MT empty

110 210 66 19682 187 84 195 M MT empty96 206 84 194 F MT98 210 94 215 F MT insects70 194 62 17672 180 84 195 F MT insects62 182 86 19436 137 122 225 M MT caddis

110 221 76 185 F MT78 200 94 206 F MT

134 233 F MT empty 60 174 F IM126 234 90 200 F MT86 198 74 194 F MT insects

122 20 70 185116 225 F MT zooplank 118 232 M MT198 264 F MT fry 84 207 F IM94 205 88 215 F MT80 194 94 195 F MT86 201 86 195 F MT56 176 122 219 F MT86 200 66 186 F IM60 180 50 168 F MT

116 227 F MT empty 52 164 F IM110 224 F MT snails 90 209 M MT82 195 106 215 F MT

132 235 M MT 88 20060 173 60 180

122 225 F MT 84 19378 200 86 20650 168 52 16964 184 66 183

120 227 F IM 98 21170 193 84 20074 195 66 176

106 222 72 188100 206 76 18574 191 90 205

104 210 78 18266 191 64 18050 168


February 2004 83


Eastern brook trout 1180 446 F M98 20634 142

100 209

Finescale sucker 152 235 62 172144 233 70 181296 281 198 255310 295 152 225120 209 46 160128 225 62 172284 290 120 21660 171 56 16764 172 22 120

142 227 24 131116 210 46 15752 160 16 110

174 243 20 120130 219 34 14382 191 60 17474 183 20 121

188 253 56 165206 260 32 14262 168 116 212

154 237 46 160160 234 20 118118 213 20 12082 189 18 116

102 199 22 124160 246 26 129136 230 22 12342 155 28 13664 170 20 119

132 224 plus 78 LNS unsampled, but similar size range52 165


February 2004 84

Lake: Halfway Date: 1-Oct-03 TDS (ppm) 270 pH: 8.9Species:



Rainbow trout 256 295 M MT 68 178424 335 M MT 70 178300 308 F MT 90 202434 350 F MT 250 281 M MT518 370 M MT 138 229 M MT166 254 F IM 66 171390 324 F MT 66 176358 317 F MT 56 174420 329 F MT 128 213 M MT360 315 F M 70 183274 289 F MT 62 179342 310 F MT 150 237282 292 F MT 76 191266 294 F MT 82 193248 275 F M 68 173264 291 M MT 56 163228 284 M MT 70 180282 285 M M 60 165244 280 M MT 68 185238 261 M M 72 187284 293 F MT 74 189248 285 F MT 70 182172 248 M MT 50 156192 270 F IM 60 172184 245 M MT 88 193192 266 F MT 60 175206 268 M MT 66 18464 176 184 264 F IM54 162 70 183170 253 M MT 118 220 F IM116 214 50 16370 181 58 167


February 2004 85

Lake: Help Date: 29-Sep-03 TDS (ppm) 150 pH: 8.5Species:



Rainbow trout 128 222 F MT 118 223 F MT80 205 F IM 120 228 F MT70 186 F MT 132 23564 176 64 185 F IM86 205 136 229 F MT80 193 F MT 138 240 F MT78 192 M MT 76 186 M MT120 222 108 217 F MT94 205 F MT 82 196 F MT82 200 F IM 76 195 F IM62 183 F IM 216 260 F MT106 217 110 220 F MT80 192 M MT 100 205 F MT114 223 F MT 20 12280 195 F MT 22 12468 183 152 240 F MT90 202 F MT 126 230 F MT80 192 F MT 140 237 M MT102 216 M MT 46 16474 193 30 14790 208 52 167104 214 F MT 24 13066 186 F MT 126 229 M MT80 195 126 230 F MT66 183 74 194102 203 F MT 104 210 M MT66 185 82 199 F MT60 176 110 232 M MT60 180 82 197 F IM70 190 F IM 96 205 F MT74 194 F IM 104 210 F MT102 220 F IM 60 172 M MT122 226 F MT 24 134126 227 F MT 28 13682 191 F MT 20 120118 224 F MT 16 11274 188 20 119120 232 F MT 20 11872 187 F MT 28 137140 230 F MT 20 12660 174 F MT 68 188104 214 F MT 22 126112 214 F MT 18 117106 217 F MT 72 183 F MT92 205 M MT 32 13682 196 F MT 96 21096 208 20 12298 206 M MT 30 14054 171 32 144110 218 F MT 22 12556 177 F IM 26 12364 177 F IM 22 115122 224 F MT 20 11486 195 F MT 20 115110 213 F MT 48 159252 286 M MT


February 2004 86


Eastern brook Trout 242 267 F M62 181 F IM224 264 M M444 335 F M160 240 F MT122 223 F MT18 12460 178 F IM252 270 F M240 271 M M172 250 F M76 185 F MT92 203 F MT58 173 F IM190 249 F M166 238 M M

Burbot 24 158150 30474 23862 221

Finescale sucker 74 179 142 212148 224 132 216142 225 134 21594 189 70 176106 202 20 12392 190 30 13560 170 32 13958 165 66 17676 180 92 19870 182 24 12320 120 56 17022 120 60 17034 142 118 20956 165 58 17026 125 66 17220 117 66 17464 176 plus 58 unsampled, similar size range


February 2004 87

Lake: Quartz Date: 16-Oct-03 TDS (ppm) 350 pH: 8.8Species:


Weight Length Sex Maturity Weight Length Sex Maturity(g) (mm) (g) (mm)

Rainbow trout 900 445 78 193608 382 F MT 82 192298 294 M MT 110 213450 358 M MT 54 167 F IM460 361 M MT 92 200716 401 F MT 78 185 F IM380 316 F MT 64 182 F IM238 283 M MT 94 203 M MT642 400 M MT 76 190 F490 353 F MT 66 180 F IM334 324 M MT 42 144 M IM474 352 F MT 52 165 M MT426 331 M MT 296 289 M MT220 261 274 291 M MT136 229 F IM 378 323 F MT164 245 F MT 750 395 F MT68 174 360 311 F MT148 236 330 310 F MT166 242 F IM 470 349 F MT110 223 M MT 342 315 F MT186 246 F MT 358 315 M MT74 192 408 333 M MT82 196 252 293 M MT100 200 308 295 F MT46 158


February 2004 88

Lake: Rocky Point Date: 1-Oct-03 TDS (ppm): 90 pH: 8.5Species:



Rainbow trout 228 273 M 184 255 M MT54 165 390 343 F MT

132 236 F IM 174 250 F MT436 336 334 308 F MT60 167 F MT 54 165

214 269 M MT 50 160252 292 M MT 252 278294 308 F MT 314 310 M MT314 310 M MT 256 272 F MT454 376 M K 324 304 M MT360 336 M K 306 299 F M384 320 250 273 F MT384 319 M MT 184 264 M MT78 190 272 298 F IM

294 296 F MT 312 304 M MT258 284 M M 70 185 F MT320 305 F MT 458 353 M M242 280 F IM 118 220420 345 F MT 332 320 F MT246 298 F MT 48 163358 323 F MT 332 310 F MT174 250 510 358 M M266 298 F MT 264 283 M MT156 256 M MT 216 270196 265 M MT 178 254 F IM154 252 M MT 210 273 F IM118 219 282 300 F MT126 223 M MT 324 320 F MT348 316 F MT 662 430 F K324 310 F MT 322 305 F MT182 255 M MT 388 325 M MT204 270 M MT 164 246 F IM240 275 M MT 160 240186 254 F MT plus 20 (160-270 mm range)478 414 M K


February 2004 89

Lake: Rosebud Date: 8-Oct-03 TDS (ppm): 130 pH: 8.9Species:



Rainbow trout 958 428 M M snails 148 230 M IM984 433 F M E 144 232 M IM650 386 M IM E 178 248 M IM528 349 F IM dragonfly larvae, snails 164 237 M IM216 256 M M chironomids 182 247 M IM160 238 M IM E 162 238 M IM90 190 M M 210 26078 183 F IM E 172 240 F MT

648 388 M IM 168 234 M IM chironomid600 367 M IM algae, bugs 114 216646 380 M IM E 166 245 M IM chironomid138 231 M IM E 218 262 M IM180 248 M IM E 150 234 M IM188 247 M IM 120 222 M IM158 231 M IM 156 234 M IM chironomid212 262 M IM E 174 246 M IM136 223 M IM snails, chironomids 140 227 M IM118 239 M IM snails 202 250 M IM132 225 M IM 170 242 M174 246 M IM 112 207 M IM170 244 M IM 148 234 M IM166 243 M IM 140 231 M IM166 242 M IM 130 225 M IM172 241 M IM 42 153 IM158 247 M IM 180 231 M IM174 246 M IM 154 228 M IM554 370 M IM E 138 230 M IM chironomid554 364 M IM 142 224 M IM156 239 M IM 144 238 M IM166 236 M IM 132 231 M IM164 240 M IM 162 244 M MT178 245 M IM 156 227 M IM154 237 M MT 144 234 M IM138 230 F IM 146 236 M IM188 248 M IM 132 223 M IM


February 2004 90

Lake: Solar Date: 16-Oct-03 TDS (ppm): 430 pH: 8.9Species:



Rainbow trout 2016 560 F MT970 437 M MT340 297 M MT1146 487 F MT742 403 F MT324 300 F IM312 325 M MT268 277 M MT314 291 M MT278 274 M MT230 258 M MT308 290 M MT298 298 F IM252 273 F IM184 259 F IM286 288 F IM340 296 M MT240 261 M MT224 270 F IM196 251164 237 M MT178 239 F IM230 266 F IM234 273 F IM232 262 M MT198 243 F IM266 285 F IM140 225 M MT174 240 M MT186 245 F IM158 230 M MT218 250 M MT224 265 M MT


February 2004 91

Lake: Three Island Date: 1-Oct-03 TDS (ppm): 70 pH: 9Species:



Rainbow trout 322 306378 319 F MT98 204382 340 M MT72 18358 176146 230474 348 M MT122 218 F MT422 343338 320 M M264 307 M MT72 188 F MT60 17364 17664 17574 18856 169128 228 F IM52 17094 19760 176132 228 M M52 160416 345 M M294 284 F M288 304 F MT256 285 M M56 170374 331 M MT64 173176 249 M MT96 200440 350 F MT54 16052 15866 17596 203264 290 M MT


February 2004 92

APPENDIX 3

Photographic plates


February 2004 93

Plate 1. Representative catch at Aid Lake.


February 2004 94

Plate 2. Representative catch at Alces Lake.


February 2004 95

Plate 3. Representative catch at Box Lake.


February 2004 96

Plate 4. Representative catch at Cameron Lake.


February 2004 97

Plate 5. Representative catch at Comfort Lake.

Plate 5. Representative catch at Comfort Lake.


February 2004 98

Plate 6. Representative catch at Halfway Lake.


February 2004 99

Plate 7. Representative catch at Help Lake.


February 2004 100

Plate 7. Representative catch at Help Lake.

Plate 8. Representative catch at Rockbluff Lake.


February 2004 101

Plate 9. Representative catch at Rocky Point Lake.

Plate 10. Representative catch at Rosebud Lake.


February 2004 102

Plate 11. Representative catch at Solar Lake.

Plate 12. Representative catch at Three Island Lake.

g.g.oliver and associates environmental...

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