fwp 2003 03 rpt changesbetweenhistoriccurrentfishrelativeabundancesize

Report 1.2.1: Changes Between Historic and Current

Fish Relative Abundance and Size Within Selected

Foothills Model Forest Watersheds

Prepared by Richard McCleary, Cameron Nelin, Chantelle Bambrick, Scott Wilson and Chad Sherburne

Fish and Watershed Research Program Foothills Model Forest

March 19, 2003

Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.

Foothills Model Forest Publication Disclaimer

The views, statements and conclusions expressed, and the recommendations made in this

report are entirely those of the author(s) and should not be construed as statements or

conclusions of, or as expressing the opinions of the Foothills Model Forest, or the partners or

sponsors of the Foothills Model Forest. The exclusion of certain manufactured products does not

necessarily imply disapproval, nor does the mention of other products necessarily imply

endorsement by the Foothills Model Forest or any of its partners or sponsors.

Foothills Model Forest i


Acknowledgements

In 2001, this project was funded through a partnership that included the Alberta

Conservation Association (ACA), Weldwood of Canada Ltd. (Hinton Division), and the

Canadian Forest Service. The funding from Weldwood was made available through the Forest

Resources Improvement Program. Additional support for this Foothills Model Forest project

was received through Alberta Sustainable Resource Development and Jasper National Park.

Mike Blackburn organized the literature review and re-sampling schedule. The 2001 field

crew that participated in re-sampling inventories was Jason Blackburn and Tyler Muhly. Jason

Blackburn developed the database for storage of the historic and current survey data. Dr. Hans

Zuuring, Professor of Forestry Biometry, Director of Qualitative Services Group, School of

Forestry, University of Montana provided a review of the statistical methods used to compare

catch rates and proportion of catchable size fish. Cameron Nelin completed analysis of the

historic and re-sample fisheries data. George Sterling provided a review of an earlier version of

this report. Fran Hanington provided editorial review of the final report.

Foothills Model Forest ii


Abstract

The purpose of this study was to determine if the replication of historical fish inventories

could provide any indication of the effects of more recent human-use activities on fish

populations and fish size within twelve watersheds in the Foothills Model Forest. In addition,

we attempted to develop two indicators of fish population sustainability that could be

incorporated into other longer-term Foothills Model Forest studies.

In 2001, a search for historical studies identified a total of 59 reports that had been

completed between 1960 and 1992 in ten of the study area watersheds. From these 59 reports,

only 33 sites were identified as candidates for re-survey. Numerous historical studies did not

describe the sampling methodology with sufficient information to permit replication. Details of

electrofishing effort and individual fork lengths were often excluded. In the late summer and fall

of 2001, current information was collected that allowed a comparison of data at 21 sites.

Information from ten of the historic-current pairs was suitable to compare catch rates

within four watersheds. Significant differences in catch rates were detected in two of those

basins. Information from four of the historic-current pairs was suitable to compare the changes

in proportion of catchable size sport fish. Each of these four sites was from a different

watershed.

The findings were compared to the results from an overview of land-use and an overview

of changes in fishing regulations and potential explanations were provided. We observed several

changes in the indicators that corresponded to changes in angling regulations, however, no

changes were detected that related to increases in land-use. More detailed studies of Rainbow

Trout in MacKenzie Creek may be required to explain observed changes in that watershed.

Follow-up survey sites were identified and recommendations for future Foothills Model

Forest before-after type monitoring exercises were presented.

Foothills Model Forest iii


Table of Contents Foothills Model Forest Publication Disclaimer ............................................................................... i Acknowledgements......................................................................................................................... ii Abstract .......................................................................................................................................... iii Table of Contents........................................................................................................................... iv List of Figures ................................................................................................................................. v List of Tables .................................................................................................................................. v 1 Introduction............................................................................................................................. 1 2 Methods................................................................................................................................... 1

2.1 Study Area ...................................................................................................................... 1 2.2 Historic Data / Literature Search .................................................................................... 2 2.3 Data Management ........................................................................................................... 3 2.4 Site Selection .................................................................................................................. 3 2.5 Field Surveys .................................................................................................................. 3 2.6 Data Analysis .................................................................................................................. 4

3 Results..................................................................................................................................... 6 3.1 Summary by Watershed.................................................................................................. 6

3.1.1 Lambert Creek ........................................................................................................ 6 3.1.2 MacKenzie Creek.................................................................................................... 9 3.1.3 Moon Creek .......................................................................................................... 11 3.1.4 Pinto Creek............................................................................................................ 11 3.1.5 Solomon Creek...................................................................................................... 12 3.1.6 Upper Erith River.................................................................................................. 14

3.2 Summary for all Monitoring Watersheds ..................................................................... 15 3.2.1 Statistical Analysis of Differences in Historic and Current Survey Catch Rates . 15 3.2.2 Changes in Proportion of Catchable Size Fish ..................................................... 16

4 Discussion............................................................................................................................. 17 4.1 Relationships Between Changes in Catch Rates, Angling Regulations and Land-use. 17 4.2 Relationships Between Changes in Proportion of Catchable Size Fish and Land-use . 19 4.3 Considerations from Observed Relationships............................................................... 19 4.4 Considerations for Future Foothills Model Forest Monitoring Efforts ........................ 19

4.4.1 Lack of Habitat Data............................................................................................. 20 4.4.2 Catch per Unit Effort Calculations from Backpack Electrofishing ...................... 20 4.4.3 Fish Identification ................................................................................................. 20 4.4.4 Statistical Limitations ........................................................................................... 20 4.4.5 Electrofishing and Fish Spawning Seasons .......................................................... 21

Foothills Model Forest iv


List of Figures Figure 1. Monitoring watersheds within the Foothills Model Forest. ........................................... 2 Figure 2. A comparison of historic and current surveyed rainbow trout captured at Location 971

in the Lambert Creek watershed. ............................................................................................ 8 Figure 3. A comparison of historic and current surveyed rainbow trout captured at Location 962

in the MacKenzie Creek watershed. ..................................................................................... 10 Figure 4. A comparison of historic and current surveyed brook trout captured at Location 131 in

the Solomon Creek watershed. ............................................................................................. 13 Figure 5. A comparison of historic and current surveyed rainbow trout captured at Location 714

in the Upper Erith River watershed. ..................................................................................... 14

List of Tables Table 1. Summary of fish species represented in selected monitoring watersheds. ....................... 6 Table 2. Catch rate comparisons for the Lambert Creek watershed (Locations 926, 927, and

972). ........................................................................................................................................ 7 Table 3. Number of catchable size sport fish (>149mm) captured in the Lambert Creek

watershed. ............................................................................................................................... 8 Table 4. Proportion of catchable size sport fish (> 149mm) comparison for the Lambert Creek

watershed. ............................................................................................................................... 9 Table 5. Catch rate comparisons for the MacKenzie Creek watershed (Locations 432 and 961). 9 Table 6. Number of catchable size sport fish (>149mm) captured in the MacKenzie Creek

watershed. ............................................................................................................................. 10 Table 7. Proportion of catchable size sport fish (> 149mm) comparison for the MacKenzie

Creek watershed.................................................................................................................... 10 Table 8. Catch rate comparisons for the Moon Creek watershed (Locations 8 and 19).............. 11 Table 9. Catch rate comparisons for the Pinto Creek watershed (Locations 88 and 978). .......... 12 Table 10. Number of catchable size sport fish (>149mm) captured in the Solomon Creek

watershed. ............................................................................................................................. 13 Table 11. Proportion of catchable size sport fish (> 149mm) comparison for the Solomon Creek

watershed. ............................................................................................................................. 13 Table 12. Number of catchable size sport fish (>149mm) captured in the Upper Erith River

watershed. ............................................................................................................................. 14 Table 13. Proportion of catchable size sport fish (> 149mm) comparison for the Upper Erith

River watershed. ................................................................................................................... 15 Table 14. Summary of statistical analysis of differences in historic and current survey catch

rates. ...................................................................................................................................... 16 Table 15. Summary of Size Distribution for all selected monitoring watersheds. ...................... 17 Table 16. Summary of changes in catch rates, fish size, angling regulations, harvest and road

development in monitoring watersheds of the FMF. ............................................................ 18

Foothills Model Forest v


1 Introduction

We selected two different before-after type strategies to learn about the potential effects

of human-use activities on fish populations. The first strategy relied on annual population

estimation at a small number of sites. This approach builds on the Tri - Creeks study. Its

strength is the continuity of the dataset from year to year. Its weakness, however, is the small

sample size that results in a poor representation of the human-use activities and ecological

conditions within the study area. The findings from this long-term monitoring effort are

described in Report 1.2.2: Long-term changes in relative abundance of Rainbow Trout at

selected sites within the Foothills Model Forest.

In our second strategy, we postulated that if a large enough number of government and

industry-related inventories had been completed within the study area watersheds, some valuable

information could be gained by replicating the historic surveys. The strength of this approach

was that a larger number of sample sites would be more representative of the range of human-use

activities and ecological conditions within the study area. Its major weakness was that fish

populations are highly variable from year to year and without a continuous population history,

the ability to arrive at definitive conclusions would be limited. Nonetheless, we determined that

the strategy warranted investigation and our findings are described in this report.

Concurrent to this study, the Foothills Model Forest (FMF) was in the process of

identifying a set of biodiversity indicators to support a long-term effort to measure forest

resource sustainability (FMF 2003). Any of the parameters from this study that provide

meaningful information related to the sustainability of aquatic resources would be candidates for

continued monitoring as part of the ongoing FMF indicators program.

2 Methods

2.1 Study Area The study area included 12 watersheds within the Foothills Model Forest (Figure 1). With the

abundance of data from a number of different years, the Tri-Creeks data provided a unique

opportunity to study trends in fish populations at specific sites over time. As a result, these data

were better suited to other analysis methods addressed in a separate report.

Foothills Model Forest 1


Figure 1. Monitoring watersheds within the Foothills Model Forest.

2.2 Historic Data / Literature Search

The first step in this project was to conduct a literature search of all past fisheries projects

completed within the study area watersheds. Data sources included:

• Alberta Sustainable Resource Development, Fish and Wildlife Division, Historic Phase II

reports

• Alberta Environment Fisheries Management Information System database

• Northern Alberta Institute of Technology forestry reports, and the

• Alberta Sustainable Resource Development library located in Edson.



2.3 Data Management A database was developed in Microsoft Access to store and manage the historic data.

Fields in the database included site location, sample methods, sample dates, sampling effort,

species composition, individual fish fork lengths and weights, and surveyed stream lengths and

widths.

The location information from the historic reports was presented in a variety of ways

including UTM coordinates, legal land description, maps, or written descriptions from the old

reports. This information was interpreted and survey sites were mapped as point data in Arcview

3.2 (ESRI 1999). UTM coordinates were then generated for each point using an Arcview

extension tool (ESRI 1999). These confirmed locations were then entered into the database.

2.4 Site Selection Once the historic sites were mapped, comparisons were made between historic sites and

existing FMF inventory sites to determine if the FMF had recently surveyed any of the historic

sites. Historic sites and FMF sites were considered to be the same location if they (1) were within

close spatial proximity, (2) were located in a stream reach with similar slope, and drainage area

size, (3) had the same stream order, and (4) were not bisected by a potential barrier such as a

road or waterfall.

Where a historic site and an FMF site were at the same location, the sample dates were

compared to see if they were from the same season. This seasonal timing was broken down into

three sampling seasons; spring, summer, and fall consisting of May-June-July, July-August, and

August-September-October respectively.

2.5 Field Surveys Where a historic site and an FMF site shared the same location and sampling season, no

further sampling was necessary to establish a historic-current pair. Those historic sampling sites

lacking a current pair were selected for inventory during the 2001 field season. Field staff used

detailed maps displaying site locations and UTM co-ordinates to determine site access and

collected fish and habitat data according to standard FMF inventory methods (McCleary et al.

2001). Field surveys were conducted at a total of 24 sites from August 9, 2001 to October 4,

2001.



2.6 Data Analysis The two most similar sampling dates were selected when more than one survey had been

completed in a year.

2.6.1 Statistical Analysis of Differences in Historic and Current Survey Catch Rates from a

Number of Sites within an Individual Basin

To test the null hypothesis that the mean historic catch rate wquals the mean current catch

rate, we used a two-tailed paired t-test (α = 0.20), (Equations 1 and 2). Fish species in a unique

paired survey were only included in this paired comparison if a sample of at least five fish were

captured in either the historic survey or the current survey. The statistics were calculated with

SPSS (v10.0) statistical software. The results of the paired t-tests were summarized in tables.

Equation 1:

Ho: µ historic catch rate = µ current catch rate Equation 2: 2P (T ≥ |t|) 2.6.2 Changes in Proportion of Catchable Size Fish

Providing an opportunity for angling is an important objective of both fishery and fish

habitat managers. Previous studies in both of these disciplines have used a 150 mm cut-off for

the minimum size fish to be sufficient for sport fishing (Koning and Keeley 1997). In addition,

for resident rainbow trout populations, maintaining a sufficient number of fish of this size could

also provide an indicator of the spawning or reproductive capacity of a population.

Previous studies that report the proportion of fish of catchable size did not include a

statistical analysis. However, such methods are used in other natural sciences applications.

To test the null hypothesis that the proportion of catchable size sport fish (> 149mm) on

the historic date and current date were equal (equations 3 and 4), we used two-tailed Z-tests (α =

0.20) as calculated in Equations 5-7 (Moore and McCabe 1993). Fish species in a unique paired

survey were only included in the comparison if a sample of at least ten fish greater than 50 mm

fork length were captured in both the historic survey and the current survey.



p1 = p2 Where p1 = proportion of historic population > 149mm p2 = proportion of current population > 149mm

Equation 3: Equation 4: )

Equation 5: 21

21

ppp

ppZ

−

−=

σ

Where: p1 = proportion of sample 1

p2 = proportion of sample 2

21 pp −σ

−1 ppσEquation 6:

p̂Where:

Equation 7: p̂

An increase in the proportion of fi

indicator only if this occurred with the ma

increase in the proportion of catchable siz

would be indicative of recruitment failure

juvenile size classes, fork length frequenc

criteria for the proportional analysis (i.e. A

captured). Based on the findings from pre

minimum of 120 mm were considered adu

Foothills Model Forest

= Standard error of the difference of proportions

2P (Z ≥ |z|

+−=

21

21)1(ˆ2 nn

nnpp

= The pooled estimate

21

2211nn

pnpn++

=

sh of catchable size would be considered a positive

intenance of juvenile size classes. The case where an

e occurs while juvenile fish are poorly represented

. Therefore, in order to confirm the presence of

y distributions were generated for all cases that met the

t least 10 fish greater than 49 mm fork length were

vious studies in the region, fish with a fork length of a

lts and smaller fish were considered juveniles.

5


3 Results

A total of 33 sites suitable for replication were identified from a total of 59 historic

reports within 10 of the 12 watersheds (Appendix 1). Of the 33 historic sites suitable for

replication, the FMF was able to obtain data to form historic-current pairs at 21 sites. Historic-

current paired surveys were not obtained for the Emerson and Lynx Creek watersheds. Data was

sufficient for an analysis of catch rates in four watersheds including Lambert, MacKenzie, Moon,

and Pinto Creek. Data was sufficient for an analysis of changes in proportion of catchable size

fish at a total of four sites from four watersheds including Lambert, MacKenzie, Solomon, and

the Upper Erith River.

A total of 14 fish species were captured between the historic and current surveys (Table

1).

Table 1. Summary of fish species represented in selected monitoring watersheds.

Species Scientific Name Abbreviation Bull Trout Salvelinus confluentus BLTR Rainbow Trout Onchorhynchus mykiss RNTR Brook Trout Salvelinus fontinalis BKTR Arctic Grayling Thymallus arcticus ARGR Burbot Lota lota BURB Mountain Whitefish Prosopium williamsoni MNWH White Sucker Catostomus commersoni WHSC Longnose Sucker Catostomus catostomus LNSC Spoonhead Sculpin Cottus recei SPSC Brook Stickleback Culaea inconstans BRST Finescale Dace Phoxinus neogaeus FNDC Pearl Dace Margariscus margarita PRDC Trout-perch Percopsis omiscomaycus TRPR Northern Pike Esox lucius NRPK

3.1 Summary by Watershed 3.1.1 Lambert Creek

3.1.1.1 Statistical Analysis of Differences in Historic and Current Survey Catch Rates

The catch rate for rainbow trout was different between the historic survey and current

survey at the 80% confidence level (Table 2).



Table 2. Catch rate comparisons for the Lambert Creek watershed (Locations 926, 927, and 972).

Species ¹ Survey Mean (# fish / 100m² / min)

Standard Deviation (# fish / 100m² / min) T-statistic P-value

Historic 0.0000 0.0000 Current 0.0003 0.0005

ARGR

Difference -0.0003 0.0005 -1.000 0.423 Historic 0.0000 0.0000 Current 0.0196 0.0320

BRST


BURB


FNDC


LNSC


NRPK

Difference 0.0005 0.0009 1.000 0.423 Historic 0.0156 0.0169 Current 0.0000 0.0000

PRDC


RNTR

Difference -0.0054 0.0019 -4.857 0.040* Historic 0.0000 0.0000 Current 0.0040 0.0049

SPSC


TRPR


WHSC

Difference 0.0484 0.0840 0.998 0.423 * Significant difference at 80 % (α= 0.20) confidence interval. ¹ ARGR = Arctic Grayling; BRST = Brook Stickleback; BURB = Burbot; FNDC = Finescale Dace; LNSC = Longnose Sucker; NRPK = Northern Pike; PRDC = Pearl Dace; RNTR = Rainbow Trout; SPSC = Spoonhead Sculpin; TRPR = Trout-perch; WHSC = White Sucker



3.1.1.2 Changes in Proportion of Catchable Size Fish

At location 971, rainbow trout from both juvenile (< 120 mm) and adult (> 120 mm)

sizes were present in 1979 and 2001 (Figure 2).

0

5

10

15

20

25

50 60 70 80 90 100

110

120

130

140

150

160

170

180

190

200

210

Fork Length (mm)

Num

ber

of fi

sh

Historic Current

HISTORIC (1979) n = 17 Minimum FL = 51 Maximum FL = 148 Mean FL = 58

CURRENT SURVEY (2001) n = 83 Minimum FL = 50 Maximum FL = 210 Mean FL = 103

Figure 2. A comparison of historic and current surveyed rainbow trout captured at Location 971 in the Lambert Creek watershed.

During the historic survey at Location 971, no rainbow trout with fork lengths greater

than 149mm were captured (Table 3). However, during the current survey, 11 rainbow trout met

this criterion.

Table 3. Number of catchable size sport fish (>149mm) captured in the Lambert Creek watershed.

Historic Current Location Species ¹ Total # # >149mm Total # # >149mm971 RNTR 17 0 83 11

¹ RNTR = Rainbow Trout

The proportion of rainbow trout of catchable size at Location 971 was different between historic

survey and current survey at the 80% confidence level (Table 4).



Table 4. Proportion of catchable size sport fish (> 149mm) comparison for the Lambert Creek watershed.

Location Species ¹ Z-value P-value 971 RNTR -1.591 0.112*

* Significant difference at 80% (α = .20) confidence interval. ¹ RNTR = Rainbow Trout 3.1.2 MacKenzie Creek


The catch rate for rainbow trout was different between the historic survey and the current

survey at the 80% confidence level (Table 5).

Table 5. Catch rate comparisons for the MacKenzie Creek watershed (Locations 432 and 961).




BLTR


MNWH


RNTR

Difference 0.0492 0.0083 8.339 0.076* * Significant difference at 80% (α = .20) confidence interval. ¹ BLTR = Bull Trout; MNWH = Mountain Whitefish; RNTR = Rainbow Trout


Although adult and juvenile size classes were present during both surveys at Location 962,

juvenile size Rainbow Trout were poorly represented in the current survey sample (Figure 3).



0

1

2

3

4

5

6

7

8

950 60 70 80 90 100

110

120

130

140

150

160

170

180

190

200

210

220

230

240

250

260

Fork length (mm)

Num

ber

of fi

shHistorical Current


CURRENT SURVEY (2001) n = 12 Minimum FL = 55 Maximum FL = 259 Mean FL = 163

Figure 3. A comparison of historic and current surveyed rainbow trout captured at Location 962 in the MacKenzie Creek watershed.

Most of the Rainbow Trout captured at Location 962 during the current survey were of

catchable size (Table 6).

Table 6. Number of catchable size sport fish (>149mm) captured in the MacKenzie Creek watershed.

Historic Current Location Species ¹ Total # # >149mm Total # # >149mm962 RNTR 39 12 12 9

¹ RNTR = Rainbow Trout

The proportion of rainbow trout of catchable size at locations 961 and 962 was different

between the historic survey and the current survey (Table 7).

Table 7. Proportion of catchable size sport fish (> 149mm) comparison for the MacKenzie Creek watershed.

Location Species ¹ Z-value P-value 962 RNTR -2.722 0.007*

* Significant difference at 80% (α = .20) confidence interval. ¹ RNTR = Rainbow Trout



3.1.3 Moon Creek


There were no differences in catch rates between the historic and current survey sites in

Moon Creek at the 80% (α = .20) confidence interval (Table 8).

Table 8. Catch rate comparisons for the Moon Creek watershed (Locations 8 and 19).




BLTR


MNWH


RNTR

Difference 0.0164 0.0232 1.000 0.500 ¹ BLTR = Bull Trout; MNWH = Mountain Whitefish; RNTR = Rainbow Trout 3.1.3.2 Changes in Proportion of Catchable Size Fish

Fork length data were not available from the historic survey at Location 19 in the Moon

Creek watershed.

3.1.4 Pinto Creek


There were no differences in catch rates between the historic survey and the current

survey sites in Pinto Creek watershed at the 80% (α = .20) confidence interval (Table 9).



Table 9. Catch rate comparisons for the Pinto Creek watershed (Locations 88 and 978).




ARGR


BLTR


MNWH


RNTR

Difference -0.0404 0.0880 -0.648 0.634 ¹ ARGR = Arctic Grayling; BLTR = Bull Trout; MNWH = Mountain Whitefish; RNTR = Rainbow Trout


Fork length information was available from the historic surveys at both sites in Pinto

Creek. However, the sample size was not greater than 10 for any fish species at any one site for

the historic survey and current survey. Therefore, no additional analysis of fish size was

presented.

3.1.5 Solomon Creek


Due to a lack of historic effort data, neither a catch rate summary nor a statistical analysis

for differences in catch rate could be completed.

3.1.5.2 Size Distribution

Brook trout were present in both juvenile and adult size classes at Location 131 in

Solomon watershed (Figure 4).



0

2

4

6

8

10

12

14

16

1850 60 70 80 90 100

110

120

130

140

150

160

170

180

190

200

210

220

230

Fork length (mm)

Num

ber

of fi

shHistorical Current

Figure 4. A comparison of historic and current surveyed brook trout capturedSolomon Creek watershed.

Brook Trout were the only fish species of catchable size (Tabl

Table 10. Number of catchable size sport fish (>149mm) captured in the Solom

Historic Current Location Species ¹ Total # # >149mm Total # # >149mm

131 BKTR 75 15 67 19 ¹ BKTR = Brook Trout

There was no difference in the proportion of catchable size Bro

in Solomon Creek at the 80% (α = 0.20) confidence interval (Table 11

Table 11. Proportion of catchable size sport fish (> 149mm) comparison for th

Location Species Z-value P-value 131 BKTR -1.165 0.244

¹ BKTR = Brook Trout

Foothills Model Forest


240

250

260

CURRENT SURVEY (1997-99) n = 67 Minimum FL = 51 Maximum FL = 221 Mean FL = 117

at Location 131 in the

e 10).

on Creek watershed.

ok Trout at Location 131

).

e Solomon Creek watershed.

13


3.1.6 Upper Erith River 3.1.6.1 Statistical Analysis of Differences in Historic and Current Survey Catch Rates

Due to a lack of historic effort data, neither a catch rate summary nor a statistical analysis

for differences in catch rate could be completed.


At Location 714, juvenile and adult size classes of rainbow trout were present at both the

historic survey and current survey (Figure 5).

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

60 70 80 90 100

110

120

130

140

150

160

170

180

190

200

Fork length (mm)

Num

ber

of fi

sh

Historic CurrentHISTORIC (1979)N = 27Minimum FL = 68Maximum FL = 189Mean FL = 116

CURRENT (1999)N = 19Minimum FL = 78Maximum FL = 199Mean FL = 134

C

Figure 5. A comparison of historic and current surveyed rainbow trout captured at Location 714 in the Upper Erith River watershed.

Catchable size rainbow trout were present at both the historic survey and current survey

(Table 12).

Table 12. Number of catchable size sport fish (>149mm) captured in the Upper Erith River watershed.

Historic Resurvey Location Species ¹ Total # # >149mm Total # # >149mm714 RNTR 27 6 19 6



There was no difference in the proportion of catchable size rainbow trout between the

historic survey and current survey at location 714, at the 80 % confidence level (Table 13).

Table 13. Proportion of catchable size sport fish (> 149mm) comparison for the Upper Erith River watershed.

Location Species Z-value P-value 714 RNTR -0.712 0.478

¹ RNTR = Rainbow Trout 3.2 Summary for all Monitoring Watersheds 3.2.1 Statistical Analysis of Differences in Historic and Current Survey Catch Rates

Statistical analysis of the differences in historic and current survey catch rates were

performed in four of the watersheds using the catch rates from either two or three sample sites

(Table 14). Differences in catch rates at the 80% confidence interval were found for rainbow

trout abundance in the Lambert and MacKenzie Creeks. Differences were not significant for any

of the other species found within these watersheds.



Table 14. Summary of statistical analysis of differences in historic and current survey catch rates.

Watershed Sample Size Species ¹

Historic Catch Rates (# fish / 100m² / min)

Current Catch Rates (# fish / 100m² / min)

Difference P-Value

ARGR 0 0.0003 -0.0003 0.423 BRST 0 0.0196 -0.0196 0.4 BURB 0.0017 0.004 -0.0023 0.463 FNDC 0 0.0294 -0.0294 0.348 LNSC 0.0087 0.0259 0.0206 0.284 NRPK 0.0005 0 0.0009 0.423 PRDC 0.0156 0 0.0169 0.251 RNTR 0.0029 0.0083 0.0019 0.040* SPSC 0 0.004 0.0049 0.294 TRPR 0.0020 0.0039 0.0033 0.423

Lambert 3

WHSC 0.0489 0.0006 0.084 0.423 BLTR 0.0031 0.0026 0.0006 0.5

MNWH 0 0.001 -0.001 0.5 MacKenzie 3 RNTR 0.0713 0.0221 0.0492 0.076* BLTR 0.0556 0.0226 0.033 0.421

MNWH 0.0015 0.0006 0.0009 0.5 Moon 2 RNTR 0.0192 0.0028 0.0164 0.5 ARGR 0.0025 0.0026 -0.0001 0.5 BLTR 0.0025 0 0.0025 0.5

MNWH 0.0085 0.0038 0.0047 0.5 Pinto 2

RNTR 0.0246 0.065 -0.0404 0.634 * Significant difference at 80% (α = .20) confidence interval. ¹ ARGR = Arctic Grayling; BLTR = Bull Trout; BRST = Brook Stickleback; BURB = Burbot; FNDC = Finescale Dace; LNSC = Longnose Sucker; MNWH = Mountain Whitefish; NRPK = Northern Pike; PRDC = Pearl Dace; RNTR = Rainbow Trout; SPSC = Spoonhead Sculpin; TRPR = Trout-perch; WHSC = White Sucker 3.2.2 Changes in Proportion of Catchable Size Fish

Statistical analysis of the differences in proportion of catchable size fish was completed

within four of the monitoring watersheds (Table 15). Significant differences were found on two

occasions. The increase in proportion of catchable size fish at the location in MacKenzie Creek

corresponded to a poor representation of juvenile age classes.



Table 15. Summary of Size Distribution for all selected monitoring watersheds.

Watershed

Species

Site #

Historic Sample size

P > 15cm

Current survey

Sample size

P > 15cm P-Value Lambert RNTR 971 17 0 83 11 0.112*

MacKenzie RNTR 962 39 12 12 9 0.007* Solomon BKTR 131 75 15 67 19 0.244

Erith RNTR 714 27 6 19 6 0.478 * Significant difference at 80% (α = .20) confidence interval. ¹ BKTR = Brook Trout; RNTR = Rainbow Trout

4 Discussion

4.1 Relationships Between Changes in Catch Rates, Angling Regulations and Land-use

Changes in catch rates between historic and current surveys were detected in two of the

four watersheds where catch rate comparisons were completed (Table 16). In Lambert Creek

watershed, an increase in catch rate corresponded to implementation of catch and release angling

regulations. Harvest and road development levels were low during both historic and current

surveys. In MacKenzie Creek watershed, a decrease in catch rate of Rainbow Trout

corresponded to the implementation of zero catch limit of Bull Trout in 1995 and full angling

closure in 2000. Harvest and road development levels remained low throughout the study. In

Moon Creek watershed, no changes in catch rate were detected despite an implementation of

more restrictive angling regulations. There was little change in harvest levels and there was a

decrease in road density from high to medium. In the Pinto Creek watershed, no change in catch

rate was detected despite an increase in angling restrictions, harvest extent and road

development.

To allow additional catch rate analyses, current surveys could be completed at two sites

in both Anderson Creek watershed and Lynx Creek watershed, as well as one additional site in

the Upper Erith River watershed. All of these watersheds have had some increase in either

harvest level or road development.



Table 16. Summary of changes in catch rates, fish size, angling regulations, harvest and road development in monitoring watersheds of the FMF.

Harvest Information ¹ Index of Road Density ²

Watershed

# of

pot

entia

l site

s ide

ntifi

ed

from

his

toric

repo

rts

# of

cur

rent

repl

icat

e si

tes

# of

pot

entia

l site

s lac

king

a

curr

ent r

eplic

ate

Significant change in catch

rate detected

(yes / no) ( +/- to indicate

increase or decrease)

Significant change in

proportion of catchable size

fish

(yes / no)

Related angling regulation changes

H

isto

ric %

H

arve

sted

Cur

rent

%

Har

vest

ed

Cha

nge

His

toric

Cur

rent

Cha

nge

Anderson 2 0 2Future field inventory required

Future field inventory required

Implementation of catch and release restrictions med high med high high low

Antler 0 - - - - - - - - - - -Fish 0 - - - - - - - - - - -

Lambert 4 4 0 Yes (+) RNTR

Yes (+) RNTR

Implementation of catch and release restrictions low low low low low low

Lynx 2 0 2Future field inventory required

Future field inventory required

Implementation of catch and release restrictions low med low low high med

MacKenzie 4 3 1Yes (-)

RNTR

Yes (+) RNTR

* low juvenile recruitment

• Zero Bull Trout limit introduced in 1995

• Full closure of stream to fishing in 2002

low low low low low low

Moon 2 2 0 No Insufficient sample size

Implementation of catch and release restrictions med med low high med low

Pinto 4 2 2 No Insufficient sample size

Implementation of catch and release restrictions low med med low med med

Solomon 1 1 0 Insufficient historic data

No

BKTR

Implementation of catch and release restrictions low low low low low low

Teepee 0 - - - - - - - - - - -Upper Erith

River 2 1 1 Insufficient historic data

No RNTR

Implementation of catch and release restrictions low low low low high high

¹ Harvest Information: < 10 % = low, 10-30 % = medium, > 30 % = high ² Index of Road Density: ≤ 0.2 = low, 0.3-0.4 = medium, ≥ 0.5 = high



4.2 Relationships Between Changes in Proportion of Catchable Size Fish

and Land-use

Changes in proportion of catchable size fish were detected in two of the four watersheds

where those comparisons were completed (Table 16). In Lambert Creek watershed, an increase

in proportion of catchable size fish corresponded to the implementation of catch and release

angling regulations. Harvest and road development levels remained low through both survey

dates. In MacKenzie Creek watershed, an increase in proportion of catchable size Rainbow

Trout corresponded to very low juvenile recruitment and therefore should be considered an

indicator of concern for the health of that population. This change corresponded to the

implementation of more restrictive angling regulations including the zero catch limit on Bull

Trout in 1995 and full angling closure in 2000. In Solomon Creek watershed, no significant

changes in the proportion of catchable size Brook Trout were detected despite the more

restrictive angling regulations and lack of increase in land-use. In the Upper Erith River

watershed, no change in proportion of catchable size Rainbow Trout was detected despite the

increase in angling restrictions and high increase in road development.

To allow additional analyses of proportion of catchable size fish, the data from eight

other historic sites could be reviewed to determine which sites would meet the sample size

criteria for this test.

4.3 Considerations from Observed Relationships Via a major highway, Lambert Creek is in close proximity to the towns of Edson and

Robb. As a result, this watershed may have historically had the highest angling pressure of all

the monitoring watersheds. Therefore, it seems plausible that the Rainbow Trout population in

that watershed may have responded favourably to increased restrictions in angling regulations.

In MacKenzie Creek, the decrease in Rainbow Trout catch rate is more difficult to

explain. One possible explanation is the recent angling regulation changes. The province-wide

ban on Bull Trout harvest may have resulted in an increase in Bull Trout use of MacKenzie

Creek, which is an important Bull Trout spawning stream. Any increase in Bull Trout numbers

may have resulted in increased Rainbow Trout predation in the MacKenzie Creek watershed.

Investigating other potential factors seems warranted.



4.3 Considerations for Future Foothills Model Forest Monitoring Efforts 4.4.1 Lack of Habitat Data

In order to practice adaptive forest management, any negative change in an aquatic

resource would have to be linked to a particular forest management activity. For any changes

other than those related to angling or angler access, some measure of habitat impact would be

required. Most of the historic surveys did not contain habitat data that could have been

replicated. In addition, specific hypotheses and methods related to habitat features should be

formulated prior to initiation of future monitoring programs. Residual pool depths and spacing

data have been collected at all sites and their potential as habitat indicators will be evaluated as

part of this study.

4.4.2 Catch per Unit Effort Calculations from Backpack Electrofishing

Electrofishing effort was calculated based on area and time, however, power was not

considered. Power is influenced by a number of factors including pulse width, pulse frequency,

output voltage, water conductance, and anode size (Smith-Root Inc. 2002). Standardization of

electrofisher power is a key component of maintaining consistent or comparable sampling effort

(Smith-Root Inc. 2002).

Standardization was not possible given the lack of information from most historical

studies. In addition, recording water conductance has not been a standard requirement during

Foothills Model Forest (FMF) electrofishing surveys. Therefore, changes should be made to

FMF protocols to ensure that standardization of electrofishing power on any subsequent surveys

can be achieved.

4.4.3 Fish Identification

During the historic surveys in Lambert Creek watershed, Pearl Dace were captured and

no Finescale Dace was captured, while the reverse was true during the current surveys. These

results indicate the possibility of a fish identification error. The current program could be

expanded to include a more frequent use of voucher specimens or more rigorous testing of fish

identification abilities.

4.4.4 Statistical Limitations

The use of catch rates as an indicator of fish population status presented several

limitations including the very low sample size (n = 2 or 3) and high variability between sites in a



watershed. As a result, the possibility of both Type 1 and Type 2 error remained high. These

problems were not associated with the use of proportion of catchable size fish.

4.4.5 Electrofishing and Fish Spawning Seasons

Damage to eggs within redds may occur as a result of electrofishing. Consequently,

several jurisdictions require that electrofishing in known Bull Trout streams occurs prior to their

spawning season. The FMF should consider adopting this practice.




5 Literature Cited

Koning, C.W., and E.R. Keeley. 1997. Fish Habitat Rehabilitation Procedures in Watershed Restoration Technical Circular No.9. British Columbia Ministry of Environment, Lands and Parks and Ministry of Forests.

Cao, Y.D.P. Larsen, and R.M. Hughes. 2001. Evaluating sampling sufficiency in fish assemblage surveys: a similarity-based approach. Canadian Journal of Fisheries and Aquatic Sciences. Vol. 58: 1782-1793. ESRI (Environmental Systems Research Institute). 2000. Arcview 3.2a GIS software. FMF (Foothills Model Forest). 2003. Report 1.2.2: Long-term changes in relative abundance of

Rainbow Trout at selected sites within the Foothills Model Forest. Prepared for the ACA, Weldwood of Canada (Hinton Division) and ASRD. FMF, Hinton, Alberta.

McCleary, R., C. Johnson, and C. Nelin. 2001. 2000 ACA Annual Report – An evaluation of the effects of human-use on fish: A description of fish populations and habitats in selected watersheds within the Foothills Model Forest. Report completed for the Fisheries Management Enhancement Program, Alberta Conservation Association by the Foothills Model Forest. Moore, D.S. and G.P. McCabe. 1993. Introduction to the Practice of Statistics, second

edition. W.H. Freeman and Company. New York. Smith-Root Inc. 2002. Principles and Techniques of Electrofishing. Vancouver, WA, USA. SPSS Inc. 1999. SPSS 10.0 for Windows software. Chicago, IL, USA.

fwp 2003 03 rpt changesbetweenhistoriccurrentfishrelativeabundancesize

Documents

foothills model forest

fish size

fish populations

canadian forest service

selected fmf watersheds

chad sherburne fish

final report

resampling inventories