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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
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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.
Foothills Model Forest 2
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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.
Foothills Model Forest 3
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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.
Foothills Model Forest 4
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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).
Foothills Model Forest 6
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
Difference -0.0196 0.0320 -1.062 0.400 Historic 0.0017 0.0029 Current 0.0040 0.0037
BURB
Difference -0.0023 0.0044 -0.901 0.463 Historic 0.0000 0.0000 Current 0.0294 0.0419
FNDC
Difference -0.0294 0.0419 -1.215 0.348 Historic 0.0087 0.0103 Current 0.0259 0.0307
LNSC
Difference -0.0173 0.0206 -1.450 0.284 Historic 0.0005 0.0009 Current 0.0000 0.0000
NRPK
Difference 0.0005 0.0009 1.000 0.423 Historic 0.0156 0.0169 Current 0.0000 0.0000
PRDC
Difference 0.0156 0.0169 1.601 0.251 Historic 0.0029 0.0039 Current 0.0083 0.0037
RNTR
Difference -0.0054 0.0019 -4.857 0.040* Historic 0.0000 0.0000 Current 0.0040 0.0049
SPSC
Difference -0.0040 0.0049 -1.411 0.294 Historic 0.0020 0.0035 Current 0.0039 0.0068
TRPR
Difference -0.0019 0.0033 -1.000 0.423 Historic 0.0489 0.0835 Current 0.0006 0.0006
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
Foothills Model Forest 7
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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).
Foothills Model Forest 8
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
3.1.2.1 Statistical Analysis of Differences in Historic and Current Survey Catch Rates
The catch rate for rainbow trout was different between the historic survey and the current
survey at the 80% confidence level (Table 5).
Table 5. Catch rate comparisons for the MacKenzie Creek watershed (Locations 432 and 961).
Species ¹ Survey Mean (# fish / 100m² / min)
Standard Deviation (# fish / 100m² / min) T-statistic P-value
Historic 0.0031 0.0044 Current 0.0026 0.0036
BLTR
Difference 0.0006 0.0008 1.000 0.500 Historic 0.0000 0.0000 Current 0.0010 0.0013
MNWH
Difference -0.0010 0.0013 -1.000 0.500 Historic 0.0713 0.0130 Current 0.0221 0.0047
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
3.1.2.2 Changes in Proportion of Catchable Size Fish
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).
Foothills Model Forest 9
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
HISTORIC (1983) n = 39 Minimum FL = 74 Maximum FL = 225 Mean FL = 130
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
Foothills Model Forest 10
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
3.1.3 Moon Creek
3.1.3.1 Statistical Analysis of Differences in Historic and Current Survey Catch Rates
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).
Species ¹ Survey Mean (# fish / 100m² / min)
Standard Deviation (# fish / 100m² / min) T-statistic P-value
Historic 0.0556 0.0619 Current 0.0226 0.0255
BLTR
Difference 0.0330 0.0363 1.284 0.421 Historic 0.0015 0.0021 Current 0.0006 0.0008
MNWH
Difference 0.0010 0.0013 1.000 0.500 Historic 0.0192 0.0272 Current 0.0028 0.0040
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
3.1.4.1 Statistical Analysis of Differences in Historic and Current Survey Catch Rates
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).
Foothills Model Forest 11
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
Table 9. Catch rate comparisons for the Pinto Creek watershed (Locations 88 and 978).
Species ¹ Survey Mean (# fish / 100m² / min)
Standard Deviation (# fish / 100m² / min) T-statistic P-value
Historic 0.0025 0.0035 Current 0.0026 0.0036
ARGR
Difference -0.0001 0.0001 -1.000 0.500 Historic 0.0025 0.0035 Current 0.0000 0.0000
BLTR
Difference 0.0025 0.0035 1.000 0.500 Historic 0.0085 0.0120 Current 0.0038 0.0054
MNWH
Difference 0.0047 0.0066 1.000 0.500 Historic 0.0246 0.0107 Current 0.0650 0.0773
RNTR
Difference -0.0404 0.0880 -0.648 0.634 ¹ ARGR = Arctic Grayling; BLTR = Bull Trout; MNWH = Mountain Whitefish; RNTR = Rainbow Trout
3.1.4.2 Changes in Proportion of Catchable Size Fish
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
3.1.5.1 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.
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).
Foothills Model Forest 12
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
HISTORIC (1992) n = 75 Minimum FL = 58 Maximum FL = 252 Mean FL = 105
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
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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.
3.1.6.2 Changes in Proportion of Catchable Size Fish
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
Foothills Model Forest 14
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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.
Foothills Model Forest 15
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF 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.
Foothills Model Forest 16
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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.
Foothills Model Forest 17
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
Foothills Model Forest 18
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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.
Foothills Model Forest 19
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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
Foothills Model Forest 20
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
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.
Foothills Model Forest 21
Report 1.2.1 - Changes Between Historic and Current Fish Relative Abundance and Size in Selected FMF Watersheds.
Foothills Model Forest 22
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.