Preliminary Report: Stream Crossings and Arctic Grayling Conservation in the Athabasca River Basin

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CONSERVATION REPORT

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Preliminary Report: Stream Crossings and Arctic Grayling Conservation in the Athabasca River Basin

Laura MacPherson1 and Troy Furukawa2 1University of Alberta, Department of Renewable Resources 751 General Services Building Edmonton, Alberta T6G 2H1 2Alberta Conservation Association #101, 9 Chippewa Rd Sherwood Park, Alberta T8A 6J7

Report Editors PETER AKU GLENDA SAMUELSON Alberta Conservation Association 2123 Crocus Road NW #101, 9 Chippewa Rd Calgary AB T2L 0Z7 Sherwood Park AB T8A 6J7

Conservation Report Series Type Preliminary Report

Disclaimer: This document is an independent report prepared by the Alberta Conservation Association. The authors are solely responsible for the interpretations of data and statements made within this report.

Reproduction and Availability: This report and its contents may be reproduced in whole, or in part, provided that this title page is included with such reproduction and/or appropriate acknowledgements are provided to the authors and sponsors of this project.

Suggested Citation: MacPherson, L., and T. Furukawa. 2010. Preliminary report: Stream crossings and Arctic Grayling conservation in the Athabasca River Basin. Produced by the Alberta Conservation Association, Sherwood Park, Alberta, Canada. 30 pp + App.

Cover photo credit: David Fairless

Digital copies of conservation reports can be obtained from: Alberta Conservation Association #101, 9 Chippewa Rd Sherwood Park AB T8A 6J7 Toll Free: 1‐877‐969‐9091 Tel: (780) 410‐1998 Fax: (780) 464‐0990 Email: info@ab‐conservation.com Website: www.ab‐conservation.com

EXECUTIVE SUMMARY

The ability to accurately estimate fish abundance allows fishery biologists and managers to monitor fish populations and formulate management strategies. Reliable fish population estimates are particularly important for species at risk, such as Arctic Grayling (Thymallus arcticus), where a lack of population information could result in inappropriately assigned management decisions. Given severe declines in Alberta Arctic Grayling populations, accurate population information is critical for fisheries managers.

In our study of the wadeable tributary streams of the Athabasca River, we evaluated the overall field efficiency of egg kick surveys, angling and electrofishing methods in estimating Arctic Grayling populations. We assessed how stream characteristics and temporal variability influenced Arctic Grayling catch rates, and compared population estimates derived from mark‐recapture and three‐pass removal methods. In turn, this allowed us to estimate capture probability (q) for small young‐of‐year (≤110 mm) and large (>110 mm) Arctic Grayling using angling and electrofishing. Lastly, we evaluated habitat fragmentation at stream crossing sites (road bridges and culverts), and at a larger sub‐basin scale. Geographic Information System (GIS) analysis was used to assess sub‐basin characteristics.

Our results indicate that angling and electrofishing should be used together in order to capture all Arctic Grayling size classes. In addition, unless water conductivities exceed 300 μS/cm, electrofishing should occur later in the summer (July 16 ‐ August 31) when catch rates are highest. Similarly, angling catch rates were highest in the late summer. A small sample size and low recapture of Arctic Grayling precluded us from drawing any definite conclusions about the accuracy of mark‐recapture and three‐pass removal abundance estimates. We were however, able to determine capture probability (q) by gear type and fish size class.

Given our findings, we created a sampling flow diagram for common fisheries management objectives. We found no evidence that Arctic Grayling populations were fragmented at stream crossing sites or at a sub‐basin scale. Despite this, we believe Arctic Grayling populations are likely already too severely impacted by cumulative

iii anthropogenic impacts, including road culverts, such that these relationships were no longer easily discernible.

Key words: Arctic Grayling, Thymallus arcticus, mark‐recapture, three‐pass removal, habitat fragmentation, bridge, culvert, Athabasca River.

ACKNOWLEDGEMENTS

This project is a result of collaborative work between the Alberta Conservation Association (ACA), Alberta Sustainable Resource Development (ASRD) and the Master’s of Science work of Laura MacPherson at the University of Alberta, Department of Renewable Resources (U of A). A special thank you to the ACA for contributing and making a NSERC IPS grant possible for Laura MacPherson. Thank you to Stephen Spencer, Don Hildebrandt, Owen Watkins, Shannon Stambaugh (ASRD) and Sierra Sullivan (U of A) for all their hard work during field sampling. A special thank you to Stephen Spencer, David Park, Michael Sullivan (ASRD), Lee Foote (U of A), Peter Aku (ACA), and Cam Stevens (Golder Associates) for guidance in project design and sampling. Mike Rodtka (ACA) provided invaluable comments and additions to this report.

v vi

TABLE OF CONTENTS EXECUTIVE SUMMARY ...... iii ACKNOWLEDGEMENTS ...... v TABLE OF CONTENTS ...... vii LIST OF FIGURES ...... viii LIST OF TABLES ...... ix LIST OF APPENDICES ...... x 1.0 INTRODUCTION ...... 1 1.1 General introduction ...... 1 1.2 Study rationale ...... 1 1.3 Study objectives ...... 2 2.0 STUDY AREA ...... 2 3.0 MATERIALS AND METHODS ...... 4 3.1 Field sampling ...... 4 3.2 Statistical analysis ...... 7 4.0 RESULTS ...... 9 4.1 Sampling method field efficiency ...... 9 4.2 Temporal variability and size selectivity ...... 9 4.3 Stream habitat and water quality characteristics ...... 13 4.4 Mark‐recapture and three‐pass removal methods ...... 15 4.5 Habitat fragmentation ...... 16 4.6 Overall sampling conclusions ...... 18 5.0 DISCUSSION ...... 19 5.1 Field efficiency ...... 19 5.2 Seasonal and temporal variation by gear type ...... 19 5.3 Size selectivity by gear ...... 20 5.4 Stream habitat and water quality characteristics ...... 21 5.5 Mark‐recapture and three‐pass removal methods ...... 21 5.6 Habitat fragmentation ...... 23 5.7 Overall sampling conclusions ...... 24 6.0 LITERATURE CITED ...... 26

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LIST OF FIGURES

Figure 1. Map of Athabasca River Basin, 2008 and 2009 study sites...... 3 Figure 2. Mean (+SE) abundance (number/km) of Arctic Grayling (ARGR) captured in Athabasca River tributary streams using electrofishing and angling during the summers of 2008 and 2009...... 11 Figure 3. Number of Arctic Grayling caught in 2008 and 2009 by angling and electrofishing in Athabasca River tributary streams ...... 12 Figure 4. Linear regression relationship between angler catch rate (fish/angler‐ hour) of Arctic Grayling and dissolved oxygen (mg/L) in Athabasca River tributary streams, 2008 and 2009 ...... 14 Figure 5. Third order polynomial regression relationship between the number of Arctic Grayling (ARGR) captured using electrofishing (fish/100s) and conductivity (μS/cm) in Athabasca River tributary streams, 2008 and 2009...... 14 Figure 6. Comparison of Arctic Grayling (ARGR) mean catch rates (+SE) upstream (U/S) and downstream (D/S) of bridge and culvert crossings using angling (#ARGR/angler‐hour) and electrofishing (#ARGR/100s) gear. ... 17 Figure 7. Comparison of Arctic Grayling (ARGR) abundances in Athabasca River sub‐basins with different road densities...... 17 Figure 8. Decision flow diagram for sampling Arctic Grayling (ARGR) in Athabasca River tributary streams for four common fisheries management objectives...... 18

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LIST OF TABLES

Table 1. Number of sites angled, electrofished, and egg kick surveyed in Athabasca River tributary streams during the summers of 2008 and 2009...... 5 Table 2. Average (+SE) monthly fork length (mm) of Arctic Grayling captured using electrofishing and angling in Athabasca River tributary streams sampled in 2008 and 2009...... 11 Table 3. Minimum, maximum, mean and standard error (+SE) of measured habitat and water quality variables at Athabasca River tributary streams, 2008 and 2009...... 13 Table 4. Arctic Grayling abundance estimates and 95% confidence intervals (CI) for large (>110 mm) and small (<110 mm) fish using mark‐recapture and three‐pass removal methods...... 15 Table 5. Capture probability (q) for electrofishing and angling of large (>110 mm) and small (<110 mm) Arctic Grayling...... 16

LIST OF APPENDICES

Appendix 1. Number of small (<110 mm) Arctic Grayling captured during the mark‐ recapture and three‐pass removal study in wadeable tributaries (n=9) in the Athabasca River Basin...... 31 Appendix 2. Number of large (>110 mm) Arctic Grayling captured during the mark‐ recapture and three‐pass removal study in wadeable tributaries (n=9) in the Athabasca River Basin...... 33 Appendix 3. Bankfull channel width, size of study area, electrofishing effort and total angler effort for mark‐recapture and three‐pass removal study sites in tributaries in the Athabasca River Basin...... 35 Appendix 4. Pearson correlation coefficients (r) for stream habitat and water quality variables measured in wadeable tributaries in the Athabasca River Basin...... 36

1.0 INTRODUCTION

1.1 General introduction

The ability to accurately estimate fish abundance allows fisheries biologists and managers to monitor fish populations and formulate management strategies. Indeed, the need for reliable fish population estimates is especially important for species at risk, where a failure to obtain credible fish population information could result in inappropriately assigned conservation designations or management decisions (Mace 1994). In Alberta, Canada, this is essential for Arctic Grayling (Thymallus arcticus), a fish species provincially listed as ‘sensitive’ (ASRD 2001). Recently, increased land use from expanding energy and forestry development, habitat fragmentation by improperly installed and maintained watercourse crossing structures, and increased angler access and angling pressure have resulted in extreme declines of Arctic Grayling populations across the province (Berry 1998; Blackburn and Johnson 2004; ASRD 2005). Since the 1950s, Alberta Arctic Grayling have experienced high population reductions, with declines estimated at 90% for approximately 50% of subpopulations. Arctic Grayling populations at the southern limit of their range (Athabasca River and tributaries) have experienced the most drastic reductions (ASRD 2005).

1.2 Study rationale

Although habitat fragmentation is listed as a major factor influencing Arctic Grayling declines (ASRD 2005), very few studies have attempted to quantify the effects of watercourse crossing structures. It is therefore important to determine if watercourse crossing structures, especially bridges and culverts, affect Arctic Grayling passage at individual crossings and on a larger sub‐basin scale. However, given recent declines in Arctic Grayling, it is first essential that fisheries biologists and managers accurately evaluate populations to plan future provincial management and conservation strategies for this fish species.

Difficulties in conducting accurate fisheries assessments often arise because capture probabilities and the vulnerability of stream fish may vary with sampling gear, species, size, behaviour, time of sampling, and habitat (Bayley and Austen 2002; Peterson et al.

2004; Kennard et al. 2006). In Alberta, there is no standardized sampling method for Arctic Grayling. Given that monitoring fish populations requires both financial and human resources (Kennard et al. 2006), it is essential to determine the most efficient and accurate means to conduct fish abundance estimates. Three‐pass removal and mark‐recapture are commonly employed fisheries techniques for estimating population abundance (Pine et al. 2003), however, in Alberta the likelihood of detecting and accurately estimating Arctic Grayling abundances using these methods is largely unknown. Defining these relationships, therefore, is critical to determining the most effective approach to sampling Arctic Grayling populations.

1.3 Study objectives

The primary objectives of our study were to determine effective Arctic Grayling monitoring protocols and the effects of road stream crossing structures on Arctic Grayling abundances in the wadeable tributary streams of the Athabasca River. Specific objectives included: i. Compare the overall field efficiency of egg kick surveys, angling and electrofishing to quantify Arctic Grayling populations. ii. Assess how stream characteristics and temporal (i.e. May ‐ August) variability affect Arctic Grayling catch rates. iii. Compare Arctic Grayling population estimates using mark‐recapture and three‐ pass removal methods. iv. Estimate capture probability (q) for small young‐of‐year (≤110 mm) and large (>110 mm) Arctic Grayling using angling and electrofishing. v. Determine the effects of stream crossing structures on Arctic Grayling abundances on a small (individual crossings) and large (sub‐basin) scale.

2.0 STUDY AREA

Our study was conducted on wadeable tributaries of the Athabasca River in the Foothills ecoregion, near the cities of Whitecourt, Edson and Hinton in west‐central Alberta (Figure 1) (NRC 2006). Basins with high historical Arctic Grayling presence were chosen for our study. Located in the Lower Foothills and Upper Foothills subregions (NRC 2006), study sites extended as far south as the Embarras River

(53˚17’N, 117˚00’W), and as far north as (54˚65’N, 115˚90’W) the Freeman River drainage. Land use in this area is dominated by the forestry and energy sectors. Recreational activities include fishing, hunting, camping, and ATV use.

Figure 1. Map of Athabasca River Basin, 2008 and 2009 study sites. ARGR = sites where Arctic Grayling were present. At some study sites multiple sampling methods were used.

3.0 MATERIALS AND METHODS

3.1 Field sampling

Field sampling occurred from May to August (2008 and 2009), and consisted of angling (July ‐ Sept 2008, June ‐ Aug 2009), electrofishing (May ‐ Aug 2008, 2009), and sampling habitat parameters (July ‐ Sept 2008, May ‐ Aug 2009). Habitat sampling included bankfull channel width (m), dissolved oxygen (mg/L), temperature (°C), conductivity (μS/cm), and pH. We performed a mark‐recapture and three‐pass removal study during late summer (2008 and 2009) on a sub‐sample of sites supporting Arctic Grayling to estimate population sizes, and capture probability (q) by size class and gear type (angling and electrofishing). We used two fish size classes (by fork length) for this analysis: small or young‐of‐year (≤110 mm) and large (>110 mm).

In 2009, from May 12 to 27, we conducted egg kick surveys at 20 sites, in 13 sub‐basins, in an attempt to locate Arctic Grayling spawning areas (Table 1). Of these sites, 14 were also electrofished and angled for Arctic Grayling. Potential spawning sites were identified in second to fourth order streams and were described as riffle‐run transitions with water depths of 0.15 to 0.5 m, water velocities of 0.35 to 0.55 m/s, and with gravel/cobble substrates (J. O’Neil, pers. comm., Huet 1959). For ease of access, surveyed sites were located at road and stream crossing intersections.

We sampled for eggs using a D‐net placed downstream of 1‐m2 sampling plots, and then we disturbed the substrate for 1 minute. This was repeated at 3 to 9 locations within each riffle‐run transition area. For three transition areas, a maximum of 18 1‐m2 plots were sampled. If no eggs were located after sampling three riffle‐run transitions, or no appropriate spawning habitat was found, field crews continued to survey the next upstream site. If eggs were located at a site, sampling stopped immediately, and the tributary was deemed to support spawning Arctic Grayling.

Table 1. Number of sites angled, electrofished, and egg kick surveyed in Athabasca River tributary streams during the summers of 2008 and 2009. Tributaries where Arctic Grayling (ARGR) and Arctic Grayling eggs were detected are denoted with an ‘X’. Number of sites in parentheses indicate number of re‐sampled sites used for the mark‐recapture and three‐pass removal study.

Number of Number of ARGR Closest Number Number of ARGR Tributary name sites egg kick eggs city of sites sites angled detected electrofished sites detected Baseline Creek Hinton 1 1 1 1 Canyon Creek Hinton 1 1 1 1 Chickadee Creek Whitecourt 3 (2) 3 (2) 3 (2) 3 X Embarras River Edson 3 2 2 3 Fox Creek Hinton 1 1 1 1 Freeman River Whitecourt 27 (5) 7 (5) 27 (5) 0 X Marsh Head Creek Whitecourt 2 1 1 2 X Oldman Creek Hinton 2 2 2 1 Pinto Creek Hinton 2 2 1 0 X Prest Creek Edson 1 0 0 1 Sakwatamau River Whitecourt 36(2) 4 (2) 36 (2) 0 X Sundance Creek Edson 4 3 3 3 X X Swartz Creek Edson 1 0 0 1 Two Creek Whitecourt 1 1 1 0 X Unnamed Tributary Hinton 1 1 1 0 Unnamed Tributary Hinton 1 1 1 1 Windfall Creek Whitecourt 1 0 0 1 Wolf Creek Edson 3 3 3 2 X

During the 2008 and 2009 field seasons, we electrofished a total of 84 sites in 18 sub‐ basins, of which 33 sites were also sample‐angled using dry flies (Table 1). An experienced three‐person crew electrofished sites for 600 m (300 m upstream and downstream of the stream crossing) using a model 12 or LR24 Smith‐Root backpack electrofishing unit. Electrofishing proceeded from downstream to upstream to avoid silting the stream and to maximize catchability. One person operated the electrofisher, while two people netted fish. Voltage, frequency, and duty cycle were adjusted to maximize capture probability without injuring any fish species (settings range: voltage=400–500 V, frequency=40–60 Hz, duty cycle=20‐25%).

Angled sites were sampled with a three‐person crew; one experienced angler and two moderately experienced anglers. Typically, when fish were captured, they were held live in buckets with ambient stream water, and then processed every 50 m. We measured fish fork length (mm) and identified the species, after which fish were returned to a downstream location. Fish were not released back into the stream unless they appeared healthy and uninjured. In rare cases (2.5%) when fish were severely injured and unable to recover, we euthanized them. Due to equipment failures, dissolved oxygen, conductivity, and pH were not recorded at all sample sites.

At 9 sites confirmed to support Arctic Grayling, we determined population estimates using both mark‐recapture and three‐pass removal methods. Each site was approximately 300 m in length. Prior to sampling, the upstream and downstream ends of each transect were blocked using beach seine nets with a 3.18 mm mesh. We took care to ensure that block nets were completely secured to the streambed. After block nets were in place, we conducted an initial pass of angling with dry flies. Arctic Grayling caught during sample angling were marked with a clip to their adipose fin.

Immediately after a pass of angling, we completed a single electrofishing pass. Fish captured from electrofishing were marked with a small clip to their pelvic fin. After the first angling and electrofishing passes, marked fish were returned to the closed section of stream where they were captured. Following the initial marking passes and an overnight recovery period (Rosenberger and Dunham 2005), field crews conducted three‐pass removal sampling with an electrofisher the following day. Before proceeding from one removal pass to another, the field crew waited for a minimum of one hour to allow fish to recover from electrofishing activity (Poos et al. 2007). Every

50 m during electrofishing passes we recorded the number of marked captures, measured fork length (mm), and released fish immediately to the stream outside of the block nets. Unmarked fish captured during the three‐pass removal effort were not marked. All block nets remained in position throughout depletion estimates. Appendices 1 and 2 provide a summary of the Arctic Grayling captured at these 9 sites.

3.2 Statistical analysis

To compare the efficiency of egg kick surveys, electrofishing and angling in detecting the presence of Arctic Grayling, we calculated a measure of field efficiency for each sampling method. As travel time was similar among the three sampling methods, it was excluded from our estimate of field efficiency. We calculated field efficiency by determining the number of fish or eggs detected during an hour of sampling with a three‐person crew. For all three sampling methods this included sites where Arctic Grayling were found with at least one gear type as well as sites that are known to support Arctic Grayling historically.

To determine how temporal variability (May to September) affected electrofishing and angling catch rates, we employed a two‐way analysis of variance (ANOVA) (α=0.05). We used a post‐hoc Holm‐Sidak Test for monthly pairwise comparisons, since data were not normally distributed. Given that only electrofishing was undertaken in May, we were unable to make comparisons for this month. Since similar catch rate trends were observed for the two years, data from the summers of 2008 and 2009 were pooled for this analysis.

To examine relationships between stream habitat and water quality variables with Arctic Grayling angling and electrofishing catch rates, we first used scatterplots to visually examine non‐linear relationships. Secondly, we used regression analyses to determine if there were any significant relationships. We fit these stream habitat and water quality regression relationships (i.e. linear or exponential) to allow for the best fit of the data. Non‐normal catch rate data were log10 transformed. In the regression analysis of electrofishing catch rate and water conductivity, we fit an exponential curve, since we expected there to be a conductivity threshold where catches would improve dramatically.

Prior to regression analyses, Pearson’s correlations between all stream habitat and water quality variables were used to examine multicollinearity. If two variables were highly correlated (r>0.7) only one was retained (Dauwalter and Fisher 2007). Furthermore, if trends were detected between habitat variables and electrofishing or angling catch rates, Pearson’s correlation tests between catch rates and Julian date were examined to determine if there was high correlation (r>0.7).

We examined the regression relationships between stream habitat variables and catch rates for small young‐of‐year (≤110 mm) and large (>110 mm) Arctic Grayling separately and results did not differ significantly. Therefore, data presented in the regression analysis were grouped regardless of Arctic Grayling size. Lastly, we used a two‐way analysis of variance (ANOVA) to determine if there was a difference in the size of Arctic Grayling captured by gear type and month. Again, since similar trends in Arctic Grayling monthly size and size selectivity by gear type were observed in the summers of 2008 and 2009, data were pooled for this analysis.

We used maximum‐likelihood methods to estimate population size (N) for mark‐ recapture and three‐pass removal data (Lockwood and Schneider 2000). The likelihood function was repeatedly evaluated at trial values of N, until a value of N was found that produces the maximum value of the likelihood function. This value is then chosen as the best or most likely population estimate.

Capture probability (q) was determined by dividing the number of marked fish by the site abundance estimate. Capture probability was then standardized for sampling effort and sample area. For electrofishing, capture probability was standardized to 10,000 seconds of effort per hectare of study area. Capture probability for angling was standardized to 10 hours of effort per hectare of study area. The capture probability (q) can then be applied to equation 1 to determine more accurate Arctic Grayling abundance estimates by size class and gear type.

C/ƒ = qN [Equation 1]

Where, C = the number of fish caught, ƒ = the unit of effort expended, q = the capture probability (catchability coefficient), and N = the absolute abundance of fish.

To determine if stream crossing structures (i.e. culverts or bridges) were impeding Arctic Grayling passage on a local site scale, we compared Arctic Grayling electrofishing and angling catch rates upstream and downstream of crossing structures. On a larger sub‐basin scale, we used geographic information system (GIS) to determine road densities (km/km2). Road densities were then compared to sub‐ basin Arctic Grayling abundances extrapolated from site catch rates.

4.0 RESULTS

4.1 Sampling method field efficiency

Of the sites electrofished (n=84) and angled (n=33), Arctic Grayling were located at only 25 sites. Using electrofishing and angling, we captured a total of 277 Arctic Grayling in the Freeman River, Sakwatamau River, Wolf Creek, Sundance Creek, Pinto Creek, Chickadee Creek, Two Creek, and Marsh Head Creek drainages (Figure 1). Of the 13 sites surveyed, we located a total of 20 Arctic Grayling eggs at one site only: Sundance Creek (Table 1). In an overall comparison of the field efficiency of using egg kick surveys, angling (using dry flies) and electrofishing to detect presence of Arctic Grayling, angling was the most successful method. On average, using a three‐person crew, angling captured 2.332 + 0.015 fish/h, while electrofishing detected 1.135 + 0.004 fish/h, and kick surveys detected 1.000 + 0.053 eggs/h.

4.2 Temporal variability and size selectivity

Arctic Grayling catch rates changed with the season. In the early summer (May 15 to July 15) and in the fall (September 1 to 8), the number of Arctic Grayling detected per

9 stream kilometer was low with both electrofishing and angling (Figure 2). Later in the summer (July 16 to August 31), Arctic Grayling detection increased and electrofishing captured more Arctic Grayling than angling (Figure 2). In a comparison of the combined summer months (May to August), there was no significant differences in Arctic Grayling catch rates between electrofishing and angling (two‐way ANOVA, F=0.86, df=1, P=0.36). However, there were differences in catch rates between months (two‐way ANOVA, F=3.18, df=4, P=0.02), specifically, between June and August catch rates (Holm‐Sidak, t=3.34, P=0.002).

There were significant differences in Arctic Grayling size by gear type (two‐way ANOVA, F=269.00, df=1, P<0.001) and between summer months (two‐way ANOVA, F=9.61, df=4, P<0.001). On average, fish caught angling were 47% larger than those caught electrofishing (Table 2). Although angling caught larger fish (mean=173.8 mm, range=100.0‐285.0 mm), angling frequently failed to capture young‐of‐the‐year. In contrast, electrofishing captured a broader size range (mean=92.1 mm, range=23.0‐282.0 mm), including young‐of‐the‐year Arctic Grayling (Figure 3).

Figure 2. Mean (+SE) abundance (number/km) of Arctic Grayling (ARGR) captured in Athabasca River tributary streams using electrofishing and angling during the summers of 2008 and 2009. Data was combined for the two summers. Sample dates are May 15‐31, June 1‐15, June 16‐30, July 1‐15, July 16‐31, August 1‐,15 August 16‐31, and September 1‐8.

Table 2. Average (+SE) monthly fork length (mm) of Arctic Grayling captured using electrofishing and angling in Athabasca River tributary streams sampled in 2008 and 2009.

May June July August September 132.0 130.0 72.6 86.0 92.0 Electrofishing + 14.0 + 11.0 + 6.9 + 2.9 + 0.8

185.4 178.0 160.0 184.0 Angling ‐ + 14.0 + 5.0 + 6.5 +17.0

Figure 3. Number of Arctic Grayling caught in 2008 and 2009 by angling and electrofishing in Athabasca River tributary streams in: a) May (electrofishing: n=4, 18 fish); b) June (electrofishing: n=6, 14 fish; angle: n=3, 10 fish); c) July (electrofishing: n=4, 36 fish; angle: n=9, 60 fish); d) August (electrofishing: n=6, 95 fish; angle: n=5, 32 fish); e) September (electrofishing: n=3, 5 fish; angle: n=4, 8 fish). Data from both summers were combined for this graph.

4.3 Stream habitat and water quality characteristics

At study sites where Arctic Grayling were detected by electrofishing or angling, bankfull channel width, temperature, dissolved oxygen, pH, and conductivity varied considerably (Table 3; Appendix 3). Bankfull channel width (m), temperature (°C), and conductivity (μS/cm) were not significantly correlated (r<0.52). However, dissolved oxygen (mg/L) and pH were highly correlated (r=0.77) (Appendix 4). Since pH was never measured below salmonid thresholds (approximately <5.0) (Ikuta et al. 1992; Thomsen et al. 1988) and was a less important water quality variable, we excluded it from our analysis.

In an analysis of the influence of stream habitat and water quality variables on Arctic Grayling catches, bankfull channel width did not significantly influence electrofishing catch rates (R2=0.076, df=17, P=0.269) or angling catch rates (R2=0.092, df=13, P=0.273). Similarly, dissolved oxygen did not significantly affect electrofishing (R2=0.000, df=6, P=0.980) results. Although not significant, there was a trend of decreasing angling catches with increasing dissolved oxygen (R2=0.279, df=13, P=0.054) (Figure 4). In addition, water temperature had no significant impact on angling (R2=0.231, df=11, P=0.114) or electrofishing (R2=0.055, df=21, P=0.292) catch rates. While conductivity did not significantly influence Arctic Grayling catch rates during angling (R2=0.055, df=11, P=0.461), it significantly explained electrofishing success (R2=0.980, df=13, P<0.001) (Figure 5). Dissolved oxygen (r=0.02) and conductivity (r=‐0.16) were not highly correlated with Julian date.

Table 3. Minimum, maximum, mean and standard error (+SE) of measured habitat and water quality variables at Athabasca River tributary streams, 2008 and 2009.

Dissolved Bankfull Temperature oxygen Conductivity Width (°C) pH (mg/L) (μS/cm) (m) Minimum 5.00 7.85 7.20 164.30 2.70 Maximum 17.80 8.37 12.80 437.00 29.80 Mean 12.58 8.14 9.49 284.49 8.52 Standard Error (+/‐) 0.66 0.05 0.57 20.88 1.28

Figure 4. Linear regression relationship between angler catch rate (fish/angler‐hour) of Arctic Grayling and dissolved oxygen (mg/L) in Athabasca River tributary streams, 2008 and 2009. Catch rate is Log10‐transformed

Figure 5. Third order polynomial regression relationship between the number of Arctic Grayling (ARGR) captured using electrofishing (fish/100s) and conductivity (μS/cm) in Athabasca River tributary streams, 2008 and 2009.

4.4 Mark‐recapture and three‐pass removal methods

Our results appear to demonstrate that abundance estimates of Arctic Grayling using mark‐recapture and three‐pass removal are quite dissimilar for both small and large size classes (Table 4). There was, however, a large amount of variability in our estimates, and 95% confidence intervals were large (Table 4). Electrofishing and angling capture probability (q) by Arctic Grayling size class varied slightly by site and sub‐basin (Table 5). On average, standardized electrofishing capture probability (10,000 s/ha) (q) was 2.4 times higher for large (q = 0.39) than small (q = 0.16) fish (Table 5). Sites that could not be analyzed to determine capture probability were omitted. No small Arctic Grayling were captured by angling and therefore there are no corresponding capture probability values. However, standardized angling capture probability (10 hours angling/ha) for large Arctic Grayling was q = 0.193.

Table 4. Arctic Grayling abundance estimates and 95% confidence intervals (CI) for large (>110 mm) and small (<110 mm) fish using mark‐recapture and three‐ pass removal methods in the FM=Freeman River, JC=Judy Creek, SK=Sakwatamau River, CC=Chickadee Creek, TC=Two Creek study sites.

Three‐ Mark‐ Lower Upper Lower Sample pass Upper Site recapture 95% 95% 95% date removal 95% CI N CI CI CI N Large Arctic Grayling FM1 21‐Aug‐08 ‐ ‐ ‐ 214 6 899 JC1 22‐Aug‐08 60 30 180 218 15 969 SK1 24‐Aug‐08 ‐ ‐ ‐ 198 4 1,381 SK2 26‐Aug‐08 21 11 63 209 7 1,191 CC1 24‐Jul‐09 ‐ ‐ ‐ 202 2 1,946 JC2 28‐Jul‐09 66 22 132 202 11 1,129 Small Arctic Grayling FM1 21‐Aug‐08 23 9 45 6,665 15 127,799 JC1 22‐Aug‐08 901 501 4,503 94 78 111 SK1 24‐Aug‐08 ‐ ‐ ‐ 13 12 14 SK2 26‐Aug‐08 48 16 ‐ 230 165 295 FM3 05‐Sep‐08 7 3 ‐ 205 128 282 TC1 26‐l‐Ju 09 ‐ ‐ ‐ 203 102 304 JC2 28‐Jul‐09 529 265 1,587 110 98 122 CC2 05‐Aug‐09 ‐ ‐ ‐ 1,376 1210 1,542

Table 5. Capture probability (q) for electrofishing and angling of large (>110 mm) and small (<110 mm) Arctic Grayling in the FM=Freeman River, JC=Judy Creek, SK=Sakwatamau River, CC=Chickadee Creek, TC=Two Creek study sites. Electrofishing capture probability (q) values are standardized at 10,000 seconds/ha and angling capture probability is standardized at 10 hours/ha.

Site Sample Electrofishing Angling date q small fish q large fish q small fish q large fish FM1 21‐Aug‐08 0.20 ‐ ‐ 0.052 JC1 22‐Aug‐08 0.11 0.05 ‐ 0.086 SK1 24‐Aug‐08 0.18 0.08 ‐ 0.090 SK2 26‐Aug‐08 0.08 0.29 ‐ 0.050 FM3 05‐Sep‐08 0.17 ‐ ‐ ‐ CC1 24‐Jul‐09 ‐ ‐ ‐ 0.119 TC1 26‐Jul‐09 ‐ 1.16 ‐ 0.389 JC2 28‐Jul‐09 0.14 0.35 ‐ 0.073 CC2 05‐Aug‐09 0.26 ‐ ‐ 0.687 Average 0.16 0.39 ‐ 0.193

4.5 Habitat fragmentation

In our comparison of Arctic Grayling above and below bridges (n=12) and culverts (n=7), we found that angling catch rates did not differ significantly. When electrofishing, we found that catch rates were not significantly different above and below bridges, but 85% more Arctic Grayling were captured above culverts (Figure 6). Arctic Grayling were detected at culverts with no hang height and at one culvert with a slight hang height (0.04 m).

At a larger sub‐basin scale, it appears that there is no relationship between sub‐basin road densities and Arctic Grayling abundances in the Athabasca River nbasi (Figure 7).

Figure 6. Comparison of Arctic Grayling (ARGR) mean catch rates (+SE) upstream (U/S) and downstream (D/S) of bridge and culvert crossings using angling (#ARGR/angler‐hour) and electrofishing (#ARGR/100s) gear.

Figure 7. Comparison of Arctic Grayling (ARGR) abundances in Athabasca River sub‐basins with different road densities.

4.6 Overall sampling conclusions

Given our findings, we created a decision flow diagram for four common fisheries management objectives (Figure 8). In order to monitor Alberta Arctic Grayling populations, managers may choose to analyze recruitment, conduct a size structure analysis, attempt to determine a population estimate, or simply determine if Arctic Grayling are present. Dependent on specific objectives, the flow diagram determines when and how to sample and the appropriate capture probability (q) to use according to gear type and Arctic Grayling size (Figure 8).

Figure 8. Decision flow diagram for sampling Arctic Grayling (ARGR) in Athabasca River tributary streams for four common fisheries management objectives. Electrofishing catchability (q) values are standardized at 10,000 s/ha and angling catchability is standardized at 10 hrs/ha. *For a complete size structure analysis streams should be both electrofished and angled.

5.0 DISCUSSION

Despite declining Arctic Grayling populations in Alberta, sampling and monitoring remains inconsistent throughout the province. Thus, a fundamental step in Alberta Arctic Grayling management and conservation depends on the availability of accurate and timely population estimates and monitoring protocols. The results presented in our study will provide resource managers with the information required to evaluate Arctic Grayling populations in wadeable tributary streams of the Athabasca River.

5.1 Field efficiency

In our measure of the overall field efficiency of detecting Arctic Grayling presence by angling, electrofishing and egg kick surveys, we found that angling produced slightly higher detection of Arctic Grayling with a three‐person field crew. Although electrofishing is often the preferred sampling method for Arctic Grayling in wadeable streams (Bohlin et al. 1989; Bonar et al. 2009), our results indicate that angling using dry flies could be an equally effective or complimentary sampling method. In contrast, egg kick surveys appeared to be least successful of the three methods. This may be a result of low densities of Arctic Grayling in sampled streams, that appropriate spawning sites were not located, or that larger portions of basins must be sampled to ensure higher levels of egg detection. Despite our findings, Arctic Grayling egg kick surveys could be useful if the study goal was to locate spawning areas, and field crews could dedicate the necessary effort to ensure large areas of potential spawning habitats were sampled.

5.2 Seasonal and temporal variation by gear type

Our estimates of Arctic Grayling abundances in wadeable tributary streams of the Athabasca River using angling and electrofishing indicate that in early summer both sampling methods detected very few Arctic Grayling. Later in the summer angling and electrofishing catches increased, with more Arctic Grayling captured with electrofishing than with angling. Angling catches are likely linked to Arctic Grayling feeding activity as they rely on sight when feeding. As such, during the spring and early summer Arctic Grayling feeding activity may be reduced due to the energetic

19 costs associated with the harsher hydraulic conditions in higher velocity streams (Frankiewicz et al. 1993), or that drifting invertebrates could not be detected or captured in the more turbid stream waters (Reynolds et al. 1989; Braaten et al. 1997). Later in the summer when water levels decreased and clarity improved, we wsa higher Arctic Grayling angling catches. Alternatively, more adult fish may have migrated into the area throughout the summer, improving angling catches. The higher electrofishing efficiency can be attributed to the numerous small, young‐of‐year fish (<110 mm) fish captured in several sampled nursery streams.

5.3 Size selectivity by gear

In our investigation of size selectivity by gear type we found that electrofishing was the most efficient method to capture small young‐of‐the‐year Arctic Grayling, while adult fish were more susceptible to angling with dry flies. Contrary to our findings, numerous electrofishing studies have found that larger fish are easier to capture (Bayley and Dowling 1993; Peterson et al. 2004; Buckmeier and Schlechte 2009). Theoretically, electrofishing efficiency should increase exponentially with fish length (Bohlin et al. 1989). For instance, Peterson et al. (2004) found that electrofishing capture efficiency was greatest for the largest size classes of Bull Trout (Salvelinus conﬂuentus) and Westslope Cutthroat Trout (Oncorhynchus clarki lewisi).

In practice however, differences in fish behaviour and the surrounding habitat are more important for fishing efficiency (Bohlin et al. 1989). The differences of our findings may be a result of Arctic Grayling antipredator avoidance behaviour. When disturbed in our study, Brook Trout (Salvelinus fontinalis) and Rainbow Trout (Oncorhynchus mykiss) were often observed concealing themselves under larger substrate or undercut banks making them easier to capture (pers. obs.). Conversely, upon an electrofishing disturbance, adult Arctic Grayling were observed rapidly swimming away either upstream or downstream of sampling crews without stopping to conceal themselves (pers. obs.). Similarly, Ernst and Nielson (1981) found that European Arctic Grayling (Thymallus thymallus) avoided the electrical field, resulting in poor catchability. Angling, therefore, was likely a more successful method for adult Arctic Grayling since field crews could remain relatively undetected.

5.4 Stream habitat and water quality characteristics

Our results indicate that there was a relationship between dissolved oxygen (DO) and Arctic Grayling angling catch rates. However, we suspect that the apparent relationship is simply an artifact of the seasonality of angling catches. Dissolved oxygen decreases with increasing water temperatures and we observed higher angling catch rates as the summer proceeded and stream temperatures increased. Indeed, abundance estimates of several freshwater minnow and sucker species was not influenced by water chemistry (dissolved oxygen, specific conductivity, turbidity and nitrate concentrations) (Poos et al. 2007).

Surprisingly, we found no relationship between bankfull channel width d an electrofishing catch rates. Rosenberger and Dunham (2005) illustrated that stream size had a consistent negative effect on rainbow trout sampling efficiency. Although stream size has been shown to bias catch rates of other salmonid species (Habera et al. 1992; Rosenberger and Dunham 2005), Arctic Grayling capture probabilities were not correlated to bankfull channel width. Perhaps, our difficulties in detecting Arctic Grayling using a backpack electrofisher prevented us from noting any discernible differences between different stream widths.

Our study results also suggest that conductivity plays an important role in determining successful electrofishing captures of Arctic Grayling. Electrofishing effectiveness varies with physical factors such as water conductivity (Bohlin et al. 1989). Although our sample size is small, we found that water conductivities over 300 μS/cm greatly improved Arctic Grayling catches, especially for larger adult fish. Since conductivity increases with increasing water temperatures (Bohlin et al. 1989), conductivities will often be greatest in the summer.

5.5 Mark‐recapture and three‐pass removal methods

Given the small sample size and low catchability of Arctic Grayling, abundance estimates in our comparison of mark‐recapture and three‐pass removal methods are highly variable and we were unable to detect a signal amongst the noise. We were unable to draw any definite conclusions in a comparison of mark‐recapture and three‐ pass removal methods. Often, we recaptured very few, if any Arctic Grayling during

21 the mark‐recapture study. As a result, in many cases we were unable to estimate Arctic Grayling abundances using these methods. Furthermore, our abundance estimates derived from the three‐pass removal method were likely inaccurate as we did not meet all the necessary assumptions for this method to be effective (Zippin 1958).

In comparisons of these two sampling methods, many authors have cautioned the use of the removal method to estimate fish abundance (Zippin 1958; Peterson and Cederholm 1984; Peterson et al. 2004). The removal model can overestimate sampling efficiency and underestimate abundances estimates due to declining capture probabilities with successive removal passes (Zippin 1958; Rosenberger and Dunham 2005; Dauwalter and Fisher 2007). For instance, in their study Rosenberger and Dunham (2005) suggest that the assumptions of the removal method were not met and decreasing sampling efficiencies over removal passes resulted in underestimated population sizes and overestimates of sampling efficiency. Additionally, in the removal method Rainbow Trout sampling efficiency decreased with increasing stream size and amount of woody debris. Conversely, they concluded that Rainbow Trout abundances could be rigorously evaluated using the mark‐recapture method (Rosenberger and Dunham 2005). While increasing the number of removal passes may help decrease this bias, more passes are time consuming and costly (Peterson et al. 2004).

In contrast, mark‐recapture estimates are accepted as less susceptible to sampler and environmentally induced biases that can alter abundance estimates and are more precise than the removal method (Zippin 1958; Peterson and Cederholm 1984). Despite our inconclusive results, we tend to agree with previous research and suggest the use of less time intensive mark‐recapture studies in future Arctic Grayling sampling efforts.

This study, however, did enable us to calibrate grayling catchability (q) by gear type and fish size. This will allow fisheries managers to correct catch data for Arctic Grayling catchability and provide a more reliable index of population size for Athabasca River tributary streams. Further studies, however, should be conducted to corroborate our recommendations and capture probability estimates.

5.6 Habitat fragmentation

The dramatic declines in provincial Arctic Grayling populations since the 1950s have been attributed to land use activities from forest harvest, energy sector development, agriculture, habitat fragmentation, and increased angling pressure (ASRD 2005). Arctic Grayling require cold, clean, and continuous rivers and streams making them vulnerable to land use activities (Scott and Crossman 1973; Nelson and Paetz 1992; ASRD 2005). In addition, due to their later maturity, slow growth, and aggressive feeding habits, Arctic Grayling are susceptible to over exploitation (Scott and Crossman 1973; ASRD 2005).

On a local site scale, our results suggest that upstream passage by Arctic Grayling is unimpeded by bridges and culvert stream crossing structures. Not surprisingly, bridges are generally known to be ecologically benign structures that allow continuous fish passage with movement patterns similar to natural reaches (Benton et al. 2008; Pluym et al. 2008). Similarly, we demonstrated Arctic Grayling abundances were comparable above and below bridge crossings.

Culverts, however, have been known to disrupt salmonid passage. For instance, Burford et al. (2009) found that the upstream movement of Westslope Cutthroat Trout and Brook Trout through culverts was significantly lower than natural reaches, and that the probability of passage was low for small trout (<100 mm) at outlet drops greater than 0.15 m and for large trout (>100 mm) at outlet drops greater than 0.21 m. Nonetheless, in our study of Arctic Grayling Athabasca River tributaries, there were no significant differences in Arctic Grayling abundances above and below culvert crossings. Arctic Grayling were, however, only generally detected at culverts with no physical hang height, with the exception of one culvert with a slight hang height of 0.04 m. As a result, we were unable to determine if there is a threshold for hanging culverts to impede Arctic Grayling passage.

At a larger sub‐basin scale our results suggest Arctic Grayling abundances are unaffected by increasing road densities. Contrary to our findings, higher road densities are often associated with the loss of sensitive and specialist fish species and the decreasing integrity of river systems. For example, in the Battle River, Alberta, the

23 biological integrity of fish communities decreased linearly with increasing road densities (Stevens and Council 2008).

Arctic Grayling are a highly migratory species, moving large distances and require a variety of stream habitats to carry out life processes (Nelson and Paetz 1992; Stanislawski 1997; Tchir et al. 2003). Historically, Arctic Grayling have been distributed throughout basins (Ward 1951; Nelson and Paetz 1992). In our study, however, Arctic Grayling were only located in larger streams in the lower reaches of sub‐basins. These larger‐order streams are more likely to have no downstream barrier structures, but rather bridges and large passable culverts installed that accommodate the bigger stream width and flow.

Thus, while our results appear to indicate that Arctic Grayling are unaffected by culvert crossings on site‐based and sub‐basin scales, we propose that Arctic Grayling are simply unaffected by large non‐hanging culverts. Due to the large amount of industrial development and extensive culvert networks in sampled Athabasca River tributaries, fragmentation of Arctic Grayling habitat has likely already occurred.

5.7 Overall sampling conclusions

To ensure accurate Arctic Grayling population monitoring and estimates, Alberta fisheries biologists and managers need a greater understanding of how Arctic Grayling catch rates differ by time of year, habitat and gear type. Our results have demonstrated that in the tributary streams of the Athabasca River, these variables do influence Arctic Grayling catch rates. From this study we have developed an Arctic Grayling decision flow diagram with four fisheries management objectives to guide future sampling efforts. Specifically, if possible, sampling should be avoided in the earlier summer months of May and June, as Arctic Grayling are difficult to capture and both angling and electrofishing catch rates are low. However, if sampling does occur during this period, electrofishing in water with conductivity >300 μS/cm would likely maximize catchability. Dependent on specific objectives, the ideal sampling period for electrofishing and angling is July and August. We have shown that electrofishing enables the detection of small young‐of‐the‐year Arctic Grayling, while angling with dry flies is the most efficient means to collect larger adult Arctic Grayling (Figure 8).

Once sampling has occurred catch rates can be adjusted by gear type and Arctic Grayling size class to get a more reliable population estimate.

Undoubtedly, there will be variations in Arctic Grayling densities among Athabasca River tributaries and throughout Alberta. Sampled streams in our study were generally on the southern limit of Alberta’s Arctic Grayling range where population declines have been most pronounced. In addition, sampled areas have experienced high forest and energy sector development and extensive bridge and culvert networks that have likely resulted in low Arctic Grayling densities. Therefore, the outlined protocols should be used as a guide until rsimila region‐specific studies have also been undertaken. Perhaps, in areas with higher densities of Arctic Grayling, sampling is feasible in May and June. The long‐term success of Alberta’s Arctic Grayling populations depends on consistent monitoring and management efforts. It is our hope that this study will provide an initial step to the formulation of rigorous Arctic Grayling standard sampling protocols.

6.0 LITERATURE CITED

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7.0 APPENDICES

Electrofishing Angle Electrofishing Angle Site Start Date End Date Pass #1 Marking Run Marking Run Recap Pass #1 Recap Pass #1

FM1 8/21/2004 8/22/2008 3 0 4 1 0 JC1 8/22/2008 8/23/2008 57 0 37 1 0 SK1 8/24/2008 8/25/2008 6 0 4 0 0 SK2 8/26/2008 8/27/2008 4 0 7 1 0 FM3 9/5/2008 9/6/2008 1 0 3 1 0 JC2 7/28/2009 7/29/2009 22 1 28 1 0 CC2 8/5/2009 8/6/2009 5 0 2 0 0

Appendix 1 continued.

Electrofishing Angle Electrofishing Angle Total Total Total Site Pass #2 Pass #3 Recap Pass #2 Recap Pass #2 Recap Pass #3 Recap Pass #3 Marked Captured Recap

FM1 5 1 0 6 0 0 3 15 2 JC1 33 2 0 9 2 0 57 79 5 SK1 5 0 0 2 0 0 6 11 0 SK2 4 0 0 1 0 0 4 12 1 FM3 2 0 0 2 0 0 1 7 1 JC2 25 2 0 16 0 0 23 69 3 CC2 3 0 0 5 0 0 5 10 0

Appendix 2. Number of large (>110 mm) Arctic Grayling captured during the mark‐recapture and three‐pass removal study in wadeable tributaries (n=9) in the Athabasca River Basin. FM=Freeman River, JC=Judy Creek, SK=Sakwatamau River, CC=Chickadee Creek, TC=Two Creek study sites.

Electrofishing Angle Electrofishing Angle Site Start Date End Date Pass #1 Marking Run Marking Run Recap Pass #1 Recap Pass #1

FM1 8/21/2004 8/22/2008 0 1 5 0 0 JC1 8/22/2008 8/23/2008 2 10 7 1 1 SK1 8/24/2008 8/25/2008 2 9 1 0 0 SK2 8/26/2008 8/27/2008 6 3 3 0 0 CC1 7/24/2009 7/25/2009 0 3 2 0 0 TC1 7/26/2009 7/27/2009 2 4 0 0 0 JC2 7/28/2009 7/29/2009 6 6 2 0 1 CC2 8/5/2009 8/6/2009 0 17 0 0 0

Appendix 2 continued.

Electrofishing Angle Electrofishing Angle Total Total Total Site Pass #2 Pass #3 Recap Pass #2 Recap Pass #2 Recap Pass #3 Recap Pass #3 Marked Captured Recap

FM1 1 0 0 0 0 0 1 6 0 JC1 3 0 0 5 1 0 12 15 3 SK1 0 0 0 3 0 0 11 4 0 SK2 3 2 0 1 1 0 9 7 3 CC1 0 0 0 0 0 0 3 2 0 TC1 0 0 0 0 0 0 6 0 0 JC2 6 1 1 3 0 0 12 11 3 CC2 0 0 0 0 0 0 17 0 0

Appendix 3. Bankfull channel width, size of study area, electrofishing effort and total angler effort for mark‐recapture and three‐ pass removal study sites in tributaries in the Athabasca River Basin. FM=Freeman River, JC=Judy Creek, SK=Sakwatamau River, CC=Chickadee Creek, TC=Two Creek study sites.

Bankfull Size of Angling Electrofishing Electrofishing Electrofishing Electrofishing width study area marking run marking run effort pass #1 effort pass #2 effort pass #3 Site Start date End date (m) (ha) effort (h) effort (s) (s) (s) (s) FM1 8/21/2004 8/22/2008 5.3 0.2 4.4 1265 1240 1031 884 JC1 8/22/2008 8/23/2008 4.8 0.1 2.8 1273 1093 737 973 SK1 8/24/2008 8/25/2008 7.3 0.2 4.0 1016 936 1073 973 SK2 8/26/2008 8/27/2008 3.2 0.1 2.8 1028 1072 808 900 FM3 9/5/2008 9/6/2008 2.7 0.1 2.9 1247 1294 1187 1159 JC2 7/28/2009 7/29/2009 7.0 0.2 3.9 813 817 830 799 CC2 8/5/2009 8/6/2009 8.4 0.3 3.7 855 904 938 867 CC1 7/24/2009 7/25/2009 4.4 0.1 3.7 816 898 904 925 TC1 7/26/2009 7/27/2009 11.0 0.3 5.7 869 976 917 1018

Appendix 4. Pearson correlation coefficients (r) for stream habitat and water quality variables measured in wadeable tributaries in the Athabasca River Basin. Highly correlated variables (r>0.7) are shaded.

Dissolved Bankfull Temperature pH Conductivity Oxygen Width

Temperature ‐ ‐0.24 ‐0.53 0.28 0.02

pH ‐ ‐ 0.77 0.00 0.23

Dissolved Oxygen ‐ ‐ ‐ ‐0.05 0.26

Conductivity ‐ ‐ ‐ ‐ ‐0.22

Bankfull Width ‐ ‐ ‐ ‐ ‐

CONSERVATION REPORT SERIES The Alberta Conservation Association acknowledges the following partner for their generous support of this project