Relative Abundance of Arctic Grayling (Thymallus Arcticus) in the Parsnip, Table and Anzac Rivers in 2003

PEACE REGION

Relative abundance of Arctic grayling ( Thymallus arcticus ) in the Parsnip River in 2005

C.A. Mackay and B.G. Blackman

September 2012

FWCP – Peace Region Report No. 351

The Fish & Wildlife Compensation Program – Peace Region is a cooperative venture of BC Hydro and the provincial fish and wildlife management agencies, supported by funding from BC Hydro. The Program was established to enhance and protect fish and wildlife resources affected by the construction of the W.A.C. Bennett and Peace Canyon dams on the Peace River, and the subsequent creation of the Williston and Dinosaur Reservoirs.

Fish and Wildlife Compensation Program ––– Peace Region

9228 – 100 th Avenue, Fort St. John, BC, V1J 1X7

Website: www.fwcp.ca

This report has been approved by the Fish and Wildlife Compensation Program – Peace Region Fish Technical Committee.

Citation : Mackay, C.A., and B.G. Blackman 2012. Relative abundance of Arctic grayling ( Thymallus arcticus ) in the Parsnip River in 2005. Fish and Wildlife Compensation Program – Peace Region Report No. 351. 18 pp.

Author(s): C.A. Mackay 1 and B.G. Blackman 2 Correspondence: 1 British Columbia Conservation Foundation, #200A–1383 McGill Road, Kamloops, B.C. V2C 6K7 2 BC Hydro - Fish and Wildlife Compensation Program – Peace Region 9228 – 100 th Avenue, Fort St. John, BC V1J 1X7 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

ABSTRACT

Arctic grayling (Thymallus arcticus ) populations in the Williston Reservoir watershed declined severely during the early 1980s. In 1995, the Arctic grayling was designated as “red-listed” (QS1 B.C. Conservation Data Centre) or critically imperilled within the watershed because of the number of populations that had disappeared. In 1995, studies were initiated on the Arctic grayling populations of the Parsnip River and its tributaries, the Table and Anzac rivers. These studies were designed to determine the status of the stocks and the factors limiting grayling production, identify possible enhancement options, and develop methods to monitor population trends. Population monitoring was conducted by using beach seining to determine grayling densities in a 22-km index area on the Parsnip River. In 2005, 287 grayling were captured from 30 beach seine sets that covered 3216 linear metres of shoreline. There were 40.9 young-of- the-year grayling and 56.0 one-year-old grayling captured per kilometre of shoreline sampled. These density indices were not significantly different ( P < 0.05) from those recorded in 2000, 2001 and 2003. The average fork length of grayling captured was 44.5 mm for young-of-the- year, and 113.7 mm for one-year-olds. Young-of-the-year and one year olds were larger (48.7 mm and 127 mm vs 42.8 mm and 112.5 mm) in the upper (km 63 to 73) versus lower (km 51 to 63) portion of the index area. Overall, the grayling fry distribution was clumped and unpredictable each year.

i Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

Table of Contents

Abstract ...... i

TABLE OF CONTENTS ...... II LIST OF TABLES AND FIGURES ...... III INTRODUCTION...... 1

STUDY AREA ...... 2 METHODS ...... 4

JUVENILE RELATIVE ABUNDANCE IN THE PARSNIP RIVER ...... 4 JUVENILE DISTRIBUTION AND SIZE IN THE PARSNIP RIVER ...... 5 RESULTS ...... 6

JUVENILE RELATIVE ABUNDANCE IN THE PARSNIP RIVER ...... 6 JUVENILE DISTRIBUTION AND SIZE IN THE PARSNIP RIVER ...... 6 DISCUSSION...... 9

JUVENILE RELATIVE ABUNDANCE IN THE PARSNIP RIVER ...... 9 JUVENILE DISTRIBUTION AND SIZE IN THE PARSNIP RIVER ...... 9 MANAGEMENT IMPLICATIONS ...... 10 Literature Cited...... 12

ii Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

List of Tables and Figures

TABLE 1. F ISH CAPTURED BY BEACH SEINE AT 30 SITES ON THE PARSNIP RIVER FROM KM 73 TO 51. S AMPLING WAS COMPLETED BETWEEN JULY 19 AND 23, 2005...... 7 TABLE 2. M EAN NUMBER OF YOY AND 1+ GRAYLING CAPTURED BY SITE GIVEN AS NO ./ KM FOR 2005, 2003, 2001, AND 2000 FROM KM 73-51 OF THE PARSNIP RIVER ...... 7 TABLE 3. A VERAGE FORK LENGTH (FL) AND WEIGHT (W T) OF GRAYLING CAPTURED BY BEACH SEINE IN THE PARSNIP RIVER ...... 8 TABLE 4. M EAN FORK LENGTH OF YOY AND ONE YEAR OLD GRAYLING SAMPLED BY BEACH SEINE ON THE PARSNIP RIVER FROM 1998 TO 2005. L OWER SITES ARE DOWNSTREAM OF THE ANZAC RIVER BETWEEN KM 48 - 63; UPPER SITES ARE BETWEEN KM 63 - 73 OF THE PARSNIP RIVER ...... 8

FIGURE 1. T HE 2005 BEACH SEINE STUDY AREA (HIGHLIGHTED ) BETWEEN KM 51 AND 73 OF THE PARSNIP RIVER ...... 3 FIGURE 2. C OLUMNS SHOW THE MEAN NUMBER OF 0+ AND 1+ GRAYLING CAPTURED PER KM AT INDEX BEACH SEINE SITES BETWEEN 51 AND 73 KM OF THE PARSNIP RIVER . E RROR BARS REPRESENT STANDARD ERROR OF THE MEAN . ( N=30, 30, 31, 62)...... 14 FIGURE 3. N UMBER OF YOY GRAYLING CAPTURED PER 100 METRES FOR EACH SITE BETWEEN KMS 51 AND 73 OF THE PARSNIP RIVER EACH YEAR . S ITES WITH VALUES OF -1 HAD ZERO GRAYLING ...... 15 FIGURE 4. N UMBER OF 1+ GRAYLING CAPTURED PER 100 METRES FOR EACH SITE BETWEEN KMS 51 AND 73 OF THE PARSNIP RIVER EACH YEAR . S ITES WITH VALUES OF -1 HAD ZERO GRAYLING ...... 16 FIGURE 5. F ORK LENGTH FREQUENCY DISTRIBUTION OF GRAYLING CAPTURED IN THE PARSNIP RIVER BY BEACH SEINE IN 2005. D ATA ARE SUMMARIZED BY SITES DOWNSTREAM AND UPSTREAM OF WHERE THE ANZAC RIVER FLOWS INTO THE PARSNIP AT 63 KM ...... 17 FIGURE 6. F ORK LENGTH DISTRIBUTION OF GRAYLING CAPTURED AT DIFFERENT LOCATIONS IN THE INDEX AREA IN 2005. I NCLUDING THE SIZE AND CAPTURE LOCATIONS OF AGED FISH ...... 18

iii Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

INTRODUCTION

In the early 1980s, Arctic grayling ( Thymallus arcticus ) (hereafter grayling) populations within the upper Peace River (Williston Reservoir) drainage declined drastically (Northcote 1993; Lashmar and Ptolemy 2002). Williston Reservoir, the largest body of fresh water in British Columbia, was formed in 1968 when the W.A.C. Bennett Dam was constructed. Minimal fisheries information existed prior to the construction of the dam. Grayling were the most numerous sport fish found in most tributaries flowing into the reservoir in 1975 (Bruce and Starr 1985), and they were also plentiful within the reservoir (Barrett and Halsey 1985). By the early 1990s, grayling populations had virtually disappeared from all rivers that had a drainage area less than 1500 km 2 and which flowed directly into the reservoir (Blackman 2001). Research since 1988 in the area has focused on grayling distribution and recruitment estimates. Studies undertaken by the Fish and Wildlife Compensation Program – Peace Region (FWCP-Peace) have contributed to the available information on grayling stocks in the area. Results of these studies prompted the B.C. Conservation Data Centre to implement a “red-listed” designation for Arctic grayling within the Williston Reservoir watershed. Regulations for catch and release of the species were also enacted in 1996 to preserve existing stocks. The FWCP- Peace is mandated to mitigate impacts of hydroelectric development on fish and wildlife within the Peace Williston watershed. Because the Arctic grayling has been designated as a red-listed species within the watershed, the FWCP-Peace has given it management priority (Blackman 2002a). The FWCP-Peace conducted studies on the Arctic grayling in the Parsnip River from 1995 to 2005. The projects have enabled the development of a management plan that focuses on identifying grayling critical habitats and limiting factors, initiating long-term monitoring of changes in grayling numbers, and exploring the possibility of re-establishing populations within historic habitats (Blackman 2001). An underlying goal of all projects is to preserve and restore Arctic grayling within the watershed (Blackman 2002a.) The objectives of the 2005 Parsnip River project were to continue long-term monitoring of grayling populations by: 1. conducting beach seine sampling to determine the distribution and relative abundance of young-of-the-year and one-year-old grayling at index sites on the Parsnip River; and 2. comparing relative abundance of grayling with previous years.

1 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

Additionally, length and weight data were collected, tissue samples were taken for genetic analysis for a related study, and scale samples were collected in an ongoing effort to distinguish size ranges for age cohorts of grayling in the Parsnip River.

Study Area The most southerly distribution of Arctic grayling in B.C. occurs in the Parsnip River and its tributaries (Fig. 1) (Blackman 2002a).The Parsnip River has a drainage area of 4669 km 2 and flows out of the Parsnip Glacier north for 175 km into the Williston Reservoir (Bruce and Starr 1985). From 1985 to 1995, the river’s average daily flow rate was 142 m 3 sec -1, with an average daily maximum of 824 m 3 sec -1 and a minimum of 23 m 3 sec –1 (Water Survey of Canada 2001). The river has a 0.3% gradient with unconfined banks of fluvial silts, resulting in poor bank stability and low water clarity (Bruce and Starr 1985). There are two reaches (White 1998) on the index section (km 51 to km 75) of the Parsnip River. Wetted width for each was between 60 and 70 m. The upper boundary of Reach 3 is at km 55; the upper boundary of Reach 4 is at km 75 (Blackman 2002b). In both reaches, gravel is the dominant substrate; cobble is subdominant. Moderate to good spawning potential is available in both reaches, which have 35% riffle habitat and numerous gravel bars (Blackman 2002b). Beach seine sites were located between km 51 and 73 (Fig. 1). Fish species identified within the Parsnip River include the Arctic grayling, rainbow trout (Oncorhynchus mykiss ), bull trout ( Salvelinus confluentus ), lake whitefish ( Coregonus clupeaformis ), mountain whitefish ( Prosopium williamsoni ), burbot ( Lota lota ), northern pikeminnow ( Ptychocheilus oregonensis ), longnose suckers ( Catostomus catostomus ), largescale suckers ( C. macrocheilus ), white suckers ( C. commersoni), prickly sculpins ( Cottus asper ), slimy suckers ( C. cognatus ), and longnose dace ( Rhinichthys cataractae ) (Anonymous 1978). Other species found in this drainage include the kokanee ( Oncorhynchus nerka ), brassy minnow ( Hybognathus hankinsoni ), peamouth chub ( Mylocheilus caurinus ), and redside shiners (Richardsonius balteatus ) (Anonymous 1978; McPhail and Carveth 1993).

2 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

Figure 1. Location of the 2005 beach seine study area (km 51–73) on the Parsnip River.

3 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

METHODS

Juvenile Relative Abundance in the Parsnip River The number of grayling captured per kilometre of shoreline sampled by beach seine in a 22- km section of the Parsnip River was used as an index of grayling abundance. Relative abundance estimates are used to track population trends within a species over time provided three assumptions are met: (1) comparable methods are used in each sampling period, (2) sampling bias remains constant among years, and (3) surveys provide independent samples (MELP 1998). Water levels in the Parsnip River differ every year, and stream morphology is dynamic, which makes it impossible to sample the same sites each year. Therefore, in order to use comparable methods and to maximize beach seining efficiency, sampling was targeted at low velocity (< 0.5 ms -1), shallow (0.6–1.0 m) glides with gravel substrate. These areas are also the preferred habitat of one-year-old grayling in this river (Blackman and Hunter 2001). Sampling effort was also focused on sites with no woody debris, side bars, and smaller substrates. To address sampling bias among years, sampling was done during the same time period, and thirty, 100-m long (on average) beach seine sets were used in the same section of the Parsnip River each year. Surveys were completed in 1998, 2000, 2001 and 2003, which meets the assumption of independent samples. The seine net was 35 m x 5 m with 25 m of 13-mm mesh and a 10-m bag of 4-mm mesh. The length of each seine set was measured with a laser rangefinder from the point where the net was set to where the downstream end of the net was landed. UTM coordinates were recorded at each landing site. The net was set from a small inflatable boat and was taken out approximately 15–20 m from shore, depending on water velocity, and then drifted downstream to the landing site. Fish of all species that were caught were counted. To minimize fry stress and mortality, all suckers were counted and quickly removed from the net. No distinction was made between species of sculpins, and largescale and white suckers were not separated because they are reported to hybridize in these waters (McPhail and Carveth 1993). In 1998, the area from km 62 to 71 of the Parsnip River was sampled several times using beach seines to provide information on grayling habitat use. In 2000, 90 sites between km 39 and 90 were sampled primarily to determine grayling distribution and abundance. Data from a sub sample (km 51–73) of sites sampled in 2000 were compared with the beach seine data collected from 2001, 2003 and 2005 as a means of tracking grayling population trends based on relative abundance. Data from 1998 are presented to provide additional size data.

4 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

The mean number of young-of-the-year (YoY, 0+) and one year old (1+) grayling captured per kilometre for each site, based on site length, was calculated. Mean densities of grayling captured from beach seine sites between km 51 and 73 of the Parsnip River in 2000, 2001, 2003, and 2005 were then compared. The number of fish captured per site was converted to the number per 100 m and then transformed to log base 10 (X + 1) for the statistical comparisons. Differences in each age group among years was tested using ANOVA, and then was compared between years using post hoc testing if a significant difference ( P < 0.05) was detected. Linear regression analysis was used to determine if changing the set length could bias the capture rate. The variables, set length and capture density, were transformed to log base 10 (X + 1). If regression reveals a relationship, and average set length varied among years, then sampling bias was not constant.

Juvenile Distribution and Size in the Parsnip River Grayling, rainbow trout, bull trout, kokanee, and burbot were sampled for weight (g) and fork length (FL) (mm). When sampling adjacent areas, the fish were left in buckets until all seining was completed. Based on previous surveys, mountain whitefish were recorded as young-of-the- year (FL < 80 mm) or older (FL > 80 mm). Grayling were categorized as YoY (FL ≤ 77 mm), one- year-olds (FL ≥ 78 mm and ≤ 151 mm), or two years and older (FL > 151 mm). These categories were based on length/age determinations from scales collected in July 2005 and from previous years (Blackman et al. 2004). These length/age data were also consistent with those from the Sukunka River (Stuart and Chislett 1979), which originates only a few kilometres from the headwaters of the Anzac River. Mean sizes and weights were based on all fish sampled that met the size categories, rather than only on fish that were aged. Scale samples were collected from selected specimens and sent to the B.C. provincial aging lab in Abbotsford, B.C. for age determination.

5 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

RESULTS

Juvenile Relative Abundance in the Parsnip River Seining was conducted from July 19 to 23, 2005. Thirty beach seine sites covering 3216 linear metres of shoreline habitat were sampled between km 51 and 73 of the Parsnip River. Mountain whitefish (795) were the most numerous species captured followed by grayling (287) and then sculpins (96) (Table 1). The number of fish and species composition was highly variable between sites. The average number of grayling captured per kilometre was 40.9 ± 60.3 SD for YoY and 56.0 ± 80.5 SD for age one. There was no difference in YoY ( P = 0.092) or age one ( P = 0.12) grayling captured among years (Table 2, Figure 2).

There was a significant relationship between set length and the number of YoY captured per 100 m ( P = 0.026). More YoY grayling were captured in shorter sites. There was not a significant relationship between set length and the number of one-year-olds captured per 100 m ( P = 0.35). There were no significant relationships ( P > 0.05) between set length and grayling density during the previous sampling periods.

Juvenile Distribution and Size in the Parsnip River The distribution of grayling along the 22-km section of the Parsnip River sampled appeared to be clumped with no regular pattern (Figures 3, 4). Based on ages from the scale samples, one-year-old grayling ranged in size from 84 to 151 mm; two-year-olds ranged from 97 to 188 mm. Only one grayling aged as YoY was greater than 77 mm. It was 82 mm. Previous scale analyses determined 77 mm as the maximum length for YoY at this time of year; therefore, the single 82-mm YoY was considered to be an anomaly, and the age group was maintained as ≤ 77 mm. Grayling ranging from 78 to 151 mm were considered to be one-year-olds. The average fork length of grayling sampled in 2005 was 44.5 mm (range 22–77 mm) for YoY, and 113.7 mm (range 80–151 mm) for one-year-olds (Table 3). There was a distinct difference in the length frequency distribution of grayling captured upstream from the confluence of the Anzac River (km 63) and those captured downstream from that point (Figures 5, 6). The grayling captured upstream from the confluence show a shift to larger median fork lengths within age groups. This pattern is generally reflected in average fork lengths of each age group

6 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman upstream and downstream of the Anzac, however, these lengths are highly variable within each group of sites and this pattern was not consistent each year.(Table 4).

Table 1. Fish captured by beach seines located from km 73 to 51 on the Parsnip River, July 19–23, 2005. Location Set Mountain WSU on River Length Grayling Whitefish LW RB BT LSU RSC NSC LNC CC PCC /CSU (km) (m) 0+ 1+ >1+ 0+ 1+ 73.0 90 1302140000001000 72.2 80 6201921110001010 72.0 150 6 3 086100 0 0 4 0 1 0 0 2 1 68.0 115 3002020001000 0 70 67.5 80 74225150000000 0 00 67.2 50 7 0 1308 0 0 0 0 0 6 012440 67.0 110 3001400000000 0 20 61.2 80 1015033100 0 0 0 0 0 0 0 3 0 61.0 120 2005300130301340 60.2 86 200490010100040 60.0 110 1190141 0 0 0 1 0 0 0 0 1 0 60.0 115 3605560000007 0 00 59.0 105 100600000010010 58.2 80 130861000000010 58.2 85 12223190000000 0 40 58.0 80 42411690100000 0 10 57.5 100 3121120201000 0 00 57.3 100 303 0300 0 0 0121 0 0 0 0 0 57.1 110 170690000000000 57.0 140 102 0373 0 0 0 3371 6 1 3 0 56.0 130 100200000000040 55.7 100 010310000000010 55.5 110 020200000001040 55.0 60 3100790413205000 54.3 170 2 5 1 1814 0 0 1 0 18 0 11 0 0 0 54.0 140 1411040015000 2 40 53.0 140 2 5 0668 0 0 1146 1 2 0 4 0 52.0 140 320450010000010 51.4 140 2171187 0 0 1 4 2 0 0 0 0 0 51.0 100 000830212000000 Total 3216 116 160 11 566 229 2 10 10 53 67 13 34 28 96 1 No. of fish/100m - 3.5 4.9 0.3 17.3 7.0 0.1 0.3 0.3 1.6 2.0 0.4 1.0 0.9 2.9 0.0 Percent of catch - 8.3 11.5 0.8 40.5 16.4 0.1 0.7 0.7 3.8 4.8 0.9 2.4 2.0 6.9 0.1 LW-lake whitefish, RB-rainbow trout, BT-bull trout, LSU-longnose sucker, RSC-redside shiner, NSC- northern pikeminnow, LNC-long nose dace, WSU/CSU-white sucker/coarse scale sucker, CC-sculpin, PCC-peamouth chub. Grayling 0+ <77 mm, 1+ =78-151mm, >1+>151mm, Mountain Whitefish 0+ ≤ 80 mm, 1+>80 mm

Table 2. Mean number of young-of-the-year and one-year-old grayling captured from km 73 to 51 on the Parsnip River in 2005, 2003, 2001 and 2000. Young-of-Year One year Old Sample Year 2005 2003 2001 2000 2005 2003 2001 2000 Site Mean (# fish/ km) 40.9 17.2 31.3 39.3 56.0 30.0 46.0 29.8 St. Deviation 60.3 24.2 49.4 49.8 80.5 29.9 68.2 50.1 Number of Sites 30 30 31 62 30 30 31 62

7 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

Table 3. Mean fork length (FL) and weight (Wt) of young-of-the-year and one-year-old grayling captured by beach seines on the Parsnip River from 1998 to 2005.

Young-of-the-year One year old 2005 2003 2001 2000 1998 2005 2003 2001 2000 1998 Mean FL (mm) 44.5 56.9 45.2 48.7 49.8 113.7 97.5 98.3 100 113.9 St. Deviation 14.0 15.2 15.8 14 5.9 15.1 18.2 15.9 16.2 10.9 Range 22-77 26-77 20-76 20-74 34-67 80-151 78-145 78-144 78-152 90-145 Number of fish 117 81 117 383 192 164 129 143 240 109

Mean Wt (g) 2.5 2.9 2.4 2.6 1.3 16.6 10 10.4 10.6 14.9 St. Deviation 1.5 0.8 0.9 0.9 0.5 6.7 6.8 8.5 6.2 6.2 Range 1.0- 6.8 0.4- 4.6 0.3- 5.0 0.5- 4.7 0.3- 2.8 4.1- 39 2.8- 31 4.1- 83 4.4- 39 6.0- 55

Number of fish 44 58 53 150 151 146 109 143 224 109 Note—not all grayling were weighed because at times wind and rain made collecting accurate weights impossible. Smaller YoY were not sampled as frequently as larger fish so the mean weight could be biased.

Table 4. Mean fork length of young-of-the-year (YoY) and one-year-old grayling sampled by beach seines on the Parsnip River from 1998 to 2005. Lower sites are downstream of the Anzac River between km 48 and 63; upper sites are between km 63 and 73.

Year 2005 2003 2001 2000 1998 Dates July 19-23 July 17-19 July 17-Aug 2 July 20-Aug 9 July 14-16 Location Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper YOY Mean F.L. (mm) 42.8 48.7 60.4 36.3 45.4 43.7 51.5 48.4 45.9 47.7 St. Deviation 15.4 8.0 13.4 6.2 16.6 7.8 13.6 11.7 4.8 7.0 Range 22-77 36-64 27-77 26-48 21-76 31-56 20-74 27-74 34-59 32-67 No. Fish 84 33 69 12 103 14 171 110 57 219 One Year Mean F.L. (mm) 112.5 127.0 98.3 107.9 101.9 101.0 96.0 104.4 117.4 114.4 St. Deviation 14.8 11.6 21.8 16.5 21.0 16.3 12.9 16.5 17.5 11.1 Range 80-151 102-146 78-151 78-150 78-154 81-151 79-151 79-140 90-154 95-153 No. Fish 150 15 107 28 128 25 112 82 31 87 One Year Mean weight (g) 16.0 22.5 11.1 14.0 11.7 10.4 9.6 11.7 16.1 15.0 St. Deviation 6.4 6.1 8.8 7.2 8.7 6.1 5.2 6.0 8.7 5.2 Range 4-39 12-38 4-37 5-31 4-39 5-33 5-39 4-27 6-38 8-38 No. Fish 132 15 99 15 126 24 96 82 31 87 Weights of young-of-the-year are not included because of the increased error associated with weighing very small fish under field conditions. The smallest fish were not measured; therefore, the average weights for this group would be biased.

8 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

DISCUSSION

Juvenile Relative Abundance in the Parsnip River There were no differences in the number of YoY or one-year-old grayling captured between years. This is consistent with previous results that indicated there was no relationship in densities of each age group among years (Blackman et al. 2004). The P value of 0.092 for YoY density indicated there was no significant difference among years, at 95% CI but at a 90% CI the 2005 group was more abundant. This could be a result of increased survival due to reduced stream flow fluctuations, which is a common occurrence with grayling (Armstrong 1986; Northcote 1993), or it could be due to increased numbers of spawners, or to sampling error. Stream flow is critical to grayling in their first year because it can dramatically affect fry abundance (Armstrong 1986; Clark 1992). Further evaluation showed evidence of sampling error with the negative relationship between number of YoY grayling captured per 100 m and length of the site. This revealed that number captured per 100 m varied with site length in 2005. This is the first year that sampling bias due to site length occurred. A limitation of the sampling regime used is that seining is designed primarily to monitor changes in the abundance of one-year-old grayling; therefore, it may not be as reliable for young-of-the-year. The mesh size of the net wings (13 mm), longer site lengths, and sites with larger substrates makes effective capture of fry more difficult. Finer mesh nets, shorter site lengths and sites with smaller substrates would give better data for young-of-the-year but would not be effective at capturing one-year-old grayling, which in this system, prefer glide habitats 60– 100 cm deep over gravel or cobble substrates (Blackman and Hunter 2001).

Juvenile Distribution and Size in the Parsnip River Distribution of grayling was clumped and highly variable in 2005, similar to results obtained from the other beach seine surveys conducted on the Parsnip River since 1998. Size distribution was also non-regular with some sites dominated by larger fry and others by smaller fry. In most watersheds, grayling fry, during their first season, tend to remain near the area where they hatched (Armstrong 1986; Northcote 1993). The same appears to be true for this watershed (Blackman and Hunter 2001). The range of fry sizes is assumed to be a result of spawning occurring over an extended period of time at a given location (e.g., one month in 1997; Blackman 2002c) rather than to the movement of fry into the area from other locations. Scale

9 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman sample analyses confirmed that the large size range of fry classed as young-of-the-year did not include small one-year-olds. The length frequency distribution of grayling can be different upstream and downstream of the confluence of the Anzac River. In 2000, 2003 and 2005, one-year-old grayling were smaller downstream of the confluence, but in 2001 and 1998 there was no difference. This may be the result of a number of one-year-old grayling originating from fry produced in the Anzac River the previous year. Grayling fry in the Anzac River are smaller (average fork lengths for YoY are 8.4 mm smaller) than those in the Parsnip River, and are assumed to move into the Parsnip for rearing in their second and third summers (Blackman and Hunter 2001). Differences in the size of young-of-the-year fry in the Parsnip River are not obvious and are more dependent on the distribution and success of early and late spawners, and when spawning actually took place.

Management Implications There is a need to develop economically feasible methods for monitoring grayling populations in the Williston Reservoir watershed. Catch and release regulations for grayling have been in place since 1996, and a number of plans have been developed for protecting and enhancing existing grayling populations in the watershed. However, the beach seine data (as well as an adult monitoring program in the tributaries) suggest that recruitment in the Parsnip River has not changed under the present management scheme. The ability to detect change is somewhat limited under the current monitoring program (i.e., alternate year juvenile surveys in the Parsnip River and adult surveys in the Table and Anzac Rivers), and there is no ability to determine the cause of any changes that do occur. The sensitivity of the monitoring program could be improved, and determining the relative contributions of grayling fry from the Parsnip and its tributaries to the adult population could help identify when and where, and possibly why, population changes occur. The sensitivity of detecting population trends is limited by the low numbers of fish, their clumped distribution, and variable sampling regimes due to changing water levels. There are two ways to increase the power of the sampling methods: (1) increase the frequency of independent sampling events, or (2) increase the number of index sites (MELP 1998). A large increase in the number of beach seine sites is not practical because it would require 300 sites to make a significant gain in the confidence of the estimates (C. Swartz, pers. comm.). Increasing the number of sites to this degree would require sampling in sub marginal habitat, which means that previously collected data would not be comparable. Increasing the sampling frequency to each

10 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman year would increase the power of detecting population trends and would allow tracking of cohort abundance and survival between years. In order to improve monitoring sensitivity, the potential for sampling bias must be addressed. To minimize sampling bias, site lengths should be consistent among years. The optimal solution is to sample the same sites each year and keep the set lengths close to 100 m. It is a lower priority to maintain the number of index sites at 30 if some sites are not available due to water levels. In light of the differences in distributions above and below the confluence of the Anzac River, sampling distribution should be kept consistent among years to avoid bias. Data collected to date suggest that grayling fry from the Table and Anzac rivers move into the Parsnip River to rear in their second and third years, and adult grayling originating in these tributaries and the Parsnip River mainstem use these tributaries as summer feeding streams (Blackman and Hunter 2001; Stamford 2001; Blackman 2002c; Clarke et al. 2005). Determining their dependence on moving between these rivers during different life stages and the numerical contribution of each potential source (Table, Anzac and Parsnip rivers) would benefit current efforts to monitor juvenile grayling populations in the Parsnip River, as well as adult populations in the tributaries. This may also provide insights into the importance of the mainstem habitat in maintaining tributary populations, which could help explain the disappearance of numerous tributary populations 10 years after the reservoir was flooded. One way to achieve this would be to examine populations every year and use genetic and elemental signature methods to determine the contributions of fry hatched in the Table, Anzac, and Parsnip rivers to the overall population. A fall sampling and marking program would also help in identifying factors that affect grayling survival and abundance. These measures would provide further insights into population trends of grayling in the Parsnip River, and increase the success of Arctic grayling management in the Williston Reservoir watershed.

11 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

LITERATURE CITED

Anonymous. 1978. Report on environmental studies for the McGregor River diversion project Vol. 1–4 Prepared by Reid, Crowther and Partners Limited for B.C. Hydro and Power Authority.

Armstrong, R.H. 1986. A review of Arctic grayling studies in Alaska 1952–1982. Biology Paper. University of Alaska, No. 23.

Barrett, D.T., and T.G. Halsey. 1985. Fisheries resources and fisheries potential of Williston Reservoir and its tributary streams—Volume I: Fisheries resources and fisheries potential of Williston Reservoir and its tributary streams.. Fish Tech Circ. No. 68. B.C. Ministry of Environment, Fish and Wildlife Branch.

Blackman, B.G. 2001. A strategic plan for the conservation and restoration of Arctic grayling in the Williston Reservoir watershed. Peace/ Williston Fish and Wildlife Compensation Program. Report No.241. 16 pp.

Blackman, B.G. 2002a. The distribution and relative abundance of Arctic grayling ( Thymallus arcticus ) in the Parsnip, Anzac, and Table rivers. Peace/Williston Fish and Wildlife Compensation Program. Report No.254. 15pp.

Blackman, B.G. 2002b. An information summary on Arctic grayling from the Williston Reservoir watershed with data gap analysis and recommendations. Peace/Williston Fish and Wildlife Compensation Program. Report No. 258. 28pp.

Blackman, B.G. 2002c. Radio telemetry studies of Arctic grayling migrations to overwinter, spawning and summer feeding areas in the Parsnip River watershed 1996–1997. Peace/Williston Fish and Wildlife Compensation Program. Report No. 263. 26pp.

Blackman, B.G., and M.J. Hunter. 2001. 1998 Arctic grayling ( Thymallus arcticus ) surveys in the Table, Anzac and Parsnip rivers. Peace/Williston Fish and Wildlife Compensation Program. Report No.237. 39 pp plus appendices.

Blackman, B.G., E.B. Murphy, and D.M Cowie. 2004. Relative abundance of Arctic grayling (Thymallus arcticus) in the Parsnip, Table and Anzac rivers in 2003. Fish and Wildlife Compensation Program – Peace Report No. 350. 33 pp plus appendices.

Bruce, P.G., and P.J. Starr. 1985. Fisheries resources and fisheries potential of Williston Reservoir and its tributary streams. Volume II Fisheries resources potential of Williston Lake tributaries—A preliminary overview. Fish Tech Circ. No. 69. B.C. Ministry of Environment, Fish and Wildlife Branch.100pp plus appendices.

Clark, R.A. 1992 Influence of stream flows and stock size on recruitment of Arctic grayling (Thymallus arcticus ) in the Chena River, Alaska. Can J. Fish. Aquat. Sci. 49:1027–1034.

12 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

Clarke, A.D., K .Telmer, and J.M. Shrimpton. 2005. Population structure and habitat use by Arctic grayling ( Thymallus arcticus ) in tributaries of the Williston Reservoir using natural elemental signatures. Peace/Williston Fish and Wildlife Compensation Program Report No. 300. 61pp

Lashmar, M., and J. Ptolemy. 2002. Williston watershed Arctic grayling. Wildlife at Risk in British Columbia brochure. ISBN 0-7726-7705-0 .B.C. Ministry of Water Land and Air Protection.

McPhail, J.D., and R. Carveth. 1993. Field key to the freshwater fishes of British Columbia. Fish Museum, Department of Zoology, University of British Columbia, Vancouver B.C.

Ministry of Environment, Lands and Parks (MELP). 1998. Species inventory fundamentals: Standards for components of British Columbia’s biodiversity No. 1, Version 2.0. Resources Inventory Committee, Province of British Columbia, Victoria, B.C. 118pp.

Murphy, E.B., and B.G. Blackman. 2004. Relative abundance trends in Arctic grayling (Thymallus arcticus) populations of the Parsnip, Table, and Anzac rivers in 2001. Fish and Wildlife Compensation Program - Peace Report No.293. 27pp.

Northcote, T.G. 1993. A review of management and enhancement options for the Arctic grayling (Thymallus arcticus ) with special reference to the Williston Reservoir watershed in British Columbia. Fish. Manage. Rep. No. 79. 45pp.

Stamford, M.D. 2001. Mitochondrial and microsatellite DNA diversity throughout the range of a cold adapted freshwater salmonid: phylogeography, local population structure, and conservation genetics of Arctic grayling ( Thymallus arcticus ) in North America. Peace/Williston Fish and Wildlife Compensation Program No. 248. 90pp plus appendices.

Stuart, K.M., and G.R. Chislett.1979. Aspects of the life history of Arctic grayling in the Sukunka drainage. B.C. Fish and Wildlife Branch. 75pp plus appendices.

Water Survey of Canada. April 2001. Available from http://www.msc.ec.gc.ca/wsc/index_e.cfm?cname=main_e.cfm

White, T.C. 1998. Stream video/gps survey conducted on six tributary rivers to Williston Lake. Prepared for B.C. Environment Watershed Restoration Program, Prince George, B.C. by Environmental Dynamics Inc. 173 pp.

Zar, J.H. 1984. Biostatistical analysis. 2 nd edition. Prentice Hall, New Jersey.

Personal Communications

Dr. C Swartz. Simon Frazier University February 2006 [email protected]

13 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

80 2005 2003 2001 2000

0 YOY One Year Old

Figure 2. Mean number of young-of-the-year (YoY) and one-year-old grayling captured per km at index beach seine sites between km 51 and 73 km of the Parsnip River, 2005 (n = 30), 2003 (n = 30), 2001 (n = 31) and 2000 (n = 62). Error bars represent standard error of the mean.

14 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

29 2005

-1 51 55 59 63 67 71

29 2003

-1 51 55 59 63 67 71

29 2001

-1 51 55 59 63 67 71

2000

-1 51 55 59 63 67 71 River KM Figure 3. Number of young-of-the-year (YoY) grayling captured per 100 m for each site between km 51 and 73 of the Parsnip River, 2005, 2003, 2001 and 2000. Values of -1 indicate sites where no YoY were captured.

15 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

29 1+ 2005

-1 51 55 59 63 67 71 River km

1+ 2003

-1 51 55 59 63 67 71

1+ 2001

-1 51 55 59 63 67 71 River KM

29 1+ 2000

-1 51 55 59 63 67 71 River km Figure 4. Number of one-year-old (1+) grayling captured per 100 m for each site between km 51 and 73 of the Parsnip River, 2005, 2003, 2001 and 2000. Values of -1 indicate sites where no 1+ grayling were captured.

16 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

Downstream N=244 Upstream N=51

30% 0+ 1+ >1+

20%

10%

0% 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 Fork length (mm)

Figure 5. Fork length frequency distribution of grayling captured in the Parsnip River by beach seine in 2005. Data are summarized by sites downstream and upstream of the Anzac River, which flows into the Parsnip at 63 km. 0+ ≤77 mm, 1+ 78-151 mm,>+1>151 mm

17 Relative abundance of Arctic grayling in the Parsnip River in 2005 Mackay & Blackman

200

GR 175 aged as 0 aged as 1+ aged as 2+ 150

125

100 GR Fork Length (mm)

25 50 55 60 65 70 75 Location (km) on the Parsnip River

Figure 6. Fork length distribution of grayling captured at different locations in the index area in 2005, and highlighting the size and capture locations of fish that were aged.