EA3009

A PRELIMINARY REPORT ON JUVENILE WHITE STURGEON HABITAT USE IN THE LOWER , 2007-2008

Prepared for Fraser River Sturgeon Conservation Society

Prepared by: G. Glova1, T. Nelson2, K. English1, and T. Mochizuki1

1LGL Limited environmental research associates 9768 Second Street Sidney, V8L 3Y8

2Fraser River Sturgeon Conservation Society, Vancouver, BC

May 2008

Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

Table of Contents

Executive Summary...... iv 1. Introduction...... 1 1.1 Literature Review...... 4 1.2 Sampling Rationale...... 5

2. Methods...... 6 2.1 Field Sampling...... 6 2.2 Sturgeon Ageing...... 7 2.3 Sturgeon Diet...... 7 2.4 Data Compilation and Analysis ...... 8

3. Results...... 8 3.1 General...... 8 3.2 Distribution of Sturgeon...... 10 3.3 Size of Sturgeon...... 15 3.4 Other Fish Species ...... 19 3.5 Significance of Environmental Variables ...... 19

4. Discussion...... 24

5. Conclusion ...... 25

6. Recommendations...... 25

7. Acknowledgments...... 25

8. References...... 27

Appendix...... 29

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List of Figures

Figure 1: Map of Lower Fraser River. Circles indicate sites >15 m deep (from Canadian Hydrographic Series, Sept 2004)...... 3

Figure 2: Relative frequency of juvenile white sturgeon caught, lower Fraser River, September 2007-March 2008...... 10

Figure 3: Sites sampled and juvenile white sturgeon caught in lower Fraser River, September-November 2007 ...... 11

Figure 4: Sites sampled and juvenile white sturgeon caught in lower Fraser River, December 2007-March 2008 ...... 12

Figure 5: Juvenile white sturgeon caught ≤300 mm fork length in lower Fraser River, September 2007-March 2008...... 13

Figure 6: Plot of effort (number of nets set) and number of white sturgeon caught in the lower Fraser River, September 2007-March 2008...... 14

Figure 7: Plot of effort (number of nets set) and number of white sturgeon caught <450 mm long in the lower Fraser River, September-November 2007...... 15

Figure 8: Size frequency of white sturgeon caught in the lower Fraser River, September 2007-March 2008...... 16

Figure 9: Size frequency of juvenile white sturgeon caught <450 mm long in the lower Fraser River, September-November 2007...... 16

Figure 10: Size frequency of juvenile white sturgeon <450 mm long caught above and below Mission, lower Fraser River, September 2007-March 2008...... 18

Figure 11: Scatter-plots of sturgeon catch as a function of surface water temperature (ºC) and water depth (m), lower Fraser River, September2007-March 2008...... 20

Figure 12: Scatter-plots of sturgeon catch as a function of catch of the three most common bycatch species: sculpins, peamouth chub, and northern pikeminnow, lower Fraser River, September2007-March 2008...... 21

Figure 13: Plot of sturgeon catch for two size groups in relation to water depth, lower Fraser River, September2007-March 2008...... 22

Figure 14: Relative frequency of juvenile sturgeon catch by substrate type, for substrates with n >10, lower Fraser River, September2007-March 2008...... 23

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List of Tables

Table 1: Condition of juvenile white sturgeon sampled in the lower Fraser River, September 2007-March 2008...... 9

Table 2: Spearman rank correlation coefficients (rs), and P-values, for relationships between sturgeon catch and 5 habitat variables in 518 tangle-net sets...... 19

Table 3: Parameter estimates, model tests (chi sq), and P-values for logistic ...... 20

List of Plates

Plate 1: Upper: juvenile white sturgeon 210 mm fork length caught in the Matsqui area (7 November 2007)...... 17

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Executive Summary Juvenile white sturgeon (Acipenser transmontanus) were sampled in the lower Fraser River (from the mouth to the Harrison River area) by soft mesh tangle netting in a wide range of habitats from September 2007 to March 2008 to gather baseline habitat use information on the younger sector of this endangered subpopulation of fish. The bulk of sampling was carried out during the September-November period, with a minimal effort (3-4 days/month) in December, January and March to identify possible shifts in habitat use seasonally. In addition to sturgeon catch data, information on physical habitat and non-sturgeon fish caught at each of the sites sampled were recorded. Water temperature ranged from a high 18.6 °C in September to a low 1.7 °C in January, and was still low (~5 °C) by late March. Salinity values up to 5.7 ppt were recorded on the bottom in the lower river, with trace levels (0.01 to 0.05 ppt) up to approximately 80 km upstream from the river mouth. Dissolved oxygen ranged from approximately 4-11 mg/l.

The main findings of this baseline study are as follows: Of the total 518 nets set, sturgeon were caught at 129 of the sites, a total of 304 fish in all, with the catches ranging from 1- 7 fish, but most frequently consisted of a single individual. The fish ranged in size from 193 to 1500 mm fork length, with 42% of them being less than 300 mm long. Very few fish were caught below 220 mm in length. The sturgeon caught were widely scattered from Deas Island to the Sumas River area, with the higher catches occurring in the Annacis and Hatzic areas, and to some extent in the Port Mann Bridge, Stave and Matsqui areas. They occupied a wide range of water depths (1.3-26 m), but more commonly were found in slow-flowing areas less than 5 m deep with fine substrates in side channels, side pools, backwaters and nearshore mainstem open channels. No sturgeon were caught at bottom salinities >0.6 ppt. The catch dropped off markedly with decreasing water temperatures, with very few (14 in all) sturgeon caught during the winter period. Northern pikeminnow (Ptychocheilus oregonensis), although abundant in the catch, had no statistically significant effect on the catch of juvenile white sturgeon.

From the catch information gathered during the September-November period, it appears that the juveniles of this subpopulation of white sturgeon are widely scattered, with preferred sites being the Annacis, Matsqui and Hatzic areas – these may be the preferred areas year round. Because of exceedingly low catch rates, further sampling during low water temperatures (<7 °) is not recommended. Sampling during the May-June period (before the onset of high flows in summer) is more likely to give results indicative of where juvenile sturgeon spend the winter.

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1. Introduction The ongoing lower Fraser River white sturgeon (Acipenser transmontanus) monitoring and assessment program by Fraser River Sturgeon Conservation Society (FRSCS) volunteers and others since 1999 is providing a considerable body of valuable information on abundance and movements of taggable-size fish of this subpopulation. However, very little is known of the basic life history of the juveniles of this subpopulation. Of particular importance is an adequate understanding of the habitat requirements of young sturgeon (say first four years of life), so that these habitats can be conserved and protected, and improved where feasible, since habitat of the early life stages may well be limiting recovery of the population overall. Continuing development in the lower Fraser is a major threat to the remaining habitat for juvenile sturgeon which is poorly documented at present. From the ongoing sturgeon monitoring and assessment program in the lower Fraser River, there are indications that juvenile sturgeon abundance and growth may be declining. It is important therefore to acquire as much information as possible on the habitat requirements of the juvenile component of this subpopulation. The goal of the present study was to gather information on juvenile white sturgeon habitat use in the lower Fraser River (Figure 1) by sampling this subpopulation during the late summer, autumn, and winter periods (September 2007 through March 2008). The study area extended from the Harrison River area to the mouth of the Fraser River. As this is a baseline study, sampling was conducted across seasons to determine if the distribution and habitat use of juvenile sturgeon differ with season. The results reported herein are largely descriptive, including GIS-based mapping showing the distribution of juvenile white sturgeon captured in the lower Fraser River during the period of study. The study objectives were: • Conduct a review of the literature on habitat use of juvenile white sturgeon in the Columbia and Fraser river systems. • Obtain information regarding design and specifications of the nets and techniques used by the white sturgeon monitoring and assessment team in Oregon and Washington on the lower Columbia River who have been successfully sampling juvenile white sturgeon in the Columbia River below Bonneville Dam (as well as in some reservoirs) since 1992. • Construct the required number and sizes of nets required for the lower Fraser River sampling program. • Conduct a reconnaissance survey in the mainstem Fraser River downstream of mouth of the Harrison River to assess sites suitable for routine sampling of juvenile white sturgeon. • Conduct routine sampling in selected sites from August through November 2007, and intermittently from December through March 2008. • Collect habitat assessment and physical data at sampling sites. • Enter the data into an Access database (compatible with MOE mapping group).

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• Produce a descriptive report and GIS-based mapping products that present project results and findings. • Distribute reporting and mapping products to end-users including government/municipal resource managers, habitat specialists, and planners.

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Figure 1: Map of Lower Fraser River. Circles indicate sites >15 m deep (from Canadian Hydrographic Series, Sept 2004).

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1.1 Literature Review The literature available on habitats used by juvenile white sturgeon is not exhaustive. Some scattered information is available in annual reports of the Washington and Oregon Departments of Fish and Wildlife, Bonneville Power Administration, and US Fish and Wildlife Service. The more substantive body of information on juvenile white sturgeon habitat was found in a few reports and primary publications.

Information from studies to date on juvenile white sturgeon in the Columbia and Fraser river systems indicates they occupy a fairly broad spectrum of physical habitat. Parsley et al. (1993) reported that juvenile white sturgeon sampled by gill netting in the lower Columbia River occupied a wide range of water depths (2-58 m) and substrates, but slow to moderate velocities (0.1-1.2 m/s mean water velocity; 0.1-0.8 m/s near substrate velocity). On the other hand, within the upper Columbia River on the Canadian side, juvenile sturgeon are often associated with the lower reaches or confluences of tributaries, large backwaters, side channels and sloughs (Failing and Gregory 2003; Bennett et al. 2005) as well as deep, slow-flowing mainstem areas (RL & L 2000; Golder 2003; Neufeld and Spence 2004).

North et al. (1993) reported that although white sturgeon were caught at all depths by gill netting in three lower Columbia River reservoirs, most were taken at depths from 10-30 m. However, in this study, too few samples were taken in shallow water to confirm white sturgeon’s preference for deeper water, although the authors do mention that fishers have reported good seasonal catches of white sturgeon from shallow water flats supporting mussel beds. No meaningful relationship was established between fish size and water depth by North et al. (1993).

North et al. (1993) found that catches of white sturgeon were generally greater in the tailraces and declined with distance downstream in the reservoirs. Moreover, the catch varied with season, peaking in June-July with the water temperature rising to about 18 °C (but declining at warmer temperatures) and decreasing by August-September as temperatures declined. The fish tended to move downstream in summer and upstream in autumn - a pattern also noted by Hayes et al. (1978) in an unimpounded reach of the mid Columbia River – and generally covered extensive distances in a relatively short time period.

The report by Lane and Rosenau (1993) based on quite extensive sampling of juvenile white sturgeon by gill netting between April and November in the lower Fraser River provides some of the best habitat information available in the literature. In the three sites which were sampled in more detail (Hatzic Slough, Nicomen Slough, and the Big Eddy backwater), they found that juvenile white sturgeon catches during summer were greater in areas that proportionally had considerable habitat with water up to more than five meters in depth. In contrast, none were caught further upstream in Nicomen Slough where the water was less than five meters deep. Similarly, in both the lower Hatzic and Big Eddy, sturgeon catch rates were significantly higher in the deeper than in the shallower areas of these two sites. In another study (Mussell and Nelson 2006), a small

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sturgeon (180 mm fork length) was caught in the lower Fraser River near the mouth of the Sumas River in a back eddy approximately 10 m deep with fine substrate.

In addition to water depth, Lane and Rosenau (1993) found that the pattern of flow was an important variable of juvenile white sturgeon habitat in the lower Fraser River. At the sites referred to above, the current was not unidirectional, but varied with tidal influence (Nicomen), river water levels (Big Eddy backwater), and operation of in-channel flood control facilities (lower Hatzic Slough). Overall, the water velocity at these sites was slow (range 0.04 to 0.35 m/s), the water was turbid (secchi disc readings <2m), and the substrates were mainly sand, silt and clay, with a mix of sand and gravel in some areas.

From findings on seasonal movements of juvenile sturgeon in the study by Lane and Rosenau (1993), it appears that temperature has an important influence on their distribution seasonally. Juvenile sturgeon entered the sloughs in spring/summer when temperatures were increasing and emigrated in the autumn when temperatures decreased. The critical temperature for sturgeon entering or exiting the sloughs was found to be between 13 and 15°C. During summer, water temperatures in the sloughs and backwaters are usually warmer (~1-2 °C) than the Fraser River mainstem. Similarly, Haynes and Gray (1981) found that white sturgeon in the mid Columbia River move during summer when water temperatures are above 13 °C and remain more or less sedentary during winter low temperatures. Seasonal differences in movements may be partly related to optimizing their growth potential. Lane and Rosenau (1983) found that juvenile white sturgeon fed excess rations in laboratory trials at temperatures as high as 24 °C grew rapidly compared with those reared at lower temperatures, suggesting they have the potential to grow rapidly in warmer, food-abundant areas during summer in the wild.

1.2 Sampling Rationale Prior to assembling the field sampling components for this study, we communicated directly with Mr. Brad Cady (WDFW biologist in charge of the juvenile white sturgeon sampling program on the Columbia River, Washington) to get first-hand information on design and specifications of the nets and sampling techniques used by the Washington and Oregon study teams. These researchers have extensive experience in sampling juvenile sturgeon and tracking recruitment/abundance trends in the Columbia River below Bonneville Dam, as well as in some of the reservoirs. They use tangle nets that are 200 ft (61 m) long and 8 ft (2.4 m) deep made of soft, multi-strand braided 2 inch (51 mm) mesh. Their sampling program annually terminates about the end of September as catch rates of sturgeon drop off markedly as water temperatures decline. However, as ours is a baseline study, we decided to continue sampling in late autumn through winter in the hope of obtaining seasonal information on habitat used by juvenile sturgeon in the lower Fraser River. As soon as the net design and specifications were decided upon, the required materials (netting, floats, lead lines, anchors, buoys) were ordered and the number and sizes of nets fabricated. All of the nets were made of soft, multi-strand braided 2 inch mesh. We opted to make nets 50 ft (15.2 m) long x 8 ft deep as they would be more appropriate for sampling a variety of habitats (mainstem, side channels, backwaters, sloughs, and others) and provide more site-specific information on catch of juvenile sturgeon in the lower

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Fraser River. In a few instances where longer nets were considered appropriate, two nets were joined together. Two field crews, made up entirely of First Nations, were used: one to sample sites in the reach approximately downstream from Mission to the mouth of the Fraser River, the other to sample upstream of this reach to the Harrison River area. Both field crews consisted of a field crew leader and one technician, with all members being very familiar with the river, navigational and boat safety issues, and fish netting procedures. Prior to initiating the field program, a one-day reconnaissance survey was conducted of the overall study reach to asses the suitability of sites for routine sampling and issues relating to boat traffic, commercial fishing, and others. 2. Methods

2.1 Field Sampling The bulk of sampling of juvenile white sturgeon in the lower Fraser River was conducted from September through November 2007, with limited sampling (3-4 days/month) in December, January and March. Sampling was not conducted in February as water temperatures were still as low as in the December/January period. Ideally, we would have liked to start sampling earlier in summer, but for various logistical reasons it was not possible to do so. In Washington, sampling juvenile white sturgeon in the Columbia system is generally not continued beyond September as catch rates drop off markedly as temperatures decrease. However, as this was a baseline study we decided to include some sampling during the winter period in the hope of identifying possible seasonal differences in juvenile white sturgeon distribution and/or habitat use in the lower Fraser River. Initially, it was intended to conduct strategic, stratified sampling at designated sampling locations approximately once monthly to identify spatial-temporal shifts in juvenile white sturgeon habitat use. However, as catch rates were exceedingly low with no sturgeon caught at a large proportion of the sites, additional sites within the study reach during the September-November period were sampled to further collection of data/information on habitats used by juvenile sturgeon. Sampling during the December-March period was mainly limited to sites at which reasonable catches of sturgeon were made during September-November to determine if they were present at these sites during winter, with a few new sites sampled in an effort to determine their winter distribution. Overall, a variety of habitats was sampled, including mainstem pools, open channels and side pools, backwaters, side channels, and sloughs to obtain information on the range of habitat conditions used by juvenile white sturgeon. A fishing vessel approximately 8 m long with an aluminum hull was used by the crew conducting sampling in the lower reach, whereas in the upper reach an approximately 5- m long aluminum boat powered by a 50 hp motor was used which was appropriate for the shallower water conditions. On any one day, 5-10 nets were set by the lower crew, and 5- 6 nets by the upper crew which was limited by space available on the boat. The nets were set in the afternoon (~1500 h onward) on the bottom and retrieved the following morning. The location of each of the sets was recorded from the GPS unit onboard the boats. The fish caught were removed as the net was brought up, with any sturgeon present removed immediately and placed into a large, plastic container with fresh water. Other native fish

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species were identified to species, counted and released, and mortalities recorded. Any non-native fish present in the catch were identified to species, measured, and disposed of as stipulated by conditions on the sampling permits. For all sturgeon captured (including dead fish), fork length and girth were recorded. Fish of taggable size (>200 mm FL) were scanned for presence of a PIT tag and any untagged, live fish was tagged with a PIT tag as per standard tagging procedures of the ongoing Lower Fraser River White sturgeon Monitoring and Assessment Program (Nelson et al. 2007). The condition code of individual sturgeon at time of release was recorded as to one of five categories: 1 = vigorous, no bleeding; 2 = vigorous, but bleeding; 3 = lethargic; 4 = lethargic and bleeding; 5 = dead. Any dead juvenile sturgeon was frozen for examination of gut contents and other uses at a later date.

At the sites sampled, the habitat components measured included water depth (with depth sounder), and water temperature, dissolved oxygen, conductivity and total dissolved solids at surface and bottom levels with a Hach meter. In the upper reach, bottom water samples for measurement were collected with a Van Doren type sampler as the bottom could not be reached with the Hach meter sensor cable. Surface water velocity was estimated by measuring the time it took for a floating object to drift a given distance downstream; bottom water velocity was not measured as no suitable current meters were available. For sites in the lower reach, salinity at the surface and bottom was measured with a YSI salinometer equipped with a 12-m long sensor cable. A sample of substrate at each site was collected with a metal scoop bucket perforated on the sides and weighted on one side so that it would lie on its side when on the bottom and scoop a small portion of bed material for determination of substrate type. The habitat and fish data collected at each of the sites were recorded on a standardized data form (see Appendix) printed on waterproof paper. The completed original data forms were forwarded via courier or postal delivery to LGL Limited on a fairly regular basis, with back-ups (photocopies) made before sending.

2.2 Sturgeon Ageing As only one young sturgeon was available for ageing during this study, it was decided to hold this specimen in the freezer until completion of the 2008-2009 field sampling program when a few more dead fish may become available for ageing from otoliths. In addition, a limited number of samples of the leading pectoral fin ray from young sturgeon may be collected for ageing as per the method used by the Oregon Department of Fish & Wildlife. If sufficient samples are available, a comparison could be made of ageing young sturgeon from pectoral rays and otoliths.

2.3 Sturgeon Diet Juvenile sturgeon mortality amounted to a total of four fish during this study. With the limited sample size available for examination of stomach contents it was decided to hold these samples in the freezer until the following year when more fish may be available for diet analysis. ‘Stomach pumping’, a method commonly used by fisheries biologists to extract foods eaten without having to sacrifice the fish was considered inappropriate in the present study as the method can result in high mortality of juvenile sturgeon (Brad Cady, Washington, pers. comm.).

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2.4 Data Compilation and Analysis Upon receiving the field data forms in the office, they were checked for completeness and in instances where information was missing, the field crew leader was contacted in an effort to complete the information record. The data were then entered into an Access database for use with other software packages. Excel charts were used to plot sturgeon catch in relation to various environmental variables. GIS-based mapping was used to plot the distribution of sturgeon caught by season in the lower Fraser River study reach. An examination of the fish catch data revealed it to be highly skewed, and exhibited the expected negative binomial error structure that is typical of catch and count data. To fit the continuous variables in this data set, non-parametric statistics were used throughout. Data from the total tangle-net sets made were used to calculate Spearman-rank correlations between sturgeon catch and five habitat variables: surface temperature, water depth, sculpin catch, peamouth chub catch and northern pikeminnow catch. Given that 5 comparisons were made, correlations were considered to be statistically significant only if the P-value was less than the Bonferroni adjusted alpha of 0.01 (i.e., 0.05/5). At each of the tangle-netting sites, the substrate was classified as one of: boulder, cobble, gravel, sand, silt, mud, or combinations thereof. Only 5 substrate classes were recorded at more than 10 of the sites: mud (149), silt (109), sand (155), mud/silt (11), and silt/sand (20) – these were used to test the statistical significance of substrate in relation to sturgeon catch. 3. Results

3.1 General Tangle-netting was performed at 518 sites in various habitats of the lower Fraser River from the mouth to the Harrison River area from September 2007 through March 2008. The bulk of the sampling effort occurred during the September to November period with 383 nets set. From December to March, a total of 135 nets was set. The habitat types sampled (number of nets set in each type is bracketed) included the mouth of the Fraser (1), mainstem pool (12), slough (42), backwater (42), side pool (45), side channel (121) and mainstem open channel (208). For approximately 9% of the sets habitat type was not recorded (forgotten by field crews). Water depth at the sites sampled ranged from 1-27 m, with the average depth being 5.5 m.

Plots, showing minimum and maximum and average values monthly of the various water quality parameters measured at the sites sampled are presented in the Appendix (Figure 1). For each of the parameters, plots of the surface and bottom values are similar. During the period of study, water temperature recorded ranged from a high 18.6 ºC in September to a low 1.7 ºC in January, and was still low (~5 °C) by late March. Dissolved oxygen levels were lower during the September-October period, averaging slightly above 7 mg/l, and higher during winter (10-11 mg/l in December). Salinity values up to 1.9 ppt at the surface and 5.7 ppt on the bottom were recorded in the lower Fraser River, with trace levels (0.01 to 0.05 ppt) up to approximately 80 km upstream from the mouth. Conductivity of the lower Fraser on average was approximately 100 mS/cm from September through November, and increased moderately during the winter months and at

Page 8 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009 sites where saline conditions were recorded (e.g., conductivity up to 340 mS/cm at 5.7 ppt salinity).

Sturgeon were captured at 129 of the sites, a total of 304 individuals in all. Of the total catch, 2%, 16%, 18%, 19%, and 33% were taken in mainstem pools, side channels, side pools, backwaters, and mainstem open channels, respectively; 12% of the catch was taken at sites for which no habitat type was recorded. Of the sturgeon for which condition was recorded, more than 90% were vigorous, with no bleeding, with between 4.5% and 8.1% noted as lethargic (Table 1). No sturgeon were caught at other than very dilute or non-saline conditions, with 78.6%, 20.7% and 0.7% of the catch, respectively, taken at sites that were purely fresh water, <0.1 ppt, and between 0.5 and 0.6 ppt salinity. Approximately 80% of the sturgeon caught for which dissolved oxygen was recorded occurred at sites ranging from 4.3-8.5 mg/l.

Table 1. Condition of juvenile white sturgeon sampled in the lower Fraser River, September 2007-March 2008.

Conditon <300 mm ≥ 300 mm Code 1 No. of Fish % No. of Fish % 1 100 90.1% 146 94.2% 200.0% 0 0.0% 398.1% 7 4.5% 400.0% 0 0.0% 521.8% 2 1.3% Not coded 17 21 1 Condition code: 1 = vigorous, no bleeding; 2 = vigorous, but bleeding; 3 = lethargic; 4 = lethargic and bleeding; 5 = dead.

The distribution of sturgeon catches was strongly skewed (Figure 2), and exhibited the expected negative binomial error structure that is typical of catch and count data. For almost 80% of the nets set, no sturgeon were caught. Sturgeon catches ranged from 1-7 fish, with a single fish being the most frequent catch.

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80%

60%

40%

20% Relative Frequency

0% 0 1 2 3 4 5 6 7 8 9 10 11 12 Catch (# sturgeon)

Figure 2: Relative frequency of juvenile white sturgeon caught, lower Fraser River, September 2007-March 2008.

3.2 Distribution of Sturgeon In order to convey seasonal differences in the catch, the distribution of the sites sampled and juvenile white sturgeon caught in the lower Fraser River are shown separately for the September-November and December-March periods.

In the September-November period (Figure 3), the higher catches were made around Annacis Island and Hatzic areas, and to some extent in the Port Mann Bridge and Matsqui areas. Other sites of capture ranging from 1-4 fish were widely scattered from Deas Island to the Sumas River area, but none was caught upstream of the Sumas River confluence to the Harrison River area. Despite the considerable effort, no sturgeon were caught in the North Arm of the lower Fraser River. Similarly, none was caught in the Albion area which also received considerable sampling effort.

During the December-March period ( Figure 4), virtually no sturgeon were caught, with the exception of two fish taken in the Annacis area (19 rkm) in December, and two and 10 fish respectively in the Matsqui (75 rkm) and Hatzic (83 rkm) areas in March. These fish ranged from 280-860 mm in length, with the smallest one taken in the Annacis area.

Juvenile white sturgeon 300 mm long, or less, were widely scattered in areas from Annacis Island to the Sumas River, but with the higher catches occurring in the Annacis, Matsqui and Hatzic areas (Figure 5). These appear to be the favoured areas by the smaller (i.e., <300 mm long) as well as the larger juvenile sturgeon sampled within the lower Fraser River.

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Figure 3: Sites sampled and juvenile white sturgeon caught in lower Fraser River, September-November 2007.

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Figure 4: Sites sampled and juvenile white sturgeon caught in lower Fraser River, December 2007-March 2008.

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Figure 5: Juvenile white sturgeon caught ≤300 mm fork length in lower Fraser River, September 2007-March 2008.

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A plot of the number of nets set and catch of juvenile white sturgeon for the overall study period (Figure 6) shows peak numbers were captured from approximately 83-86 rkm (the Hatzic area), with a second but smaller peak from approximately 21-25 rkm (Annacis area). At a few sites both upstream and downstream of the Hatzic and Annacis areas, the number of sturgeon caught amounted to five or more fish. Very few sturgeon were captured between approximately 40 and 65 rkm. Most of the sampling effort occurred between 10 and 100 rkm. Further upstream, the effort was minimal as there was relatively little suitable habitat available for sampling by tangle netting.

50

45 t

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10 Number of Nets Set and Number of Sturgeon Caugh Sturgeon of Number and Set Nets of Number

5

0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 River Kilometer

Number of Sturgeon Captured Number of Nets Set

Figure 6: Plot of effort (number of nets set) and number of white sturgeon caught in the lower Fraser River, September 2007-March 2008.

The distribution of sturgeon caught <450 mm long for the September-November period (Figure 7) was very similar to that for all sturgeon caught during the September-March period (Figure 6), with peak numbers taken in the Hatzic and Annacis areas, and catches of five or more fish both upstream and downstream of these areas. As in the overall sturgeon catch, very few fish <450 mm long were captured in the reach between approximately 40 and 65 rkm. A comparison of differences in the effort (red line) between Figure 6 and Figure 7 gives an indication of where sampling occurred during winter (mainly between 10 and 30 rkm and the Hatzic area, 83-86 rkm).

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10 Number of Nets Set and Number of Sturgeon Caught of Sturgeon Number and Set of Nets Number 5

0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 River Kilometer

Number of Sturgeon Captured Number of Nets Set

Figure 7: Plot of effort (number of nets set) and number of white sturgeon caught <450 mm long in the lower Fraser River, September- November 2007.

3.3 Size of Sturgeon The fish caught from September through March ranged from 193 to 1500 mm fork length (average length, 353 mm), with the smallest fish taken in a side pool at 83 rkm on 25 September. The bulk of the catch ranged in size from approximately 220-420 mm long (Figure 8). Very few fish were caught below 220 mm in length. Sturgeon less than 300 mm long made up 42% of the catch, whereas those between 300 and 499 mm in length comprised 46% of the total number captured.

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15 Number of sturgeon Number 10

5

0 000 050 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500 1550 Fork Length (mm)

Figure 8: Size frequency of white sturgeon caught in the lower Fraser River, September 2007-March 2008.

A size-frequency plot of sturgeon <450 mm long caught during the September-November period (Figure 9) shows evidence suggestive of a bimodal distribution with the main peak consisting of fish 310 mm long, and a secondary peak of fish about 240 mm long. Vaguely, there is the suggestion of a third peak in fish numbers for fish around 400 mm long. Examples of small sturgeon caught are shown in Plate 1.

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Number of sturgeon of Number 10

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0 150 170 190 210 230 250 270 290 310 330 350 370 390 410 430 Fork Length (mm)

Figure 9: Size frequency of juvenile white sturgeon caught <450 mm long in the lower Fraser River, September-November 2007.

Page 16 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

Plate 1: Upper: juvenile white sturgeon 210 mm fork length caught in the Matsqui area (7 November 2007); Lower: juvenile white sturgeon (the smaller one is ~205 mm fork length) caught in lower Fraser River, autumn 2007.

Page 17 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

The size frequency of sturgeon caught in the reach from the mouth of the Fraser River to Mission (Mission Bridge) was similar to that of the fish caught in the study reach upstream of Mission (not shown). For both reaches, most of the fish were <400 mm long. A size frequency plot of sturgeon caught <450 mm long (in 10 mm size groups) above and below Mission (Figure 10) suggests the existence of three year classes in the catch above Mission; for the catch below Mission individual year classes are less apparent, with the size frequency tending towards a unimodal distribution. There were higher catches of smaller sturgeon (<250 mm long) in the area upstream of Mission.

Above Mission

18 16 14 12 10 8 6

Number of Sturgeon Number 4 2 0 150 170 190 210 230 250 270 290 310 330 350 370 390 410 430 Fork Length (mm)

Below Mission

18 16 14 12 10 8 6

Number of Sturgeon 4 2 0 150 170 190 210 230 250 270 290 310 330 350 370 390 410 430 Fork Length (mm)

Figure 10: Size frequency of juvenile white sturgeon <450 mm long caught above and below Mission, lower Fraser River, September 2007-March 2008.

Page 18 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

3.4 Other Fish Species Non-sturgeon fish caught during the field sampling program consisted of several native fish species (see table in Appendix) and five non-native fish, all black crappies, two of which were measured (132 mm and 195 mm FL). Northern pikeminnow (Ptychocheilus oregonensis), sculpins (Cottidae) and Peamouth chub (Mylcheilus caurinus) constituted 81.6%, 8.3% and 4.2%, respectively, of the total 3,345 native fish caught. The significance of the catch of each of these three native fish species/categories in relation to sturgeon catch is tested statistically in the following section.

3.5 Significance of Environmental Variables The significance of each of five environmental variables (surface water temperature, water depth, sculpin catch, peamouth chub catch and northern pikeminnow catch) on sturgeon catch was tested by Spearman rank correlation. The relationship between surface water temperature and sturgeon catch was highly significant (Table 2; Figure 11) after the Bonferroni adjustment was made. The catch dropped off markedly with decreasing temperatures; below 7ºC very few sturgeon were caught. None of the other relationships were statistically significant, but the correlation between sturgeon catch and Peamouth chub catch was borderline (P = 0.0107; Table 2; Figure 12). Although water depth was not significant, the sturgeon catch was greater in areas less than 5 m deep. The relationship between sturgeon catch and pikeminnow catch was not significant, although there are indications that the sturgeon catch declined with increasing pikeminnow catch.

Similar statistical results were found when sturgeon catch numbers were treated as ‘present’ (Catch ≥1) or ‘absent’ (Catch = 0). Logistic regression models were constructed to describe the probability of sturgeon presence as a function of the five habitat variables. Surface water temperature was a highly significant predictor of sturgeon presence, but none of the other four relationships were statistically significant (Table 3).

Table 2. Spearman rank correlation coefficients (rs), and P-values, for relationships between sturgeon catch and 5 habitat variables in 518 tangle-net sets. Statistically significant P-values are shown in bold. Others were not significant after application of the Bonferroni correction factor. Also shown are the minimum and maximum observed values for each of the 5 variables.

Variable Min Max rs P Surface Temperature (C ) 1.7 18.6 0.270 < 0.0001 Water Depth (m) 127-0.024 0.59 Sculpin Catch 011-0.003 0.95 Peamouth Chub Catch 0 11 0.112 0.011 Pikeminnow Catch 0 97 0.026 0.55

Page 19 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

Table 3: Parameter estimates, model tests (chi sq), and P-values for logistic regressions describing the probability of sturgeon presence as a function of 5 habitat variables in 518 tangle-net sets. Statistically significant P-values are shown in bold.

Variable intercept slope Chi sq. P Surface Temperature (C ) -2.76 0.15 41.86 < 0.0001 Depth (m) -1.34 0.04 2.37 0.12 Sculpin Catch -1.06 -0.09 1.20 0.27 Peamouth Chub Catch -1.13 0.08 1.11 0.29 Pikeminnow Catch -1.03 -0.01 1.53 0.22

14 12 10 8 6 4 Sturgeon Catch 2 0 0 5 10 15 20 Surface Temperature

14 12 10 8 6 4 Sturgeon Catch 2 0 0 5 10 15 20 25 30 Depth

Figure 11: Scatter-plots of sturgeon catch as a function of surface water temperature (ºC) and water depth (m), lower Fraser River, September2007-March 2008.

Page 20 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

15

10

5

Sturgeon Catch 0 024681012 BullheadSculpin Catch Catch

15

10

5

Sturgeon Catch 0 024681012 Peamouth Chub Catch

15

10

5

Sturgeon Catch 0 0 20 40 60 80 100 120 Pikeminnow Catch Figure 12: Scatter-plots of sturgeon catch as a function of catch of the three most common bycatch species: sculpins, peamouth chub, and northern pikeminnow, lower Fraser River, September2007-March 2008.

A plot of sturgeon catch by size group (<300 mm and >300mm fork length) in relation to water depth (Figure 13) shows a similar pattern for both size groups. The number of sturgeon caught decreased with increasing water depth, with the catch of both size groups being greater in areas less than 5 m deep. No sturgeon <300 mm in length were caught in areas greater than 20 m deep.

Page 21 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

120

100

80

>=300 mm 60 <300 mm

40 Number of Sturgeon of Number

20

0 <5 5-10 10-15 15-20 20-25 25-30 Water Depth (m)

Figure 13: Plot of sturgeon catch for two size groups in relation to water depth, lower Fraser River, September2007-March 2008.

Plots of the relative frequency of sturgeon catch in relation to substrate types are shown in Figure 14. There was a significant effect of substrate on ranked sturgeon catch (Chi sq = 27.4; df = 4; P <0.0001). The significant effect was largely a result of larger catches in silt, and a mix of silt/sand habitats, relative to the catches in sand, mud, and a mix of mud/silt habitats. Very rarely, a sturgeon was caught on a mix of sand/gravel substrate.

Page 22 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 Mud 12 Mud/silt 13 13 0 0.25 0.5 0.75 1 0 0.25 0.5 0.75 1

0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 Sturgeon Catch 10 10 11 11 12 Sand 12 Silt 13 13 0 0.25 0.5 0.75 1 0 0.25 0.5 0.75 1

0 1 2 3 4 5 6 7 8 9 10 11 12 13 Silt/sand 0 0.25 0.5 0.75 1

Relative Frequency

Figure 14: Relative frequency of juvenile sturgeon catch by substrate type, for substrates with n >10, lower Fraser River, September2007-March 2008.

Page 23 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

4. Discussion The emphasis in this baseline study was to sample a wide range of sites in the lower Fraser from the mouth to within the vicinity of the Harrison River to determine the areas used by juvenile white sturgeon seasonally and characterize their preferred areas. The findings of this study are preliminary, but suggest that the juveniles of this subpopulation of sturgeon from September through November are widely scattered from Deas Island to the Sumas River area, with preferred sites being the Annacis and Hatzic areas, and to some extent the Port Mann Bridge, Stave, and Matsqui areas. They occupied a wide range of water depths, but more commonly were found in areas less than 5m deep with fine substrates (silt, or a mix of silt and sand) in side channels, side pools, backwaters and nearshore mainstem open channels. A wide range of water depths occupied by juvenile sturgeon has also been reported by others (e.g., Lane and Rosenau 1993, lower Fraser River; Parsley et al. 1993, lower Columbia River). These authors reported that water velocities of sites occupied by juvenile sturgeon were slow to moderate. Our findings regarding substrates favoured by juvenile sturgeon agree with those reported by Lane and Rosenau (1993) for habitats sampled in the Hatzic, Nicomen and Big Eddy areas, who found that sturgeon were mainly caught in areas of fine substrate (sand, silt, clay).

From the present study, we have very little information to report on areas occupied by juvenile sturgeon in the lower Fraser River during winter. The sturgeon catch was highly negatively correlated with decreasing water temperature, with very few fish caught below 7 °C. The few fish that were caught in the Annacis, Matsqui and Hatzic areas may be due to very low numbers of fish present, or fish may have been present in reasonable numbers in these areas (as noted during the September-November period), but were largely sedentary during prevailing low winter temperatures (<5 °C). From a study on seasonal movements of white sturgeon in the mid Columbia River, Haynes and Gray (1981) found that the fish remained more or less sedentary during winter low temperatures. Sturgeon sampling in the lower Columbia River system by the Washington Department of Fish and Wildlife is not conducted beyond September as catch rates drop off markedly with declining temperatures (Brad Cady, WDFW, pers. comm.). Although sturgeon catches may in part change seasonally because of fish behavioural/ontogenetic reasons, they are probably largely related to temperature which changes seasonally and affects fish movement.

Northern pikeminnow, although abundant in the catch in the present study, was found to have no statistically significant effect on the catch of juvenile white sturgeon. Likewise, the catch of sculpins had no significant effect on sturgeon catch, whereas that of the peamouth chub was weakly significant. Although statistically non-significant or weak, for each of these native fishes there are indications that the catch of juvenile sturgeon tended to decline with increasing native fish catch. Predation on young sturgeon by northern pikeminnow and sculpins may partly account for this trend, whereas the trend associated with peamouth chub may be more attributed to competition for resources (e.g., food).

We believe no young-of-year (y-o-y) sturgeon were captured in the present study. The smallest sturgeon captured was 193 mm long. Although juvenile sturgeon up to 180 mm

Page 24 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

in length caught in the lower Columbia River system by end of September are confirmed to be age 0 fish (McCabe and Tracy 1994; Ruth Farr, unpublished data, pers. comm.), growth of young sturgeon in the Fraser River is probably not as rapid. A sturgeon 180 mm long was captured toward mid July 2007 in one of the fish wheels operated at the Mission railway bridge by LGL Limited in 2007. Several other 200-400 mm long juvenile sturgeon were captured by this same fishwheel when it was operated close to shore in 3-4 meters of water. This fishwheel was one of three operated at different sites across the river channel adjacent to the Mission railway bridge from 22 June through 27 September 2007. No juvenile sturgeon were captured at the other sites. At the time of capture, the 180-mm long sturgeon would have been at least age 1+since spawning of white sturgeon usually occurs in May and June, or later for some stocks (Scott and Crossman 1973). Triton (2004) reported observing (from a helicopter) sturgeon spawning in clear water in the Nechako River during the day on 18 May 2004. Perrin et al. (2003) by back-tracking from sturgeon eggs collected in the lower Fraser River ranging from 0- 65 h post spawning, estimated that spawning occurred between early July and early August. Although the spawning period may be more protracted than that estimated by Perrin et al., almost certainly, the smallest sturgeon caught in the present study was age 1+, or older. Most of the sturgeon caught that were <450 mm long probably constituted three age classes (possibly ages 1+, 2+ and 3+ fish). For management, protection and conservation of this endangered subpopulation of white sturgeon in the Fraser River, it is important that the age of these young fish be confirmed in future study. 5. Conclusion From the rather extensive sampling conducted from the September-November period, it appears that the juveniles of this subpopulation of white sturgeon in the lower Fraser River are widely scattered, with preferred sites being the Annacis, Matsqui and Hatzic areas. They occupy a wide range of water depths but more frequently were found in slow- flowing areas less than 5 m deep with fine substrates. Because of exceedingly low catch rates, further sampling during low water temperatures (<7 °C) is unlikely to provide information on where juvenile sturgeon are during winter. Sampling during the May-June period (before the onset of high flows in summer) is more likely to give results indicative of where juvenile sturgeon spend the winter and would provide a comparison of their distribution and habitat preferences seasonally with that of the present study. 6. Recommendations The emphasis in Year 2 (2008-2009) of this study program should be largely on filling in the gaps of the present study. As sampling did not get started in Year 1 until September, a major gap is the lack of juvenile sturgeon habitat use information for the spring-early summer period. Other gaps include lack of information on the whereabouts and habitat use of the very young year classes of sturgeon, as well as confirmation of age of these fish. To fill in the gaps it is recommended that the emphasis in Year 2 be limited primarily to sites where the higher catches occurred in Year 1 in the lower Fraser River (from the mouth to Harrison River confluence), with some additional sampling of new sites that appear highly likely to have juvenile sturgeon. This approach should expedite filling the gap on habitats occupied by juvenile sturgeon during the spring-early summer

Page 25 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009 period and allow for some seasonal comparison of juvenile sturgeon habitat use. It is recommended that the following works be undertaken in Year 2: • Conduct soft mesh tangle netting and gather juvenile sturgeon habitat use information in selected sites (within the vicinity of Deas Island, Annacis Island, Port Mann Bridge, Barnston Island, Crescent Island, Matsqui, Hatzic and Nicomen Island) from May-August period; in addition, include some sampling of new sites that appear highly likely to be inhabited by juvenile sturgeon. • Collect and analyze samples for age determination of the younger year classes of juvenile sturgeon. • Compare the findings of sites sampled in Years 1 & 2 to determine possible seasonal change in juvenile sturgeon habitat use. 7. Acknowledgments We express our sincere thanks and gratitude to the following sources for funding of this study:

BC Ministry of Environment Fisheries and Oceans Canada, Species at Risk Program – Aboriginal Involvement Fisheries and Oceans Canada, Habitat Stewardship Program Fraser River Sturgeon Conservation Society Vancouver Foundation, Environment Advisory Committee

We thank the following people for their contributions to this study: Erin Stoddard of MOE for his continued support and interest throughout the period of study; Rick Hansen for his unfailing support, enthusiasm, interest and help in all phases of this work; Robin Tamasi for his excellent GIS mapping skills, David Robichaud for conducting the statistical analyses; Ralph Roberts for his role as Field Crew Coordinator and Field Team Leader of the lower river reach during the field sampling program; Rennie Matson for technical assistance and use of his fishing boat for sampling in the lower river; Troy Ganzeveld for his role as Field Team Leader and use of his boat for sampling the upper river reach; Cej Mussell for assistance during the reconnaissance survey in identifying suitable sites for sampling in the upper river reach; Michael Link of LGL Ltd., Anchorage, for the use of their salinometer throughout the study period; Jim Rissling for his assistance regarding sampling equipment and PIT tag data management; Kelsey Ned and Farley Antone for technical assistance with the field sampling program; Brad Cady, Brad James, and Ruth Farr for helpful discussion and information regarding sampling of sturgeon in the lower Columbia River which we could apply to sampling sturgeon in the lower Fraser River.

Page 26 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

8. References Bennett, W.R., G. Edmundson, E.D. Lane, and J. Morgan. 2005. Juvenile white sturgeon (Acipenser transmontanus) habitat and distribution in the Lower Fraser River, downstream of Hope, BC, Canada. Journal of Applied Ichthyology 21: 375-380. Cuerrier, J.P. 1951. The use of pectoral fin rays to determine age of sturgeon and other species of fish. Canadian Fish Culturist 11: 10-18. DeVore, J.D., B.W. James, C.A. Tracy, and D.A. Hale. 1995. Dynamics and potential production of white sturgeon in the unimpounded lower Columbia River. Transactions of the American Fisheries Society 124: 845-856. Elliott, J.C. and R.C. Beamesderfer. 1990. Comparison of efficiency and selectivity of three gears used to sample white sturgeon in a Columbia River reservoir. California Fish and Game 76: 174-180. Golder Associates Ltd. 2003. Upper Columbia River juvenile white sturgeon monitoring, Phase 1 investigations, fall 2002. Report prepared for BC Hydro, Castlegar, BC. Haynes, J.M., and R.H. Gray. 1981. Diel and seasonal movement of white sturgeon , Acipenser transmontanus, in the mid-Columbia River. Fisheries Bulletin 79: 367- 370. Haynes, J.M., R.H. Gray, and J.C. Montgomery. 1978. Seasonal movements of white sturgeon (Acipenser transmontanus) in the mid-Columbia River. Transactions of the American Fisheries Society 107: 275-280. Laidlaw, K.A. and M.L. Rosenau. 1998. An assessment of putative white sturgeon spawning habitat in areas impacted by scuffle dredging in the Fraser River: Hope to Mission. BC Ministry of Environment, Lands and Parks. Regional Fisheries Report No. LM557. 13 p. Lane, E.D. and M.L. Rosenau. 1993. The conservation of sturgeon stocks in the lower Fraser River watershed. A baseline investigation of habitat, distribution, age and population of juvenile white sturgeon (Acipenser transmontanus) in the lower Fraser River, downstream of Hope. BC Habitat Conservation Fund Project – Final Report. McCabe, G.T., Jr., and C.A. Tracy. 1994. Spawning and early life history of white sturgeon, Acipenser transmontanus, in the lower Columbia River. Fishery Bulletin 92 (4): 760-772. Mussell, CEJ., and T. Nelson. 2006. Lower Fraser juvenile white sturgeon habitat assessment. Year 1 (Progress Report). Prepared for Fisheries and Oceans Canada. Nelson, T. C., W.J. Gazey, and K. K. English. 2007. Status of white sturgeon in the lower Fraser River: Report on the findings of the Lower Fraser River White Sturgeon Monitoring and Assessment Program 2006. Report prepared for the Fraser River Sturgeon Conservation Society, Vancouver, BC.

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Neufeld, M.D., and C.R. Spence. 2004. Kootenay Fisheries Investigations Sturgeon and Burbot Progress, 2002-03. Ministry of Water, Land and Air Protection, Nelson, BC. North, J.A., R.C. Beamesderfer, and T.A. Rien. 1993. Distribution and movements of white sturgeon in three lower Columbia reservoirs. Northwest Science 62 (2): 105-111. Paragamian, V.L., G. Kruse, and V. Wakkinen. 2001. Spawning habitat of Kootenai River white sturgeon, post-Libby Dam. North American Journal of Fisheries Management 21: 22-33. Perrin, C.J., L.A. Rempel, and M.L. Rosenau. 2003. White sturgeon spawning habitat in an unregulated river: Fraser River, Canada. Transactions of the American Fisheries Society 132: 154-165. Parsley, M.J., and K.M. Kappenman. 2000. White sturgeon spawning areas in the lower Snake River. Northwest Science 74: 192-201. Parsley, M.J., L.G. Beckman, and G.T. McCabe, Jr. 1993. Habitat use by spawning and rearing white sturgeon in the Columbia River downstream of McNary Dam. Transactions of the American Fisheries Society 122: 217-227. R.L. & L. Environmental Services Ltd. 2000. Fraser River white sturgeon monitoring program – comprehensive report (1995- 1999). Final report prepared for BC Fisheries. R.L. & L. Report No. 815F: 92 p + appendices. Robichaud, D., K. K. English, R. C. Bocking, and T. C. Nelson. 2006. Direct and delayed mortality of white sturgeon caught in three gear-types in the lower Fraser River. Report prepared for Tsawwassen First Nation Fisheries, Delta, BC, by LGL Limited, Sidney, BC. Scott, W.B., and E.J. Crossman. 1973. Freshwater Fishes of Canada. Bulletin 184. Fisheries Research Board of Canada, Ottawa. 966 pp. Triton Environmental Consultants Limited. 2004. Adult white sturgeon monitoring – Nechako River 2004. Report prepared for Alcan Primary Metal, Kitimat, BC.

Page 28 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

Appendix

Surface Conductivity Bottom Conductivity

450 450 400 400 350 350 300 300 Average Average 250 250 Minimum Minimum 200 200 Maximum Maximum 150 150 100 100 50 50 0 0 910111213 91011121 3 Month Month

Surface Salinity Bottom Salinity

6 6

5 5

4 4 Average Average 3 Minimum 3 Minimum Maximum Maximum 2 2

1 1

0 0 91011121 3 910111213 Month Month

Surface Dissolved O2 Bottom Dissolved O2

12 12

10 10

8 8 Average Average 6 Minimum 6 Minimum Maximum Maximum 4 4

2 2

0 0 910111213 910111213 Month Month

Surface Temperature Bottom Temperature

20 20 18 18 16 16 14 14 12 Average 12 Average 10 Minimum 10 Minimum 8 Maximum 8 Maximum 6 6 4 4 2 2 0 0 9 1011121 3 9 1011121 3 Month Month

Figure 1: Plots of water quality parameters measured at sites sampled in the lower Fraser River, September 2007-March 2008. In some months between November and March, there are no data for dissolved oxygen and bottom conductivity.

Page 29 Surveys of Juvenile White Sturgeon and Their Habitat in the Lower Fraser River 2007-08 EA3009

Table 1: Catch of native fish species in lower Fraser River, September 2007-March 2008.

Species Number of fish Northern pikeminnow 2728 Sculpins 276 Peamouth chub 143 108 Herring 34 23 Crayfish 7 Steelhead 6 Coho salmon 5 4 Starry flounder 4 Flounder sp. 2 Sucker sp. 2 Dolly Varden 1 Cutthroat trout 1 Eulachon 1 3,345

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Field Data Form

Page 31