An assessment of growth of young-of-the-year lake sturgeon in the Kaministiquia River, ON,

2006

Lake Superior

M.J. Friday

Technical Report No. 06.06

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TABLE OF CONTENTS

List of Tables ………………………………………………………………………….. iList of Figures …………………………………………………………………………. iiIntroduction ……………………………………………………………………………. 1Objectives………………………………………………………………………………. 1

Study Area ……………………………………………………………………………… 1

Materials and Methods ………………………………………………………………. 3Water Temperature ……………………………………………………………… 3Cumulative Daily Water Temperature ………………………………………….. 3Total River Flows…………………………………………………………………. 3

Results ………………………………………………………………………………….. 3Seining …………………………………………………………………………….. 5Visual Search …………………………………………………………………….. 5Growth …………………………………………………………………………….. 5

Discussion……………………………………………………………………………… 8

Acknowledgements ………………………………………………………………….. 9

References ……………………………………………………………………………... 10

Appendix ……………………………………………………………………………….. 11

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LIST OF TABLES

Table Pg.

1 Total length of individual lake sturgeon captured on the Kaministiquia River from July 4 to August 11, 2006 7

A1 The period of larval drift from 2004 to 2006 and projected date when juvenile sturgeon could reach 100 mm based on 770 cumulative thermal units. 11

A2 A comparison of drift netting results from 2004 to 2006 12

A3 The growth projection (growth = 1.7mm/d) to 100 mm and back calculations to date of larval drift among five juvenile lake sturgeon collected in the Kaministiquia River from 1994 to 2002. 12

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LIST OF FIGURES

Figure Pg.

1 The sites that were searched for young-of-the-year lake sturgeon on the Kaministiquia River, 2006 2

2 The capture location of young-of-the-year lake sturgeon at site 1 on the Kaministiquia River, 2006 4

3 Kaministiquia River mean daily total river flow and young-of-the-year lake sturgeon catch 2006 4

4 Total length of individual young-of-the-year lake sturgeon captured on the Kaministiquia River from July 4 to August 11, 2006. 6

5 Growth of young of the year lake sturgeon in the Kaministiquia River, 2006 6

6 Growth of young-of-the-year lake sturgeon in the Kaministiquia River 2006, in relation to cumulative thermal units. 7

A1 The larval drift catches from 2004 to 2006 and projected timeframe of growth to 100 mm based on cumulative thermal units. 12

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INTRODUCTION

Nine Lake Superior tributaries, namely the Sturgeon River in Michigan, the Bad River in Wisconsin and the Big Pic, Black Sturgeon, Goulais, Gravel, Kaministiquia, Michipicoten, and Nipigon Rivers in Ontario, are known to support self-sustaining lake sturgeon populations (Auer 2003). These tributaries are also utilized by populations of sea lamprey for spawning and are commonly treated with a lampricide that can be lethal to young sturgeon. During laboratory exposures, juvenile lake sturgeons less than 100 mm (with the exception of sac fry) were very sensitive to the lampricide 3-triflouromethyl-4-nitrophenol (Boogaard et al. 2003). Toxicity data also showed that lake sturgeons over 100 mm were less sensitive to lampricides.

In 1998 a Sturgeon Protocol was developed for lampricide application to State designated tributaries that contain lake sturgeon populations. Unpublished data from the U. S. Fish and Wildlife Service, Marquette Biological Station indicates that most juvenile lake sturgeon reach 100 mm in July; therefore, according to the protocol, lampricide treatments are to occur after August 1st in tributaries that flow into U.S. waters of Lake Superior that have populations of lake sturgeon (DFO 2006). Unfortunately, growth rates for young-of-the-year (YOY) lake sturgeon in Canadian tributaries to Lake Superior is lacking.

Lake sturgeon populations are known to have at least two separate spawning events during a spawning season which is mainly influenced by water temperature (Kempinger 1988) This spawning behaviour has been documented in the Kaministiquia River with spawning occurring at temperatures of approximately 13°C (usually the last week of May) and then again at 16°C (timing variable) (Friday 2004, 2005). Depending on the rate of river warming, the time between spawning events may be days or in some cases weeks apart and result in two groups of offspring that would reach 100 mm at different times. In 2004 and 2005, lake sturgeon in the Kaministiquia River spawned approximately 37 d and 12 d apart respectively (Friday 2004, 2005). In 2006, Friday reported that adult lake sturgeon in the Kaministiquia River spawned on two occasions approximately 3 d apart and larvae drifted from the spawning site during one event that lasted 16 d (June 1 to 16). OBJECTIVES

Because the Kaministiquia River was scheduled for treatment from August 11 to 13, 2006, we attempted to locate nursery areas on the Kaministiquia River and capture YOY lake sturgeon to monitor growth in order to determine the date when they reached an average total length of 100 mm.

STUDY AREA

The search for YOY lake sturgeon focused around a number of islands downstream of the Harstone Bridge (Site 1), approximately 5 kilometres downstream from

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Figure 1. The sites that were searched for young-of-the-year lake sturgeon on the Kaministiquia River, 2006.

Ft. William Historical Park

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the spawning site at Kakabeka Falls and 42 river kilometres (rkm) from the confluence with Lake Superior (Figure 1). During a preliminary habitat assessment in early May 2006 it was noted that the downstream portion of the islands have extensive sand deposits that continue out into the main river channel. It has been reported that this habitat is preferred by juvenile sturgeon (Quinlan 2000, Kempinger 1996). As well, two YOY lake sturgeon were captured (on July 5 and 11, 2001) while seining a small channel between the uppermost islands (Figure 1). The islands above the Harstone Bridge at rkm 43 (site 2) and the island in front of Fort William Historical Park at rkm 18 (site 3), were also searched (Figure 1). These locations had areas of mud, sand and fine gravel substrates.

MATERIALS AND METHODS

A bag seine (15.5m x 1m x 5mm) was used to capture age 0 lake sturgeon. The seine net was pulled in an upstream direction through shallow, near shore areas (< 1 m depth) with slow moving current. In addition, these areas were searched visually, usually in the morning, with polarized sunglasses and dip nets.

Captured sturgeon were measured and released. Water depth (cm) and GPS coordinates were recorded at each capture site.

Water Temperature Water temperature was recorded using a Vemco Minilog - T data logger located approximately 500 m downstream of Kakabeka Falls spawning site (Figure 1). Temperature was recorded hourly from April 24 to October 13 (excluding May 6 to 8).

Cumulative Daily Water TemperatureTo establish a relationship between YOY growth and mean daily water temperature; cumulative daily water temperature units (CTU) were calculated using the equation developed by Kempinger (1988).

Total River FlowsMean daily total river flows for the Kaministiquia River was provided by Ontario Power Generation.

RESULTS

From July 4 to August 11, 30 YOY lake sturgeon were captured by seining and dipnetting at site 1 (Figure 2). These fish were captured along the river margins at depths that ranged from 20 to 55 cm during total river flows between 21 and 32.5 m3∙s-1 (Figure 3). The YOY sturgeon ranged in length from 51 to 135 mm (Table 1). One was caught seining and twenty nine were caught with dip nets. The mean daily water temperature from the end of the larval drift period to the date the first

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Figure 2. The capture location of young-of-the-year lake sturgeon at site 1 on the Kaministiquia River, 2006.

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Figure 3. Kaministiquia River mean daily total river flow and young-of-the-year lake sturgeon catch, 2006.

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YOY was captured was 19.8°C. The mean daily water temperature during the drift period (June 1 to 16) was 19.3°C.

SeiningDuring two evening seine net tows (July 4 - 22:45) at site 1, one lake sturgeon (62 mm) was captured. No lake sturgeon were captured at site 1 during four daytime seine net tows on July 4.

Visual SearchDuring 20 days (28.8 hrs) of visual searching at site one, 29 YOY lake sturgeons were captured. The catch per unit effort was approximately 1.0 YOY/hr. The first individual was captured on July 4 (51 mm) and the last was captured on August 11 (135 mm) (Figure 4). Windless days with surface calm were most productive. No YOY lake sturgeon were captured during visual searches at site two (July 14) and three (July 11).

GrowthYoung-of-the-year lake sturgeon grew approximately 1.7 mm a day from the larval drift stage in June 2006 (mean TL = 20 mm) to August 11 (Figure 5). The first YOY captured > 100 mm was on July 25. The growth projection of the 2006 year class from June through August is shown in Figure 5. On days when two or more sturgeon were captured the greatest difference in total length between individuals was 23 mm (Table 1).

Larval growth was described by the equation: y = 1.7219x + 255.43

Where:

y = size of larval sturgeon (mm)

x = Julian day

The CTU value required to attain a length of 100 mm from the date when larval drift commenced in 2006 (June 1) was approximately 770 (Figure 6).

Larval growth, in relation to CTU was described by the equation:

y = 0.1249x + 3.9337

Where:

y = size of larval sturgeon (mm)

x = cumulative thermal units (CTU)

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Figure 4. Total length of individual young-of-the-year lake sturgeon captured on the Kaministiquia River from July 4 to August 11, 2006.

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Figure 5. Growth of young-of-the-year lake sturgeon in the Kaministiquia River, 2006.

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Table 1. Total length of individual lake sturgeon captured on the Kaministiquia River from July 4 to August 11, 2006.

Date Total length (mm)Size

difference (mm)

Fish 1 Fish 2 Fish 3 Fish 44-Jul-06 51 62 115-Jul-06 58 61 62 69 1110-Jul-06 7611-Jul-06 60 62 84 2412-Jul-06 66 70 85 1913-Jul-06 65 88 2317-Jul-06 7718-Jul-06 78 84 93 1519-Jul-06 9120-Jul-06 9321-Jul-06 9724-Jul-06 9525-Jul-06 102 109 111 931-Jul-06 1129-Aug-06 130 135 511-Aug-06 135

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Figure 6. Growth of young-of-the-year lake sturgeon in the Kaministiquia River 2006, in relation to cumulative thermal units.

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DISCUSSION

Young-of-the-year lake sturgeons were captured at the downstream portion of the “Harstone islands” from early July to mid August 2006. This period of summer river residency at age 0 is similar to findings documented by Quinlan (2000) in the Bad River, Kempinger (1996) in the Wolf River and Benson et al. (2005) in the Peshtigo River.

The nursery habitat at the Harstone islands is shallow, protected from the main river current (low velocities), has some marginal emergent aquatic vegetation and is dominated by fine to coarse sand substrates. These observations are similar to age 0 habitat preferences documented by Kempinger (1996) in the Wolf River, Benson et al. (2005) in the Peshtigo River and Holtgren and Auer (2004) in the Sturgeon River.

The mean growth rate of juveniles in the Kaministiquia River from the larval drift stage in June to August 11, 2006 was 1.7 mm/day. Quinlan (2000) documented growth rates in the Bad River, from the larval stage in May 1998 (mean TL = 18 mm, n = 11) to August 18 at 1.5 mm/day. The difference in mean daily growth may be due to water temperature, small sample size or other environmental factors. The difference in total length observed between individuals captured on the same day indicates that larvae from the entire drift period are using this area as nursery habitat. The July 11th catch (TL = 60 and 84 mm) may be individuals from the beginning and end of the larval drift period.

Based on 2006 growth data (1.7 mm/day) from the Kaministiquia River, YOY would attain a length of 100 mm by July 25 (Figure 4). In 1998, Quinlan (2000) projected that juvenile lake sturgeon in the Bad River would reach this length by July 1. Lake sturgeon from the Bad River reached 100 mm much earlier than Kaministiquia River sturgeon mainly because of earlier spawning times (Bad River 1998 = April 25, Kaministiquia River 2006 = May 21) and drift periods (Bad River 1998 = May 1 to 14, Kaministiquia River 2006 = June 1 to 16).

The mean length of larval sturgeon captured during drift netting on the Kaministiquia River is approximately 20 mm (Friday 2006). Therefore, an additional 80 mm of growth is required to achieve the 100 mm threshold for better survival during sea lamprey treatments. Using the 2006 growth rate (1.7 mm/day) it took approximately 47 d from the date of drift to attain this length.

From 2004 to 2006 the spawning dates and period of larval drift have been documented in the Kaministiquia River (Appendix 1, Table A1). If we assume 770 CTU for growth to 100 mm, juvenile sturgeon would have reached this minimum length anywhere from mid July to late September depending on the year (Appendix

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1, Table A1, Figure A1). The variability among years is primarily related to the date when spawning occurs which is strongly influenced by water temperature and the rate of river warming. In all years the first spawning event occurred around May 21 when water temperature was approximately 13°C. The timing of the second spawning event however, was variable did not occur until water temperature was approximately 16°C.

During the 2004 and 2005 drift netting the second drift event represented 47% of the total catch (Appendix 1, Table A2). This suggests that the second spawning event may have been equally important to larval production as the first spawning event. These late drifters however are more susceptible to lampricide treatments.

From 1994 to 2002 five juvenile sturgeons ranging in total length from 35 – 80 mm have been collected in the Kaministiquia River at a number of locations (Appendix 1, Table A3). Two were captured by trawling, two were captured by seining and one was a mortality due to lampricide treatment. The mortality was collected just upstream of the Whitefish River confluence on August 12, 2002 by the Department of Fisheries and Oceans Sea Lamprey Control (Weise personal communication 2003). This is approximately 800 m downstream of the nursery area identified in 2006. This fish was likely from a late second spawning event, similar to what was observed in 2004. The estimated growth projections to 100 mm and approximate date of larval drift for the five age 0 sturgeon collected in the Kaministiquia River are presented in Appendix 1 (Table A3).

The timing of spawning events and water temperature throughout the period of summer growth seem to be the most important factors governing when YOY lake sturgeon will reach 100 mm and be less sensitive to lampricide treatments. Using the treatment scheduling rationale from the 1998 Sturgeon Treatment Protocol (sturgeon in US tributaries attain a length of 100 mm by July 1, therefore treatments are scheduled after Aug 1 or later) these data suggest lampricide treatments in Canadian tributaries to Lake Superior should be scheduled after September 1 or later to protect young-of-the-year lake sturgeon. Alternatively, in rivers where lampricide treatment is scheduled, continuous temperature loggers could be deployed after ice-out to determine the date of spawning (13°C and 16°C) and when 770 CTU is attained.

ACKNOWLEDGEMENTS

This study was made possible through funding provided by the Canada Ontario Agreement respecting the Great Lakes Basin Ecosystem and the Great Lakes Sustainability Fund. The contributions of OMNR staff including Karen Schmidt (lead technician) and Kim Armstrong for report review and the assistance of summer field staff are greatly appreciated. I would also like to thank Ontario Power Generation for providing flow data.

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REFERENCES

Auer, N.A. [Ed.]. 2003. A lake sturgeon rehabilitation plan for Lake Superior. Great Lakes Fish. Comm. Misc. Publ. 2003-02.

Benson, A. C., T. M. Sutton, R. F. Elliott, and T. G. Meronek. 2005. Seasonal movement patterns and habitat preferences of age 0 lake sturgeon in the lower Peshtigo River, Wisconsin. Transactions of the American Fisheries Society 134: 1400 -1409.

Boogaard, M. A., T. D. Bills, and D. A. Johnson. 2003. Acute toxicity of TFM and a TFM/Niclosamide mixture to selected species of fish, including lake sturgeon (Acipenser fulvescens) and mudpuppies (Necturus maculosus) in laboratory and field exposures. J. Great Lakes Res. 29 (Supplement 1): 529 – 541.

DFO, Sea Lamprey Control. 2006. Protocol for application of lampricides to streams with populations of young-of-the-year lake sturgeon (Acipenser fulvescens). 6 p.

Friday, M. J. 2004. The Migratory and Reproductive Response of Spawning Lake Sturgeon to Controlled Flows over Kakabeka Falls on the Kaministiquia River, 2004. Upper Great Lakes Management Unit – Lake Superior, Ontario Ministry of Natural Resources, Technical Report 06.01 27 p.

Friday, M. J. 2005. The Migratory and Reproductive Response of Spawning Lake Sturgeon to Controlled Flows over Kakabeka Falls on the Kaministiquia River, ON 2005. Upper Great Lakes Management Unit – Lake Superior, Ontario Ministry of Natural Resources, QUIK Report 05.01 13 p.

Friday, M. J. 2006. The Migratory and Reproductive Response of Spawning Lake Sturgeon to Controlled Flows over Kakabeka Falls on the Kaministiquia River, ON 2006. Upper Great Lakes Management Unit – Lake Superior, Ontario Ministry of Natural Resources, QUIK Report 06.02 13 p.

Holtgren, J. M., and N. A. Auer. 2004. Movement and habitat of juvenile lake sturgeon (Acipenser fulvescens) in the Sturgeon River/Portage Lake system, Michigan. Journal of Freshwater Ecology 19: 419 – 432.

Kempinger, J. J., 1988. Spawning and early life history of the lake sturgeon in the Lake Winnebago system, Wisconsin. Am. Fish. Soc. Symp. 5: 110 – 122.

Kempinger, J. J., 1996. Habitat, growth, and food of young lake sturgeons in the Lake Winnebago system, Wisconsin. N. Am. J. Fish Manag. 16, 102-114.

Quinlan, 2000. Studies of larval and juvenile lake sturgeon in the Bad River, 1997-1998. United States Department of the Interior. Ashland Fishery Resources Office Internal Report. 13 p.

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APPENDIX 1

Table A1. The period of larval drift from 2004 to 2006 and projected date when juvenile sturgeon could reach 100 mm based on 770 CTU.

Year ~ First Spawning

Period of first drift event

Projected date to reach 100 mm

Second Spawning

Period of second drift event

Projected date to reach 100 mm

2004 May 21 June 10 - June 24 Aug 15 – Aug 30 June 27 July 12 - July 20 Sept 13 - Sept 24

2005 May 22 June 7 - June 17 Aug 1 - Aug 7 May 31 June 18 - June 25 Aug 8 - Aug 14

2006 May 21 June 1 - June 16 NA NA NA July 25 – Aug 4

In 2004 adults spawned approximately 37 d apart (~ May 21 and June 27) which resulted in two larval drift events (Friday 2004). Based on a CTU value of 770, larvae from the first spawning may have reached 100 mm from August 15 – August 30 while the larvae from the second spawning may have reached 100 mm from Sept 13 - Sept 24 (Table A1, Figure A1).

In 2005, adults spawned approximately 12 d apart (~ May 22 and May 31) which resulted in two overlapping but distinct drift events (Friday 2005). Based on a CTU value of 770, larvae from the first spawning may have reached 100 mm from August 1 - August 7 while the larvae from the second spawning may have reached 100 mm from August 8 - August 14 (Table A1, Figure A1).

In 2006, spawning occurred approximately 3 d apart and larvae drifted from the spawning site by June 16 and may have reached 100 mm from July 25 to August

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4 (Table A1, Figure A1) (Friday 2006).

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Figure A1. The larval drift net catches from 2004 to 2006 and projected timeframe of growth to 100 mm (delineated by brackets) based on 770 CTU.

Table A2. A comparison of drift netting results from 2004 to 2006.

Study Year

Overnightsampling events (#)

Total hours

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Catch per Unit Effort (Larvae/hr)

Start of first drift event

Larvae caught in 1st drift event

Duration of first

drift event

Larvae caught in 2nd drift

event

Duration of second drift

event

2004 38 6890 445 0.06 Jun 10 234 (52.2%) 18 days 211 (47.8%) 8 days

2005 23 5187 884 0.17 Jun 7 465 (52.6%) 12 days 419 (47.4%) 7 days

2006 20 3586 934 0.26 Jun 1 - 16 days - -

Table A3. The growth projection (where growth = 1.7mm/d) to 100 mm and back calculations to date of larval drift among five juvenile lake sturgeon collected in the Kaministiquia River from 1994 to 2002.

Capture date Total length (mm)

Days (d) of growth from larval drift date to

capture date

~ Date of drift

Days (d) from capture date to attain 100 mm

~ Date to reach 100

mm12 Aug 2002 78 (78 – 20) ÷ 1.7 = 34 d a July 9 (100 – 78) ÷ 1.7 = 13 d b Aug 25

5 Jul 2001 35 (35 – 20) ÷ 1.7 = 9 d June 27 (100 – 35) ÷ 1.7 = 38 d Aug 12

11 Jul 2001 35 (35 – 20) ÷ 1.7 = 9 d July 2 (100 – 35) ÷ 1.7 = 38 d Aug 18

18 July 1994 60 (60 – 20) ÷ 1.7 = 23 d June 25 (100 – 60) ÷ 1.7 = 23 d Aug 10

18 July 1994 80 (80 – 20) ÷ 1.7 = 35 d June 13 (100 – 80) ÷ 1.7 = 12 d Jul 30

a = [Total length (when caught) – mean larval length at drift (20 mm)] ÷ growth (1.7 mm day) = d

b = [Length threshold (100 mm) - capture length] ÷ growth (1.7 mm day)] = d