Saskatchewan River Sturgeon Report 2012
Report contact: Michael Pollock Ph.D. Instream Flow Ecologist Wate r Quality Services 101 -108 Research Drive Saskatoon, SK, S7N3 Phone: (306) - 964-1556 Fax: (306) - 933-6820 Email: [email protected]
2012/2013 Report Contributions
1. Field crew John Salamon Iain Phillips Nicole Prestie Kate Prestie Lance Lamontagne Tyler Shemrock Meghan Carr Brett Vallee Michael Pollock
2. Analysis GIS analysis: Michael Pollock and Meghan Carr Background research: Michael Pollock and Meghan Carr Stable Isotope analysis: Iain Phillips, Dave Braun and Bjoern Wissel River2D Model creation: Michael Pollock and Kangsheng Wu
3. Report preparation and editing Mike Pollock Glen McMaster Meghan Carr
4. Funding SaskPower Ministry of the Environment (Fish and Wildlife Development Fund) Government of Canada (Habitat Stewardship Program)
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Table of contents
Table of contents ...... 3
Figure Legend ...... 7
Table Legend ...... 10
Executive Summary ...... 12
1.0 Introduction ...... 18
1.1 Sturgeon life history and status ...... 18
1.2 Saskatchewan River populations ...... 21
1.3 Water Security Agency mandate and history of flow management ...... 23
1.4 Study objectives ...... 27
1.4.1 Habitat availability in relation to flow ...... 27
1.4.2 Habitat use and availability ...... 29
1.4.3 Population abundance and health ...... 29
2.0 Materials and Methods ...... 30
2.1 Habitat availability in relation to flow ...... 30
2.1.1 Data collection ...... 31
2.1.2 Flow regime selection ...... 33
2.1.3 Data Organization and River2D model creation ...... 33
2.2 Habitat use and migration ...... 35
2.2.1 Surgical implant of tags ...... 35
2.2.2 Telemetry tracking ...... 36
2.2.2.1 Remote passive towers ...... 36
2.2.2.2 Aerial tracking ...... 37
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2.2.2.3 Vehicle and snowmobile tracking ...... 38
2.2.2.4 Boat tracking ...... 38
2.2.3 Telemetry analysis ...... 39
2.3 Population abundance and health ...... 40
2.3.1 Mark and recapture ...... 40
2.3.1.1 Abundance ...... 44
2.3.2 Stable isotope analysis ...... 44
Stable isotope analysis can be used to link an organism with its environment. It can be
used to link organisms to their source of energetic input (i.e. diet; Pollock et al. 2010) via
nitrogen and carbon signatures, or in the case of the current report it can link sturgeon to
recently inhabited areas via deuterium...... 44
2.3.2.1 Sampling and sample treatment ...... 44
2.3.2.2 Stable isotope analyses ...... 46
2.3.2.3 Data analyses ...... 47
2.3.3 Genetic analysis ...... 49
2.3.4 Population structure and flow ...... 49
3.0 Results ...... 49
3.1 Sturgeon River2D model results ...... 49
3.2 Telemetry ...... 53
3.2.1 Migration distance ...... 57
3.2.2 Migration destination and river use ...... 58
3.2.3 Migration timing ...... 58
3.2.4 Area use ...... 59
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3.2.5 Catch order ...... 63
3.3 Population health ...... 65
3.3.4 Population age structure ...... 65
3.3.5 Reproductive success and historic flow ...... 67
3.3.6 Stable isotope results ...... 67
3.3.7 Genetic analysis ...... 71
3.3.7.1 Genetic Diversity ...... 71
4.0 Discussion ...... 73
4.1 River2D modeling ...... 73
4.1.1 River2D summary and recommendations ...... 74
4.2 Migration and telemetry ...... 75
4.2.1 Telemetry and migration summary and recommendations ...... 76
4.3 Population abundance and health ...... 76
4.4 Overall conclusions ...... 77
4.5 Future work...... 78
5.0 References ...... 81
Appendix One: Historical South Saskatchewan River Flow ...... 88
Appendix Two: Sturgeon habitat suitability curves: Velocity, depth and substrate habitat suitability used in the River2D model for Lake Sturgeon within the Saskatchewan River as adapted from Fisheries and Oceans (2009)...... 89
Appendix Three: Genetics report from Institute for Watershed Science...... 90
Appendix Four: Images from River2D analysis...... 107
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Appendix Five: Summary of migration distances covered in 2010, 2011 and 2012 (rkms) by sturgeon tagged in 2009 at the forks (sturgeon found less than three times outside the wintering grounds were not used for analysis given insufficient data)...... 142
Appendix Six: Timing of migration of lake sturgeon from the wintering grounds (downstream of
The Forks) and back again in 2010 and 2011...... 143
Appendix Seven: Morphometrics and tagging data for all lake sturgeon captured in the 2012 survey near Borden Saskatchewan on the North Saskatchewan River...... 144
Appendix Eight: Area use and migration maps for radio tagged sturgeon in the Saskatchewan
River system based on 2011 telemetry relocation...... 148
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Figure Legend
Figure 1-1: Historic distribution of lake sturgeon in North America (adapted from Scott and
Crossman 1973)...... 18
Figure 1-2: Site locations for areas sampled in 2008 field work...... 23
Figure 1-3: Site locations for areas sampled in 2009 field work...... 24
Figure 1-4: Locations of all River2D analyzed sites from 2010-2011...... 25
Figure 1-5: Capture locations of all sturgeon tagged from 2009 to 2012...... 26
Figure 1-6: Comparisons of monthly flows pre-Gardiner dam (1911-1966) versus post-Gardiner
Dam (1967-2008) in the South Saskatchewan River near Saskatoon (data contained in: http://www.wsc.ec.gc.ca/hydat/H2O/index_e.cfm Station number 05HG001)...... 28
Figure 2-1: Diagram of River Surveyor, BioSonics unit and RTK Rover on survey boat...... 32
Figure 2-2: Example of path used in data collection for River2D modeling...... 32
Figure 2-3: Location of 2012 River2D site on the South Saskatchewan River and locations of flow cross sections within the site...... 34
Figure 2-4: Diagram of passive tower configuration...... 37
Figure 2-5: Photograph of the antenna attachment on the wing strut used in aerial surveys...... 39
Figure 2-6: Photograph of telemetry survey setup on snow machine...... 40
Figure 2-7: Photograph of telemetry survey method used for open water tracking...... 41
Figure 2-8: Photograph of t-bar tag location...... 42
Figure 2-9: Photograph of PIT tag and PIT scanner...... 43
Figure 2-10: Photograph of location and example of a pattern used in elastomer tagging...... 43
Figure 2-11: Study area in the Saskatchewan River system, with collection locations for lake sturgeon and freshwater mussels in 2011...... 45
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Figure 3-1: Linear regression models for habitat quantity and quality versus discharge at the
South Saskatchewan River site...... 51
Figure 3-2: Summary of lake sturgeon telemetry observations made per individual by boat and stationary tower between October 9 2011 and October 31st 2012 in the Saskatchewan River
System...... 54
Figure 3-3: Sturgeon relocations by week (each colour represents a unique week of tracking) in the 2012 open water season (May to October) ...... 56
Figure 3-4: Comparison of distance travelled by tagged sturgeon that overwintered below The
Forks of the North and South Saskatchewan River in 2010 (n=22), 2011 (n=23) and 2012 (n=8)
...... 57
Figure 3-5: Mean (+1SD) migration data for lake sturgeon over wintering below The Forks of the North and South Saskatchewan River in 2010, 2011 and 2012...... 59
Figure 3-6: Correlation between the number of sturgeon relocations over three years and calculated home range size (Pearson Correlation, two-tailed, N=32, R=0.10, P=0.55)...... 61
Figure 3-7: Correlation between mass and calculated home range size for lake sturgeon over a three year time period (Pearson Correlation, two-tailed, N=32, 0.046, P=0.78)...... 62
Figure 3-8: Correlation between length and calculated home range size for lake sturgeon over a three year time period (Pearson Correlation, two-tailed, N=32, R=0.097, P=0.56)...... 62
Figure 3-9: Correlation between body condition and calculated home range size for lake sturgeon over a three year time period (Pearson Correlation, two-tailed, N=32, R=-0.33, P=0.04).
...... 63
Figure 3-10: Correlation between chronological catch order and sturgeon length in the 2012 field season (Spearman rank correlation, N = 102, R = 0.17, P =0.08 (two-tailed)...... 64
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Figure 3-11: Correlation between chronological catch order and sturgeon mass in the 2012 field season (Spearman random correlation, N = 102, R = 0.21, P =0.14 (two-tailed)...... 64
Figure 3-12: Correlation between chronological catch order and sturgeon girth in the 2012 field season (Spearman random correlation, N = 102, R = 0.22, P =0.22 (two-tailed)...... 65
Figure 3-13: Simple linear regression used to age sturgeon captured in the 2009 survey (made from data contained in Bruch et al (2009)...... 66
Figure 3-14: Frequency distribution of sturgeon age classes in our 2010, 2011 and 2012 field surveys...... 67
Figure 3-15: Flow (m3•s-1) in the North, South, and Mainstem Saskatchewan River from October
2010 to September 2011...... 68
Figure 3-16: Box plots of the values of δD for each site, taxa, and tissue type combination.
Values for the mussels (Lampsilis siliquoidea) represent muscle tissue from the foot of mussel individuals. Boxes present the maximum and minimum values (whiskers), the upper and lower quartiles (75th and 25th percentiles), and the median (central horizontal line within box). Solid circles above or below each box represent outliers and are more than 1.5 IQRs (interquartile range)...... 69
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Table Legend
Table 2-1: Tagging date, individual morphometrics and summary statistics for the 12 sturgeon tagged on the North Saskatchewan River near Borden in 2012...... 36
Table 3-1: Summary of River2D model from the South Saskatchewan River reach indicating the change in weighted usable area (ha) for each life stage as a function of discharge (cms)...... 50
Table 3-2: Results of River2D simple linear regression analysis for the 2012 South
Saskatchewan Site comparing useable habitat with increased flow...... 52
Table 3-3: Summary of the number of years and magnitude of discharge available for each sturgeon life stage in the South Saskatchewan River...... 53
Table 3-4: Qualitative summary of migration patterns over the past three years for the lake sturgeon population tagged below The Forks of the North and South Saskatchewan River in
2009. To be counted as returning in fall sturgeon must have been recorded in the wintering grounds by October of the respective year...... 55
Table 3-5: Home range data for all sturgeon tracked for at least one full season in the past three years including relocation number, number of years track and biometrics for tracked individuals.
...... 60
Table 3-6: Correlation matrix of lake sturgeon mass and potentially predictive variables
(Trophic Position, δD blood, δD muscle, and α)...... 70
Table 3-7: Table of most probable migration origins for each lake sturgeon...... 71
Table 3-8: Sampling groups for Saskatchewan River lake sturgeon with adjusted number of samples (N), mean number of alleles observed per locus (A), standardized allelic richness averaged over all loci (As), expected and observed heterozygosity (HE and HO), and Wright’s within-population diversity coefficient (FIS)...... 73
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Table 3-9: Summary of estimated mean and 95% confidence intervals for effective population sizes (Ne) and effective number of breeders (Nb) for Saskatchewan River lake sturgeon...... 73
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Executive Summary
Lake Sturgeon throughout North America are believed to be at an historically low population abundance. Throughout the late 19th and early 20th century recreational and commercial exploitation is believed to have been the primary cause for the initial decline. With most states and provinces prohibiting or tightly controlling sturgeon harvest, exploitation is no longer seen as the current cause for decline or delayed recovery. The problems faced by current populations include habitat degradation and fragmentation caused by large hydro-electric dams.
Saskatchewan’s sturgeon population mirror those found throughout North American. Operation of two large dams on the Saskatchewan River system (Gardiner Dam and E.B. Campbell) is suspected to contribute to habitat degradation resulting from flow management and fragmentation. As owners and operators of Gardiner Dam the Water Security Agency (Formally the Saskatchewan Watershed Authority) has completed the final year of a three year study examining the potential impact of Gardiner Dam’s operation on the Sturgeon population within the downstream rivers. Over the course of the study we have focused our efforts on three specific areas: 1) Population abundance and health; 2) Habitat selection and; 3) Interaction between flow and sturgeon habitat.
With respect to population abundance and health we focused on the area immediately downstream of the confluence of the North and South Saskatchewan River. This area is currently and historically known to contain a significant portion of the Saskatchewan Rivers sturgeon population. Sturgeon from this location were also used as the primary population source for our radio tagging and telemetry study (habitat selection). The Forks population was
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also the focus of genetic research examining diversity, effective population size and the number of female breeders per year. Finally, our first efforts to examine the interaction between flow and sturgeon habitat occurred in the first 10 kms downstream of the North and South Saskatchewan
River confluence.
Following examination of the habitat downstream of The Forks, other regions were selected for intensive analysis for three reasons: 1) they contain either confirmed spawning or clusters of sturgeon found via telemetry or historical knowledge; 2) they are affected by the operation of
Gardiner Dam (Exception North Saskatchewan River); 3) they are near the location of proposed hydro-electric dams.
The goal of the Water Security Agency’s three year project include: 1) develop hydraulic models
(River2D) to quantify the impact of flow on sturgeon habitat; 2) determine the type and location of habitat and migration patterns preferred by sturgeon (via telemetry) and; 3) quantify sturgeon health including abundance, diet, age class structure, impact of flow on recruitment and genetic health.
Following three years of study we have reached the following conclusions (2010, 2011 and 2012 results combined below):
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1) 2010, 2011, and 2012 River2D Analysis
River2D analysis on six sites spanning all three rivers (South Saskatchewan, North
Saskatchewan and Saskatchewan) indicates a significant relationship between flow and
habitat availability.
Sites sampled on the North Saskatchewan and mainstem of the Saskatchewan River
display abundant adult and sub-adult habitat but minimal spawning and fry habitat with
the exception of the James Smith site on the mainstem.
Examination of our final site in 2012 on the South Saskatchewan River revealed a
significant amount of spawning habitat but relatively poor overwintering conditions for
adults and sub adults.
Historic flow records indicate that all habitats, particularly spawning and fry habitat,
receive the flows needed approximately one out of two years to create optimal habitat, so
though minimal in size, the habitat appears to be frequently available.
It is important to note that a significant relationship between flow and habitat does not
indicate an impact in itself, in fact given the health of the population it would appear
sturgeon have thrived under the current flow regime.
2) 2010, 2011 and 2012 Telemetry Summary
Sturgeon followed similar migration patterns in the three years of data collection.
The areal extent of habitat used by sturgeon showed little variation among years.
Sturgeon used all three rivers (North Saskatchewan, South Saskatchewan and
Saskatchewan River mainstem) with The Forks region providing a common and crucial
wintering ground.
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The population preference is to migrate (i.e. leave the wintering grounds for the majority
of the ice-off season) each year and each sturgeon migrated at least once in the three year
study. Specifically, 30 % migrating one of every two years, ~3% migrating one in three
years.
Efforts to radio tag sturgeon at Wapiti (68 river kilometers (rkms) downstream of The
Forks), Saskatoon (269 rkms upstream of The Forks on the South Saskatchewan River),
and Borden (214 rkms upstream of The Forks on the North Saskatchewan River)
confirmed the importance of The Forks overwintering habitat as the majority of fish
tagged at these distant locations returned to The Forks in the fall.
Home range size analysis focused on all three years of telemetry and found a mean size
of 3099.1 ha + 1 SD of 1736.2 ha. Further, a significant negative correlation was found
between body condition (i.e. body reserves).
3) 2010, 2011 and 2012 Population Health Summary
Age structure analysis indicates an age range of 1-37 with no missing age classes at The
Forks and 1-31 years at the Borden sampling site (North Saskatchewan River 214 rkms
upstream of The Forks).
2010 and 2011 sampling at The Forks indicated an abundance of young individuals, thus
the population is reproducing successfully. Populations at Borden displayed similar
patterns with an abundance of 1-3 year old individuals.
Genetic analysis of 64 individuals indicates the population is more diverse than one
would expect in a diminished population, though the effective population size and
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number of females contributing to the population in a given year were smaller than
expected.
The number of sturgeon in the one to ten year age classes was significantly correlated
with the occurrence of above median flows (annually and seasonal) in the South, North
and Saskatchewan Rivers.
It is important to note, as stated above, correlation with flow is not in itself an indication
that flow is currently hampering population growth or recruitment. In fact, a correlation
between flow and recruitment is common in naturalized system.
4) Overall Conclusions
Though only a single year of sampling occurred at Borden, results indicated
representation in all age classes as did The Forks and the potential of a overwintering
population.
While flow is statistically linked to both habitat availability and recruitment it appears
current flow regimes have allowed the population to thrive.
Given the statistical link between flow and sturgeon recruitment, it may be possible to
manipulate flow to increase either habitat availability or recruitment should this be
desired in the future.
Genetic analysis does not indicate that population genetics will hamper population
recovery.
Sturgeon obtain ~85% of their food energy from crayfish.
Sturgeon make significant migrations (> 100 rkms/year) using all three rivers.
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Home range size is significant for this species (~3000 ha or 30 km2) relative to the size of
the river they inhabit. This indicates that any fragmentation may affect the population’s
ability to thrive.
5) Future Work
A resident sturgeon population (i.e. overwintering population) within the North
Saskatchewan River has never been documented. This is of particular importance for
three reasons:
o 1) If a resident sturgeon population does not exist in the North Saskatchewan
River it places even greater importance on The Forks site with respect to
protection and recovery.
o 2) If sturgeon become listed under the Species At Risk Act locating all population
centers will be crucial to recovery and survival.
To date The Forks sturgeon have presented a relatively choreographed migration pattern
with respect to timing, distance traveled, etcetera. Tagged individuals should be followed
for the remainder of the radio tags battery life to gain all information possible on this
unique species particularly as it relates to critical habitat.
Further, the migration patterns of other populations within the watershed should be
documented to ensure the critical habitat and migration routes of additional population
centers are considered and known.
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1.0 Introduction
1.1 Sturgeon life history and status
The lake sturgeon (Acipenser fulvescens) is a relatively large, cartilaginous, benthic fish, endemic to the Central United States, Great Lakes, and the Hudson Bay drainages of Canada
(Peterson et al. 2007, see Figure 1-1 for historical range). The oldest sturgeon fossils date back to the Upper Cretaceous (~ 100 million years ago); however, the earliest members of the group evolved in the Lower Jurassic approximately 200 million years ago (Bemis et al.1997). Sturgeon are characterized by a long life span (~100 years), late age-at-maturity (~15-25 years), and protracted spawning periodicity (~3-5 years) which make it unique among North America‘s freshwater fishes (Harkness and Dymond 1961; Scott and Crossman 1973; Becker 1983).
Figure 1-1: Historic distribution of lake sturgeon in North America (adapted from Scott and Crossman 1973).
Given its unique nature it is not a surprise that the lake sturgeon has been an integral part of many first nation cultures for thousands of years. In fact, over 100 uses for sturgeon have been
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documented among native peoples including sustenance (flesh for food), material fabrication
(skin for bags, scutes for arrow heads) and medicines (oil)
(http://www.saskriversturgeon.ca/human_impact/first_nations.html). Despite the significant decline in numbers, lake sturgeon continue to be revered both culturally and as a valued food source to First Nations peoples.
Lake sturgeons have been known to science for nearly 200 years (originally named Acipenser fulvescens by Rafinesque in 1818) and have been in a population decline for approximately half that time. Although once abundant throughout their range, severe overfishing in the late 1800s and early 1900s significantly decreased most populations (Auer 1999, 2004; Bogue 2000).
Despite this aggressive harvest most authors agree that commercial harvest was not the sole reason for the sturgeon‘s dramatic decline, nor is it a hindrance to potential recovery (Beamish et al. 1998).
The complex factors leading to the collapse of the sturgeon population was recognized as early as 1930 by Bajkov and Neave. In their paper focusing on the Lake Winnipeg sturgeon fishery they state that the decrease of sturgeon populations in North America was due to extensive fishing coupled with slow growth. The fact that female lake sturgeon do not reach sexual maturity until age 24-28 is undoubtedly one of the reasons populations have struggled to regain their former numbers (Anderson 1986). Furthermore, females are only able to spawn every 3-7 years and males every 2-4 years (Auer 1999) posing further limitations on population growth.
While these factors are enough to hamper recovery efforts, most authors agree that the issue of most relevance to current sturgeon populations is habitat loss and degradation.
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In conjunction with their warning regarding overfishing Bajkov and Neave (1930) stated that habitat loss and degradation are the most likely causes behind the sturgeon‘s inability to recover.
It was suggested that prohibition of fishing, even for ten years, would only delay the collapse of a fishery with no hopes for long term recovery. Given this fact, Bajkov and Neave recommended a multifaceted approach including the protection of the young and remaining large individuals, as well as the creation of special reserves comprising spawning grounds and lakes, with total prohibition of fishing in such areas. Though such steps were taken to aid in population recovery, through the 1950‘s it was recognized that pollution and other anthropomorphic influences remained the primary causes of sturgeon population decline. These findings reenergized attempts to recover and improve lost and degraded habitat (Anderson 1956). Despite early recognition of the problem, and efforts made, today‘s sturgeon populations continue to face similar problems.
As evidence of this fact Beamish et al. (1998) published a paper regarding the plight of lake sturgeon stating that all sturgeon species face the possibility of extinction due to continued overexploitation, pollution, habitat destruction, and degradation. By comparing the works of
Beamish et al. (1998) and Bajkov and Neave (1930) it is clear little progress has been made in the recovery of lake sturgeon on a continental scale in the past half century.
However, in recent years there have been several successful efforts made to recover a handful of populations. Though efforts and subsequent recoveries have been variable (Caroffino 2009), stocking programs (Chalupnicki et al. 2011), dam removal (Dieterman et al. 2010), artificial habitat restoration (Roseman 2011) have all lead to population improvements and in at least one case a population appears to be recovering naturally (Bauman 2010). In fact, the lower St.
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Lawrence currently boasts, what they suspect to be a sustainable commercial harvest of lake sturgeon (Mailhot et al. 2011). While significant work remains, over significant amounts of time, there are encouraging signs that we are beginning to understand what needs to be done to recover and maintain sturgeon populations.
1.2 Saskatchewan River populations
The population of sturgeon within the Saskatchewan Rivers, not unlike those found in eastern
Canada and the United States, are challenged by many of the problems described above (Wallace
1991, 1999; Pollock et al. 2009, 2010, 2011). As described above sturgeon populations began to decline in the 1950s and have yet to recover to historical numbers (Wallace and Leroux 1999). A series of studies by Wallace (1991, 1999) and Wallace and Leroux (1999) concentrating on the
Saskatchewan River between EB Campbell Dam and Cedar Lake resulted in several recommendations including a stop to all harvests, initiation of egg collection and stocking programs, and efforts to improve habitat by way of flow management. Beyond the work of
Wallace and Pollock, little is known with respect to the population of sturgeon within
Saskatchewan‘s borders.
This data scarcity is especially true of the population upstream of François Finlay Dam. To our knowledge the only work conducted in recent years on the Saskatchewan population between the
Alberta border and François Finlay Dam was conducted by the Saskatchewan Watershed
Authority in the summers of 2008, 2009, 2010, 2011 and 2012 resulting in reports in 2009, 2010,
2011 and the current report. Pollock et al. (2009) identified five key reaches that contain a
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significant amount of food resources and preferred foraging habitat under significant influence of anthropogenic or natural flows (see Figure 1-2 for site locations in 2008).
These sites underwent further study in the summer of 2009 resulting in the identification of a key area in the main stem of the Saskatchewan River (see Figure 1-3 for site locations in 2009) below The Forks of the North and South Saskatchewan Rivers. In the field season of 2009, 37 sturgeon were implanted with radio tags forming the basis of the telemetry analysis within the current report. In 2010 intensive habitat analysis began with two River2D models being created for the reaches immediately downstream of The Forks. This was followed by an additional three reaches in 2011 including two on the mainstem and one on the North Saskatchewan River and lastly in the summer of 2012 a final reach was examined on the South Saskatchewan River (see
Figure 1-4 for location of all River2D reaches).
Similarly, from 2009 to 2011 over 500 sturgeon have been uniquely tagged at The Forks to create population estimate and health assessment discussed below. The 2010 and 2011 report
(Pollock et al. 2011) contained analysis of key population parameters (i.e. age, size, diet, etc) and identification of sturgeon clusters in the open water season (i.e. potential spawning or foraging grounds) resulting in the further intensive habitat analysis in 2010 and 2011.
In subsequent years we have uniquely tagged sturgeon in other sites including 55 at Wapiti
(including seven radio tags), 102 at Borden (including 14 radio tags) and 14 at Saskatoon
(including two radio tags) (see Figure 1-5). These individuals continue to provide relevant data as we expand our understanding of sturgeon life history.
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Figure 1-2: Site locations for areas sampled in 2008 field work.
1.3 Water Security Agency mandate and history of flow management
The Water Security Agency, as part of its mandate to ensure safe and abundant water supplies, owns and operates 45 dams throughout the province. Of these 45 structures only one, Gardiner
Dam located on the South Saskatchewan River (see Figure 1-2), has the potential to impact lake sturgeon and their habitat. Gardiner Dam serves several functions for the province of
Saskatchewan including recreation, flood and drought control, irrigation, domestic and industrial water supplies and hydropower. It is the operation of Gardiner Dam as a hydro peaking facility that has the greatest potential impact on the sturgeon population.
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Figure 1-3: Site locations for areas sampled in 2009 field work.
Since operation of the dam began in 1967 the hydrograph on the South Saskatchewan River, and subsequently the main stem of the river, have been significantly impacted (Figure 1-4). This reversal of the hydrograph and decrease in annual spring flooding events are known to have significant impacts on fishes (see Craig 2000 for a comprehensive review of the impacts of dams on fishes). Further, alongside the sturgeon are several species of fishes within the Saskatchewan
Rivers, which are not endangered, but are impacted by many of the problems facing sturgeon.
These impacts can include water quality, destruction of habitat or significant changes to the hydrograph (Figure 1-5). These changes can have complex impacts on aquatic communities
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resulting in population declines, shifts in community structure, a decrease in biodiversity, and in the most extreme cases, complete loss of ecological function and extirpation of populations
(Craig 2000).
Figure 1-4: Locations of all River2D analyzed sites from 2010-2011.
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Figure 1-5: Capture locations of all sturgeon tagged from 2009 to 2012.
To ensure lake sturgeon survival, Fisheries and Oceans Canada (DFO) is currently reviewing the species status for the purposes of listing it under the Species At Risk Act (SARA). Should the sturgeon become listed water and fisheries managers will need to examine their practices to ensure compliance with SARA. As managers of the provinces water supply the Water Security
Agency is dedicated to quantifying potential impacts resulting from flow management and is proactively examining solutions that will aid in the recovery of Saskatchewan‘s sturgeon population.
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1.4 Study objectives
Field work conducted by SWA in 2012 can be broken into three categories: 1) develop hydraulic models (River2D) to quantify the impact of flow on sturgeon habitat in the South Saskatchewan
River; 2) quantify sturgeon migration and examine sturgeon distribution (via telemetry) and; 3) quantify sturgeon health including abundance, survival rate, diet, age class structure and genetic diversity on the North Saskatchewan River near Borden.
1.4.1 Habitat availability in relation to flow
The goal of this component of the project was to quantify the impact that flow fluctuations have on sturgeon habitat. One reach downstream of Saskatoon was selected for examination in 2012 based on results of previous year’s telemetry results. Similarly, reaches were selected in 2011 based on 2010 previous year’s results. These sites of interest had all or some of the following traits: significant amounts of forage, historical presence of sturgeon, clusters of sturgeon
(confirmed by telemetry) and confirmed spawning activity (confirmed via egg mats). Results of this component of the study will include detailed assessment of the current impact of flow and provide managers with the data necessary to make informed decisions with respect to flow management.
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1400 Pre-Gardiner dam average flows 1200 Plus one Standard Deviation Minus one Standard Deviation 1000
800
600
400 Average monthly (CMS) monthly flows Average 200
0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1400 Post-Gardiner dam average flows 1200 Plus one Standard Deviation Minus one Standard Deviation 1000
800
600
400 Average monthly (CMS)monthly flows Average 200
0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Figure 1-6: Comparisons of monthly flows pre-Gardiner dam (1911-1966) versus post-Gardiner Dam (1967-2008) in the South Saskatchewan River near Saskatoon (data contained in: http://www.wsc.ec.gc.ca/hydat/H2O/index_e.cfm Station number 05HG001).
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1.4.2 Habitat use and availability
Habitat use and migration by sturgeon within the Saskatchewan Rivers watershed was investigated as part of the three year plan. The goal of this portion of the project was to locate migration routes and areas used by sturgeon during critical biological periods. Once located these regions will be characterized (i.e. substrate type, depth, etc.) including the collection of the data needed to create hydrological models identical to those discussed in the current report.
To locate these key areas 60 adult sturgeon were tagged with radio transmitters and have been tracked weekly or bi-weekly since October of 2009.
1.4.3 Population abundance and health
Study of population health includes data on population abundance, survival, age structure, diet, genetic diversity and forage availability. Over the past two years population studies have focused on The Forks site. Priority switched in 2012 to attempt to garner data on a population that may be independent of The Forks. A site on the North Saskatchewan River was selected near Borden
Saskatchewan. This site was selected based on historical catch records accompanied by the fact that radio tagged sturgeon from The Forks seldom travelled that far west on the North
Saskatchewan River (see Figure 1-5 for location).
Age structure and health of individuals were calculated with length and mass data collected from all sturgeon during tagging efforts. The length of individuals were compared with data from similar studies to get an estimate of population age structure (Bruch et al. 2009).
29 Saskatchewan River Sturgeon Project 2012 Report |
Samples of fin, blood and muscle were collected from all fish captured during the tagging effort for stable isotopes (blood and muscle), DNA analysis (fin), disease analysis (fin: data not reported here) For any potential future analysis a set of samples (fins) and blood was collected from each individual.
The sum of all data sections discussed in section 1.3 will allow the Water Security Agency to create a comprehensive set of data that can inform regulators and managers as to the health and status of the sturgeon population. It will also provide much needed data for informed decisions regarding potential impacts, mediation and ultimately it will assist all stakeholders in creating a secure future for this unique species.
2.0 Materials and Methods
2.1 Habitat availability in relation to flow
The goal of this portion of the study is to quantify the impact of flow on sturgeon habitat and forage resources in a single reach on the South Saskatchewan River (Figure 1-4). Specifically, hydraulic modeling (River2D), in combination with known or suspected sturgeon habitat preferences, will predict the impact various flow regimes will have on preferred habitat through various life stages. The data produced from these models will provide crucial information that can be used by resource managers who must balance environmental health with societies needs.
30 Saskatchewan River Sturgeon Project 2012 Report |
2.1.1 Data collection
To model the effects of flow on river reaches, bathymetric and multiple flow cross section surveys were conducted as well as simultaneous water surface elevation. Sites were surveyed between mid August and the end of September 2012 between the hours of 09:00 to 19:00 hours.
Bathymetric data was collected using a BioSonics bathymetric unit (model DT-X Digital
Scientific Echosounder, DT-X Digital Transducer, Differential Global Positioning System
(DGPS) and Visual Acquisition software version 6.0) which collected depth and substrate type and UTM data (see http://www.biosonicsinc.com/docs/hardware-specifications.pdf ). The unit mount consisted of an eight foot beam (4”x 4” treated wood) bolted through the oarlocks to the hull of the boat approximately 1.5 meters back from the bow (see Figure 2-2). The transducer was attached to the beam via a custom aluminum pole which allowed the transducer to be set at an appropriate depth (averaged approximately 27cm below water). The DGPS was mounted to the top end of the same pole) to provide accurate UTM values for transducer location. A real
Time Kinematic (RTK) survey grade GPS unit (two Sokkia GSR2700 ISX receiver units, one operating as base, one as rover) was run simultaneously to collect water elevation data within ±
0.01m for each reach (see http://www.sokkiacanada.com/Products/Detail/GSR2700ISX.aspx ).
The base was set up at a known location on shore and served as a reference point for the rover which was set up in the bow of the boat (see Figure 2-1). The heights of the receivers were factored into the calculations as well as the water displaced by the boat beneath the rover.
Bathymetric and water surface elevation data was collected at each reach in three steps. The first step was to survey transects as close to the shore as possible and then connect these shorelines with transects perpendicular to the shore at the start and end of the reach (i.e. creating a rectangle
31 Saskatchewan River Sturgeon Project 2012 Report |
encompassing the area to be surveyed). The second set of data was a series of transects (5-6) parallel to the shore from the start to the end of the reach. The third set of data consisted of transects run perpendicular to the shorelines approximately every 300m along the length of the reach creating a grid-like pattern of transects (See Figure 2-2 for data collection pattern).
DGPS antenna
RTK Rover
4 X 4 beam Aluminum rigging
Waterline Biosonics transducer River Surveyor Jon Boat
Figure 2-1: Diagram of River Surveyor, BioSonics unit and RTK Rover on survey boat.
Legend Boundary transect Parallel transects Perpendicular transects
Figure 2-2: Example of path used in data collection for River2D modeling.
32 Saskatchewan River Sturgeon Project 2012 Report |
Flow data was collected with a velocity accuracy of ± 0.25% and depth accuracy of 1% using a
SonTek River Surveyor unit (S5 model, River Surveyor Live-PC Software version 1.51, River
Surveyor Utilities Software version 1.51) (see http://www.sontek.com/pdf/faqs/20091104- riversurveyor-faq.pdf). The mount was similar to the set up for the BioSonics unit with an eight foot beam (4”x 4” treated wood) bolted perpendicular to the hull of the boat and the River
Surveyor transducer attached to the beam via a custom aluminum pole. The RTK unit was again run simultaneously to collect water elevation data for each transect within the reach (see Figure
2-4 for flow cross section collection pattern). Data was collected along transects run at temporary benchmarks approximately every 500m to 600m within the reach perpendicular to both shores.
2.1.2 Flow regime selection
To select ecologically relevant flow regimes an analysis and summary of 1976-2010 historic flow records in the South Saskatchewan River (Hydro Station number D5HG001) was conducted using data available on the Canadian Water Survey data (http://www.ec.gc.ca/rhc- wsc/default.asp?lang=En&n=4EED50F1-1). These dates were selected as they represent the time frame in which all captured sturgeon have existed. Selected regimes included median (i.e. second quartile) annual discharges as well as the zero, first, third and fourth quartile (see
Appendix One for historical South Saskatchewan River flow).
2.1.3 Data Organization and River2D model creation
Creating the River2D model is a four step process which is outlined by its creators on their website (http://www.river2d.ualberta.ca). The first three steps (bed file creation, mesh file
creation and River2D model) are created with the data as described above (bathymetry, elevation data, substrate type, and flow data). The fourth step which incorporates the data specific to species and life stage of interest requires an understanding of the preferred habitat. With respect to sturgeon, the data required was collected by DFO who had conducted a similar project examining the impacts of flow on the Saskatchewan River below E.B. Campbell Dam (data received from Doug Watkinson, DFO) (see Appendix Two for habitat parameters).
Figure 2-3: Location of 2012 River2D site on the South Saskatchewan River and locations of flow cross sections within the site.
34 Saskatchewan River Sturgeon Project 2012 Report |
2.2 Habitat use and migration
The purpose of this portion of the study is to locate the geographic regions and associated habitat preferred by sturgeon. Of specific interest is the location of spawning habitat as well as the location of summer/wintering and forage grounds. The current report will summarize data from the last three years of field work. We will also quantify the start and end of the annual migration defined as the date leaving the wintering grounds (i.e. passing a radio tower) and the date returning (first time found in the wintering grounds or having past the tower).
2.2.1 Surgical implant of tags
One of the primary goals of the 2012 field season was to implant up to 20 sturgeon with radio telemetry tags from a site on the North Saskatchewan River. All work was conducted under the animal care authority of the University of Regina (animal utilization protocol 09-10). Radio tagging occurred immediately below the Highway 16 bridge near Borden Saskatchewan between
May and August of 2012. This site was selected for three reasons. First, the area is known to have a relatively large number of sturgeon insuring the success of tagging efforts; second, telemetry data indicates that this site may be independent of The Forks.
In total 12 sturgeon were tagged at the Borden location (see Table 2-1 for tagging date and morphometrics). All tags were purchased from Advanced Telemetry Systems and were divided into three sizes (part number F1860B, 162 g; part number F1855B, 87 g; part number F1850B,
27 g). (for further detail on tagging process and surgeries see Pollock et al 2010).
35 Saskatchewan River Sturgeon Project 2012 Report |
Table 2-1: Tagging date, individual morphometrics and summary statistics for the 12 sturgeon tagged on the North Saskatchewan River near Borden in 2012.
Date Field ID Length (m) Girth (m) Mass (kg) Tag Frequency June 7/2012 16 0.865 0.35 5.02 148.065.46 July 25/2012 49 1.118 0.46 11.65 148.065.40 July 26/2012 51 1.295 0.53 15.4 148.065.49 August 2/2012 64 1.35 0.46 13.65 148.065.48 August 2/2012 65 1.06 0.405 8.25 148.254.05 August 9/2012 75 0.94 0.4 7.8 148.054.03 August 16/2012 85 1.12 0.445 9.8 148.065.39 August 16/2012 86 1.17 0.45 11.65 148.065.31 August 22/2012 88 1.23 0.45 12.25 148.65.36 August 22/2012 91 0.95 0.37 6.35 148.024.09 August 23/2012 96 1.43 0.5 17.85 148.065.18 August 28/2012 98 0.94 0.38 6.05 148.054.00
2.2.2 Telemetry tracking
Tracking efforts were conducted on a weekly basis though summer and fall months and bi- weekly during the winter months via several methods (see below). For the purposes of this report data from October of 2009 to October of 2012 will be used.
2.2.2.1 Remote passive towers
Immediately following surgery three remote towers were set up on the river to allow for continuous monitoring of sturgeon movement within the tower area. Tower locations were selected based on three criteria: 1) known sturgeon congregations; 2) peaks of land allowing for reception over a large area; 3) readily available road or trail access. Towers were moved as needed during radio tagging over the last three years.
36 Saskatchewan River Sturgeon Project 2012 Report |
All towers contain a receiver/datalogger provided by Advanced Telemetry Systems (model
R4500C), a 12 volt deep cycle marine battery and two antennas (See Figure 2-3) for tower set up). The battery and receiver/datalogger were buried approximately 5 cm below the soil in a locked steel box. Towers were checked weekly at which time batteries were exchanged and data from the previous week was downloaded to a field laptop. Data from the towers was primarily used to get a fix on the location of sturgeon and the timing of movements. These data were then used to coordinate trips, using methods better able to precisely locate individuals.
antenna
Antenna pole
Ground level
Strong box 12 Volt battery
Receiver/datalogger
Figure 2-4: Diagram of passive tower configuration.
2.2.2.2 Aerial tracking
Similar to the remote passive towers, aerial tracking was used to get an approximate location for individuals which were later tracked using more precise methods. Aerial surveys were conducted as needed over the winter months when other methods failed to produce the needed results (i.e.
37 Saskatchewan River Sturgeon Project 2012 Report |
several attempts to find individuals). Similarly, a flight was conducted in early spring 2010 before ice off to help guide future efforts. Flights were conducted in a two seat single engine
Cessna with a single antenna attached to the wing strut (see Figure 2-4). Flights covered the entire portion of the Saskatchewan River from Codette Reservoir to the confluence of the North and South Saskatchewan River. Flights were conducted in the morning hours between 07:00 AM and 10:00 AM approximately 300 m above the river.
Flight surveys were conducted in 2009 and 2010 but were not used in 2011 or 2012 due to budget constraints and unreliable data acquisition.
2.2.2.3 Vehicle and snowmobile tracking
Along with checking the remote towers weekly attempts were made to cover as much of the river by truck or snow machine as conditions would allow (see Figure 2-5 for snow machine set up).
Vehicle and snowmobile tracking was conducted in the winter of 2009/2010 and 2010/2011 but where not conducted in 2011/2012 due to the sedentary nature of the population demonstrated in the first two years.
2.2.2.4 Boat tracking
The most valuable and precise data was collected during the open water season by boat (May to
October). To keep effort consistent a weekly survey was conducted covering the entire study area from the city of Borden (Bridge at Highway 16) on the North Saskatchewan to Wapiti then from Saskatoon (downstream of the weir) on the South Saskatchewan until the confluence.
Surveys were conducted using a boat configured with an antenna able to rotate 360 degrees (see
38 Saskatchewan River Sturgeon Project 2012 Report |
Figure 2-6 for boat configuration). This allowed for precise location of individuals throughout the open water season.
Figure 2-5: Photograph of the antenna attachment on the wing strut used in aerial surveys.
2.2.3 Telemetry analysis
Analysis of telemetry data for the current report includes the time from October of 2009 to
October of 2012. Analysis includes geographic area use including seasonal preference, direction travelled and annual area use. Telemetry analysis was conducted using ArcGIS 10.
39 Saskatchewan River Sturgeon Project 2012 Report |
Figure 2-6: Photograph of telemetry survey setup on snow machine.
2.3 Population abundance and health
The purpose of this section is to assess the abundance, survival, age structure, diet composition and genetic components of the Saskatchewan River population.
2.3.1 Mark and recapture
The purpose of mark and recapture is to determine the abundance and survival rate of sturgeon within our study areas (using Program MARK) and to gain important population samples and parameters (e.g. length, mass, tissue samples, etc). The process of marking fish began in the fall
40 Saskatchewan River Sturgeon Project 2012 Report |
of 2009 at The Forks and continued throughout the spring, summer and fall of 2010 and 2011 using the same fishing methods.
Figure 2-7: Photograph of telemetry survey method used for open water tracking.
The process of marking fish began in the fall of 2009 at The Forks and continued throughout the spring, summer and fall of 2010 and 2011 using the same fishing methods. Population surveys then switched to the Borden location in 2012, though methods remained identical (see Figure 1-5 for all population assessment locations). Marking individuals for future identification included tagging with T-bar (see figure 2-7) and Passive Integrated Transponder (PIT) tags (see Figure 2-
9. All sturgeon received at least one T-bar tag and one PIT tag. If it appeared that the first T-bar
41 Saskatchewan River Sturgeon Project 2012 Report |
tag was not secure a second T-bar tag was added. All captured fish were checked for existing T- bar and PIT tags. If an individual possessed previous tags they were left in place and none were added unless the tag did not seem secure. In addition sturgeon captured in 2011 and 2012 that were too small for PIT or T-bar tags (< 50cm) where injected with an elastomer compound in a unique pattern in the ventral snout (see Figure 2-10). Similar to T-bar and PIT tags this process allows for individual identification in the future. All fish captured in the mark recapture study were weighed and measured in addition to tissue samples being collected.
Figure 2-8: Photograph of t-bar tag location.
42 Saskatchewan River Sturgeon Project 2012 Report |
Figure 2-9: Photograph of PIT tag and PIT scanner.
Figure 2-10: Photograph of location and example of a pattern used in elastomer tagging.
43 Saskatchewan River Sturgeon Project 2012 Report |
2.3.1.1 Abundance
Though 102 fish were captured in the summer of 2012 only two were recaptures, thus abundance could not be calculated for this population.
2.3.2 Stable isotope analysis
Stable isotope analysis can be used to link an organism with its environment. It can be used to link organisms to their source of energetic input (i.e. diet; Pollock et al. 2010) via nitrogen and carbon signatures, or in the case of the current report it can link sturgeon to recently inhabited areas via deuterium.
2.3.2.1 Sampling and sample treatment
The lake sturgeon samples used in this study were collected from August 28 to September 30,
2011 from three separate locations using methods outlined above (see Pollock et al. 2011 for specific information on site location and methods used). Location one was ~ 1rkm downstream of The Forks (n = 8), location two referred to as Horseshoe Bend was ~10 km downstream of the confluence (n = 3), and at the beginning of the Codette Reservoir ~ 40 km downstream of the confluence (n = 1; Figure 2-10). Samples unique to this portion of the study include blood collected in capillary tubes as and muscle plugs recovered from the hole made when installing a pit-tag.
We captured freshwater mussels (Mollusca: Unionidae) via active search at a single site on each of the North, South, and Mainstem Saskatchewan River (Figure 2-10) from August 7-21, 2010.
At each site we collected five fatmucket mussels (Lampsilis siliquoidea [Barnes, 1823]) and
44 Saskatchewan River Sturgeon Project 2012 Report |
recorded their biometric dimensions (right valve volume, left valve volume, total length along long axis of valve, max width, and max girth).
Finally, we collected snails (Gastropoda: Lymnaeidae) from the littoral zone and macrophyte beds of the Mainstem Saskatchewan River at the same area as the downstream site for fatmucket mussels above (see Figure 2-11), and identified all as the giant pond snail (Lymnaea stagnalis
[Linnæus, 1758]).
Figure 2-11: Study area in the Saskatchewan River system, with collection locations for lake sturgeon and freshwater mussels in 2011.
All samples collected were placed on ice in the field and frozen upon return to the laboratory until analysis.
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We identified the mussels and snails collected in this study using the keys in Clarke (1973), and deposited representative voucher specimens (empty valves) in the Royal Saskatchewan Museum
(Regina, Saskatchewan) and Water Security Agency of Saskatchewan Voucher Collection
(Saskatoon, Saskatchewan).
2.3.2.2 Stable isotope analyses
All samples for isotopic analysis were dried at 60°C for 48 hours then homogenized. For δD isotope measurement, unionid mussel muscle and lake sturgeon muscle tissue were lipid extracted by soaking and rinsing in a solution of 2:1 (v/v) chloroform-methanol and weighed into silver capsules. Analyses of the stable hydrogen isotopes used the comparative-equilibration method from Wassenaar and Hobson (2003) with calibrated keratin protein, hydrogen-isotope reference material. Lake sturgeon muscle, lake sturgeon blood, and unionid muscle were flash pyrolysized at high-temperature (1,350 °C) to obtain the H2 for stable isotope analysis through continuous-flow isotope-ratio mass spectrometry at Environment Canada in Saskatoon,
Saskatchewan.
Samples prepared for δ15N and δ13C were not lipid extracted, but dried and homogenized as with the δD samples and packed in tin capsules. Capsules were then combusted in an Elemental
Combustion System (Costech) that led into a ThermoQuest (Finnigan-MAT) Delta Plus isotope ratio mass spectrometer (IRMS) at the University of Regina, Environmental Quality Analysis
Laboratory (EQAL). The stable nitrogen and carbon isotope analysis used calibrated bovine liver and wheat flour, respectively, as internal laboratory standards (University of Regina,
46 Saskatchewan River Sturgeon Project 2012 Report |
EQUAL Lab). Samples split in the laboratory and analyzed in duplicate (n = 121 of total run) returned a range of 0.2‰ for both δ15N and δ13C.
Stable isotope ratio results are expressed in delta notation (δ), in units of per mil (‰), Isotope values were normalized to the international standard for hydrogen (Vienna Standard Mean Ocean
Water-Standard Light Antarctic Precipitation standard scale [VSMOW-SLAP]), carbon (Pee Dee
Belemnite), and nitrogen (air). Hydrogen results are reported for non-exchangeable δ2H.
2.3.2.3 Data analyses
We determined contributing river flows to the Mainstem Saskatchewan River from each of the
North and South Saskatchewan Rivers using Environment Canada’s Hydat Stations at Prince
Albert (Station 05GG001) and Saskatoon (Station 05HG001) respectively (see http://www.ec.gc.ca/rhc-wsc/default.asp?lang=En&n=894E91BE-1). We summarized flow data per month from a period of one year prior to the collection of lake sturgeon included in this project (October 2010 – September 2011).
We were able to estimate the trophic position of lake sturgeon using the equation provided by
Post (2002) and their invertebrate prey lower on the food web (Equation 1). Specifically, we used fatmucket mussels as the isotopic primary consumption baseline for pelagic foodweb reference, and snails (Lymnaea stagnalis [Linnaeus, 1758]) as the reference for littoral zones of the river. we assumed no trophic fractionation of the carbon isotopes.
(1)
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15 15 15 In this equation TP is the trophic position, δ Nconsumer is the consumer δ N value, while δ Nsnail
15 15 15 and δ Nmussel are the mean δ N values for snails and mussels respectively. Δδ N, however, is the δ15N mean trophic discrimination factor and I chose this to be 3.4‰ taken from Post (2002).
Finally, α is the estimated proportion of nutrients in the consumer originating from the base of littoral food web (Equation 2).
(2)
13 13 13 13 13 Here, δ Cconsumer is the consumer δ C value, while δ Csnail and δ Cmussel are the mean δ C
13 values for snails and mussels respectively. In this equation, δ Cconsumer values were corrected for the effect of lipids using equation 3 for aquatic animals in table 1 from Post et al. (2007).
We used Pearson Correlation Coefficients to investigate potential relationships between specific sturgeon biometric characters (length, width, girth etc.) and isotopic variables (δD, δ15N, and
δ13C). Further, we used a two-tailed, paired t-test to compare δD values of tissue types within lake sturgeon. The δD values met the assumptions of normality (Shapiro-Wilk) and equal variance and did not need to be transformed. In addition, we used an Analysis of Variance
(ANOVA) to compare δD values in each source population of mussels from the North, South, and Mainstem Saskatchewan Rivers to determine if source populations are significantly different.
We then assigned lake sturgeon to their most probable migration route using a univariate normal- likelihood assignment test with mussel δD values from each of the South, North, and Mainstem
Saskatchewan Rivers as a binning model. For this analysis, we used lake sturgeon blood δD values, as they would most accurately represent the isotopic history over the course of the
48 Saskatchewan River Sturgeon Project 2012 Report |
summer due to their faster tissue turnover relative to muscle tissue. Sturgeon were then assigned to a particular river from their migration period based on the most probable bin assignment.
All statistical tests were performed using the “Analysis” tools within the SigmaPlot 12 software
(Systat Software Inc., Chicago, IL, USA). All reported means are least-squares means with 95% confidence intervals, and statistical significance was determined with an α = 0.05.
2.3.3 Genetic analysis
Nonlethal fin samples of several age classes of lake sturgeon from the Saskatchewan River (The
Forks) were collected in the 2010 and 2011 field seasons. DNA was extracted from 77 individual fin clips and sent to Institute for Watershed Science for analysis. For a full description of methods, materials and analysis see Appendix Three
2.3.4 Population structure and flow
As previously mentioned morphometrics were collected from all captured individuals when possible. Recorded lengths will be used to estimate the age structure of the population using a model developed from data in Bruch et al. 2009. Age data were compared to historic flow records in attempts to correlate flow condition and cohort size.
3.0 Results
3.1 Sturgeon River2D model results
As previously mentioned, one reach on the South Saskatchewan River was surveyed in 2012.
Analysis included various flow regime models (using historical flow data and data discharge on
49 Saskatchewan River Sturgeon Project 2012 Report |
the day) using five life stages of sturgeon for a total of 35 models (see Table 3.1 for model summary and Appendix Four for all model images). In summary, the South Saskatchewan River reaches offer the most optimum habitat for adult and sub-adult individuals as well as spawning habitat while offering minimal habitat for fry and very limited habitat for juveniles.
Table 3-1: Summary of River2D model from the South Saskatchewan River reach indicating the change in weighted usable area (ha) for each life stage as a function of discharge (cms).
Flow Spawning Fry Juvenile Sub Adult Adult (cms) (ha) (ha) (ha) (ha) (ha) 56 13 2 0 11 10 90 22 3 0 19 18 129 28 2 0 26 24 164 31 2 1 32 28 199 33 1 1 37 31 231 34 1 2 41 34 273 35 1 2 45 37
To expand on the predictive nature of the models simple linear regressions (Figure 3-1 and
Tables 3-2) were performed for each life stage at each discharge (total of five regression models). The purpose of the regression analysis was two-fold. First, to determine if the relationship between flow and habitat availability is statistically significant and second, to include flows not directly tested by River2D. Analysis indicated a significant relationship between flow and habitat availability for all life stages (see Table 3.2 for statistical analysis and
Figure 3.1 for model representation).
To add further utility to the model, and to gain an understanding as to the effects of the current water management regime, calculations were performed on the last 37 years of flow data (37 years selected as it is the limit of the current population age structure found in the Saskatchewan
River system) to determine the number of years the South Saskatchewan River met each model
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prediction for each specific life stage. The hydrological calendar was divided into sub-sections representing the time of year crucial to each life stage. The entire calendar year (i.e. annual median flow) was used to determine habitat availability for adults, sub-adults and juveniles as these life stages span all 12 months. When estimating available habitat for the spawn only May and June records were used (median of the two) while May to August were used (median of the four months) to correlate the current flow management with fry habitat.
Analysis of the South Saskatchewan River (see Table 3.3 for all results) indicates that 59.4% of years offered less than median habitat (defined as median annual cms < 199) for adult, sub-adult and juvenile, while 51% of years offered below median habitat (defined as a median value of
<145 cms) crucial to the spawn, 46% of years offered below average habitat (defined as median flow < 128) for fry.
50 Spawning 45
Fry )
2 40 Juvenile 35 Sub-adult 30 Adult 25 20 15 10
Available habitat (ha habitat Available 5 0 0 50 100 150 200 250 300 Discharge (cms)
Figure 3-1: Linear regression models for habitat quantity and quality versus discharge at the South Saskatchewan River site.
51 Saskatchewan River Sturgeon Project 2012 Report |
Table 3-2: Results of River2D simple linear regression analysis for the 2012 South Saskatchewan Site comparing useable habitat with increased flow.
Lifestage Spawning Fry Juvenile Sub adult Adult Equation y = 0.0946x+12.5 y = -0.008x+2.9 y = 0.0082x-0.38 y = 0.1579x+4.34 y = 0.1163x+7.0788 R2 0.87 0.9 0.95 0.98 0.95 P-value 0.003 0.025 0.002 <0.001 <0.001 1 12.64 2.91 -0.38 4.50 7.20 12 13.68 2.82 -0.29 6.23 8.47 23 14.72 2.73 -0.20 7.97 9.75 34 15.76 2.64 -0.10 9.71 11.03 45 16.80 2.55 -0.01 11.45 12.31 56 17.84 2.47 0.08 13.18 13.59 67 18.88 2.38 0.17 14.92 14.87 78 19.92 2.29 0.26 16.66 16.15 89 20.96 2.20 0.35 18.39 17.43 100 22.00 2.11 0.44 20.13 18.71 111 23.04 2.03 0.53 21.87 19.99 122 24.08 1.94 0.62 23.60 21.27 133 25.12 1.85 0.71 25.34 22.55 144 26.16 1.76 0.80 27.08 23.83 155 27.21 1.67 0.89 28.81 25.11 166 28.25 1.59 0.98 30.55 26.38 177 29.29 1.50 1.07 32.29 27.66 188 30.33 1.41 1.16 34.03 28.94 199 31.37 1.32 1.25 35.76 30.22 210 32.41 1.23 1.34 37.50 31.50 221 33.45 1.15 1.43 39.24 32.78 232 34.49 1.06 1.52 40.97 34.06 243 35.53 0.97 1.61 42.71 35.34 254 36.57 0.88 1.70 44.45 36.62 265 37.61 0.79 1.79 46.18 37.90 276 38.65 0.71 1.88 47.92 39.18
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Table 3-3: Summary of the number of years and magnitude of discharge available for each sturgeon life stage in the South Saskatchewan River.
Discharge <56 57-90 91-129 130-164 165-199 200-231 232-273 >273 Years at flow Adult/Sub- 1 6 2 6 4 9 8 1 adult/Juvenile Spawn 5 8 6 1 2 2 3 10 Fry 4 6 7 5 3 0 2 10
3.2 Telemetry
The following analysis will focus on results from October 7th, 2011 to October 31st 2012 (i.e. considered the 2012 season). However, where possible and appropriate comparisons and/or analysis will be conducted using data collected in previous years (2009/2010). In total 304 unique relocations were made within the 2012 sampling period (note: if an individual was encountered more than once in a day it counted as a single observation). The observation period began with 41 trackable individuals and ended the season with an additional twelve tags deployed (see Table 2-1). For frequency of individual relocations (fish tracked at least once in
2012) see Figure 3.2 (N = 39). For visual representation of all 2012 relocations see Figure 3-3.
Of the 41 sturgeon tracked in 2011, 28 were found at least once during the 2012 open water season. In addition ,11 fish tagged in 2012 near Borden where also found and included in Figure
3-2. Of the remaining fish, two were last recorded as mortalities in 2011, five have exceeded the battery life of their tags and are no longer trackable and the remainder were not found and had either avoided detection or left the study area.
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Of the 37 sturgeon originally tagged at The Forks in 2009, 20 maintained live batteries and remained in the study area in 2012. These 20 individuals offer a three year glimpse into sturgeon migration patterns (Table 3-4). Of the 20 potential migrants 10 migrated in each of the past three years and returned to The Forks, eight migrated two of the three years and two migrated only one of the three years. For visual representation of each sturgeon migration see Appendix Eight.
Figure 3-2: Summary of lake sturgeon telemetry observations made per individual by boat and stationary tower between October 9 2011 and October 31st 2012 in the Saskatchewan River System. 45 40 35 30 25 20
15 Occurrence 10 5
0
148.024.11
148.065.11
148.024.21
148.065.05
148.065.12
148.065.15
148.065.37
148.065.75
148.024.05
148.024.09
148.065.03
148.065.18
148.065.24
148.054.00
148.065.22
148.065.31
148.065.39
148.065.48
148.065.49
148.024.01
148.024.06
148.065.13
148.065.16
148.065.40
148.065.06
148.065.20
148.065.33
148.065.41
148.065.01
148.024.08
148.065.02
148.065.21
124.024.02
148.024.00
148.065.14
148.065.17
148.065.23
148.065.19 148.065.04 Individual Frequency
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Table 3-4: Qualitative summary of migration patterns over the past three years for the lake sturgeon population tagged below The Forks of the North and South Saskatchewan River in 2009. To be counted as returning in fall sturgeon must have been recorded in the wintering grounds by October of the respective year.
2010 2011 2012 Tag ID Spring Fall Spring Fall Spring Fall migration return migration return Migration Return 148.065.02 Yes Yes Yes Yes Yes Yes 148.065.03 Yes Yes Yes Yes Yes No 148.065.04 Yes Yes Yes Yes Yes Yes 148.065.051 Yes Yes Yes Yes - - 148.065.082 Yes Yes Yes No - - 148.065.11 No - Yes Yes No No 148.065.12 Yes Yes No - Yes No 148.065.13 Yes Yes Yes Yes Yes No 148.065.14 Yes No Yes Yes Yes No 148.065.15 Yes Yes Yes Yes Yes No 148.065.16 Yes Yes Yes Yes No No 148.065.17 Yes Yes Yes Yes Yes No 148.065.19 Yes Yes Yes Yes No No 148.065.20 Yes Yes Yes Yes Yes Yes 148.065.21 No - No - Yes Yes 148.065.22 No - Yes Yes Yes No 148.065.23 No - Yes Yes Yes Yes 148.065.24 Yes Yes Yes Yes Yes Yes 148.065.262 Yes No Yes No - - 148.065.75 Yes Yes Yes Yes Yes No Total 100% 70% 90% 80% 70% 25%
1 Too few relocations to calculate migration in 2012 2 Individual not relocated in 2012
55 Saskatchewan River Sturgeon Project 2012 Report |
Figure 3-3: Sturgeon relocations by week (each colour represents a unique week of tracking) in the 2012 open water season (May to October) 3.2.1 Migration distance
Migration distance was calculated for sturgeon relocated at least three times outside of the wintering grounds and was not calculated for sturgeon tagged in 2012 but did include fish tagged in 2009 or 2011. Further, to be eligible for this analysis sturgeon had to be present at The Forks in spring and have returned to The Forks by the end of October 2012. In 2011, 23 meet the criteria and migrated an average of 209.9 rkms + 244.6 rkms (mean + 1 SD) (see Figure 3.4 for summary and Appendix Five for individual records). This is a small increase over the 169.1 rkms + 70.8 kms (mean + 1 SD) noted in 2010 (n =22) (Pollock 2010), and the 185.8 rkms +
101.9 (n=8) (mean + 1 SD) noted in 2012. Analysis of distance traveled among years revealed no significant differences (Kruskal-Wallis, two-tailed, H = 0.50, DF = 2, P = 0.78).
500.0
400.0
300.0
200.0
100.0 Migration distance distance (kms) Migration 0.0 Total distance Total distance Total distance -100.0 2010 2011 2012
Figure 3-4: Comparison of distance travelled by tagged sturgeon that overwintered below The Forks of the North and South Saskatchewan River in 2010 (n=22), 2011 (n=23) and 2012 (n=8)
3.2.2 Migration destination and river use
Though migration distance and river choice analysis between years was possible in the 2011 report, low sample sizes precluded analysis for the 2012 data set. With only eight confirmed migrants returning to The Forks by October 2012 we did not have a large enough sample size for any one river to compare between years.
3.2.3 Migration timing
This section will compare the timing (i.e. start and end dates) of the annual migration taken by sturgeon in 2010, 2011 and 2012. To meet the criteria for analysis of migration initiation sturgeon must have initiated a migration in all three years and must have been relocated at least three times away from the wintering grounds. Seven sturgeon meet these criteria. To meet the criteria for migration return sturgeon must have been recorded as leaving the wintering grounds and then recorded on the return. Unfortunately only three sturgeon meet this criteria in all three years. This is a large enough sample size for return date analysis but should be viewed with caution as this is a very small representation of the population.
With respect to migration initiation no significant differences were found between 2010, 2011 and 2012 start dates (Kruskal-Wallis: N = 8, H=0.5, P = 0.78) (see Figure 3.5 for summary and
Appendix Six for individual records). Similarly, return to the migration grounds (Kruskal-
Wallis: N = 13, H = 1.16, DF = 2, P = 0.56) (see Figure 3.5 for summary and Appendix Six for individual records) was not significantly different among years.
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300
250
200
150
100
50 Annual Julian DayAnnualJulian 0 2010 2010 2011 2011 2012 2012 Initiation Return Initiation Return Initiation Return date date date date date date
Figure 3-5: Mean (+1SD) migration data for lake sturgeon over wintering below The Forks of the North and South Saskatchewan River in 2010, 2011 and 2012.
3.2.4 Area use
To determine the amount of habitat used by sturgeon over the past three years ArcGIS was used to analyze home range size using relocations from October 2009 to October 2012. Specifically,
Hawth’s tools (with the spatial analysis extension) was used to conduct a Kernel analysis followed by a 95% volume contour to estimate home range size. Analysis was conducted for all sturgeon that were tracked for at least one full season. This resulted in 32 individuals being analyzed.
Analysis indicates an annual home range size ranging from 714 ha to 7252 ha with a mean of
3099.1 ha + 1 SD of 1736.2 ha. (see Appendix 8 for actual home range locations and table 3-5 for individuals values).
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Table 3-5: Home range data for all sturgeon tracked for at least one full season in the past three years including relocation number, number of years track and biometrics for tracked individuals.
Fish code Home Number Year Mass Length Body condition Range (ha) relocations tracked (kg) (m) index 148.024.00 988 23 2 8.5 1 850.0 148.024.01 1456 6 1 13 1.18 791.2 148.024.02 3070 14 2 8 0.97 876.5 148.024.08 4375 10 2 9 1.05 777.5 148.024.15 3583 44 2 7 0.96 791.2 148.024.16 2520 26 2 11 1.04 977.9 148.024.18 2678 20 2 12 1.1 901.6 148.024.19 790 78 1 18.1 1.17 1130.1 148.024.20 714 87 1 10 0.97 1095.7 148.024.21 2531 51 2 15 1.23 806.1 148.024.22 4486 47 2 7 1 700.0 148.024.23 2670 58 2 12 0.99 1236.7 148.024.24 2110 34 2 16.5 1.13 1143.5 148.065.01 2808 8 2 15 1.21 846.7 148.065.02 3930 86 3 21 1.27 1025.2 148.065.03 1939 55 3 25 1.37 972.3 148.065.04 7187 126 3 16 1.2 925.9 148.065.05 2372 88 3 20 1.31 889.6 148.065.06 1454 9 2 12.3 1.12 875.5 148.065.11 1187 84 3 11 1.06 923.6 148.065.12 2935 38 3 18 1.32 782.6 148.065.13 7252 60 3 14 1.21 790.3 148.065.14 2136 102 3 24 1.39 893.6 148.065.15 3240 54 3 12 1.03 1098.2 148.065.16 1879 47 3 17 1.12 1210.0 148.065.17 3200 66 3 10 0.94 1204.0 148.065.19 5847 89 3 16 1.25 819.2 148.065.20 6387 47 3 18 1.25 921.6 148.065.21 5388 85 3 16 1.18 973.8 148.065.22 1520 102 3 13 1.06 1091.5 148.065.23 4097 70 3 26.5 1.53 739.9 148.065.24 1636 50 3 22.5 1.4 820.0 148.065.26 2148 31 1 20 1.27 976.4 148.065.33 3441 6 1 23 1.375 884.7 148.065.37 5434 6 2 12 1.1 901.6 148.065.41 3779 6 1 11 1.1 826.4 148.065.75 3170 56 3 22 1.27 1074.0 165.065.08 1429 84 2 24 1.29 1118.0
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To ensure that the variation in the number of relocations did not affect our analysis of home range size a Pearson correlation was conducted comparing home range size versus the number of times a sturgeon was located in the past three years. Results indicate no significant correlation between the number of times a sturgeon was relocated and its home range size (Figure 3-6,
Pearson Correlation, two-tailed, N=32, R=0.10, P=0.55). Readers are reminded that analysis did not include individuals that were not tracked for at least one full year.
8000
7000
6000
5000
4000
3000
2000
Home range size (ha) size range Home 1000
0 0 10 20 30 40 50 Relocations
Figure 3-6: Correlation between the number of sturgeon relocations over three years and calculated home range size (Pearson Correlation, two-tailed, N=32, R=0.10, P=0.55).
Further analysis attempted to link an individual’s home range size with biometric variables including length, mass and body condition ((Mass/Length3)*100). Results indicate that neither mass (Figure 3-7; Pearson Correlation, two-tailed, N=32, R=-0.046, P=0.78) nor length (Figure
3-8; Pearson Correlation, two-tailed, N=32, R=0.097, P=0.56) were significantly correlated with
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home range size. However, a significant correlation exists between body condition index and home range size (Figure 3-9; Pearson Correlation, two-tailed, N=32, R=-0.33, P=0.043).
8000 7000 6000 5000 4000 3000
2000 Home range size (ha) size range Home 1000 0 0 10 20 30 40 50
Mass (kg)
Figure 3-7: Correlation between mass and calculated home range size for lake sturgeon over a three year time period (Pearson Correlation, two-tailed, N=32, 0.046, P=0.78).
8000 7000 6000 5000 4000 3000
2000 Home range size (ha) size range Home 1000 0 0 10 20 30 40 50 Length (m)
Figure 3-8: Correlation between length and calculated home range size for lake sturgeon over a three year time period (Pearson Correlation, two-tailed, N=32, R=0.097, P=0.56).
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8000 7000 6000 5000 4000 3000 2000
Home range size (ha) size range Home 1000 0 0 10 20 30 40 50 Body condition index
Figure 3-9: Correlation between body condition and calculated home range size for lake sturgeon over a three year time period (Pearson Correlation, two-tailed, N=32, R=-0.33, P=0.04).
3.2.5 Catch order
An unexpected result of the 2010 and 2011 field season was a significant increase in the size of sturgeon captured as the field season progressed (Pollock et al. 2010, 2011). A similar analysis was conducted on sturgeon captured at the Borden site on the North Saskatchewan River in
2012. However, the 2012 samples revealed length (Spearman Rank Correlation, R = 0.17, p =
0.08, Figure 3-10), mass (Spearman Rank Correlation, R = 0.21, p =0.14, Figure 3-11) and girth
(Spearman Rank Correlation, R = 0.22, p =0.22, Figure 3-12) did not increase significantly as the field season progressed.
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1.6
1.2
0.8 Length (m) Length 0.4
0 0 20 40 60 80 100 120
Catch order
Figure 3-10: Correlation between chronological catch order and sturgeon length in the 2012 field season (Spearman rank correlation, N = 102, R = 0.17, P =0.08 (two-tailed).
25
20
15
10 Mass (kg) Mass
5
0 0 20 40 60 80 100 120 Catch order
Figure 3-11: Correlation between chronological catch order and sturgeon mass in the 2012 field season (Spearman random correlation, N = 102, R = 0.21, P =0.14 (two-tailed).
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0.6
0.5
0.4
0.3 Girth (m) Girth 0.2
0.1
0 0 20 40 60 80 100 120 Catch order
Figure 3-12: Correlation between chronological catch order and sturgeon girth in the 2012 field season (Spearman random correlation, N = 102, R = 0.22, P =0.22 (two-tailed).
3.3 Population health
We recorded mass, length, girth, tags number (current and prior if present) date and time data for all captured individuals. These data were used for analysis in the current report and are included for potential future use (see Appendix Seven).
3.3.4 Population age structure
The current study examined the population age structure with the ultimate goal of correlating missing or abundant age classes to historical flow records. Age analysis was conducted using a model developed from data within Bruch et al. 2009 (see Figure 3-13 for model used). Results indicate an age class range from one to 31 years of age with no missing age classes (Figure 3-
14). It should be noted that averaging was used to get a closer estimate of the true numbers of individuals in each age class. Specifically, for ages 1-10 the number presented is the average of
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the year stated as well as one year before and after. For individuals 10-20 years old an average which included two years before and after the stated age was used. For individuals 21-30 four years on either side of the stated date was used to find the average. Finally, for individuals over
30 five years on either side of the stated date were used.
In all years surveyed (2010-2012) we see the most abundance in the lowest age classes at both sample sites (Borden and The Forks). Data summary indicates a significant population spike in younger years indicating successful spawning must be occurring within the immediate or surrounding area (Figure 3-14). It should be noted that gear size (size 7 Snell hook) biased our sampling to the exclusion of the young-of-the-year sturgeon.
45 y = 0.3663x - 21.437 40 R² = 0.8345 35 30 25 20
Age (years) Age 15 10 5 0 60 80 100 120 140 160 180
Total length (cm)
Figure 3-13: Simple linear regression used to age sturgeon captured in the 2009 survey (made from data contained in Bruch et al (2009).
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45 North Saskatchewan River 2012 40 The Forks 2012 35 The Forks 2011 30
25
20
15 Sturgeon number/ageSturgeon 10
5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 Age (years)
Figure 3-14: Frequency distribution of sturgeon age classes in our 2010, 2011 and 2012 field surveys.
3.3.5 Reproductive success and historic flow
Though this analysis was conducted in previous reports (Pollock 2011) the relatively small sample size (i.e. 102 sturgeon) was not large enough to obtain a reliable result. The age range is heavily biased towards younger individuals which is more an artifact of smaller sample sizes than an indication of flows impacts on reproduction. This artifact was overcome in the 2011 report by a large sample size (>500 individuals).
3.3.6 Stable isotope results
River flows peaked in mid-June of 2011 in the North and South Saskatchewan Rivers (Figure 3-
15), but overall volume of water contributing to the Mainstem Saskatchewan River was
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relatively equal between the two rivers at 10, 325,000 dam3 and 13,569,000 dam3 in the each river respectively.
Figure 3-15: Flow (m3•s-1) in the North, South, and Mainstem Saskatchewan River from October 2010 to September 2011.
Lake sturgeon in this study had significantly lower δD values in their blood relative to their muscle tissue (t(18) = -5.38, P < 0.001), and within each tissue had wide-ranging δD values spanning 79.96‰ (-259.03‰ to -186.07‰) in blood and 43.98‰ (-194.03‰ to -150.05‰) in their muscle tissue (Figure 3-16). However, there was no correlation between lake sturgeon blood δD and their muscle δD (r = 0.16, P > 0.05).
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Figure 3-16: Box plots of the values of δD for each site, taxa, and tissue type combination. Values for the mussels (Lampsilis siliquoidea) represent muscle tissue from the foot of mussel individuals. Boxes present the maximum and minimum values (whiskers), the upper and lower quartiles (75th and 25th percentiles), and the median (central horizontal line within box). Solid circles above or below each box represent outliers and are more than 1.5 IQRs (interquartile range).
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Further, we found no significant correlations between δD and either trophic position or α (Table
3-6), but found significant correlations between lake sturgeon mass (as a proxy of age) and both trophic position (r = 0.71, p < 0.05) and α (r = 0.91, p < 0.01; see Table 3-6).
Table 3-6: Correlation matrix of lake sturgeon mass and potentially predictive variables (Trophic Position, δD blood, δD muscle, and α).
Lake Sturgeon Mass (kg) Trophic Position δD Blood δD Muscle Trophic Position 0.71* δD Blood -0.34 0.02 δD Muscle 0.47 0.29 -0.16 α 0.65 0.91** 0.01 0.34 Note: α is the proportion of nutrients in the lake sturgeon diet derived from the base of the littoral food web. * indicates P < 0.05, and ** indicates P< 0.01.
We found a significant difference in the δD of mussels from the river sources (ANOVA, F2,10 =
7.2, P < 0.05), with the North Saskatchewan River mussels having the most positive δD values
(mean = -202.7 ± 3.6), the South Saskatchewan River mussels the most negative δD values
(mean = -219.9 ± 10.5), and the mussels from the Mainstem of the Saskatchewan River downstream of the forks having values between both these contributing sources (mean = -210.7
± 1.4).
Assignment of likelihood-of-origin for each lake sturgeon determined that eight lake sturgeon originated from the South Saskatchewan River, three from the Mainstem of the Saskatchewan
River, and one migrated up the North Saskatchewan River (Table 3-7). These data match perfectly with the known migration routes taken by sturgeon as verified by telemetry analysis.
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Table 3-7: Table of most probable migration origins for each lake sturgeon.
Lake Lake Sturgeon Sturgeon Probability of Origin Migration origin as confirmed Identity North South Mainstem by telemetry Sask Sask 0908115503b 0.00 0.88 0.12 South Saskatchewan River 1060-3b 0.08 0.20 0.72 Mainstem Saskatchewan River 174-0409b 0.01 0.99 0.00 South Saskatchewan River 1907115503b 0.00 0.66 0.34 South Saskatchewan River 200-0435b 0.00 1.00 0.00 South Saskatchewan River 206-0441b 0.85 0.09 0.06 North Saskatchewan River 212-0447b 0.00 0.43 0.57 Mainstem Saskatchewan River 239-0474b 0.00 1.00 0.00 South Saskatchewan River 240-0475b 0.00 1.00 0.00 South Saskatchewan River 242-0477b 0.01 0.25 0.74 Mainstem Saskatchewan River 265-0500b 0.00 0.97 0.03 South Saskatchewan River WAP 26b 0.00 1.00 0.00 South Saskatchewan River
3.3.7 Genetic analysis
A total of 77 lake sturgeon were analyzed from three different ages. Three of these fish, samples were excluded from the analyses due to incomplete data (missing data at 4 or more loci). In addition, locus AfuG122 was removed from analysis due to a large amount of missing data and data from locus AfuG204 was not included as this locus appeared to be monomorphic in the
Saskatchewan River population.
3.3.7.1 Genetic Diversity
Genetic characteristics of the sampled lake sturgeon within each sample grouping are summarized in Table 3-8. One Locus was removed from the study due to monomorphic occurrence (i.e. seen in all individuals). With the exception of the monomorphic locus
(AfuG204), all microsatellite loci used exhibited variation among the samples. Allelic richness
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ranged from two to eight alleles per locus with a mean value of 3.75 alleles/locus. Allele frequencies for the 12 microsatellite loci included in the analysis are reported for all sample groups in (See Appendix three). Neither Standardized allelic richness or heterozygosity varied significantly between age groups.
The estimated mean effective population size (Ne) estimates for the total population were broadly similar across all methods used, with mean values between 28 to 32.8. Although Ne estimates were generally similar and within an order of magnitude across all methods used, some significant differences were observed for cohort-specific estimates (Table 3-9). For adults (age
23) the linkage disequilibrium (LDNe) and Bayesian (OneSAMP) estimators gave significantly different values for Ne (26.1 and 13.3 respectively, with non-overlapping 95% confidence intervals) (Table 3-9). Ne estimates from, these methods also had non-overlapping 95% confidence intervals for the juvenile (age 2) while larval (age 1) sturgeon did not differ (Table 3-
9).
The relatedness-based estimation method in COLONY (Jones and Wang 2009) yielded similar estimates to the frequency-based estimators, although variance estimates were large due to the limited sample sizes (Table 3-9). COLONY also generated a number of effective breeders (Nb) estimate of 28 effective breeders (parents) for the larval cohort (Table 3-9); the sample size for the adult cohort was not sufficiently large for this method to be applied. As LDNe estimates of
Ne from single cohorts also reflect Nb (Luikart et al. 2010), the LDNe result for the adult and larval cohorts should be considered Nb estimates as well.
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Table 3-8: Sampling groups for Saskatchewan River lake sturgeon with adjusted number of samples (N), mean number of alleles observed per locus (A), standardized allelic richness averaged over all loci (As), expected and observed heterozygosity (HE and HO), and Wright’s within-population diversity coefficient (FIS).
N A As HE HO FIS Whole population 64 3.75 2.86 0.516 0.534 -0.024 Adult (age 23 cohort) 12 2.92 2.65 0.470 0.479 0.032 Juveniles (age 2 cohort) 6 2.83 n/a 0.499 0.569 -0.051 Larvae (age 1) 45 3.75 2.87 0.514 0.546 -0.046 * Adapted From Wozney and Wilson 2013
Table 3-9: Summary of estimated mean and 95% confidence intervals for effective population sizes (Ne) and effective number of breeders (Nb) for Saskatchewan River lake sturgeon.
LDNe (Ne) OneSamp (Ne) Colony (Ne) Colony (Nb) Whole population 32.8 (20.6-65.5) 32.2 (27.1-41.7) 28 (17-50) 12 (3-∞) Adults (age 23) 26.1 (58.7-∞) 13.3 (11.3-18.9) n/a n/a Juveniles (age 2) 21.9 (12-∞) 8.2 (7.0-12.1) n/a n/a Larvae (age 1) 22.9 (13.8-41.8) 28.3 (24.3-36.3) 20 (12-39) 28 (4-∞) * Adapted From Wozney and Wilson 2013
4.0 Discussion
4.1 River2D modeling
From the data collected in 2012 the following conclusions can be drawn
1) Analysis of the South Saskatchewan River indicates an abundance of spawning habitat as
well as adult and sub-adult habitat.
2) As in previous years (Pollock et al. 2010, 2011) habitat quantity and quality for all life
stages was significantly linked with flow.
3) Though discharge and habitat are statistically linked the increase in habitat slows as flow
rises above ~125 cms.
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4.1.1 River2D summary and recommendations
1) While a significant relationship between flow and habitat occurred in all surveyed
reaches across our three year project (six reaches in total Pollock et al. 2010 and
2011), flow does not appear to be limiting recruitment or adult survival on either the
Saskatchewan River mainstem or North Saskatchewan River. In contrast, no direct
evidence exists (i.e. population survey) allowing us to conclude that flow has or has
not affected populations in the South Saskatchewan River.
2) In the South, North and Mainstem of the Saskatchewan River there are a high
numbers of years in which optimal habitat is available. In the North and Mainstem of
the Saskatchewan River the presence of successful recruitment (i.e. large population
of young fish) and the fact that there are no missing age classes adds further evidence
of a healthy population.
3) However, as noted in previous reports (Pollock et al. 2011) there are several instances
of high flow years being significantly linked to high recruitment years, but again, it
would appear that these high flow years occur often enough to sustain recruitment
and survival.
4) In conclusion, though it seems the population is currently healthy, reproductively
successful and has abundant habitat throughout the majority of the Saskatchewan
River system, it is important to note that this does not mean that changes to flow
could not benefit the population but rather, it can be stated, flow management does
not appear to be the cause of historical decline or a hindrance to population recovery.
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4.2 Migration and telemetry
1) Of the 60 sturgeon tagged since 2009, 41 remain with the remainder being lost due
to tag battery life.
2) Of the 37 sturgeon tagged at The Fork in 2009, 20 maintain live batteries and
remained in the study area. Of these 20 individuals 10 migrated in each of the past
three years and returned to The Forks, eight migrated two of the three years and two
migrated only one of the three years.
3) There was no significant difference in migration distance among years.
4) The timing of spring migration was not significantly different between years.
5) Similarly the return migration was not significantly different between years.
6) Area use has indicated that adult sturgeon have a home range size of approximately
3099.1 ha + 1 SD of 1736.2 ha. Further it appears that sturgeon with higher body
reserves use less area than sturgeon with poorer reserves. One might speculate that
this difference is due to the need for individuals in poorer condition to locate
additional food sources. This hypothesis is supported by our 2011 program MARK
analysis that demonstrated that sturgeon in poorer body condition were more likely
to engage in migration when compared to individuals in better condition (Pollock et
al 2011).
7) Unlike previous years there was not a significant increase in the size of sturgeon
captured throughout the field season, though a trend toward longer individuals (i.e.
older) did occur. This trend may indicate, as demonstrated at The Forks, that this
area is an overwintering area and larger individuals were returning from the spring
migration.
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4.2.1 Telemetry and migration summary and recommendations
1) Sturgeon followed similar migration patterns in the three years of data collection.
2) Sturgeon make use of all three rivers (North Saskatchewan, South Saskatchewan and
Saskatchewan River mainstem) with The Fork region providing a common and
crucial wintering ground.
3) The population preference is to migrate each year though some individuals migrate
one or two of every three years and in one case only once in three years.
4) Due to their extensive migrations work on any portion of the rivers within ~300 rkms
from The Forks should consider sturgeon health in any future projects.
4.3 Population abundance and health
1) Age structure analysis indicates an age range of 1-31 with no missing age classes at
the Borden site. Note: the upper range is most certainly higher, however due to slow
growth rates our model is not able to differentiate fully grown young (i.e. in their 30s)
and old (i.e. > 40 years old) individuals.
2) Though population abundance analysis could not be conducted, recapturing only two
individuals out of 102 catches is indirect and preliminary evidence of an abundant
population.
3) Using the δD (deuterium) in the blood of 12 lake sturgeon we conclude that eight of
the lake sturgeon likely migrated up the South Saskatchewan River, three down the
Mainstem Saskatchewan River, and a single lake sturgeon migrated up the North
Saskatchewan River. These results were consistent with telemetry data from the
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same time period suggesting deuterium can be used to determine migration
preference for sturgeon in a given year.
4) Past work on stable isotope analysis indicates a strong preference for crayfish
(Orconectes virilis) in the sturgeon diet.
5) Past work indicated that the smallest sturgeon in the current study focus their efforts
on smaller crayfish instead of focusing on a smaller food source (i.e. chironomids,
snails, etc). From this we can say that crayfish play a crucial role in the diet of
Saskatchewan River lake sturgeon throughout their lives.
6) Genetic analysis of sturgeon from The Forks site indicates greater than expected
diversity in the population with no change in diversity among age classes or historical
bottlenecks.
7) Genetic analysis also revealed an effective population size smaller than expected as
was the number of breeding females each year.
8) It should be noted that the number of breeding females per year could be misleading
as some females may have spawned several hundred kilometers away and left
offspring at that location and thus not be counted in our survey.
4.4 Overall conclusions
1) It appears the region below The Forks is a crucial wintering area for a population that
uses a much larger part of the Saskatchewan River Watershed. Thus any actions that may
result in damage or degradation to this area, or associated migration routes, should be
carefully considered.
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2) While flow is statistically linked to habitat availability it appears current flow regimes
have allowed the population to thrive in the Saskatchewan River system. However, direct
evidence of a healthy and abundant South Saskatchewan River population does not exist
downstream of Gardiner Dam and is preliminary for the North Saskatchewan River.
3) Given the statistical link between flow and sturgeon it may be possible to manipulate
flow to increase either habitat availability or recruitment should this be desired in the
future.
4) Preliminary work on the North Saskatchewan River population assessment may indicate
(through presence of young of year and telemetry data) that a population exists around
the Borden area that does not depend on the region below The Forks as a wintering hole.
5) Genetic analysis indicates that recovery will not be hindered by low diversity.
6) Sturgeon are dependent on crayfish for a significant portion of their diet. The crayfish
population appears to be abundant and widespread at this time.
4.5 Future work
Several key questions and data gaps remain before a comprehensive understanding of the dynamics of the Saskatchewan River lake sturgeon population is understood, particularly in how it relates to flow. For example, further habitat analysis has yet to be completed on the South
Saskatchewan River between Gardiner Dam and The Forks. This section of river is most likely to be impacted by flow management given its location immediately downstream of a hydro peaking station and its lack of feeder streams to mitigate flow.
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Similarly, the location and abundance of a resident sturgeon population within the South
Saskatchewan River has not been documented. From our telemetry data it is apparent that sturgeon that over winter at The Forks make use of the South Saskatchewan but it is not known if a separate population exists and remains within the South Saskatchewan River. This is of particular importance for three reasons: 1) If present, a South Saskatchewan River population will be under increased risk for flow related problems; 2) If a resident sturgeon does not exist in the South Saskatchewan River it places even greater importance on The Forks site with respect to protection and recovery; 3) If sturgeon become listed under the Species At Risk Act locating all population centers will be crucial to recovery and survival.
Similarly, and arguably of greater importance, the 2012 field season offers preliminary evidence of a resident population in the North Saskatchewan near Borden. Investigation of the North
Saskatchewan River should be considered a higher priority relative to the South Saskatchewan
River as it is more likely to house an independent population. This is due to increased habitat availability, anecdotal catch by anglers and no habitat fragmentation or degradation from managed flows. Further work should be completed that would allow for a population abundance estimate and establishment of critical habitat and migration routes.
To date The Forks sturgeon have presented a relatively choreographed migration pattern with respect to timing, distance traveled, etc. These sturgeon should be followed for the remainder of the radio tags battery life to gain all information possible on this unique species particularly as it relates to critical habitat. Further, the migration patterns of other populations within the
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watershed must be documented to ensure the critical habitat and migration routes of additional population centers are considered and known.
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5.0 References
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Kalinowski ST. 2005. HP-Rare: a computer program for performing rarefaction on measures of allelic diversity. Mol. Ecol. Not. 5:187-189.
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Phillips ID, Pollock MS, and McMaster G. 2010. The influence of the Gardiner Dam on the thermal and biological condition in the Saskatchewan River System. Science, Information, and Monitoring, Saskatchewan Watershed Authority, Saskatoon, Saskatchewan. 38 pp.
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Pollock MS, Salamon JP, Phillips JP, Young AG and McMaster G. 2009. The use of risk assessment analysis to identify quality and at risk habitat for the Saskatchewan Rivers Lake Sturgeon (Acipenser fulvescens) population. Saskatchewan Watershed Authority. 129 pp.
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Pollock MS, Salamon JP, Phillips JP, Carr M and McMaster G. 2011. Saskatchewan Watershed Authority Saskatchewan River Sturgeon Report. 250 pp.
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Wallace RG. 1999. Lake sturgeon in the lower Saskatchewan River: Spawning sites, general habitat and tagging, 1994 to 1997. Saskatchewan Environment and Resource Management, Fish and Wildlife Technical Report 99-3, ix and 91 pp.
Wallace RG and Leroux DR. 1999. Lake Sturgeon in the lower Saskatchewan River: Radio tracking and index fishing, 1994-1997. Saskatchewan Environment and Resource Management, Fish and Wildlife Technical Report 99-4, viii and 93 pp.
Waples RS and Do C. 2008. LDNE: a program for estimating effective population size from data on linkage disequilibrium. Mol. Ecol. Res. 8:753-756.
Welsh A, Blumberg M and May B. 2003. Identification of microsatellite loci in lake sturgeon, Acipenser fulvescens, and their variability in green sturgeon, A. medirostris. Molecular Ecology Notes 3:47-55.
Welsh A, Hill T, Quinlan H, Robinson C and May B. 2008. Genetic assessment of lake sturgeon population structure in the Laurentian Great Lakes. N. Amer. J. Fish. Manag. 28:572-591.
White GC and Burnham KP. 1999. Program MARK: survival estimation from populations of marked animals. Bird Study Supplement 46:120-139.
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Wozney KM and Wilson CC. 2013. Genetic Diversity of Lake Sturgeon in the Forks section of the Saskatchewan River: assessment of resident diversity and estimation of effective population size (Ne). Technical Report prepared for the Saskatchewan Watershed Authority. 14pp.
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Appendix One: Historical South Saskatchewan River Flow
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Median
1976 357 319 263 180 81.1 80.2 77.5 215 216 230 212 327 215.5 1977 354 264 126 74.4 50.2 52.2 49.5 49.2 47.4 52.7 160 216 63.55 1978 219 175 183 141 55.8 243 166 133 237 230 227 238 201 1979 358 384 304 139 160 196 73.2 77.4 51.2 124 162 193 161 1980 241 344 186 111 68.1 152 141 59.5 97.9 169 256 267 160.5 1981 318 293 180 177 127 492 384 491 272 227 244 232 258 1982 354 318 250 191 99.2 57.6 62.4 104 120 163 206 276 177 1983 333 322 217 137 128 68.1 71.3 83.3 113 145 136 232 136.5 1984 201 112 95.4 80.2 51.6 54.9 50.5 51.5 53.4 47.9 113 104 67.55 1985 103 113 56.8 76 117 69.6 48.2 49.8 47.5 51.8 145 222 72.8 1986 248 250 187 71.4 76.2 217 169 191 149 317 271 274 204 1987 262 269 290 178 98.4 50.9 55.7 55.3 82.4 161 192 172 166.5 1988 262 269 59.2 69.1 51.6 42.1 47.9 52.5 46.1 47.7 80.8 145 55.85 1989 262 269 217 62.6 61 58.2 55 58.3 57.3 84.2 154 246 73.4 1990 262 269 217 167 196 521 447 214 143 243 278 254 248.5 1991 262 269 217 157 139 151 427 291 199 263 268 231 246.5 1992 232 261 162 74.5 52.6 47.9 49.2 56.8 111 138 243 221 124.5 1993 254 154 76.5 95.4 139 189 662 577 446 388 351 251 252.5 1994 328 340 257 230 233 98.3 84.6 109 119 110 169 229 199 1995 262 234 179 105 84 540 611 343 254 277 299 260 261 1996 336 319 273 273 396 317 276 177 191 243 251 271 273 1997 362 269 278 241 367 380 203 127 100 192 213 218 229.5 1998 241 238 144 88.2 95.4 202 630 212 145 141 196 217 199 1999 303 301 251 129 99.6 108 109 215 199 193 214 238 206.5 2000 259 288 221 146 121 107 102 99.3 96.5 97.7 162 206 133.5 2001 206 153 97.8 80.1 66.8 64.7 58.4 61.4 66.2 71.2 120 146 75.65 2002 136 86.8 67.9 55.1 49.8 212 282 135 138 170 260 230 137 2003 224 247 218 183 303 349 162 202 112 111 172 184 193 2004 206 149 89.7 84.7 67.9 63.3 63.3 63.3 59.8 101 236 243 87.2 2005 241 273 239 142 141 836 661 238 449 419 369 253 263 2006 333 385 344 233 242 323 222 149 122 128 197 239 236 2007 239 243 276 188 313 406 280 161 150 148 198 224 231.5 2008 275 268 157 90.9 115 356 316 183 179 212 210 200 205 2009 260 238 137 94.4 97 93.5 81.3 74.7 78 138 163 227 117 2010 256 232 128 68.9 72.9 402 484 207 199 287 210 244 221 2011 159 244 276 285 767 1380 747 308 260 216 249 280 278 Monthly 262 269 202 133 99.4 151.5 125 130 119.5 154.5 208 230.5 196 Median
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Appendix Two: Sturgeon habitat suitability curves: Velocity, depth and substrate habitat suitability used in the River2D model for Lake Sturgeon within the Saskatchewan River as adapted from Fisheries and Oceans (2009).
Spawning Fry Juvenile Sub-adult Adult Velocity (m/s) suitability (_/1) Velocity (m/s) suitability (_/1) Velocity (m/s) suitability (_/1) Velocity (m/s) suitability (_/1) Velocity (m/s) suitability (_/1) 0 0 0 0 0 1 0 1 0 1 0.05 0 0.05 0 0.05 1 0.05 1 0.05 1 0.1 0 0.1 1 0.1 1 0.1 1 0.1 1 0.25 0 0.25 1 0.25 1 0.25 1 0.25 1 0.3 0.25 0.3 1 0.3 1 0.3 1 0.3 1 0.4 0.5 0.4 0.5 0.4 1 0.4 1 0.4 1 0.5 1 0.5 0 0.5 0.5 0.5 1 0.5 1 0.8 1 0.8 0 0.8 0.25 0.8 1 0.8 1 1 1 1 0 1 0 1 0.5 1 1 2 0 2 0 2 0 2 0 2 0 Depth (m) suitability (_/1) Depth (m) suitability (_/1) Depth (m) suitability (_/1) Depth (m) suitability (_/1) Depth (m) suitability (_/1) 0 0 0 0 0 0 0 0 0 0 0.05 0 0.05 0 0.05 0 0.05 0 0.05 0 0.3 0 0.3 0.25 0.3 0 0.3 0 0.3 0 0.5 0 0.5 0.5 0.5 0 0.5 0 0.5 0 1 0 1 1 1 0.25 1 0.25 1 0.25 3 0.5 3 1 3 0.5 3 0.5 3 0.5 4 0.5 4 1 4 1 4 1 4 1 7.5 0.25 7.5 1 7.5 1 7.5 1 7.5 1 8 0 8 1 8 1 8 1 8 1 10 0 10 1 10 1 10 1 10 1 Substrate type suitability (_/1) Substrate type suitability (_/1) Substrate type suitability (_/1) Substrate type suitability (_/1) Substrate type suitability (_/1) Silt/sand 0 Silt/sand 1 Silt/sand 1 Silt/sand 1 Silt/sand 1 Sand/gravel 0 Sand/gravel 1 Sand/gravel 1 Sand/gravel 1 Sand/gravel 1 Gravel-cobble 1 Gravel-cobble 0.2 Gravel-cobble 0.8 Gravel-cobble 0.8 Gravel-cobble 0.8 cobble to 1 cobble to boulder 0.2 cobble to boulder 0.8 cobble to boulder 0.8 cobble to boulder 0.8 boulder
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Appendix Three: Genetics report from Institute for Watershed Science.
Genetic Diversity of Lake Sturgeon in the Forks section of the Saskatchewan River:
assessment of resident diversity and estimation of effective population size (Ne)
A technical report generated for the Saskatchewan Water Authority
by
Kristyne Wozney and Chris Wilson Institute for Watershed Science, Trent University, Peterborough, ON K9J 7B8
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Background and Objective Like most species of sturgeon globally, lake sturgeon are of significant conservation concern across most of their range (COSEWIC 2006). As a large-bodied, highly migratory species, lake sturgeon require hundreds of kilometers of continuous habitat to support viable populations. Riverine habitat is particularly important for completing their life cycle, as adults depend on rapids for spawning habitat and larval sturgeon require substantial reaches with downstream flow before settling out of the current to begin foraging as juveniles (Harkness and Dymond 1961, Scott and Crossman 1998). The long generation time and dependence on free-flowing riverine habitats make lake sturgeon highly vulnerable to habitat alteration and other anthropogenic disturbances. The risk to annual recruitment is further exacerbated by the multi-year intervals between successive bouts of reproduction by individual fish, with male lake sturgeon typically spawning only once every two to three years and females every three to five years (Harkness and Dymond 1961, Forsythe et al. 2012). One of the largest and most stable populations of lake sturgeon in western Canada in the Saskatchewan River, with an estimated number of approximately 3300 adults throughout the river (COSEWIC 2006). Despite the persistence of lake sturgeon in the Saskatchewan River, adult numbers are low enough that this designated conservation unit (DU) within the Canadian range has been listed as Endangered (COSEWIC 2006, Cleator et al. 2010). Existing phylogeographic data has shown that lake sturgeon in the Saskatchewan River historically formed a continuous population from the river’s headwaters in Alberta to its outflow in Lake Winnipeg (Kjartanson 2009). As well as being the most geographically widespread population in western Canada, lake sturgeon in the Saskatchewan River are also the most genetically representative extant group of the Missourian refugium ancestral population that recolonized the western half of the species range following the end of the Pleistocene glaciations (Kjartanson 2009). In more recent times, habitat alteration and construction of dams over the past 200 years has fragmented this formerly continuous population, resulting in demographically isolated contemporary populations in adjoining habitat fragments. Numbers of lake sturgeon in the Saskatchewan River have been estimated at less than 200 adults in the North Saskatchewan River and approximately 500 adults in the
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South Saskatchewan River (ASRD 2002), with a total population estimate of approximately 3,300 adults (COSEWIC 2006, Cleator et al. 2010). To date, no studies 1 have estimated the effective population size (Ne) or effective number of adults contributing to individual yearclasses (effective number of breeders, or Nb), although both are important genetic parameters for informing management and conservation planning of wildlife populations (Reed et al. 2003, Luikart et al. 2010). As annual recruitment in localized populations of lake sturgeon may be limited to a small number of adults that reproduce in a given year (Harkness and Dymond 1961, Forsythe et al. 2012), quantifying the effective number of breeders per cohort and effective population size of local populations will provide much-needed information for their sustainable management.
The goal of this study was to estimate the effective population size (Ne) and effective number of breeders (Nb) of lake sturgeon in the Saskatchewan River (Forks area) using different genetic estimators. The study capitalized on nonlethal fin samples collected from lake sturgeon in the Saskatchewan River as part of a mark-recapture study initiated in 2009 by the Saskatchewan Water Authority, in order to obtain genetic estimates of Ne and Nb without impacting the population. Multilocus genotype data based on 12 microsatellite loci from three cohorts [age 23 (adults) and ages 1 and 2
(juveniles)] were used to estimate Ne and Nb for the population and these specific cohorts.
Methods Nonlethal fin samples of several age classes of lake sturgeon from the Saskatchewan River (Forks) were provided by the Saskatchewan Watershed Authority. DNA was extracted from 77 individual fin clips using a simple lysis extraction in a 96 well plate using 250 L lysis buffer [50 mM Tris pH 8, 1000 mM NaCl, 1 mM EDTA, 1% sodium dodecyl sulphate (weight per volume), and 1 mg proteinase K] per well and incubated overnight at 37C. DNA was precipitated using 500 L of 80% isopropanol per well and centrifugation at 2000 gravities for 30 minutes. Supernatant was removed and
1 The COSEWIC (2006) status report generated an approximate demographic Ne estimate of <670 based on multiple assumptions and population estimates, but was not empirically quantified.
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the remaining pellets were rinsed with 1mL of 70% ethanol, followed by re- centrifugation. DNA pellets were air dried at room temperature for 20 minutes, then dissolved in 150L 1x TE (10mM Tris pH8, 1 mM EDTA). Extraction yields and quantity were tested using electrophoresis in 1.5% agarose gel stained with SybrGreen (Cedar Lane Laboratories, Burlington, Ontario) alongside a molecular mass ladder (BioShop, Burlington, Ontario). Samples were amplified and genotyped at 14 microsatellite loci that were previously identified for lake sturgeon (McQuown et al. 2002; Welsh et al. 2003). Multiplex reactions were performed in 15L reactions containing 1x PCR Buffer
(Qiagen, Mississauga, Ontario), 2mM MgCl2 (Qiagen, Mississauga, Ontario), 2mM each dNTP (BioShop, Burlington, Ontario), 0.2mg/ml BSA (BioShop, Burlington, Ontario), 0.025U Taq DNA polymerase (Qiagen, Mississauga, Ontario), and approximately 10ng of template DNA. Multiplex reactions contained the following primer concentrations Multiplex 1- Afu68 [0.25M], AfuG63 [0.22M], AfuG122 [0.25M], AfuG195 [0.25M], AfuG74 [0.28M] and AfuG67 [0.25M]; Multiplex 2- AfuG160 [0.25M], AfuG204 [0.23M], Afu68b [0.3M], AfuG61 [0.25M] and AfuG71 [0.25M]; Multiplex 3- AfuG9 [0.35M] and AfuG112 [0.38M]. The locus AfuG56 was amplified singly using primer concentrations of 0.3M due to problems with non-specific amplification. PCR cycling was 95oC for 11 minutes followed by 35 cycles of 94oC to denature double-stranded DNA, primer annealing at 55oC, and DNA synthesis/extension at 72oC (1 minute at each temperature step), with a final extension of 60oC for 45 minutes. Amplified products for all samples were run on an AB 3730 automated sequencer with a ROX-350 size standard (Applied Biosystems, Foster City, California). Microsatellite genotypes were scored using GeneMapper version 3.1 (Applied Biosystems, Foster City, California) and visual proofreading. The program CREATE (Coombs et al. 2007) was used to format the resultant multilocus genotypes for analysis by several genetic software packages. Samples that were missing data at four or more loci were excluded from analyses.
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Analysis Allele frequencies within river sections were calculated for all groups of samples in GENALEX version 6.2 (Peakall and Smouse 2006). Total allele counts and standardized allelic richness for a sample size of 10 individuals (20 alleles) were calculated in HP-Rare (Kalinowski 2005); the number of private alleles and heterozygosity estimates for each sample site were calculated using GENALEX (Peakall and Smouse 2006). The inbreeding coefficient (FIS) for all sample grouping was calculated in GENEPOP version 4.0 (Rousset 2007). Effective population size (Ne) was calculated for each sample group using a number of different estimators based on linkage disequilibrium (LDNe; Waples and Do 2008), coalescent (OneSamp; Tallmon et al. 2008), and kinship reconstruction algorithms (COLONY 2.0; Jones and Wang 2009). In addition, the effective number of breeders (Nb) contributing to single cohorts was estimated using heterozygosity excess (Luikart and Cornuet 1999) and demographic reconstruction of potential parent-offspring and sib- relationships based on maximum likelihood estimates of relatedness coefficients in COLONY 2.0 (Jones and Wang 2009).
Results A total of 77 lake sturgeon were analyzed from three different ages. Three of these fish, samples 02, 26 and 27 were excluded from the analyses due to incomplete data (missing data at 4 or more loci). In addition, locus AfuG122 was removed from analysis due to a large amount of missing data and data from locus AfuG204 was not included as this locus appeared to be monomorphic in the Saskatchewan River population. Analysis of samples using COLONY version 2.0 (Jones and Wang, 2009) indicated that a number of samples (eight pairs and one trio) had identical genotypes. Of the samples provided, Fish 5 had an identical genotype to Fish 121, Fish 18 with Fish 135, Fish 28 with Fish 74, Fish 48 with Fish 83, Fish 55 with Fish 96, Fish 56 with Fish 148, Fish 97 with Fish 105, Fish 98 with Fish 117 and Fish 32 had the same genotype as both Fish 77 and Fish 94. As no further identifying information was provided for these fish, it was not possible to assess whether these were recapture events of the same individuals or separate individuals with matching genotypes. As a result, all analyses
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were conducted both with and without duplicate fish from each pair included. In addition to those listed above, Fish 33 and Fish 150 also had identical genotypes but were not excluded as the fish were different ages based on data provided by the Saskatchewan Watershed Authority. Fish 24 was listed in both age 1 and age 14 and was excluded in analysis of age 1 fish but included in analysis with the entire population.
Genetic Diversity Genetic characteristics of the sampled lake sturgeon within each sample grouping are summarized in Table 1. With the exception of the monomorphic locus AfuG204, all of the microsatellite loci used in this study exhibited variation among the sampled lake sturgeon from the Saskatchewan River (Table 1). Allelic richness ranged from two (AfuG195, AfuG61 and AfuG71) to 8 alleles per locus (AfuG68), with a mean value of 3.75 alleles per locus. Allele frequencies for the twelve microsatellite loci included in the analysis are reported for all sample groups in Appendix 1. No private alleles were observed between cohorts within the dataset. Standardized allelic richness did not vary significantly between sample groups, ranging from 2.65 in the adult fish to 2.87 in larval sturgeon (duplicates removed). Observed levels of heterozygosity (HE) were also similar across age classes regardless of sample size, and did not differ significantly from expected values (Table 1).
The estimated mean effective population size (Ne) and effective number of breeders (Nb) including 95% confidence intervals are summarized in Table 2. Ne estimates for the total population were broadly similar across all methods used, with mean values between 24.9 and 27 (Table 2). Removal of duplicate genotypes resulted in slightly higher estimates (28 to 32.8), most likely due to a rarefaction effect of retaining equal observed genotypic diversity within a smaller sample size (Kalinowski 2005). Estimates for the full dataset and larvae with duplicate genotypes removed were not significantly different regardless of calculation method (Table 2). Although Ne estimates were generally similar and within an order of magnitude across all methods used, some significant differences were observed for cohort-specific estimates (Table 2). For the adult (age 23) cohort, the linkage disequilibrium (LDNe) and Bayesian (OneSAMP) estimators gave significantly different values for Ne (26.1 and 13.3 respectively, with
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non-overlapping 95% confidence intervals) (Table 2). Ne estimates from these methods also had non-overlapping 95% confidence intervals for the juvenile (age 2) and larval (age 1, including duplicate genotypes) sturgeon, although there was no consistent directional or size bias in Ne values generated by the two algorithms (Table 2). The relatedness-based estimation method in COLONY (Jones and Wang 2009) yielded similar estimates to the frequency-based estimators, although variance estimates were large due to the limited sample sizes (Table 2). COLONY also generated a Nb estimate of 10 effective breeders (parents) for the larval cohort (Table 2); the sample size for the adult cohort was not sufficiently large for this method to be applied. As observed for the other estimation methods, removal of duplicate genotypes from the larval (age 1) cohort resulted in a substantially higher estimate (Nb = 28), although the two Nb estimates for the larval sturgeon were not significantly different due to their high variances. As
LDNe estimates of Ne from single cohorts also reflect Nb (Luikart et al. 2010), the LDNe result for the adult and larval cohorts should be considered Nb estimates as well. As observed and expected heterozygosity were not significantly different within cohorts, the heterozygosity departure method for calculating effective number of breeders (Luikart and Cornuet 1999) gave variance range estimates from zero to infinity, and could not be used for reliable estimates of Nb (data not shown).
Discussion As the 4th longest river system in Canada, the Saskatchewan River is a significant part of the remaining distribution of lake sturgeon (Harkness and Dymond 1961). In addition, lake sturgeon in the river comprise the single greatest representation of Missourian-ancestry dating back to the Wisconsin glaciation, and as such represent a significant genetic legacy for the species as a whole (Kjartanson 2009). The population segment in the Forks section of the river is of high importance to the recovery of the Saskatchewan River DU (Cleator et al. 2010), and should be safeguarded as such.
The results of this study show clear evidence of low Ne and Nb in lake sturgeon yearclasses in the Forks segment of the Saskatchewan River, despite retention of substantial genetic diversity. From a genetic standpoint, the Saskatchewan River population shows higher levels of genetic diversity than might be expected given its
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Endangered status. As shown elsewhere, it may be the case that declines in population size are still too recent for genetic losses from anthropogenic activities to be apparent (DeHaan et al. 2006, Wozney et al. 2011). The observed levels of diversity are in agreement with other data from the Saskatchewan River population (Kjartanson 2009, McDermid et al. 2011), and are comparable to stable populations in the Great Lakes and eastern Canada (DeHaan et al. 2006, Welsh et al. 2008, Wozney et al. 2011).
The close agreement between expected and observed levels of heterozygosity (HE and HO) within and among yearclasses failed to show evidence for recent population bottlenecks. Wozney et al. (2011) observed similar retention of genetic diversity within fragmented population segments of lake sturgeon in the Ottawa River in eastern Canada despite demographic evidence of population declines (Haxton and Findlay 2008). DeHaan et al. (2006) similarly failed to detect genetic evidence of historical population bottlenecks despite >90% reduction in local population sizes. By contrast, McDermid et al. (2011) detected genetic evidence of historical bottlenecks from a number of lake sturgeon populations in Canadian rivers, although not from the Saskatchewan River. The broad consistency among estimation methods reflects the genetic diversity and resources within the population in general as well as specific yearclasses. It should be stressed, however, that Ne estimates reflect the genetic resources of populations, rather than actual numbers or census estimates of population size (Lande 1988, Luikart et al.
2010). The lower values of Nb for the two cohorts is to be expected as not all adults will reproduce in a given year (Harkness and Dymond 1961, Forsythe et al. 2012, Velez- Espino and Koops 2009). A study on green sturgeon, A. medirostris, in California’s
Sacramento River obtained Nb estimates between 10 to 28 per year over a five-year with
Nc between 140 and 1600 (Israel and May 2010). Similarly, Moyer et al. (2012) asssessed Ne and Nb of Atlantic sturgeon (A. oxyrinchus oxyrinchus) in the Altahama
River, Georgia: two key findings of their study were that contemporary Ne was an order of magnitude lower than historical (evolutionary) Ne, and that the effective number of breeders (Nb) ranged between 7% and 45% less than observed numbers of spawning adults.
As detectable changes will be a function of population size (both actual and Ne), decreases in diversity can be expected to occur more rapidly in smaller populations
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(Luikart et al. 2010). For long-lived species such as lake sturgeon, their long generation time and individual longevity act as buffers against population loss, but also make them vulnerable to demographic fluctuations or reductions (Lande 1988, Velez-Espino and Koops 2009). Despite this, early life stages have been identified as the most vulnerable components for lake sturgeon recovery (Velez-Espino and Koops 2009, 2012). Accordingly, the genetic data should not be considered in isolation: both genetic and demographic parameters need to be factored in for assessing persistence and recovery probabilities of populations (Lande 1988, Robert 2011).
The estimates of Ne and Nb obtained in this study also raise concerns relating to long-term sustainability, as all estimates are well below those recommended for maintaining short-term resilience and adaptive potential over long-term (Velez-Espino and Koops 2009, 2012; Cleator et al. 2010). The recovery potential assessment for lake sturgeon in the Saskatchewan River identified recovery targets of 5,860 adults (586 spawning females per year) per population segment (Cleator et al. 2010), and simulations have suggested target population sizes of 1,000 adults and 1,188 adult females to have respective 95% and 99% probabilities of persistence for 40 generations (Velez-Espino and Koops 2009, 2012). As both Ne and Nb reflect both demographic and genetic parameters of populations (Lande 1988, Luikart et al. 2010), the low values of both underscore the importance of ensuring that existing spawning and juvenile nursery habitats are maintained to guard against future erosion or loss of existing genetic diversity, as is predicted for other fragmented rivers (McDermid et al. 2011, Wozney et al. 2011). Given the importance of the Saskatchewan River population to lake sturgeon recovery in western Canada (COSEWIC 2006), it will be essential to safeguard adult numbers as well as breeding and juvenile nursery habitat to ensure the persistence of the Forks population and its contribution to the broader recovery effort in the Saskatchewan River.
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References
Alberta Lake Sturgeon Recovery Team (ALSRT). 2011. Alberta lake sturgeon recovery plan, 2011-2016. Alberta Environment and Sustainable Resource Development, Alberta Species at Risk Recovery Plan No. 22. Edmonton, AB. 98p.
Alberta Sustainable Resource Development (ASRD). 2002. Status of the Lake Sturgeon (Acipenser fulvescens) in Alberta. Alberta Sustainable Resource Development, Fish and Wildlife Division, and Alberta Conservation Association, Wildlife Status Report No. 46, Edmonton, AB. 30 pp.
Cleator, H., K.A. Martin, T.C. Pratt, R. Campbell, M. Pollock, and D. Watters. 2010. Information relevant to a recovery potential assessment of Lake Sturgeon: Saskatchewan River populations (DU2). DFO Canada Scientific Advisory Secretariat Research Document 2010/081. vi+36p.
Coombs, J.A., B.H. Letcher, and K.H. Nislow. 2008. CREATE: a software to create input files from diploid genotypic data for 52 genetic software programs. Molecular Ecology Notes 8: 578-580.
COSEWIC. 2006. COSEWIC assessment and update status report on the lake sturgeon Acipenser fulvescens in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa, ON. xi+107p. (www.sararegistry.gc.ca/status/status_e.cfm).
DeHaan, P. W., F.T. Libants, R.F. Elliott, and K.T. Scribner. 2006. Genetic population structure of remnant lake sturgeon populations in the upper Great Lakes basin. Transactions of the American Fisheries Society 135: 1478-1492.
Forsythe, P.S., J.A. Crossman, N.M. Bello, E.A. Baker, and K.T. Scribner. 2012. Individual-based analyses reveal high repeatability in timing and location of reproduction in lake sturgeon (Acipenser fulvescens). Canadian Journal of Fisheries and Aquatic Sciences 69: 60–72.
Harkness, W.J.K. and J.R. Dymond. 1961. The lake sturgeon: the history of its fishery and problems of conservation. Fish and Wildlife Branch, Ontario Department of Lands and Forests, Toronto.
Haxton, T.J. and C.S. Findlay. 2008: Variation in lake sturgeon abundance and growth among river reaches in a large regulated river. Canadian Journal of Fisheries and Aquatic Sciences 65: 645-657.
Israel, J.A. and B. May. 2010. Indirect genetic estimates of breeding population size in the polyploid green sturgeon (Acipenser medirostris). Molecular Ecology 19: 1058-1070.
Jones, O. and J. Wang. 2009. COLONY: a program for parentage and sibship inference from multilocus genotype data. Molecular Ecology Resources 10: 551-555.
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Kalinowski, S.T. 2005. HP-Rare: a computer program for performing rarefaction on measures of allelic diversity. Molecular Ecology Notes 5: 187-189.
Kjartanson, S.L. 2009. Population structure and genetic diversity of lake sturgeon (Acipenser fulvescens): evaluation of Designatable Units. M.Sc. Thesis, University of Toronto.
Lande, R. 1988. Genetics and demography in biological conservation. Science 241: 1455- 1460.
Luikart, G. and J.-M. Cornuet. 1999. Estimating the effective number of breeders from heterozygote excess in progeny. Genetics 151: 1211–1216.
Luikart, G., N. Ryman, D.A. Tallmon, M.K. Schwartz, and F. W. Allendorf. 2010. Estimation of census and effective population sizes: the increasing usefulness of DNA- based approaches. Conservation Genetics 11: 355–373.
McQuown, E., G.A.E. Gall, and B. May. 2002. Characterization and inheritance of six microsatellite loci in lake sturgeon. Transactions of the American Fisheries Society 131: 299-307.
Moyer, G.R., J.A. Sweka, and D.L. Peterson. 2012. Past and present processes influencing genetic diversity and effective population size in a natural population of Atlantic sturgeon. Transactions of the American Fisheries Society 141: 56-67.
Peakall, R. and P.E. Smouse. 2006. GENALEX 6: genetic analysis in Excel. Population genetic software for teaching and research. Molecular Ecology Notes 6: 288-295.
Robert, A. 2011. Find the weakest link. A comparison between demographic, genetic and demo-genetic metapopulation extinction times. BMC Evolutionary Biology 2011, 11:260
Rousset, F. 2008. GENEPOP’007: a complete re-implementation of the GENEPOP software for Windows and Linux. Molecular Ecology Notes 8: 103-106. Software available at http://kimura.univ-montp2.fr/~rousset/Genepop.htm
Scott, W.B. and E.J. Crossman. 1973: Freshwater Fishes of Canada. Fisheries Research Board of Canada, Minister of Supply and Services Canada, Ottawa.
Tallmon, D.A., A. Koyuk, G. Luikart, and M.A. Beaumont. 2008. ONeSAMP: A program to estimate effective population size using approximate Bayesian computation. Molecular Ecology Resources 8: 299-301.
Velez-Espino, L.A. and M.A. Koops. 2009. Recovery potential assessment for lake sturgeon in Canadian Designatable Units. North American Journal of Fisheries Management 29: 1065–1090.
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Velez-Espino, L.A. and M.A. Koops. 2012. Capacity for increase, compensatory reserves, and catastrophes as determinants of minimum viable population in freshwater fishes. Ecological Modelling 247: 319– 326.
Waples, R.S. and C. Do. 2008. LDNE: a program for estimating effective population size from data on linkage disequilibrium. Molecular Ecology Resources 8: 753-756.
Welsh, A., M. Blumberg, and B. May. 2003. Identification of microsatellite loci in lake sturgeon, Acipenser fulvescens, and their variability in green sturgeon, A. medirostris. Molecular Ecology Notes 3:47-55.
Welsh, A., T. Hill, H. Quinlan, C. Robinson, and B. May. 2008. Genetic assessment of lake sturgeon population structure in the Laurentian Great Lakes. North American Journal of Fisheries Management 28: 572-591.
Wozney, K.M., T.J. Haxton, S. Kjartanson, and C.C. Wilson. 2011. Genetic assessment of lake sturgeon (Acipenser fulvescens) population structure in the Ottawa River. Environmental Biology Fishes 90: 183-195.
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Table 1. Sampling groups for Saskatchewan River lake sturgeon with adjusted number of samples (N), mean number of alleles observed per locus (A), standardized allelic richness averaged over all loci (As), expected and observed heterozygosity (HE and HO), and
Wright’s within-population diversity coefficient (FIS).
N A As HE HO FIS
whole population 74 3.75 2.83 0.513 0.535 -0.035
whole population
(duplicate genotypes
removed) 64 3.75 2.86 0.516 0.534 -0.024
adult (age 23 cohort) 12 2.92 2.65 0.470 0.479 0.032
juveniles (age 2 cohort) 6 2.83 n/a 0.499 0.569 -0.051
larvae (age 1 cohort) 55 3.75 2.83 0.510 0.545 -0.056
larvae (age 1; duplicate
genotypes removed) 45 3.75 2.87 0.514 0.546 -0.046
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Table 2. Summary of estimated mean and 95% confidence intervals for effective population sizes (Ne) and effective number of breeders (Nb) for Saskatchewan River lake sturgeon.
LDNe (Ne) OneSamp (Ne) Colony (Ne) Colony (Nb)
whole 26.7 (22.8-
population 24.9 (16.4-39) 33.3) 27 (16-48) 33 (4-∞)
whole
population
(duplicate
genotypes 32.8 (20.6- 32.2 (27.1-
removed) 65.5) 41.7) 28 (17-50) 12 (3-∞)
13.3 (11.3-
adults (age 23) 26.1 (58.7-∞) 18.9) n/a n/a
juveniles (age
2) 21.9 (12-∞) 8.2 (7.0-12.1) n/a n/a
27.1 (23.3-
larvae (age 1) 13.5 (8.6-20.7) 33.8) 23 (13-43) 10 (3-∞)
larvae (age 1)
(duplicate
genotypes 22.9 (13.8- 28.3 (24.3-
removed) 41.8) 36.3) 20 (12-39) 28 (4-∞)
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Appendix I: Allele frequencies for all sample groups of Saskatchewan River lake sturgeon.
whole whole population adults juveniles larvae larvae (age 1) Locus Allele/n population (no duplicates) (age 23) (age 2) (age 1) (no duplicates) AfuG195 N 74 64 12 6 55 45 161 0.237 0.242 0.208 0.500 0.216 0.219 165 0.763 0.758 0.792 0.500 0.784 0.781
AfuG63 N 74 64 12 6 55 45 127 0.007 0.008 0.000 0.000 0.009 0.010 135 0.316 0.303 0.417 0.333 0.293 0.271 139 0.579 0.583 0.583 0.333 0.603 0.615 143 0.079 0.083 0.000 0.250 0.078 0.083 147 0.020 0.023 0.000 0.083 0.017 0.021
AfuG67 N 67 58 12 6 49 40 193 0.575 0.560 0.500 0.583 0.592 0.575 241 0.045 0.052 0.000 0.167 0.041 0.050 289 0.381 0.388 0.500 0.250 0.367 0.375
AfuG68 N 74 64 12 6 55 45 108 0.033 0.030 0.042 0.000 0.034 0.031 112 0.349 0.356 0.250 0.417 0.362 0.375 124 0.276 0.273 0.333 0.500 0.241 0.229 128 0.257 0.258 0.375 0.000 0.259 0.260 132 0.086 0.083 0.000 0.083 0.103 0.104
AfuG74 N 74 64 12 6 55 45 218 0.046 0.053 0.042 0.167 0.034 0.042 222 0.237 0.242 0.208 0.333 0.233 0.240 226 0.717 0.705 0.750 0.500 0.733 0.719
Appendix I (cont’d): Allele frequencies for all sample groups of Saskatchewan River lake sturgeon.
whole whole population Adults juveniles larvae larvae (age 1) Locus Allele/n population (no duplicates) (age 23) (age 2) (age 1) (no duplicates) AfuG160 N 74 64 12 6 55 45 135 0.434 0.447 0.500 0.333 0.431 0.448 147 0.342 0.333 0.417 0.583 0.302 0.281 151 0.224 0.220 0.083 0.083 0.267 0.271
AfuG61 N 70 60 11 6 53 43 196 0.529 0.542 0.545 0.583 0.519 0.535 200 0.471 0.458 0.455 0.417 0.481 0.465
AfuG68b N 72 62 12 6 54 44 157 0.139 0.137 0.125 0.000 0.157 0.159 165 0.035 0.040 0.083 0.000 0.028 0.034 173 0.021 0.024 0.000 0.083 0.019 0.023 177 0.063 0.056 0.042 0.083 0.065 0.057 181 0.549 0.556 0.625 0.667 0.519 0.523 185 0.021 0.024 0.000 0.000 0.028 0.034 189 0.167 0.153 0.125 0.167 0.176 0.159 201 0.007 0.008 0.000 0.000 0.009 0.011
AfuG71 N 74 64 12 6 55 45 231 0.132 0.136 0.208 0.083 0.121 0.125
235 0.868 0.864 0.792 0.917 0.879 0.875 AfuG112 N 73 63 12 6 55 45 247 0.021 0.024 0.083 0.000 0.009 0.011 251 0.116 0.127 0.125 0.250 0.100 0.111 255 0.178 0.198 0.167 0.250 0.173 0.200 259 0.432 0.421 0.208 0.333 0.491 0.489 263 0.253 0.230 0.417 0.167 0.227 0.189
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Appendix I (cont’d): Allele frequencies for all sample groups of Saskatchewan River lake sturgeon.
whole whole population Adults juveniles larvae larvae (age 1) Locus Allele/n population (no duplicates) (age 23) (age 2) (age 1) (no duplicates) AfuG9 N 71 61 12 6 53 43 128 0.063 0.066 0.000 0.000 0.085 0.093 144 0.725 0.713 0.917 0.917 0.660 0.628 148 0.035 0.033 0.000 0.000 0.047 0.047 152 0.176 0.189 0.083 0.083 0.208 0.233 AfuG56 N 74 64 12 6 55 45 262 0.079 0.083 0.083 0.333 0.052 0.052 266 0.757 0.765 0.750 0.667 0.767 0.781 274 0.164 0.152 0.167 0.000 0.181 0.167
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Appendix Four: Images from River2D analysis.
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Appendix Five: Summary of migration distances covered in 2010, 2011 and 2012 (rkms) by sturgeon tagged in 2009 at the forks (sturgeon found less than three times outside the wintering grounds were not used for analysis given insufficient data).
Total distance 2011 Total distance 2010 Total distance 2012 Frequency ID (rkms) (rkms) (rkms)
148.024.15 202.1 68.5 Dead battery 148.024.16 0.0 307.2 Dead battery 148.024.18 30.5 223.6 Dead battery 148.024.21 154.6 177.8 Dead battery 148.024.22 375.2 14.0 Dead battery 148.024.23 563.0 150.5 Dead battery 148.024.24 1126.0 157.9 Dead battery 148.065.2 135.8 124.8 59.3 148.065.3 65.2 175.7 Migrated without return 148.065.4 24.6 136.8 251.6 148.065.5 127.0 247.4 Insufficient data 148.065.8 44.0 63.8 Insufficient data 148.065.11 90.5 0.0 0.0 148.065.12 0.0 151.0 Migrated without return 148.065.13 388.2 249.5 Migrated without return 148.065.14 57.3 232.9 Migrated without return 148.065.15 6.9 175.2 Migrated without return 148.065.16 48.8 219.3 0.0 148.065.17 271.5 174.9 Migrated without return 148.065.19 240.5 161.7 0.0 148.065.20 267.7 261.5 199.9 148.065.21 158.1 0.0 363.2 148.065.23 305.0 0.0 248.6 148.065.24 79.1 93.0 Migrated without return 148.065.75 65.4 152.8 Migrated without return
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Appendix Six: Timing of migration of lake sturgeon from the wintering grounds (downstream of The Forks) and back again in 2010 and 2011.
Frequency ID 2010 2010 2011 2011 2012 2012 Initiation Return Initiation Return Initiation Return date date date date date date 148.065.02 131 263 134 244 136 246 148.065.03 115 234 139 235 146 237 148.065.4 122 222 138 222 147 Unknown 148.065.13 139 Unknown 159 Unknown 200 Unknown 148.065.14 181 237 134 Unknown 117 Unknown 148.065.20 112 181 154 289 202 238 148.065.24 145 240 134 235 208 Unknown Mean 135.0 229.5 141.7 245.0 165.1 240.3 SD 23.6 27.3 10.4 25.8 37.1 4.9
Note: Individuals discovered relatively late in the season (i.e. end of May beginning of June far from the wintering rounds were not used in this analysis).
Appendix Seven: Morphometrics and tagging data for all lake sturgeon captured in the 2012 survey near Borden Saskatchewan on the North Saskatchewan River.
Permanent Code Mass Length Girth PIT Tag #1 T-Bar #1 T-Bar Elastomer (Kg) (m) (m) #2 52420120001 6.40 0.86 0.36 1501199875790160 7101 7102 52420120002 12.30 1.12 0.44 900 1180 01339668 7103 7104 52520120003 0.78 0.51 0.20 900 1180 01342192 52920120004 16.80 1.27 0.47 900 1180 00140035 7105 7106 52920120005 0.90 0.52 0.22 900 1180 01340329 53020120006 1.30 0.62 0.23 900 1180 01340605 53020120007 0.65 0.48 0.19 R1,R2,B3 53020120008 2.80 0.66 0.25 900 1180 01342290 53020120009 2.70 0.66 0.25 900 1180 01338683 53120120010 3.00 0.73 0.27 900 1180 01341101 53120120011 2.60 0.65 0.25 R1,R2,B4 60620120012 1.08 0.55 0.23 R1, R3, B4 60620120013 5.00 0.87 0.31 900 1180 00140057 7109 7110 60620120014 4.90 0.82 0.32 900 1180 00140014 7112 7113 60720120015 1.58 0.66 0.24 R2,R3,B4 60720120016 5.02 0.87 0.35 900 1180 00140031 7114 7115 61920120017 1.75 0.66 0.28 900 2360 00174415 61920120018 1.55 0.63 0.25 900 2360 00174357 62020120019 21.20 1.46 0.55 900 1180 00140017 7117 7118 62020120020 1.70 0.66 0.26 900 2360 00174422 62120120021 1.85 0.65 0.27 900 2360 00174397 62620120022 0.95 0.54 0.23 900 2360 00174367 62620120023 2.40 0.73 0.24 900 2360 00174382 62620120024 2.20 0.73 0.26 900 2360 00174370 62720120025 1.90 0.65 0.25 900 2360 00174402
70420120026 1.70 0.67 0.26 900 2360 00174431 70420120027 2.75 0.78 0.30 900 2360 00174378 70420120028 1.55 0.68 0.25 900 2360 00174399 61920120017 1.75 0.66 0.28 900 2360 00174415 71020120030 1.75 0.68 0.25 900 2360 00174425 71120120031 0.80 0.52 0.20 R1, O2, R3 71120120032 1.25 0.59 0.24 900 2360 00174436 71120120033 2.00 0.71 0.27 900 2360 00174385 71220120034 1.40 0.64 0.25 900 2360 00174411 71220120035 2.65 0.82 0.22 900 2360 00174366 71220120036 2.85 0.80 0.30 900 2360 00174412 71720120037 1.50 0.64 0.24 900 2360 00174360 71720120038 1.20 0.61 0.23 900 2360 00174361 71820120039 4.00 0.84 0.32 900 2360 00174429 71820120040 1.20 0.64 0.23 900 2360 00174427 71920120041 1.80 0.67 0.26 900 2360 00174407 71920120042 1.55 0.64 0.24 900 2360 00174454 72420120043 1.50 0.66 0.24 900 2360 00174396 72420120044 1.05 0.58 0.21 900 2360 00174364 72420120045 1.20 0.58 0.22 900 2360 00174444 72520120046 1.50 0.64 0.26 900 2360 00174439 72520120047 1.00 0.61 0.22 900 2360 00174438 72520120048 1.55 0.64 0.24 900 2360 00174447 72420120049 11.65 1.19 0.46 982 0003 57504274 7120 7121 72620120050 0.75 0.53 0.19 900 2360 00174358 72520120051 15.40 1.30 0.53 982 0003 57504313 7227 7202 73120120052 2.10 0.70 0.26 900 2360 00174441 73120120053 2.05 0.71 0.26 900 2360 00174404 80120120054 1.10 0.56 0.22 900 2360 00174390 80120120055 0.80 0.51 0.20 900 2360 00174365
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80120120056 1.95 0.71 0.26 900 2360 00174419 80120120057 0.85 0.53 0.20 900 2360 00174450 80220120058 1.70 0.67 0.25 900 2360 00174375 80220120059 1.40 0.61 0.23 900 2360 00174428 80220120060 1.65 0.64 0.25 900 2360 00174453 80220120061 1.35 0.62 0.23 900 2360 00174420 80220120062 2.15 0.70 0.25 900 2360 00174434 80220120063 5.85 0.96 0.36 982 0003 57504293 7203 7228 80220120064 13.65 1.35 0.46 982 0003 57504300 7229 7230 80220120065 8.25 1.06 0.41 900 1180 00139876 7231 7232 80820120066 1.75 0.62 0.24 900 2360 00174446 80820120067 1.60 0.57 0.22 900 2360 00174356 80820120068 5.00 0.88 0.35 982 0003 57504299 7233 7235 80820120069 4.00 0.84 0.33 900 2360 00174380 80820120070 1.15 0.56 0.22 900 2360 00174387 80920120071 4.95 0.90 0.33 982 0003 57504271 80920120072 1.80 0.66 0.24 900 2360 00174394 80920120073 2.20 0.68 0.27 900 2360 00174388 80920120074 0.65 0.47 0.19 R1, O2, R4 80920120075 7.95 0.94 0.40 982 0003 57504314 7236 7237 81420120076 0.33 0.38 0.15 R1, O3, R4 81520120077 1.10 0.55 0.22 900 2360 00174445 81520120078 1.30 0.61 0.24 900 2360 00174373 81520120079 1.80 0.68 0.25 900 2360 00174355 81620120080 3.90 0.83 0.33 900 2360 00174414 81620120081 1.15 0.63 0.24 900 2360 00174432 81620120082 2.70 0.79 0.29 900 2360 00174451 81620120083 1.20 0.58 0.21 900 2360 00174391 81620120084 7.35 1.05 0.38 982 0003 57504298 7238 7239 81620120085 9.80 1.12 0.45 982 0003 57504325 7240 7241
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81620120086 11.65 1.17 0.45 900 1180 00140039 7242 7243 82220120087 1.10 0.54 0.22 900 2360 00174442 82220120088 12.25 1.23 0.45 900 1180 00140080 82220120089 1.60 0.62 0.25 900 2360 00174408 82220120090 1.15 0.60 0.24 900 2360 00174433 82220120091 6.35 0.95 0.37 982 0003 57504326 82220120092 1.65 0.66 0.25 900 2360 00174417 82220120093 2.60 0.76 0.29 900 2360 00174389 82320120094 2.20 0.75 0.29 900 2360 00174395 82320120095 1.70 0.69 0.24 900 2360 00174372 82320120096 17.85 1.43 0.50 982 0003 57504296 82820120097 1.95 0.70 0.26 900 2360 00174418 82820120098 6.05 0.94 0.38 900 1180 00140076 82920120099 2.45 0.79 0.28 900 2360 00174410 80120120056 2.40 0.72 0.26 900 2360 00174419 82920120101 4.40 0.87 0.31 900 2360 00174363 117
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Appendix Eight: Area use and migration maps for radio tagged sturgeon in the Saskatchewan River system based on 2011 telemetry relocation.
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