EFFECTS OF ENVIRONMENTAL FACTORS, PHYSICAL
BARRIERS AND SEASON ON THE FISH COMMUNITY
COMPOSITION OF THE LOWER OTTAWA AND
MISSISSIPPI RIVER SYSTEMS AS DETERMINED
FROM QUANTITATIVE ELECTROFISHING
by
Andrew G. Lowles
A thesis submitted to the Department of Biology
In conformity with the requirements for
the degree of Master of Science
Queen’s University
Kingston, Ontario, Canada
(January 2013)
© Andrew G. Lowles
ABSTRACT
Environmental and physical conditions are considered primary drivers of fish community assemblages. The anthropogenic alteration of aquatic ecosystems is implicated as a primary threat to fisheries worldwide. In riverine ecosystems, river-wide barriers may alter natural fluvial processes and hinder fish movement through the system.
In this study, I use data collected from two successive years (2008 and 2009) of intensive quantitative electrofishing Casselman and Marcogliese (2008, 2009) performed in different seasons (late fall and late summer) on the lower Ottawa and Mississippi River systems, Ontario, to investigate the effects of sampling season, distance from the river mouth, water temperature, conductivity, rank of velocity and dams on fish abundance, species richness and the Shannon-Weiner Index (SWI) as a measure of species diversity.
Sampling in late summer, compared with late fall, resulted in greater species richness and diversity. Colder water temperature affected community composition, and species richness decreased upstream, while diversity did not change. In both seasons, the distance from the river mouth influenced fish community composition, whereas dams appeared to have no effect. This suggests that the continuous gradient model of the River Continuum
Concept (RCC) would be applicable in these fragmented systems, which are not heavily altered by fractionation. To effectively manage cost and accuracy when collecting fish community data in large rivers, it is essential to sample strategically during seasons likely to maximize diversity and richness. Sampling intensively during warm water months in various river reaches would likely provide the most complete representation of fish assemblage.
ii CO-AUTHORSHIP
This thesis conforms to the traditional format as outlined by the School of Graduate
Studies and Research.
Lowles, A.G., J.M. Casselman, and W.A Nelson. 2013. Effects of environmental factors, physical barriers and season on the fish community composition of the lower Ottawa and
Mississippi Rivers systems as determined from quantitative electrofishing.
iii ACKNOWLEDGEMENTS
I would like to begin by thanking my supervisors Dr. John Casselman and Dr.
William Nelson for having me as their student, and for their continued support and guidance throughout my thesis. Your guidance and mentorship has been instrumental in my development over the past three years. I would like to thank you both for providing me the opportunity to pursue my interest in fisheries science and advance my abilities as a researcher. I appreciate the additional support and guidance of my supervisory committee member, Dr. Shelley Arnott, and examiner, Dr. Paul Martin. I would like to thank Dr. Robert Montgomerie for all his help throughout my time at Queen’s University.
I would like to thank Dr. John Casselman and Lucian A. Marcogliese for allowing me to use the quantitative electrofishing data collected by AFishESci Inc. Without this data my thesis would not have been possible.
The analytical support and advice by Nathan McClure and Andy Wong have been a great asset throughout my project. Without their knowledge of R programming, data analysis would have been extremely tedious.
I would like to thank my family and friends for their support and encouragement throughout my studies. I would like to thank Dan and Lyla Galley for their continuing support throughout my time in Kingston. My parents, Doug and Marilyn, my brother
Steve, and sister-in-law, Holley, have been a tremendous support and inspiration through all aspects of my life. Finally, I want to thank my wife, Erin, and daughter Kendall for their love and encouragement throughout my studies. Without their support, none of this would have been possible. You are my motivation and the foundation on which the rest of my life is built.
iv TABLE OF CONTENTS
Abstract...... ii
Co-Authorship...... iii
Acknowledgements...... iv
Table of Contents...... v
List of Abbreviations...... viii
List of Tables...... ix
List of Figures...... xi
Chapter 1 Introduction ...... 1
Chapter 2 Review of Literature...... 6
2.1 Fish Community Composition and Structure and Fisheries Management...... 7
2.2 Niche Concept and Competition...... 8
2.3 Environmental Conditions...... 10
2.4 River Continuum Concept...... 12
2.5 Impact of River Barriers on Fish...... 14
2.6 Fish Sampling Techniques...... 15
2.7 Species and Fish Community Diversity...... 17
2.8 Research Rationale and Study Objectives...... 19
Chapter 3 Materials and Methods...... 20
3.1 Rivers Studied...... 20
3.2 Sampling Location Criteria...... 21
3.3 Data Collection...... 22
3.4 Richness and Diversity...... 25
v 3.5 Annual Changes in Fish Assemblages...... 26
3.6 Environmental Variables and Fish Assemblages...... 27
3.7 Below-Dam and Above-Dam Comparisons...... 28
Chapter 4 Results...... 40
4.1 Fish Abundance, Occurrence, Composition and Density...... 40
4.2 Species Richness...... 42
4.3 Species Diversity...... 43
4.4 Effects of Physical and Environmental Variables...... 43
4.4.1 Distance to River Mouth...... 43
4.4.2 Water Temperature...... 44
4.4.3 Conductivity...... 45
4.4.4 Velocity...... 45
4.5 Annual Change in Species Composition...... 46
4.6 Fish Assemblages and Physical and Environmental Variables...... 47
4.7 Below-Dam and Above-Dam Comparisons...... 47
Chapter 5 Discussion...... 79
5.1 Fish Abundance and Density...... 79
5.2 Species Richness and Diversity...... 80
5.3 Changes in Species Composition Between Years...... 81
5.4 Effect of Dams on Water Velocity...... 82
5.5 Effect of Physical Distance and Reach Length on Richness and Diversity...... 83
5.6 Anthropogenic Factors Affecting Richness and Diversity...... 85
5.7 Effect of Environmental Variables...... 86
vi Chapter 6 Conclusions and Summary...... 89
6.1 Conclusions and Summary...... 89
6.2 Future Research Considerations...... 90
Literature Cited...... 91
Appendix A Scientific Species Codes, Family, Genus, Species and Species’ Common names...... 104
Appendix B River Reaches and Sample Locations...... 116
Appendix C Supplementary Analysis...... 126
vii LIST OF ABBREVIATIONS
Ha Hectares
PC Principal Components
PCA Principal Component Analysis
RDA Redundancy Analysis
RCC River Continuum Concept
SAR Species at Risk
SWI Shannon Wiener Index
μs Microsiemens
viii LIST OF TABLES
Table 1. Electrofishing location survey, 2008 and 2009, Ottawa River...... 30
Table 2. Electrofishing location survey, 2008 and 2009, Mississippi River...... 31
Table 3. Electrofishing effort, 2008, Ottawa and Mississippi rivers...... 32
Table 4. Electrofishing effort, 2009, Ottawa and Mississippi rivers...... 33
Table 5. Date of sampling, distance from the river mouth, and water temperature for each location, 2008, Ottawa River...... 35
Table 6. Date of sampling, distance from the river mouth, and water temperature for each location, 2008, Mississippi River...... 36
Table 7. Date of sampling, distance from the river mouth, water temperature, conductivity and rank of velocity for each location, 2009, Ottawa River....37
Table 8. Date of sampling, distance from the river mouth, water temperature, conductivity and rank of velocity for each location, 2009, Mississippi River...... 38
Table 9. Relative species abundance, 2008, Ottawa River system...... 49
Table 10. Relative species abundance, 2008, Mississippi River system...... 51
Table 11. Relative species abundance, 2009, Ottawa River system...... 53
Table 12. Relative species abundance, 2009, Mississippi River system...... 57
Table 13. Species loadings, principal component analysis, Ottawa River system...... 59
Table 14. Species loadings, principal component analysis, Mississippi River system....60
Table A-1. Numeric species codes, family, genus and species common names...... 105
Table A-2. Species abundance at each location, 2008, Ottawa River system...... 108
Table A-3. Species abundance at each location, 2008, Mississippi River system...... 110
Table A-4. Species abundance at each location, 2009, Ottawa River...... 112
Table A-5. Species abundance at each location, 2009, Mississippi River...... 114
ix
Table C-1. Species loadings (including golden shiner), principal component
analysis, Ottawa River system...... 127
x LIST OF FIGURES
Figure 1. Map of the Ottawa and Mississippi rivers and dam locations...... 39
Figure 2. Mean fish densities per hectare for the Ottawa and Mississippi river systems in 2008 and 2009...... 61
Figure 3. Mean fish densities per hectare for river data pooled for each year and both years pooled for the Ottawa and Mississippi rivers...... 62
Figure 4. Mean species richness values for the Ottawa and Mississippi river systems in 2008 and 2009...... 63
Figure 5. Mean species richness values for river data pooled for each year and both years pooled for the Ottawa and Mississippi rivers...... 64
Figure 6. Mean Shannon Wiener Index values for the Ottawa and Mississippi river systems in 2008 and 2009...... 65
Figure 7. Mean Shannon Wiener Index values for river data pooled for each year and both years pooled for the Ottawa and Mississippi rivers...... 66
Figure 8. Pearson’s Correlation Analysis of species richness at varying distances from the river mouth for the Ottawa River and Mississippi rivers, 2008 and 2009...... 67
Figure 9. Pearson’s Correlation Analysis of Shannon-Wiener Index values at varying distances from the river mouth for the Ottawa and Mississippi rivers, 2008 and 2009...... 68
Figure 10. Pearson’s Correlation Analysis of species richness at varying water temperatures for the Ottawa and Mississippi rivers, 2008 and 2009...... 69 Figure 11. Pearson’s Correlation Analysis of Shannon-Wiener Index values at varying water temperatures for the Ottawa and Mississippi rivers, 2008 and 2009...... 70
xi Figure 12. Pearson’s Correlation Analysis of species richness at varying levels of conductivity for the Ottawa and Mississippi rivers, 2008 and 2009...... 71
Figure 13. Pearson’s Correlation Analysis of Shannon-Wiener Index values at varying levels of conductivity for the Ottawa and Mississippi rivers, 2008 and 2009...... 72
Figure 14. Pearson’s Correlation Analysis of species richness at varying water velocities for the Ottawa and Mississippi rivers 2009...... 73
Figure 15. Pearson’s Correlation Analysis of Shannon-Wiener Index values at varying water velocities for the Ottawa and Mississippi rivers 2009...... 74
Figure 16. Principal component analysis of the Ottawa River system community...... 75
Figure 17. Principal component analysis of the Mississippi River system...... 76
Figure 18. Redundancy analysis of environmental variables and species composition of the Ottawa River system, 2009...... 77
Figure 19. Redundancy analysis of environmental variables and species composition of the Mississippi River system, 2009 survey...... 78
Figure B-1. Ottawa River. Reach 1- Lac des Deux Montagnes. Locations 26, 1 and 27...... 117
Figure B-2. Ottawa River. Reach 2 – Lac Dollard des Ormeaux. Locations 2, 28, 29 and 3...... 118
Figure B-3. Ottawa River. Reach 3 – Lac Deschenes. Locations 4-7...... 119
Figure B-4. Ottawa River. Reach 4 – Lac des Chats. Locations 9-14...... 120
Figure B-5. Mississippi River. Reach 1 – Mississippi River mouth upstream to Galatta Dam. Locations 15-16...... 121
xii Figure B-6. Mississippi River. Reach 2 – Galatta Dam upstream to Almonte Dam. Location 17...... 122
Figure B-7. Mississippi River. Reach 3 – Almonte Dam upstream to Appleton Dam. Location 18...... 123
Figure B-8. Mississippi River. Reach 4 – Appleton Dam upstream to Carleton Place Dam. Locations 19-20...... 124
Figure B-9. Mississippi River. Reach 5 – Carleton Place Dam upstream to High Falls Dam. Locations 21-24...... 125
Figure C-1 Principal component analysis, Ottawa River system, 2008 with all sample locations included...... 128
xiii CHAPTER 1
INTRODUCTION
Increased stress imposed on waterways has created the need to monitor the response of aquatic communities to changes in physical and environmental conditions
(Bunn et al. 2010; Poirier and de Loë 2011). In freshwater aquatic ecosystems, environmental and physical conditions are considered primary drivers of fish community assemblages and regional species pools (Stauffer et al. 2000; Geener et al. 2004; Irz et al.
2007). In many systems, competition, predation and other biological interactions are important in influencing fish assemblages (Blanchet et al. 2007; Irons et al. 2007). Quist and Hubert (2005) suggest that where densities of a predator are high or competition is severe, the success of the suppressed species will be reduced, regardless of environmental conditions. They define this interaction as the Biotic-Abiotic Constraining Hypothesis.
Complex combinations of abiotic and biotic interactions may facilitate a competitive advantage of individual species (Johnson et al. 1995; Gido et al. 2009). Persson (1997) implicates pH as affecting populations of perch (Perca fluviatilis), a species that, when abundant, directly affects the abundance of other species.
In addition to environmental and physical conditions typical of lake systems, riverine systems are affected by changes in river gradient, stream order and magnitude.
The River Continuum Concept (RCC) suggests physical and chemical composition changes along the length of a river. These changes contribute significantly towards structuring aquatic communities (Vannote et al. 1980; Minshall et al. 1985; Sedell et al.
1989; Lorenz et al. 1997). At the origin, or headwater, of a stream, species diversity and nutrient concentrations are typically lower and increase towards the larger river bottoms,
1 where diversity and nutrients are in greatest supply (Sedell et al. 1989). Between these two extremes lie varying degrees of physical and chemical gradients that influence community composition (Vannote et al. 1980)
Human dependence on water for electricity, industry and transportation has changed aquatic ecosystems, with a pronounced effect on fish communities (Jackson et al. 2001b; Lotze and Milewski 2004). Among the most visible human influences on aquatic communities are species exploitations that may reduce individual species abundance and community balance (Jackson et al. 2001b; Lotze and Milewski 2003); climate change, which may alter natural environmental conditions beyond the threshold of native species (Schindler 2001; Brander 2007); species introductions, both intentional and accidental, resulting in competition with native species for resources (Cambray 2003;
Dextrase and Mandrak 2006; Irons et al. 2007); and terrestrial habitat destruction that may change water chemistry (Bojsen and Barriga 2002). Riverine alteration away from natural seasonal processes such as flow regulation and river impoundment may limit access to spawning habitat and reduce species abundance and distribution (Schick and
Lindley 2007; Schilt 2007; Reid et al 2008; Wang et al. 2011).
Further changes in both physical and chemical processes are magnified by the regulation of large river systems for hydroelectricity, transportation and recreation.
Changes resulting from river impoundment are implicated as a primary threat to fish community assemblages of riverine ecosystems worldwide (Schick and Lindley 2007;
Haxton and Findlay 2009; Wang et al. 2011). Hydroelectric dams dramatically modify hydrology and alter the natural state of large riverine ecosystems (Haxton and Chubbuck
2002). Changing environmental conditions that result from large-scale impoundments
2 may include water warming (Friedl and Wüest 2002; Malmqvist and Rundle 2002), sediment loading (Molisani et al. 2006), changes in nutrient cycles (Friedl and Wüest
2002), decreased dissolved oxygen (Wellner and Dinger 1989), and abnormal seasonal water velocity fluctuations (Malmqvist and Rundle 2002). Large-scale water retention in riverine systems not only alters environmental conditions but limits the physical connectivity of riverine ecosystems, preventing migratory species from reaching areas of biological importance (Katano et al. 2006; Welsh and McLeod 2010).
Fish ladders have been put in place in an attempt to alleviate the impact of barriers and create connectivity for migratory species; however, their success has varied because not all fish species are able to use them (Calles and Greenberg 2009; Schilt 2007).
Species capable of bypassing hydroelectric facilities on their upstream migrations may experience reduced survival on downstream passages as fish ladders do not appear to be used for downstream movement and may expose fish to turbines (Carr and Whoriskey
2008). Recent concerns surrounding Species at Risk (SAR) and decreasing biodiversity have implicated anthropogenic impacts as primary factors driving change in species assemblages and causing extinction.
In order to recognize changes in fish assemblages, managers are faced with the challenge of collecting detailed community data. A high-quality assessment of fish community composition in natural environments is difficult to obtain because of inherent difficulties in sampling techniques (passive methods, fish body shape, etc.) and environmental conditions (current, dense vegetation, etc.) (Perrow et al. 1996; Scholten
2003). This task becomes increasingly problematic in large river ecosystems, where the estimation of fish densities is a major hurdle in fisheries management and ecology
3 (Scholten 2003), but is necessary to measure the impacts of varying environmental conditions and anthropogenic influences on fish communities.
Most netting techniques are passive and rely on the movement of fish to become captured. Netting commonly targets a specific fish community, and may be biased to a number of physiological and behavioural fish traits (Murphy and Willis 1996; Garner
1997). In contrast to common passive fishing techniques, electrofishing is an active technique where the sampling boat follows a predetermined transect and uses a calculated amperage, voltage and width of electrical field to sample all fish within a calculated area.
The electrofishing unit may be adjusted so that it samples all fish within the electrical field, regardless of body size or shape (Casselman 2008), allowing for an accurate comparison of relative fish abundance comparable with less effort and cost than conventional methods (Copp 2010).
Previous studies have used a variety of collection techniques to examine the influence of physical and environmental variables and the impact of barriers and river fragmentation on individual species (Arthaud et al. 2010; Ivan et al. 2010). Studies of species richness and diversity frequently occur in small-order tributaries (Katano et al.
2006; Bond et al. 2010). This study used fish community data from two successive years of quantitative electrofishing on the lower reaches of the Ottawa River and its tributary, the Mississippi River, in Ontario, Canada, to investigate the influence on fish assemblages of key environmental factors such as sampling season; water temperature, conductivity, and velocity; and river connectivity. Environmental variables are easily measured and must be considered when the electrofishing unit is calibrated. In addition, physical upstream distance from the river mouth tests the applicability of the RCC in
4 dammed waterways and provides important insights into the dispersal capabilities of fish species. This investigation analyzes the correlation of physical and environmental factors correlate with shallow water fish community structure and fish species diversity in a large, highly regulated temperate riverine environment.
5 CHAPTER 2
REVIEW OF LITERATURE
The ecological niche of a species is characterized by their position within an ecosystem, and is comprised of habitat requirements and functional role. Species introductions, extirpations and general shifts in population may have cascading effects on ecosystem function and biodiversity (Cambray 2003). In riverine environments, conditions may fluctuate temporally and spatially along a longitudinal gradient, creating niche variability for individual species within the community (Vannote et al. 1980; Heggenes et al. 1999).
Anthropogenic influences such as river impoundment alter the natural conditions of rivers, resulting in changes to species composition (Pool et al. 2010). In order to monitor such changes, species composition in fish communities must be measured in the most efficient manner to maximize accuracy and minimize effort, thus cost (Maher et al.
1994).
Quantitative electrofishing provides a more complete measure of fish within a calculated area than do conventional methods (Casselman 2008). At the time of fishing, water conditions (water temperature and conductivity) are used to calculate catch area, sampling all fish within the area. Electrofishing data may be used to explore relationships between species community and environment. Indices are often used to describe communities where numerical values are assigned to describe the number of species and their distribution in a particular area of measurement (Tuomisto 2010a,
Tuomisto 2010b). These indices provide insight into relationships between environmental and physical conditions and fish communities and can be applied to fish sampling methodologies and fisheries management strategies.
6 2.1 Fish Community Composition and Structure and Fisheries Management
Fish community composition is determined by a complex combination of species interactions and niche factors (Werner and Gilliam 1984; Bonin et al. 2009), species tolerance to environmental conditions (Buisson et al 2008; Bonin et al. 2009) and the availability of species in regional species pools (Jackson et al. 2001a; Leps 2001; Gido et al. 2009). In riverine ecosystems, species are influenced by changes in physiochemical characteristics associated with downstream gradient (Minshall et al. 1985).
Anthropogenic influences have had a pronounced impact on modern-day fish community structure (Rosso and Quirós 2009), from the impoundment of rivers for power generation and the associated change in natural fluvial processes (Schilt 2007;
Reid et al. 2008; Wang et al. 2011) to the introduction of alien species (Cambray 2003;
Strayer 2010). Humans continue to contribute to the shaping of fish assemblages (Minns
1989; Winston et al. 1991; Schindler 2001). The reshaping of fish community structure is often a deliberate attempt to increase commercial yield or to improve recreational opportunities. Traditional fisheries management approaches often target and manage for a single species in an attempt to achieve short-term harvest goals (Pitchford et al. 2007).
Contemporary approaches to fisheries management must consider not only natural processes but also anthropogenic influences on aquatic ecosystems (Minns 1989;
Collares-Pereira and Cowx 2004). Managers must aim to protect the habitat of species at risk and mitigate the factors that have caused their decline.
In order to achieve current goals in management and biodiversity, data collection representative of modern technology facilitates a more complete ecological picture
(Neebling and Quist 2011). Managers must attempt to balance the biological, social and
7 economic objectives in fisheries management (Lane and Stephenson 1995). Modern data collection methods are capable of more accurate population estimates because of their efficiency and less biased collection methods. Technology has increased the ability of researchers to make connections between fish populations and ecological conditions.
2.2 Niche Concept and Competition
In determining fish community composition, each species has a fundamental niche that reflects different environmental conditions. The fundamental niche may be used as an estimation of potential geographic distribution of a species in response to environmental and physical conditions such as water temperature or velocity (Malanson et al. 1992; Soberón and Peterson 2005). When the requirements of a species’ fundamental niche have been satisfied, a series of competitive and predator/prey interactions influences the species’ realized niche (Persson 1997; Jackson et al. 2001a;
Gido et al. 2009). The realized niche is the actual niche space occupied by an organism subject to competition, in the natural environment (Malanson et al. 1992). For example, the realized niche of yellow perch (Perca flavescens) in the Ottawa River is one of a middle trophic level species, where the perch prey upon smaller baitfish species such as golden shiner (Notemigonus crysoleucas) but are prey themselves of larger piscivores such as largemouth bass (Micropterus salmoides) and walleye (Sander vitreus).
Interspecific competition resulting from several species competing for the same limited resource often results in competitive exclusion (Bonin et al. 2009) and has become more common with the introduction of exotic species (Ross 1991). Competition may be for food, shelter, spawning habitat, etc., causing the depressed species to seek
8 lower-quality environments. Blanchet et al. (2007) found that the presence of introduced rainbow trout (Oncorhynchus mykiss) significantly affected habitat selection and apparent survival of native brown trout (Salmo trutta fario). Intraspecific competition may have a strong influence on the reproductive success and survival of individuals within a population. Intraspecific competition appears to be infrequent outside of controlled experiments (Reichard et al. 2004). However, this may be difficult to measure in natural settings where external factors can mask the effects of intraspecific interactions. Species are in apparent competition when, through a shared predator, the presence of either species has negative impacts on the density of the other (Holt 1977). The interactions between prey species and a shared predator are important in structuring fish communities
(Persson 1997). In the presence of select predatory species, small-bodied prey species within their geographical range and fundamental niche are absent (Jackson et al. 2001a).
These species interactions are the driving forces that shape fish communities. Since riverine ecosystems are dynamic, changing conditions may favour different species at any given time. For instance, predation by piscivorous species can virtually eliminate the coexistence of smaller-bodied prey species, such as cyprinid assemblages, that demonstrate strong negative relationships with larger-bodied predators (Jackson et al.
2001a). Species capable of tolerating fluctuating environmental conditions or migrating to a section of river where conditions are favourable are likely to be successful.
Food web dynamics can be affected by longitudinal gradients in temperature, flow, and depth, resulting in varying species composition throughout the length of a river
(Romanuk et al. 2006). Often predictably, food webs change with differing community compositions resulting from changes in temperature and nutrients along the longitudinal
9 gradient of a stream (Vannote et al. 1980). In riverine ecosystems, clear, cooler water is found near the headwaters, where different aquatic invertebrates and fish communities may be found despite their having access to warmer downstream areas. This is common in Lake Ontario’s cold-water tributaries, where cold-water species such as trout are common in the upper reaches, although summer temperatures around the river mouth will not support resident trout and they are replaced by warm-water piscivores such as pike and bass. An increased risk of predation may also cause prey species to utilize other areas within the water body to avoid predation (Luek et al. 2010; Jackson et al. 2001a).
2.3 Environmental Conditions
In aquatic ecosystems, physical and chemical factors, including temperature, dissolved oxygen, acidity, turbidity, gradient, flow, and depth, all play important and often limiting roles in determining fish assemblages (Merigoux et al. 1998; Meador and
Goldstein 2003; Costas et al. 2009; Haxton and Findlay 2009). The ecological integrity and community composition of riverine ecosystems depend on the natural dynamics of thermal regimes (Olden and Naiman 2010).
Water temperature is among the most influential environmental factors determining fish community composition (Buisson and Grenouillet 2009). Each species has an optimal temperature and lethal limits, or tolerance, to temperature fluctuations
(Portner and Peck 2010). A species’ geographical range may be limited by seasonal temperature regimes (Jackson et al. 2001a). Thermal conditions within a single water body may affect the vertical distribution of fish (Schindler 2001). In deeper water bodies, water stratifies as density changes with temperature, resulting in spatial segregation of
10 fish assemblages corresponding to temperature within the water column (Blanchfield et al. 2009). Streams and rivers are prone to elevated temperature in slow-moving sections, affecting species occurrence, abundance and survival (Lyons et al. 2010). Being ectothermic, fish require a range of temperature regimes at various life stages, and any single species may require different thermal conditions and habitats to satisfy the requirements of survival, growth and reproduction (Buisson et al. 2008, Costas et al.
2009).
While temperature is of primary importance, dissolved oxygen levels may affect fish community composition (Merigoux et al. 1998). A strong link exists between dissolved oxygen and water temperature, as the ability of water to concentrate dissolved oxygen increases at cooler water temperatures. Large predatory species generally have greater oxygen requirements than many smaller species (Danylchuk and Tonn 2003;
Ohman et al. 2006), which may result in the loss of larger predatory species from winter anoxic events in lakes (Nurnberg 1995).
Current velocity and depth are also important habitat variables that affect riverine fish communities (Bain et al. 1988; Jackson et al. 2001a; Leclerc and Desgranges 2005;
Bond et al. 2010). River morphology influences water velocity and depth of streams developing riffle-pool sequences or a more gradual gradient of slow-moving water
(Jackson et al. 2001a). Riverine ecosystems are subject to variability in flow regimes.
Within a stretch of river where current velocity increases in the main channel, species may have specialized adaptations to cope with increased flow (Dettmers et al. 2001).
Stream flow may indirectly affect fish through alterations in habitat suitability, nutrient cycling, and food availability (Dettmers et al. 2001; Arthaud et al. 2010).
11 The direct effects of stream flow may cause potentially lethal oxygen levels and temperatures in wide, slow-moving sections of river where prolonged sun exposure increases water temperatures and decreases oxygen solubility (Schlosser 1990; Olden and
Naiman 2010). Smaller rivers and headwater streams are seasonally subject to fluctuating or surging environmental conditions as a result of lower buffering capabilities relative to large rivers that demonstrate increasing environmental stability downriver
(Jackson et al. 2001a). When water flow has been altered to suit the anthropogenic needs of hydroelectricity and recreation, organisms may be exposed to unpredictable water conditions (Bain et al. 1988).
Point source contamination of surface water from large tracts of agricultural or pasture land (Meador and Goldstein 2003), as well as urbanization (Wheeler et al. 2005), often leads to decreased water quality on a gradient downstream from headwaters because of the accumulation of nutrients and pollutants from the surrounding catchment basin (Karr and Dudley 1981; Meador and Goldstein 2003; Wheeler et al. 2005). These areas of contamination and increased agricultural runoff may cause localized spikes in conductivity and nutrient concentration (Wheeler et al. 2005; Jeffries et al. 2010).
2.4 River Continuum Concept
The River Continuum Concept (RCC) states that naturally flowing waterways are subject to a series of predictable changes in physiochemical characteristics associated with a downstream gradient (Minshall et al. 1985). Changes observed in temperature, oxygen saturation, water velocity, conductivity, etc. between upstream and downstream reaches of a river systems may be dramatic, creating very different environmental and
12 physical conditions throughout a single waterway. Vannote et al. (1980) suggest that river systems are a continuous system of physical gradients, that river biota can be predicted within a riverine system where species occurring in downstream reaches capitalize on the shortcomings of upstream species, and that each river reach establishes producer and consumer communities reflective of physical characteristics of the river channel. It is generally accepted that species diversity in riverine ecosystems increases progressively with distance downstream from the headwaters (Joy and Death 2001).
Contrary to the continuous gradient model of the RCC, regulated waterways are subjected to different factors, producing different aquatic ecosystems (Sedell et al. 1989).
A disconnect between river reaches as a result of dams and lakes causes impounded reaches to be considered independent of successive reaches. Sedell et al. (1989) studying the Moisie River, Quebec, Canada, suggest that lakes act in a similar fashion, causing segregation, and that the RCC cannot be applied to all river systems. Specifically, constraints with both the natural riffle-pool systems and dammed river impoundments are not addressed by the RCC, which does not consider differences in river reaches. The construction of large, lentic-type environments reflective of river impoundments creates large areas of heated surface water, alters thermal regimes, facilitates stratification and causes shifts in natural nutrient movement. Thus, the RCC must consider river morphology and cannot be applied to all riverine ecosystems (Minshall et al. 1985; Sedell et al 1989).
13 2.5 Impact of River Barriers on Fish
Riverine ecosystems are often impounded for production of hydroelectricity and to control downstream flooding of urban areas (Angelidis et al. 2010), resulting in water retention and unnatural seasonal flows (Olden and Naiman 2010). As a result, large reservoirs are formed, creating expanses of warmer water during the summer and early fall and cooler water in the spring, resulting in downstream changes in thermal regimes and flow (Dettmers et al. 2001; Olden and Naiman 2010). Damming creates an environment that is particularly susceptible to variability where resident organisms must be capable of tolerating fluctuations. Ivan et al. (2010) suggested that damming of large rivers creates impoundments that release water of unseasonably low temperature into spawning areas utilized by walleye (Sander vitreus), resulting in decreased egg survival.
Fish dispersal is important at various life stages for species sustainability (Tewfik and Béné 2003; Beesley and Prince 2010). Dams may fragment habitat, limiting both upstream and downstream dispersal, which is necessary for spawning, refuge and nursery areas that can affect species composition and recruitment at different reaches of a river
(North et al. 1993; Schick and Lindley 2007; Han et al. 2008b). Inferences can be made on the impact of river barriers on fish diversity and richness through the comparison of locations in close proximity above and below dams. Species present historically may appear rare or absent altogether during sampling. Lake sturgeon (Acipenser fulvescens),
American eel (Anguilla rostrata) and American shad (Alosa sapidissima), which once used various reaches of the Ottawa River system (Haxton and Chubbuck 2002), may now have limited access to upstream habitat because of barriers and because these species may not use fish ladders.
14 2.6 Fish Sampling Techniques
Current knowledge of fish community composition, particularly in large rivers, is largely fragmented and often biased as a result of difficulties associated with sampling
(Lapointe et al. 2006). Collection methods focus primarily on a single targeted species or functional group because to sampling logistics and methodology (Meador and Goldstein
2003; Schultz et al. 2007; Gido et al. 2009; Haxton and Findlay 2009). Most netting techniques are passive, involving a stationary net, and rely on movement of fish to become captured or entangled. Traditional gill and trap netting protocols are subject to the biased capture or exclusion of species based on physiology (Murphy and Willis 1996) or specific size classes (Garner 1997). Fish may be caught by gill nets in three ways: 1) they may become wedged and held by the mesh around the body, 2) they may be gilled and held by the mesh slipping behind the opercula, or 3) they may become tangled and held by teeth, spines, maxillaries, or other fins without the body penetrating the mesh.
Most often fish are gilled, swimming into a net and passing only partway through the mesh. When the fish struggles to free itself, the twine slips behind the gill cover, preventing escape (Murphy and Willis 1996).
The active fishing method of electrofishing uses an electrical current run through the water between two electrodes (anode and cathode) causing uncontrolled muscular convulsions known as galvanotaxis (Murphy and Willis 1996). There are two methods of electrofishing. The first uses a backpack electrofishing unit and has the operator wading, carrying the anode and dragging the cathode, with a crew netting stunned fish. This method is typically restricted to small streams where wading can be performed safely.
15 In larger lakes and rivers, boat electrofishing is preferred. In this method, an anode mounted on the bow of the boat and large electrodes are drug midway along the sides of the boat, insulated from the boat. The electrical current, typically draws fish towards the anode, where they can be netted and sampled. The combination of galvanotaxis and the buoyant swim bladder (of most species) causes fish to float to the surface of the water, facilitating species identification and length interval estimation and rarely resulting in injury to the fish (Murphy and Willis 1996).
Electrofishing large riverine ecosystems is often limited to shallow, slow-moving reaches because of difficulties in sampling deep, fast-moving water (Lapointe et al.
2006). Sampling is usually carried out in shallow, littoral zones of large rivers. Since these areas are important to fish at various life stages (Copp 2010). When deep water-data are required, electrofishing may be paired with other fishing techniques, such as gill netting, to provide a more complete sample of fish community (Goffaux et al. 2005).
Electrofishing and seine netting of small-bodied fish communities often result in comparable catches with similar bias; however, electrofishing is less destructive to fish habitat (Garner 1997; Copp 2010).
A method of quantitative electrofishing developed by Casselman (2008) has the current adjusted to cause a response that neither attracts nor repels the fish from the area assessed. Since water conductivity affects the shape and size of the electrical field, operating conditions (current) are adjusted to standardize effort (Casselman 2008). It is relatively unbiased for size and physiology and enables a count of all fish species within a well-defined area, enabling an accurate estimate of species richness and diversity.
16 2.7 Species and Fish Community Diversity
Diversity is often used as a measure of ecosystem health. Ecosystems that demonstrate greater diversity typically have the greatest stability and an increased resistance to change (Balvanera et al. 2006). Ecosystems with lower diversity may be less tolerant to change (environmental, biological, etc.) and result in decreased ecosystem function and an inability to recover from perturbation (Worm et al. 2006). In aquatic ecosystems, diversity may be lost because of species exploitation, alien species introductions, habitat destruction, etc, all of which may impair ecosystem function and the ability to recover after a disturbance (Worm et al. 2006).
In order to quantify diversity into measurable units, diversity has been divided into several components. Gamma diversity, or observed total diversity, of a landscape can be partitioned into alpha diversity and beta diversity components. Alpha diversity, in its raw definition is richness in species on a local scale; however, measurements are often expressed as the dominance or evenness of species using a variety of indices (Whittaker
1972). Beta diversity is roughly defined as the delineation between communities along habitat gradients or on a landscape scale (Whittaker 1972; Whittaker et al. 2001;
Tuomisto 2010a).
Two components must be considered when species diversity is defined. The first component, species richness, is simply a count of the number of species found within a standard area of measurement and does not consider relative abundance (Whittaker 1972;
Molles and Cahill 2008). It is generally expected that species richness will increase with an increase in sample area (Whittaker et al. 2001). In dammed riverine ecosystems, severe environmental fluctuation and unnatural seasonal conditions, such as extremely
17 high or low water temperatures, may limit richness to species capable of tolerating changes created by water control structures (Halls et al. 1998).
The second component, species evenness, is a measure of the proportional abundance or distribution of a species within a community (Whittaker 1972; Molles and
Cahill 2008). Various methods exist to measure the evenness of species distribution within a community; however, many do not communicate important information about species richness. Therefore, a useful measurement would combine both species richness and evenness, as does the Shannon-Wiener Index (SWI) (sometimes called Shannon-
Weaver Index) (Whittaker 1972; Spellerberg and Fedor 2003; Molles and Cahill 2008):
H´ = ∑ pi ln pi
For each species, the proportion (p) is multiplied by the natural log (ln) of the proportion
(p). This is performed for each species, and the sum of the resulting values is used as the
Shannon-Wiener Index value. It is possible for a community of high richness but low evenness to have lower index values than a community where richness is low but very even.
The detailed collection of fish community data provides the foundation for contemporary fisheries management. The accuracy and efficiency of quantitative electrofishing provide an ideal methodology for connecting fish species data to environmental conditions. All fish are collected regardless of body shape or size, facilitating the measurement of community richness and diversity. The SWI is a broadly used method that results in a numerical value to define species diversity of a given sample.
18 2.8 Research Rationale and Study Objectives
The anthropogenic alteration and impoundment of large riverine ecosystems for the purpose of hydroelectricity necessitates a better understanding of how physical and environmental factors impact fish communities in order to provide fisheries managers with the tools required for species conservation and habitat management. This study uses quantitative electrofishing data collected over two sample seasons from the lower Ottawa and the Mississippi river systems to: (1) examine the relationship between longitudinal gradient and fish species richness and evenness using the Shannon-Wiener Index, (2) evaluate the relationship between water temperature, conductivity and velocity with fish- community composition, (3) examine differences in fish communities above and below barriers, and (4) examine temporal changes in fish community composition at the same locations between 2008 and 2009. The results of this study may strengthen the knowledge of species-environment relationships and influence the rationale when designing future fish community sampling protocols.
19 CHAPTER 3
MATERIALS AND METHODS
3.1 Rivers Studied
The Ottawa River is the second largest river in eastern Canada after the St.
Lawrence River, originating at Capitmitchigama Lake in west-central Quebec and stretching 1,130 kilometres south through the city of Ottawa-Hull to the St. Lawrence
River (Figure 1). This highly regulated waterway, consisting of dams and reservoirs, has a drainage area of 146,300 square kilometres, a vertical descent of 365 metres and creates a 580-kilometre natural provincial border separating Ontario and Quebec (Quebec-
Labrador Foundation 2005).
The Mississippi River is a major tributary of the Ottawa River that joins the waterway upstream of the City of Ottawa. The Mississippi watershed encompasses a drainage area of 4,450 square kilometres and has a total length of 212 kilometres (Ottawa
Gatineau Watershed Atlas 2008). The river flows generally northward from its origins in
Upper Mazinaw Lake, through the city of Carleton Place, eventually emptying into the
Ottawa River downstream of Marshall Bay.
Both the Ottawa and Mississippi rivers have undergone extensive damming for the purposes of hydroelectricity. Water control structures have been in place on both rivers for nearly 150 years (Haxton and Chubbuck 2002, Mississippi Valley Conservation
2011). There are more than 50 major water control structures on the Ottawa River system and 30 water control structures on the Mississippi River and its tributaries, including four hydroelectric facilities.
20 The shorelines of Ontario and Quebec along the lower Ottawa River are lined with houses and cottages, as the river is used for a variety of recreational and water sport activities. The upper Ottawa and Mississippi rivers run through varying degrees of urbanization and rural activity, with much of the shore bordering agriculture, pasture and wooded lands. Both rivers provide numerous angling opportunities for a variety of fish species.
The Ottawa and Mississippi River systems are composed of a highly diverse fish community of mainly cool-water and some warm-water species. In the past decade, more than 75 species of fish have been known to occur in the Ottawa River, with some under provincial protection: channel darter (Percina copelandi),Threatened; river redhorse
(Moxostoma carinatum), Special Concern; lake sturgeon (Acipenser fulvescens),
Endangered; American eel (Anguilla rostrata), Endangered (Endangered Species Act
2007, Haxton and Chubbuck 2002 ).
3.2 Sampling Location Criteria
Data were provided from quantitative electrofishing that was conducted in two consecutive years (2008 and 2009) as a component of an American eel (Anguilla rostrata) monitoring project (Casselman and Marcogliese 2009, 2010). Locations were selected based on potentially suitable eel habitat, a systematic survey of all types of fish habitat, and a combination of local and traditional knowledge of historical eel presence.
Locations were inspected during daylight hours to ensure that depth (maximum depth 3 m, preferred depth <2 m) and substrate criteria were met. Electrofishing was conducted at night with the use of high-intensity floodlights. Casselman and Marcogliese (2009, 2010)
21 reported depths ranging from 0.4 to 3.1 m (2008: 1.3 ± 0.1 m (mean depth ± 95% CI) ranging from 0.4 to 3.1 m; 2009: 1.4 ± 0.1 m (mean depth ± 95% CI) ranging from 0.5 to
2.9 m). At each location, sites were selected that included consistent habitat typical of the location with substrates consisting of soft silt, vegetation, and clay and/or mixed large rock and boulders that would provide cover for eels (Casselman 2008).
In 2008, 25 locations were sampled, of which 14 were associated with the Ottawa
River (Table 1) (Appendix B, Figures 14-17) including the mouth of the Madawaska and
Bonnechere rivers and Dochart Creek. In 2009, the same 25 locations were sampled, plus an additional four locations in the lower reaches of the Ottawa River, a total of 29 locations. In the Mississippi River system, 11 locations were surveyed (Table 2)
(Appendix B, Figures 18-22) including Joe’s Lake in the Clyde River approximately 44 km upstream from the Mississippi River (Figure 1).
Each location contained seven sites, each 200 metres in length. Sites were sampled as paired onshore and offshore transects, each with an effective electrofishing width of 1.5 metres (the electric field was standardized based on fish response) (Tables 3 and 4). To facilitate night sampling, GPS start and end waypoints were located during daylight hours and marked with a fluorescent float.
3.3 Data Collection
In this survey, the electrofishing unit was adjusted to neither attract nor repel fish from a transect of known width delineated with physical trailers (Casselman 2008).
Because large numbers of fish were electrofished, a continuous audio recording was used simply to identify each fish and estimate its length, as long as it was within the electrified
22 field (of known width and length, hence area). The protocol for this survey was different from typical electrofishing protocols, where the crew attempt to dip net all stunned fish.
From time to time, a subsample of fish was netted to confirm identification and measured to verify estimated sizes (Casselman 2008). Electrofishing operating conditions were recorded, including time, duration, amperage and electrode array.
The audio recordings were downloaded into computer files that were later transcribed onto data sheets. The data on these sheets were the basis for the fish- community samples analyzed in this study (see Casselman and Marcogliese, 2009, 2010).
Species counts for the paired (onshore and offshore) transects were combined to provide site catches as the lowest form of sampling resolution. These were coded and are displayed as a decimal numeric index, as follows:
On two occasions (at sites 9.19.5 and 8.6.2), technical issues with the recording device caused only a single transect of the pair for the sites to be recorded. Because onshore and offshore data may vary, for the purpose of consistency I removed both sites.
Because of the distance between Location 25 (Joe’s Lake) and the other locations in the watershed, it was removed from the data sets and omitted from all analyses.
Water temperature and conductivity were measured at least once at each location; however, measurements were typically taken twice per location, first at the beginning of the first site and then at the end of the last (seventh) site (Tables 5-8). Depth was measured at the start, middle and end of each site for both the onshore and offshore sides of each transect. To estimate water velocity, two independent rank estimates were subsequently provided by the electrofishing crew and averaged. Rank was standardized to
23 the site with the greatest flow, which was assigned a value of 10, and all other sites were ranked relative to this site on a scale of 1 to 10.
The relative position of each location in the river system was described as
Distance from the River Mouth. A midpoint for each location was calculated from all site waypoints provided in Casselman and Marcogliese (2010). Distance from the river mouth to the midpoint of each sampling location was measured with the measurement tool in
Google Earth and rounded to the nearest 0.1 kilometre.
Catches were sorted into species, and total length classes were tallied into categories (mm), which varied, depending upon fish size. Thirteen size categories were used, ranging from ≤ 20 to > 600 mm. The first five length categories (1 to 100 mm) used a 20-mm interval, the next four length categories (101 to 300 mm) used a 50-mm interval, and the next three categories (301 to 600 mm) used a 100-mm interval. The length of each fish > 600 mm total length was recorded individually as observed (Casselman and
Marcogliese 2009, 2010).
Sometimes large numbers of small species were stunned, making it impossible to acquire an absolute and accurate count, therefore when necessary, abundance was estimated. Under these conditions, it was not possible to identify every individual within the sample to the species level. Data were recorded to the most accurate level possible.
For many cyprinids and centrarchids, this level of precision was either family or genus.
Since cyprinids and centrarchids unidentified to species represented such a large proportion of the sample, I allocated these unidentified fish according to their proportional abundance with respect to the species or genus of that family that were positively identified in a particular site. Analyses were conducted using a numeric species
24 code (Appendix A. Table A-1), following an Ontario Ministry of Natural Resources coding system.
Species abundance and density were analyzed in two ways: 1) with all fish included, and 2) with cyprinid species removed. Removing cyprinids from the analysis facilitated the detection changes in community composition that may have been less obvious when cyprinid abundance was high.
3.4 Richness and Diversity
Species richness and diversity were calculated at the site level for both years of sampling, using all available data. Species richness is a count of the number of species within a measured area. Since species richness can be exactly quantified and data were collected within a predetermined set of parameters, it provides a comparable measurement throughout the sample. Species diversity considers both species richness and species evenness and was calculated to resolution of site level using the Shannon-
Wiener Index:
s H´ = -∑ pi Loge pi i=1 Where:
H´ = the value of the Shannon-Wiener diversity index
pi = is the proportion of the ith species
Loge = natural logarithm of pi
s = the number of species in the community
25 The minimum value of this index is zero, where all individuals are of a single species. The maximum value is equal to Log (e), when all fish are evenly distributed among the observed species at that site. This index provides a single value representative of the number of equally abundant species needed to obtain the same mean proportional species abundance observed in the data. Similar index values may be composed of a completely different set of species within the data set sharing similar evenness.
Species richness and species diversity were calculated with the statistical program
R version 2.11.1 (R Development Core Team 2010). The calculation of the Shannon-
Wiener Index was performed with the statistical package “Vegan”. Pearson’s Correlation
Analysis statistics were reported, and the null hypothesis was evaluated at the 0.05 alpha
(α) level. All means report the ± standard error mean where appropriate.
3.5 Annual Changes in Fish Assemblages
Fish community data were analyzed using principal component analysis (PCA) to compare the differences in fish community composition between the two sampling years.
Using orthogonal transformation, a PCA converts a set of correlated observations into a set of linearly correlated variables weighted by eigenvectors, called principal components
(PC). The number of PCs is less than or equal to the number of variables. The first PC is oriented in such a way that it explains the greatest variation in the data. The second PC explains the greatest amount of variation in the data that is orthogonal to the first component. This descriptive statistical technique is best suited for exploring patterns in the data, such as changes in a species’ relative abundance and community composition at a location between sampling years (Leps and Smilauer 2003).
26 Species abundances for each site within a location were pooled and reported as abundances at the location level. When there were insufficient data at a site during one year of sampling, the same site was removed from the alternative year of sampling. Any additional sites that were sampled in a location that was not sampled in both years were omitted. PCAs were performed with the statistical software CANOCO for Windows version 4.5 (1997-2002 Biometris – Plant Research International, Wageningen, The
Netherlands) and plotted with the associated CANODRAW statistical graphing software.
With the use of ordination diagrams, we can create a representative summary of the species composition of each location in a river system. In the ordination diagrams, changes along either axes represent changes in community composition and the proximity of samples implies similarity in composition between locations. We can expect that sample points that lie close to each other will be more similar in terms of relative importance of individual species populations compared with those far apart in the diagram.
3.6 Environmental Variables and Fish Assemblages
A redundancy analysis (RDA) enables the derivation of a specified number of variables from a set of independent variables that explain as much variance as possible.
RDAs were used to assess the relationship between fish assemblages and environmental variables. The environmental variable values were the calculated means of all available data at a given sample location. Species values represented the abundance of all fish sampled within a given location.
27 Data were analyzed by river system (Ottawa and Mississippi) and year (2008 and
2009), combined river data for each year, and combined both years for each river system.
All RDA were performed with the statistical software CANOCO for Windows version
4.5 (1997-2002 Biometris – Plant Research International, Wageningen, The Netherlands) and plotted with the associated CANODRAW statistical graphing software.
A permutation is the rearrangement of data by exchanging labels on data points to perform a test of significance and calculate a test score on each permutation. Test scores collected from permuted data are used to construct the distribution under the null hypothesis. The Monte Carlo method was used to test the significance of RDA analysis.
The Monte Carlo method was chosen because of the large data set and the many possible orderings of the data. Relative to the total possible number of permutations, the Monte
Carlo method takes a smaller random sample of possible replicates. The Monte Carlo permutation test was performed on RDAs with 999 permutations, and environmental variables with a level of significance (α) less than 0.05 were included.
3.7 Below-Dam and Above-Dam Comparisons
Using a standard two-sample t-test; α = 0.05, I compared the species richness and
Shannon-Wiener Index values of three paired below-dam and above-dam locations for both years of sampling. Two locations were associated with the Ottawa River system and one with the Mississippi River system. The comparisons on the Ottawa River were Lower
Duck Island (Location 3), which is situated 12.4 km downstream of Chaudière Falls Dam to Shirley’s Bay (Location 4), 15.3 km above the dam, and Location 7, 2.6 km below
Chats Falls Dam to Marshall Bay (Location 8), which is 3.4 km above the dam. On the
28 Mississippi River, I compared the location 0.3 km below Appleton Dam (Location 18) to the location 1.0 km above the dam (Location 19). Because of technical problems with the audio recordings, there were no fish data for one site at Location 18 in 2009 (9.18.5).
29 Table 1. Electrofishing location survey, 2008 and 2009, Ottawa River watershed. Locations are presented by river system starting downstream. Locations 26-29 were added for the 2009 sampling. Distance to River Mouth is calculated from the point where the Ottawa River meets the St. Lawrence River upstream to the calculated midpoint for each location. The length of the reach is the shortest measured distance between the start and end point for each reach. Distance to River Mouth Length of Location Location Description (km) Reach (km) Reach 1 - Lac des Deux Montagnes St. Lawrence River 0.0 40.0 26 Below Carillon Dam - Baie de Rigaud 30.3 1 Below Carillon Dam - Baie de Carillon 33.2 27 Below Carillon Dam - Point-Fortune 36.5 Reach 2 - Lac Dollard des Ormeaux Carillon Dam 40.0 116.0 2 Above Carillon Dame – Voyageur Provincial Park 45.5 28 Above Carillon Dame - Baie Grenville 62.0 29 South Nation River mouth 101.9 3 Below Chaudière Falls - Lower Duck Island 143.6 Reach 3 - Lac Deschenes Chaudière Falls 156.0 56.2 4 Shirleys Bay 171.3 5 Constance Bay and Creek 191.0 6 Snye - Chats Falls 208.5 7 Below Chats Falls Dam 209.6 Reach 4 - Lac des Chats Chats Falls Dam 212.2 37.6 8 Marshall Bay 215.6 9 Below first weir - Madawaska River 218.6 10 Dochart Creek 221.1 11 Baie à Webb 230.2 12 Baie à John 232.6 13 Below logging chute - Bonnechere River 237.9 14 Below Chenaux Dam 247.1 Chenaux Dam 249.8 ______
30 Table 2. Electrofishing location survey, 2008 and 2009, Mississippi River watershed. Locations are presented by river system starting furthest downriver. Distance to River Mouth is calculated from the point where the Mississippi River meets the Ottawa River upstream to the calculated midpoint for each location. The length of the reach is the shortest measured distance between the start and end point for each reach.
Distance to Length of River Mouth Reach Location Location Description (km) (km) Reach 1 - Mississippi R. mouth to Galetta Dam 0.0 3.2 15 Mississippi River Mouth 0.6 16 Below Galetta Dam 2.0 Reach 2 - Galetta Dam to Almonte Dam 3.2 27.6 17 Below Almonte Dam 30.2 Reach 3 - Almonte Dam to Appleton Dam 30.8 8.2 18 Below Appleton Dam 38.7 Reach 4 - Appleton Dam to Carleton Place Dam 39.0 8.0 19 Above Appleton Dam 40.0 20 Below Carleton Place Dam 43.4 Reach 5 - Carleton Place Dam to High Falls Dam 47.0 60.2 21 Aberdeen Island - Mississippi Lake 54.2 22 Inflow and McEwen Bay - Mississippi Lake 64.3 23 Mud Lake and Mississippi River 97.6 24 Inflow and McEwen Bay - Dalhousie Lake 107.2 107.2 ______
31 Table 3. Electrofishing effort for the Ottawa and Mississippi Rivers by location, 2008 quantitative electrofishing survey. Electrofishing effort is indicated by the number of sites, the width of field, the cumulative length of sites and area electrofished. Data from Casselman and Marcogliese 2009.
Electrofishing effort Location River Sites Width Length Area Location Date No. System (N) (m) (km) (ha) 1 Ottawa Carillon Dam - below, Baie de Carillon 2008-11-19 7 3 1.4 0.42 2 Ottawa Carillon Dam - above, southwest shore 2008-11-18 7 3 1.4 0.42 3 Ottawa Chaudière Falls - below 2008-11-05 7 3 1.4 0.42 4 Ottawa Shileys Bay 2008-10-23 7 3 1.4 0.42 5 Ottawa Constance Bay and Creek 2008-10-22 7 3 1.4 0.42 6 Ottawa Snye, downstream Chats Falls, NE shore 2008-10-19 6 3 1.2 0.36 7 Ottawa Chats Falls Dam - below, SW shore 2008-10-19 7 3 1.4 0.42 8 Ottawa Marshall Bay 2008-10-18 7 3 1.4 0.42 9 Ottawa Madawaska River - below first weir 2008-10-24 7 3 1.4 0.42 10 Ottawa Dochart Creek - below first culvert 2008-10-24 7 3 1.4 0.42 11 Ottawa Baie à Webb - north shore 2008-11-14 7 3 1.4 0.42 12 Ottawa Baie à John - north shore 2008-11-14 7 3 1.4 0.42 13 Ottawa Bonnechere River - below first chute 2008-10-30 7 3 1.4 0.42 14 Ottawa Chenaux Dam - northeast shore 2008-11-09 7 3 1.4 0.42 15 Mississippi Mississippi River - mouth 2008-10-15 7 3 1.4 0.42 16 Mississippi Galetta Dam - below 2008-10-18 7 3 1.4 0.42 17 Mississippi Almonte Dam - below 2008-10-13 7 3 1.4 0.42 18 Mississippi Appleton Dam - below 2008-11-02 7 3 1.4 0.42 19 Mississippi Appleton Dam - above 2008-11-04 7 3 1.4 0.42 20 Mississippi Carleton Place Dam - below 2008-10-17 7 3 1.4 0.42 21 Mississippi Mississippi Lake - Aberdeen Island 2008-11-01 7 3 1.4 0.42 22 Mississippi Mississippi Lake - inflow 2008-10-27 7 3 1.4 0.42 23 Mississippi Mud Lake - east shore, outflow, river 2008-11-12 9 3 1.8 0.54 24 Mississippi Dalhousie Lake - inflow and shoreline 2008-11-06 7 3 1.4 0.42
32 Table 4. Electrofishing effort for the Ottawa and Mississippi Rivers by location, 2009 quantitative electrofishing survey. Electrofishing effort is indicated by the number of sites, the width of field, the cumulative length of sites and area electrofished. Data from Casselman and Marcogliese 2010.
Electrofishing effort Location River Sites Width Length Area Location Date No. System (N) (m) (km) (ha) 1 Ottawa Carillon Dam - below, Baie de Carillon 2009-06-08 7 3 1.4 0.42 26 Ottawa Carillon Dam - below, Baie de Rigaud 2009-06-05 7 3 1.4 0.42 27 Ottawa Carillon Dam - below, Point-Fortune 2009-06-07 7 3 1.4 0.42 2 Ottawa Carillon Dam - above, southwest shore 2009-06-06 7 3 1.4 0.42 28 Ottawa Carillon Dam - above, Baie Grenville 2009-08-27 7 3 1.4 0.42 29 Ottawa South Nation River - mouth 2009-08-28 7 3 1.4 0.42 3 Ottawa Chaudière Falls - below 2009-08-31 7 3 1.4 0.42 4 Ottawa Shileys Bay 2009-09-01 7 3 1.4 0.42 5 Ottawa Constance Bay and Creek 2009-09-02 7 3 1.4 0.42 6 Ottawa Snye, downstream Chats Falls, NE shore 2009-09-09 7 3 1.4 0.42 7 Ottawa Chats Falls Dam - below, SW shore 2009-09-09 7 3 1.4 0.42 8 Ottawa Marshall Bay 2009-09-08 7 3 1.4 0.42 9 Ottawa Madawaska River - below first weir 2009-09-07 7 3 1.4 0.42 10 Ottawa Dochart Creek - below first culvert 2009-09-07 7 3 1.4 0.42 11 Ottawa Baie à Webb - north shore 2009-09-04 7 3 1.4 0.42 12 Ottawa Baie à John - north shore 2009-09-04 7 3 1.4 0.42 13 Ottawa Bonnechere River - below first chute 2009-09-05 7 3 1.4 0.42 14 Ottawa Chenaux Dam - northeast shore 2009-09-03 7 3 1.4 0.42 15 Mississippi Mississippi River - mouth 2009-09-17 7 3 1.4 0.42 16 Mississippi Galetta Dam - below 2009-09-17 7 3 1.4 0.42 17 Mississippi Almonte Dam - below 2009-09-12 7 3 1.4 0.42 18 Mississippi Appleton Dam - below 2009-09-22 7 3 1.4 0.42 19 Mississippi Appleton Dam - above 2009-09-21 6 3 1.2 0.36 20 Mississippi Carleton Place Dam - below 2009-09-14 7 3 1.4 0.42 21 Mississippi Mississippi Lake - Aberdeen Island 2009-09-11 7 3 1.4 0.42
33 22 Mississippi Mississippi Lake - inflow 2009-09-16 7 3 1.4 0.42 23 Mississippi Mud Lake - east shore, outflow, river 2009-09-24 7 3 1.4 0.42 24 Mississippi Dalhousie Lake - inflow and shoreline 2009-09-15 7 3 1.4 0.42
34 Table 5. Date of sampling, distance from the river mouth, and water temperature for each location in the Ottawa River electrofished in 2008. Locations are listed in order by distance starting at the river mouth. Distance is measured from the river mouth, upstream to the calculated midpoint of the location. Water temperature is the calculated mean values for each location.
Sample Distance Water Location Date (km) Temp (°C) 1 19-11-08 33.2 0.0 2 18-11-08 45.4 -0.3 3 5-11-08 143.6 3.5 4 23-10-08 171.3 5.0 5 22-10-08 191.0 1.0 6 19-10-08 209.0 7.0 7 19-10-08 208.5 6.5 8 18-10-08 215.6 6.0 9 24-10-08 218.6 6.5 10 24-10-08 218.7 4.5 11 14-11-08 230.2 3.0 12 14-11-08 232.1 4.0 13 30-10-08 237.9 0.0 14 9-11-08 247.8 3.0
35 Table 6. Date of sampling, distance from the river mouth, and water temperature for each location in the Mississippi River electrofished in 2008. Locations are listed in order by distance starting with the closest to the river mouth. Distance is measured from the river mouth, upstream to the calculated midpoint of the Location. Water temperature is the calculated mean values for each location.
Distance Water Temp Location Sample Date (km) (°C) 15 15-10-08 0.6 8.0 16 18-10-08 2.0 6.0 17 13-10-08 30.2 10.0 18 2-11-08 38.7 5.4 19 4-11-08 40.0 3.0 20 17-10-08 43.4 6.0 21 1-11-08 54.2 1.0 22 27-10-08 64.3 4.0 23 12-11-08 97.6 1.3 24 6-11-08 107.2 4.0
36 Table 7. Date of sampling, distance from the river mouth, water temperature, conductivity and rank of velocity for each location in the Ottawa River electrofished in 2009. Locations are listed in order by distance starting with the closest to the river mouth. Distance is measured from the river mouth, upstream to the calculated midpoint of the Location. Water temperature and conductivity are the calculated mean values for each location. Rank of velocity is the calculated average of two independent ranks of velocity and is shown as mean velocity of all sites within a location.
Distance Water Conductivity Rank of Location Sample Date (km) Temp (°C) (μs) Velocity 121. 26 8-06-09 30.3 20.4 6 1.2 1 5-06-09 33.2 18.0 74.8 1.7 27 7-06-09 36.5 16.4 65.5 4.3 2 6-06-09 45.4 16.8 74.3 1.6 28 27-09-09 62.0 23.2 76.9 2.6 177. 29 28-09-09 101.9 23.8 3 3.2 3 31-09-09 143.6 21.5 63.2 2.0 4 1-10-09 171.3 21.9 80.0 1.8 294. 5 2-10-09 191.0 22.6 4 1.9 128. 6 9-10-09 209.0 22.0 6 1.8 7 9-10-09 208.5 23.2 74.8 2.9 107. 8 8-10-09 215.6 23.4 9 2.2 108. 9 7-10-09 218.6 22.2 0 3.6 217. 10 7-10-09 218.7 22.0 3 2.8 11 4-10-09 230.2 21.7 57.9 1.2 12 4-10-09 232.1 22.3 72.7 1.4 159. 13 5-10-09 237.9 21.8 3 5.9 14 3-10-09 247.8 23.8 52.6 3.5
37 Table 8. Date of sampling, distance from the river mouth, water temperature, conductivity and rank of velocity for each location in the Mississippi River electrofished in 2009. Locations are listed in order by distance starting with the closest to the river mouth. Distance is measured from the river mouth, upstream to the calculated midpoint of the Location. Water temperature and conductivity are the calculated mean values of each location. Rank of velocity is the calculated average of two independent ranks of velocity and is shown as mean velocity of all sites within a location.
Distance Water Conductivity Rank of Location Sample Date (km) Temp (°C) (μs) Velocity 15 17-10-09 0.6 21.0 188.4 3.5 16 17-10-09 2.0 21.4 183.6 4.3 17 12-10-09 30.2 22.5 181.3 5.1 18 22-10-09 38.7 20.8 170.8 2.4 19 21-10-09 40.0 19.3 165.6 4.8 20 14-10-09 43.4 21.5 148.9 2.4 21 11-10-09 54.2 22.5 158.7 1.1 22 16-10-09 64.3 19.2 153.2 1.5 23 24-10-09 97.6 20.3 117.6 2.9 24 15-10-09 107.2 20.4 104.5 2.4
38
Figure 1. Map of the Ottawa and Mississippi rivers and dam locations.
39 CHAPTER 4
RESULTS
4.1 Fish Abundance, Occurrence, Composition and Density
Electrofishing effort was greater in the Ottawa River than in the Mississippi
River. In 2008, in the Ottawa River system, 98 sites were sampled, with one being removed because of data recorder malfunction. The 97 sites had a total sampling length of 19.4 km encompassing 5.84 ha. In 2009 in the Ottawa River system, the same 98 sites were sampled, plus an additional 28 sites, for a total of 126 sites sampled with a length of
25.2 km and an area of 7.56 ha. In 2008, 72 sites were sampled on the Mississippi River system, with a length of 14.4 km and encompassing 4.33 ha. There were 69 sites in the
Mississippi River system in 2009 with a total sampling length of 13.8 km encompassing
4.15 ha. Two additional exploratory sites were removed because they were not sampled in both years and one additional site was removed because of a malfunction in the data recorder.
During the two years of sampling, 39,406 fish were electrofished. At the original
25 Locations, more fish were observed in 2008 (n=21,346) than in 2009 (n=10,278). Two locations (26 and 27) were added in Reach 1 – Lac des Deux Montagnes and two (28 and
29) in Reach 2 – Lac Dollard des Ormeaux in the 2009 survey, which accounted for an additional 3,891 fish.
A total of 11,516 fish were sampled in the Ottawa River in 2008 (Appendix A,
Table A-2). The most abundant species were golden shiner (Notemigonus crysoleucas)
40.1% (n=4,626), yellow perch (Perca flavescens) 25.7% (n=2,959) and rock bass
(Ambloplites rupestris) 5.0% (n=576) (Table 9). The most widely distributed species
40 observed in the 97 sites were yellow perch 80.4%, rock bass 57.7% and pumpkinseed
(Lepomis gibbosus) 53.6%. In the Mississippi River system in 2008, 9,830 fish were sampled (Appendix A, Table A-3). The most abundant species were golden shiner 21.6%
(n=2,122), yellow perch 21.5% (n=2,112) and pumpkinseed 15.1% (n=1,483) (Table 10).
The most commonly occurring species over the 72 sites were yellow perch 84.7%, rock bass 83.3% and northern pike (Esox lucius) 80.56%.
In 2009, a total of 12,428 fish were sampled on the Ottawa River (Appendix A,
Table A-4). The most abundant species were yellow perch 31.1% (n=3.861), spottail shiner (Notropis hudsonius) 10.7% (n=1,328) and pumpkinseed 10.6% (n=1,312) (Table
11). Yellow perch occurred in all but 5 sites (96.0%), while pumpkinseed and rock bass were found in 73.0% and 61.1% of sites respectively. The lowest abundance was observed in the Mississippi River in 2009 (Appendix A, Table A-5), where 5,632 fish were sampled. The most abundant species were yellow perch 26.9% (n=1,515), rock bass
12.3% (n=683) and blacknose shiner (Notropis heterolepis) 11.8% (n=666) (Table 12).
The most widely distributed species were rock bass 86.3%, yellow perch 78.3% and pumpkinseed 75.4%.
In 2008, there was no significant difference in mean fish densities between the
Ottawa River system (1988 ± 631 · ha-1) and the Mississippi River system (2306 ± 455 · ha-1) (t = -0.41, df = 22, p = 0.69; Figure 2). In 2009, mean densities in the Ottawa River system (1644 ± 189 · ha-1) were not significantly different from those observed in the
Mississippi River system (1360 ± 279 · ha-1) (t = 0.26, df = 18, p = 0.80; Figure 2). There was no difference in mean densities when the Ottawa and Mississippi river systems were pooled for 2008 (2120 ± 408 · ha-1) and 2009 (1542 ± 156 · ha-1) (t = -1.61, df = 30, p =
41 0.12; Figure 3). When both years (2008 and 2009) were pooled for each river, mean fish density for the Ottawa River system (1794 ± 229 · ha-1) were not significantly different from those in the Mississippi River system (1833 ± 174 · ha-1) (t = -0.26, df = 46, p =
0.80; Figure 3). When cyprinids were removed from the analysis, there was no significant difference in fish abundance (t = -0.96, df = 316, p = 0.34) or density (t = -0.91, df = 323, p = 0.36) between years.
4.2 Species Richness
The greatest species richness (15) at a single site through two years of sampling was observed at Lower Duck Island, below Chaudière Falls Dam in the Ottawa River system (Location 3, Site 4). The greatest species richness found in the Mississippi River system was 13 species, which was recorded in the second reach of the Mississippi River system below Almonte Dam (Location 17, Site 1).
In 2008, mean species richness for the Ottawa River system (6.86 ± 0.27) was significantly lower than for the Mississippi River system (8.33 ± 0.26) (t = -3.97, df =
165, p <0.001; Figure 4). In 2009, no difference was observed in mean species richness between the Ottawa River system (8.48 ± 0.20) and the Mississippi River system (7.96 ±
0.31) (t = 1.44, df = 125, p = 0.15; Figure 4).
When data for both rivers were pooled, mean species richness in 2008 (7.49 ±
0.20) was significantly lower than in 2009 (8.29 ± 0.17) (t = -3.13, df = 345, p = 0.002;
Figure 5). Mean species richness pooled for both sampling years in the Ottawa River system ( 7.78 ± 0.17) was not significantly different from the Mississippi River system
(8.15 ± 0.20) (t = -1.42, df = 313, p = 0.16; Figure 5).
42 4.3 Species Diversity
Shannon-Wiener Index (SWI) values from the samples ranged from a low of 0 (no species observed at sample sites 8.2.6, 9.21.1 and 9.24.7) to a high of 2.09 and 2.03 for sites 9.29.6 and 9.2.2 respectively, both in the Ottawa River. In 2008, the mean SWI value for the Ottawa River system (1.19 ± 0.04) was significantly lower than that observed on the Mississippi River system (1.36 ± 0.04)(t = -2.76, df = 164, p = 0.006;
Figure 6). In 2009, the mean index for the Ottawa River system (1.44 ± 0.03) was no different from that of the Mississippi River system (1.45 ± 0.05) (t = -0.18, df = 107, p =
0.86; Figure 6).
Mean SWI values for both years pooled on the Ottawa River (1.33 ± 0.03) were no different from those observed on the Mississippi River system (1.40 ± 0.03) (t = 1.75, df = 294, p = 0.08; Figure 7). When data for both rivers were pooled by year, SWI values for 2008 (1.26± 0.03) were significantly lower than 2009 (1.44 ± 0.02) (t = 4.53, df =
326, p <0.001; Figure 7).
4.4 Effects of Physical and Environmental Variables
4.4.1 Distance to River Mouth
Pearson’s Correlations Analysis indicated that the Mississippi River system 2008
(r = -0.41, df = 70, p <0.001), and Ottawa River system 2009 (r = -0.35, df = 124, p
<0.001) (Figure 8), demonstrated a significant decline in species richness with increasing distance from the river mouth. In both samples, mean species richness near the river mouth was approximately 9.5, while upstream sites had mean values between 6.5 and 7.5.
The Mississippi River system 2009 (r = -0.01, df = 67, p = 0.92) (Figure 8) and the
43 Ottawa River system 2008 (r = 0.04, df = 95, p = 0.68) (Figure 8) demonstrated little change in species richness with change in distance from the river mouth.
Pearson’s Correlation Analysis indicated no significant relationship between distance from the river mouth and Shannon-Wiener Index values: Ottawa River system
2008 (r = 0.05, df= 95, p = 0.60), Mississippi 2008 (r = -0.14, df= 70, p = 0.23), Ottawa
River system 2009 (r = -0.01, df = 124, p = 0.91), and Mississippi River system 2009 (r =
-0.15, df = 67, p = 0.21) (Figure 9)
4.4.2 Water Temperature
In 2008, water temperatures ranged from -0.5°C to 7.0°C, with greater species richness observed at higher temperatures. The Ottawa River system, 2008, demonstrated a significant correlation between species richness and water temperature (r = 0.38, df =
26, p = 0.04; Figure 10). No significant correlation was observed in the Mississippi River system (r =0.27, df = 16, p = 0.28; Figure 10). In 2009, sampling was conducted at higher temperatures (18.7°C to 22.8°C). No significant correlations were observed between water temperature and species richness (Mississippi River - r = -0.16, df = 18, p = 0.51,
Ottawa River - r = 0.09, df = 40, p = 0.57; Figure 10).
Water temperature demonstrated no effect on Shannon-Wiener Index values:
Ottawa River system 2008 (r = 0.05, df = 26, p = 0.79), Mississippi River system 2008 (r
= 0.18, df = 16, p =0.46), Ottawa River system 2009 (r = -0.01, df = 40, p = 0.95), and
Mississippi River system 2009 (r = -0.11, df = 18, p = 0.65) (Figure 11).
44 4.4.3 Conductivity
In 2008, conductivity ranged from 67.1 to 271.2 μm. No significant correlations between species richness and conductivity were observed (Ottawa River system 2008 - r
= -0.63, df = 6, p = 0.10, and Mississippi River system 2008 - r = -0.06, df = 4, p = 0.90;
Figure 12). In 2009, conductivity ranged from 45.6 to 492.0 μm. No significant correlations were observed on the Ottawa River system 2009 (r = 0.09, df = 40, p = 0.58) or the Mississippi River system 2009 (r = 0.18, df = 18, p = 0.45) (Figure 12).
There were no correlations between conductivity and Shannon-Wiener Index values, although the Ottawa River approached significance in 2008 (Ottawa River system
2008 - r = -0.65, df = 6, p = 0.08, Mississippi River system 2008 - r = -0.14, df = 4, p =
0.79, Ottawa River system 2009 - r = 0.05, df = 40, p = 0.74), and Mississippi River system 2009 - r = 0.33, df = 18, p = 0.15; Figure 13).
4.4.4 Velocity
A rank of velocity (0-10) was assigned only for the 2009 sampling season. No correlations between velocity and species richness were observed (Ottawa River system
2009 - r = 0.05, df = 124, p = 0.59, Mississippi River system - r = 0.12, df = 67, p = 0.33;
Figure 14). No significant correlations between velocity and Shannon-Wiener Index
Values were observed (Ottawa River system - r = 0.03, df = 124, p = 0.72, Mississippi
River system - r = 0.18, df = 67, p = 0.14; Figure 15).
45 4.5 Annual Change in Species Composition
Principle Component Analysis (PCA) was used to identify similarities and differences in species composition between locations in the Ottawa River system. In
2009, distance from the river mouth was useful in predicting the species composition of locations in both the Ottawa River (r2 = 0.61, df = 16, p < 0.001) and the Mississippi
River (r2 = 0.41, df = 8, p = 0.047).
The dominance of golden shiners (n=3901) in 2008, created a substantial outlier at Location 10 and greatly influenced the preliminary results (Appendix C, Table C-1,
Figure C-1). Location 10 was removed from further analysis. The first two principal components described 41% and 17% (axis 3 = 10% and axis 4 = 8%) of the total variation in species composition (Figure 16). Sample sites were largely differentiated by the first principal component axis. The first axis contributions were dominated by yellow perch (0.9912), pumpkinseed (0.5322), and largemouth bass (0.4583), while the second axis was dominated by spottail shiner (0.9301), rock bass (0.5304) and smallmouth bass
(0.4727) (Table 13). Locations 6 and 9 displayed the greatest change in community composition.
A PCA was used to identify similarities and differences in species composition between locations on the Mississippi River system (Figure 17). The first two components of the analysis described 35% and 28% (axis 3 = 21% and axis 4 = 7%) of the variation of species community. The Mississippi River system was dominated by first axis contributions from brassy minnow (0.7675), yellow perch (0.7223), and yellow bullhead
(0.6125) and second axis contributions by pumpkinseed (0.7819), bluegill (0.5868), and
46 golden shiner (0.5866) (Table 14).The largest changes in community composition occurred at Location 20 and 21.
4.6 Fish Assemblages and Physical and Environmental Variables
Redundancy analyses (RDA) for 2008 were performed using the environmental variables distance from river mouth and water temperature. Results indicated that in
2008, in both river systems, there was no significant correlation between fish community and distance from the river mouth or water temperature.
Redundancy analyses (RDA) for 2009 were performed using the environmental variables distance from river mouth, water temperature, conductivity and velocity. In the
Ottawa River, fish community composition was significantly influenced by distance from the river mouth (p-value = 0.002; Figure 18), which accounted for 25.2% of the variation in fish species composition. Fish assemblages in the Mississippi River were significantly affected by conductivity (p-value = 0.04; Figure 19), accounting for 26.5% of the variation in fish species composition.
4.7 Below-Dam and Above-Dam Comparisons
The greatest species richness was observed below Chaudière Falls at Lower Duck
Island in 2008, where 25 species were observed and a mean site richness of 12 species
(the greatest richness for any location for the two years of sampling). Location 7, below
Chats Falls Dam, had the lowest mean site richness observed, with fewer than seven species, while Location 19, above Appleton Dam, displayed the lowest location richness, with 13 species. In six comparisons between locations immediately above and below
47 dams, no significant differences were found in species richness (t = 1.51, df = 8, p = 0.17) or Shannon-Wiener Index Values (t = 0.67, df = 10, p = 0.52).
48 Table 9. Relative abundance (proportional to 1.000) of species in the 2008 sampling of the Ottawa River system.
Location Species 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 8.10 8.11 8.12 8.13 8.14 A. brook lamprey Silver lamprey 0.024 Longnose gar Bowfin 0.007 Northern pike 0.014 0.004 0.031 0.006 0.164 0.015 0.020 0.009 0.001 0.001 0.012 0.103 0.028 Muskellunge 0.007 0.008 0.001 0.012 0.013 0.002 Central mudminnow 0.034 Mooneye Quillback White sucker 0.019 0.001 0.001 0.009 0.009 0.007 0.013 0.002 Silver redhorse 0.004 0.001 0.004 0.009 0.007 0.030 0.003 0.012 0.090 0.002 Shorthead redhorse 0.005 0.002 0.004 Greater redhorse River redhorse 0.001 Common carp Brassy minnow 0.021 0.001 0.042 0.005 Silvery minnow 0.014 0.027 0.014 Golden shiner 0.076 0.004 0.024 0.206 0.246 0.162 0.271 0.341 0.054 0.969 Emerald shiner 0.090 0.016 0.035 Common shiner Blackchin shiner Blacknose shiner Spottail shiner 0.146 0.016 0.040 0.260 0.037 0.008 0.004 0.004 Rosyface shiner 0.037 0.289 Mimic shiner Bluntnose minnow 0.039 0.205 0.247 0.269 0.068 0.102 Fallfish 0.002 0.008 Yellow bullhead
49 Brown bullhead 0.063 0.019 0.027 0.001 0.306 0.010 0.002 0.011 0.001 0.064 Channel catfish 0.001 0.002 American eel 0.001 0.002 Banded killifish 0.588 Burbot 0.002 0.003 0.002 Trout-perch Rock bass 0.019 0.042 0.012 0.009 0.019 0.112 0.030 0.252 0.003 0.111 0.023 0.018 Pumpkinseed 0.104 0.010 0.016 0.034 0.171 0.291 0.036 0.004 0.001 0.105 0.051 0.014 Bluegill 0.005 0.002 Smallmouth bass 0.012 0.001 0.030 0.009 0.001 0.067 0.100 0.146 0.001 0.056 0.006 Largemouth bass 0.005 0.011 0.017 0.003 0.025 0.009 0.014 0.012 0.038 0.002 Black crappie 0.028 0.008 0.006 0.001 Yellow perch 0.417 0.700 0.653 0.190 0.164 0.558 0.149 0.388 0.430 0.004 0.068 0.321 0.001 0.728 Sauger 0.031 0.008 0.007 0.004 0.002 0.014 Walleye 0.014 0.031 0.012 0.006 0.004 0.004 0.017 0.028 0.030 0.002 0.043 0.038 0.004 0.021 Johnny darter 0.039 0.018 0.001 0.042 Logperch 0.002 0.047 0.017 0.024 0.005 0.253 0.001 0.019 Brook silverside 0.025 0.007 0.002 0.002 Round goby 0.002 Freshwater drum Mottled sculpin 0.008 0.004 0.031
50 Table 10. Relative abundance (proportional to 1.000) of species in the 2008 sampling of the Mississippi River system.
Location Species 8.15 8.16 8.17 8.18 8.19 8.20 8.21 8.22 8.23 8.24 A. brook lamprey Silver lamprey Longnose gar Bowfin Northern pike 0.011 0.020 0.028 0.054 0.045 0.022 0.012 0.014 0.006 0.021 Muskellunge 0.002 Central mudminnow 0.001 0.149 0.012 0.026 0.217 0.002 Mooneye Quillback White sucker 0.003 0.001 0.051 0.005 0.001 0.013 0.021 0.010 Silver redhorse 0.013 0.001 0.002 Shorthead redhorse 0.004 Greater redhorse 0.002 River redhorse Common carp Brassy minnow 0.034 0.671 Silvery minnow Golden shiner 0.524 0.455 0.332 0.136 0.062 0.001 0.167 0.072 0.090 0.024 Emerald shiner 0.005 Common shiner Blackchin shiner Blacknose shiner Spottail shiner Rosyface shiner Mimic shiner Bluntnose minnow 0.295 0.150 Fallfish 0.001 0.009 0.018 Yellow bullhead 0.001 0.001 0.005 Brown bullhead 0.015 0.018 0.013 0.028 0.050 0.075 0.040 0.009 0.003
51 Channel catfish American eel 0.002 Banded killifish 0.072 Burbot 0.001 0.057 0.005 Trout-perch Rock bass 0.026 0.081 0.260 0.182 0.271 0.037 0.007 0.011 0.026 0.108 Pumpkinseed 0.036 0.020 0.051 0.051 0.007 0.154 0.485 0.086 0.090 0.037 Bluegill 0.248 0.142 Smallmouth bass 0.021 0.004 0.085 0.001 0.029 0.002 0.003 0.003 0.055 Largemouth bass 0.007 0.001 0.032 0.034 0.002 0.001 0.016 0.019 0.003 0.016 Black crappie 0.041 0.007 0.166 Yellow perch 0.328 0.384 0.130 0.264 0.006 0.051 0.214 0.656 0.425 Sauger 0.003 Walleye 0.012 0.006 0.009 0.001 0.005 0.001 0.004 0.003 0.009 0.068 Johnny darter 0.162 Logperch 0.023 0.060 Brook silverside 0.001 0.001 Round goby Freshwater drum Mottled sculpin
52 Table 11. Relative abundance (proportional to 1.000) of species in the 2009 sampling of the Ottawa River system.
Location Species 9.26 9.1 9.27 9.2 9.28 9.29 9.3 9.4 9.5 9.6 A. brook lamprey 0.001 0.018 Silver lamprey Longnose gar 0.017 0.002 0.005 0.001 0.003 Bowfin 0.001 Northern pike 0.011 0.007 0.006 0.006 0.010 0.014 0.008 0.005 0.045 0.014 Muskellunge 0.001 0.002 Central mudminnow Mooneye 0.009 Quillback 0.002 0.015 0.003 White sucker 0.001 0.002 0.001 0.001 Silver redhorse 0.003 0.009 0.035 0.003 0.017 0.005 0.013 0.007 Shorthead redhorse 0.003 0.001 0.005 Greater redhorse River redhorse Common carp 0.002 0.002 0.004 0.014 0.001 0.034 Brassy minnow Silvery minnow Golden shiner 0.032 0.075 0.176 0.047 0.133 0.047 0.018 0.132 0.291 0.189 Emerald shiner 0.013 Common shiner Blackchin shiner Blacknose shiner Spottail shiner 0.270 0.056 0.093 0.103 Rosyface shiner 0.270 0.175 Mimic shiner 0.001 Bluntnose minnow 0.045 Fallfish 0.002 Yellow bullhead
53 Brown bullhead 0.175 0.065 0.046 0.029 0.048 0.032 0.004 0.084 0.010 Channel catfish 0.008 0.003 0.014 0.001 0.003 American eel 0.016 0.004 0.001 0.010 Banded killifish Burbot 0.003 Trout-perch Rock bass 0.032 0.020 0.050 0.001 0.003 0.022 0.022 0.005 0.031 Pumpkinseed 0.294 0.239 0.041 0.262 0.174 0.051 0.011 0.270 0.150 Bluegill 0.003 0.134 0.003 0.031 0.020 0.001 0.013 Smallmouth bass 0.013 0.006 0.088 0.003 0.003 0.069 0.005 0.021 Largemouth bass 0.009 0.016 0.042 0.011 0.017 0.031 0.010 Black crappie 0.059 0.022 0.003 0.012 0.006 0.007 0.009 0.003 0.008 0.007 Yellow perch 0.330 0.419 0.373 0.484 0.482 0.502 0.536 0.273 0.196 0.353 Sauger 0.001 0.037 0.041 0.032 0.002 Walleye 0.002 0.004 0.014 0.041 0.002 0.010 0.008 0.003 0.010 Johnny darter 0.001 Logperch 0.003 0.041 0.001 0.002 0.304 0.007 Brook silverside 0.002 0.002 0.006 Round goby Freshwater drum 0.001 0.012 0.001 0.002 0.001 Mottled sculpin 0.003
54 Table 11 (continued). Relative abundance (proportional to 1.000) of species in the 2009 sampling of the Ottawa River system.
Location Species 9.7 9.8 9.9 9.8 9.9 9.10 9.11 9.12 9.13 9.14 A. brook lamprey Silver lamprey Longnose gar 0.001 0.001 0.002 0.015 0.002 0.003 Bowfin Northern pike 0.003 0.004 0.026 0.008 0.004 Muskellunge Central mudminnow Mooneye 0.002 Quillback White sucker 0.012 Silver redhorse 0.016 0.006 0.016 0.006 0.009 0.022 0.008 0.006 Shorthead redhorse Greater redhorse River redhorse 0.012 Common carp Brassy minnow 0.026 Silvery minnow 0.451 Golden shiner 0.089 0.015 0.089 0.015 0.055 0.008 0.292 0.092 Emerald shiner Common shiner 0.127 Blackchin shiner 0.015 Blacknose shiner 0.166 Spottail shiner 0.149 0.516 0.149 0.516 0.126 0.025 0.114 0.002 0.202 Rosyface shiner 0.348 0.117 0.117 0.246 0.295 0.145 Mimic shiner Bluntnose minnow 0.010 0.01 0.102 0.480 Fallfish 0.006 0.006 Yellow bullhead Brown bullhead 0.010 0.010 0.015 0.001
55 Channel catfish 0.002 0.003 0.003 0.004 0.001 American eel 0.002 0.001 0.001 0.002 Banded killifish Burbot 0.001 0.001 Trout-perch 0.043 Rock bass 0.089 0.035 0.235 0.035 0.235 0.074 0.023 0.007 0.069 0.018 Pumpkinseed 0.031 0.025 0.002 0.025 0.002 0.031 0.103 0.015 0.013 Bluegill Smallmouth bass 0.073 0.111 0.093 0.111 0.093 0.031 0.128 0.030 0.01 0.013 Largemouth bass 0.007 0.035 0.001 0.035 0.001 0.006 0.002 0.007 0.005 0.002 Black crappie 0.003 0.002 0.003 0.002 0.006 0.002 0.005 0.001 Yellow perch 0.142 0.356 0.084 0.356 0.084 0.182 0.097 0.314 0.097 0.161 Sauger 0.004 0.010 0.002 0.01 0.002 0.058 0.017 0.013 0.011 Walleye 0.011 0.013 0.005 0.013 0.005 0.034 0.023 0.004 0.012 0.005 Johnny darter Logperch 0.124 0.013 0.037 0.013 0.037 0.341 0.022 0.003 Brook silverside Round goby Freshwater drum Mottled sculpin
56 Table 12. Relative abundance (proportional to 1.000) of species in the 2009 sampling of the Mississippi River system. Location Species 9.15 9.16 9.17 9.18 9.19 9.20 9.21 9.22 9.23 9.24 A. brook lamprey Silver lamprey Longnose gar 0.007 Bowfin Northern pike 0.041 0.036 0.014 0.009 0.023 0.011 0.028 0.020 0.006 0.003 Muskellunge Central mudminnow 0.194 0.115 0.244 0.002 Mooneye Quillback White sucker 0.005 0.007 0.046 0.013 0.001 0.040 0.009 0.001 0.003 Silver redhorse 0.021 0.007 0.025 0.001 Shorthead redhorse 0.011 Greater redhorse River redhorse Common carp 0.171 0.004 Brassy minnow Silvery minnow Golden shiner 0.216 0.212 0.030 0.008 0.092 0.091 0.055 0.144 0.097 Emerald shiner Common shiner 0.004 Blackchin shiner Blacknose shiner 0.281 0.469 0.063 Spottail shiner Rosyface shiner Mimic shiner Bluntnose minnow 0.004 0.031 0.002 0.011 Fallfish 0.007 0.019 Yellow bullhead 0.005 0.005 0.013 0.027 Brown bullhead 0.036 0.018 0.066 0.010 0.028 0.011 0.020 0.009 Channel catfish 0.004
57 American eel 0.010 Banded killifish 0.008 Burbot 0.005 0.023 0.004 0.002 0.002 Trout-perch Rock bass 0.098 0.113 0.509 0.122 0.338 0.060 0.023 0.031 0.063 0.110 Pumpkinseed 0.052 0.062 0.028 0.251 0.010 0.056 0.159 0.220 0.111 0.058 Bluegill 0.010 0.004 0.002 0.386 0.355 Smallmouth bass 0.041 0.040 0.093 0.025 0.109 0.001 0.016 0.058 Largemouth bass 0.021 0.055 0.039 0.053 0.006 0.005 0.102 0.022 0.020 0.023 Black crappie 0.005 0.004 0.004 0.052 0.011 0.016 Yellow perch 0.418 0.394 0.036 0.174 0.004 0.001 0.148 0.233 0.559 0.527 Sauger 0.004 Walleye 0.010 0.026 0.007 0.001 0.002 0.001 0.004 0.005 0.023 Johnny darter Logperch 0.010 0.018 0.008 0.004 0.001 0.066 Brook silverside Round goby Freshwater drum Mottled sculpin
58 Table 13. Individual species scores for first two axis of the principal component analysis for the Ottawa River.
Species Species Code Axis 1 Axis 2 Axis 3 Axis 4 American brook lamprey 11 0.259 -0.123 0.276 0.183 Silver lamprey 13 0.266 -0.014 0.087 0.031 Longnose gar 41 0.210 -0.067 -0.292 0.095 Bowfin 51 -0.116 0.013 -0.042 -0.135 Northern pike 131 0.289 -0.208 -0.274 -0.016 Muskellunge 132 0.133 -0.141 0.189 -0.061 Central mudminnow 141 -0.158 -0.074 -0.111 -0.073 Mooneye 152 0.064 0.210 -0.005 -0.045 Quillback 161 0.281 -0.130 -0.198 0.038 White sucker 163 -0.095 -0.175 -0.009 0.037 Silver redhorse 168 0.192 0.144 0.017 0.066 Shorthead redhorse 171 0.227 -0.142 0.232 0.253 River redhorse 173 0.045 0.073 0.222 -0.127 Common carp 186 0.205 -0.149 -0.228 0.003 Brassy minnow 189 0.311 -0.100 -0.096 0.030 Silvery minnow 190 -0.030 0.474 -0.360 0.726 Golden shiner 194 0.318 0.281 -0.350 0.004 Emerald shiner 196 0.200 0.032 0.039 -0.015 Common shiner 198 -0.169 -0.063 0.087 -0.061 Blackchin shiner 199 -0.035 0.475 -0.361 0.725 Blacknose shiner 200 -0.151 -0.086 0.107 -0.015 Spottail shiner 201 -0.041 0.930 0.037 -0.026 Rosyface shiner 202 -0.200 -0.303 0.633 0.386 Mimic shiner 206 0.242 -0.151 -0.170 0.044 Bluntnose minnow 208 -0.222 0.072 0.154 -0.059 Fallfish 213 -0.137 -0.233 0.644 0.531 Brown bullhead 233 0.336 -0.249 -0.367 -0.002 Channel catfish 234 0.277 -0.084 -0.215 0.042 American eel 251 0.230 -0.182 -0.260 -0.005 Banded killifish 261 -0.267 -0.205 0.595 0.529 Burbot 271 0.215 0.219 0.211 -0.001 Trout-perch 291 -0.154 -0.030 0.026 -0.040 Rock bass 311 0.292 0.530 0.497 -0.278 Pumpkinseed 313 0.532 -0.344 -0.425 0.057 Bluegill 314 0.336 -0.198 -0.171 0.075 Smallmouth bass 316 0.213 0.473 0.455 -0.322 Largemouth bass 317 0.458 0.030 0.043 -0.120 Black crappie 319 0.350 -0.235 -0.266 0.042 Yellow perch 331 0.991 0.005 0.088 0.050 Sauger 332 0.088 0.201 -0.060 0.142 Walleye 334 0.366 0.275 0.407 -0.239 Johnny Darter 341 0.265 -0.078 0.097 -0.008 Logperch 342 -0.133 0.158 0.154 -0.219 Brook silverside 361 0.403 -0.081 0.019 0.041 Round goby 366 -0.026 -0.035 -0.069 -0.061 Freshwater drum 371 0.179 -0.054 -0.022 -0.007 Mottled sculpin 381 -0.185 0.102 -0.066 -0.156
59 Table 14. Individual species scores for first two axis of the principal component analysis for the Mississippi River.
Species Species Code Axis 1 Axis 2 Axis 3 Axis 4 Longnose gar 41 0.015 -0.133 0.015 -0.034 Northern pike 131 0.228 0.550 -0.270 0.321 Muskellunge 132 -0.472 0.313 -0.362 0.258 Central mudminnow 141 0.195 -0.177 0.116 0.368 White sucker 163 -0.005 -0.273 -0.022 0.007 Silver redhorse 168 -0.333 0.110 -0.220 0.363 Shorthead redhorse 171 0.058 -0.217 0.053 0.113 Greater redhorse 172 -0.015 -0.089 0.005 0.166 Common carp 186 0.050 -0.180 0.039 -0.026 Brassy minnow 189 0.768 0.420 -0.484 0.011 Golden shiner 194 -0.658 0.587 -0.222 0.391 Emerald shiner 196 0.010 -0.145 -0.001 -0.148 Common shiner 198 0.015 -0.133 0.015 -0.034 Blacknose shiner 200 0.047 -0.204 0.086 0.528 Bluntnose minnow 208 0.073 -0.265 0.051 -0.009 Fallfish 213 -0.152 0.009 -0.260 -0.651 Yellow bullhead 232 0.082 -0.204 0.156 0.538 Brown bullhead 233 0.613 0.387 -0.484 0.131 Channel catfish 234 0.015 -0.133 0.015 -0.034 American eel 251 -0.224 0.053 -0.149 0.238 Banded killifish 261 -0.112 -0.041 -0.096 -0.368 Burbot 271 0.329 -0.119 -0.085 0.148 Rock bass 311 -0.056 -0.178 -0.216 0.237 Pumpkinseed 313 0.168 0.782 0.581 -0.089 Bluegill 314 0.039 0.587 0.757 -0.057 Smallmouth bass 316 -0.060 -0.265 0.021 0.181 Largemouth bass 317 -0.105 0.207 0.450 -0.273 Black crappie 319 0.037 -0.042 0.208 -0.106 Yellow perch 331 -0.722 0.350 -0.442 -0.344 Sauger 332 -0.465 0.284 -0.356 0.249 Walleye 334 -0.392 0.173 -0.123 -0.127 Johnny Darter 341 0.074 -0.191 0.056 0.064 Logperch 342 -0.054 -0.192 -0.046 -0.324 Brook silverside 361 -0.587 0.388 -0.437 0.397
60
Figure 2. Mean (mean of individual site means ± standard error) fish densities per hectare for the Ottawa and Mississippi river systems in 2008 and 2009.
61
Figure 3. Mean (mean of individual site means ± standard error) fish densities per hectare for: (A) river data is combined for each year, 2008 and 2009, and (B) both years combined for the Ottawa and Mississippi rivers.
62
Figure 4. Mean (mean of individual site species richness means ± standard error) species richness values for the Ottawa and Mississippi river systems in 2008 and 2009. Asterisk (*) indicates a significant difference (p <0.05) between samples.
63
Figure 5. Mean (mean of individual site species richness means ± standard error) species richness values for: (A) river data combined for each year, 2008 and 2009, and (B) both years combined for the Ottawa and Mississippi rivers. Asterisk (*) indicates a significant difference (p <0.05) between samples.
64
Figure 6. Mean (mean of individual site Shannon Wiener Index means ± standard error) Shannon Wiener Index values for the Ottawa and Mississippi river systems in 2008 and 2009. Asterisk (*) indicates a significant difference (p <0.05) between river samples.
65
Figure 7. Mean (mean of individual site Shannon Wiener Index means ± standard error) Shannon Wiener Index values for: (A) river data is combined for each year, 2008 and 2009, and (B) both years combined for the Ottawa and Mississippi rivers. Asterisk (*) indicates a significant difference (p <0.05) between samples.
66
Figure 8. Pearson’s Correlation Analysis of species richness at varying distances from the river mouth for the Ottawa and Mississippi rivers, 2008 and 2009. Measurements for the Ottawa River system begin below Chaudière Falls at Lower Duck Island (Location 3) and progress upstream to the Chenaux Dam. Mississippi River includes all sample locations. Dotted vertical lines represent the locations of dams.
67
Figure 9. Pearson’s Correlation Analysis of Shannon-Wiener Index values at varying distances from the river mouth for the Ottawa and Mississippi rivers, 2008 and 2009. Measurements for the Ottawa River system begin below Chaudière Falls at Lower Duck Island (Location 3) and progress upstream to the Chenaux Dam. Mississippi River includes all sample locations. Dotted vertical lines represent the locations of dams.
68
Figure 10. Pearson’s Correlation Analysis of species richness at varying water temperatures for the Ottawa and Mississippi rivers, 2008 and 2009. Measurements for the Ottawa River system begin below Chaudière Falls at Lower Duck Island (Location 3) and progress upstream to the Chenaux Dam. Mississippi River includes all sample locations.
69
Figure 11. Pearson’s Correlation Analysis of Shannon-Wiener Index values at varying water temperatures for the Ottawa and Mississippi rivers, 2008 and 2009. Measurements for the Ottawa River system begin below Chaudière Falls at Lower Duck Island (Location 3) and progress upstream to the Chenaux Dam. Mississippi River includes all sample locations.
70
Figure 12. Pearson’s Correlation Analysis of species richness at varying levels of conductivity for the Ottawa and Mississippi rivers, 2008 and 2009. Measurements for the Ottawa River system begin below Chaudière Falls at Lower Duck Island (Location 3) and progress upstream to the Chenaux Dam. Mississippi River includes all sample locations.
71
Figure 13. Pearson’s Correlation Analysis of Shannon-Wiener Index values at varying levels of conductivity for the Ottawa and Mississippi rivers, 2008 and 2009. Measurements for the Ottawa River system begin below Chaudière Falls at Lower Duck Island (Location 3) and progress upstream to the Chenaux Dam. Mississippi River includes all sample locations.
72
Figure 14. Pearson’s Correlation Analysis of species richness at varying water velocities for the Ottawa and Mississippi rivers 2009. Measurements for the Ottawa River system begin below Chaudière Falls at Lower Duck Island (Location 3) and progress upstream to the Chenaux Dam. Mississippi River includes all sample locations.
73
Figure 15. Pearson’s Correlation Analysis of Shannon-Wiener Index values at varying water velocities for the Ottawa and Mississippi rivers 2009. Measurements for the Ottawa River system begin below Chaudière Falls at Lower Duck Island (Location 3) and progress upstream to the Chenaux Dam. Mississippi River includes all sample locations.
74
Figure 16. Principal component analysis of the Ottawa River system 2008 (open circles) and 2009 (closed circles). Location 10 for both years was removed from the analysis. The first axis explains 41% and the second axis explains 17% of the variation in fish community.
75
Figure 17. Principal component analysis of the Mississippi River system. Locations with open circles represent locations sampled in 2008 and shaded circles represent the 2009 samples. The first axis explains 35% and the second axis explains 28% of the variation in fish community.
76
Figure 18. Redundancy analysis of environmental variables and species composition (codes available in Appendix A, Table A-1), Ottawa River, 2009. Distance from river mouth accounted for 25.2% of the variation is fish community composition.
77
Figure 19. Redundancy analysis of environmental variables and species composition of the Mississippi River system in the 2009 survey. Conductivity accounted for 26.5% of the variation in fish community composition.
78 CHAPTER 5
DISCUSSION
5.1 Fish Abundance and Density
In the Ottawa and Mississippi River systems, fish density appeared greater in
2008 than in 2009; however, likely because of variability in catch among sites, analysis between years failed to show significance. When minnows were excluded from the density analysis, fish density and abundance were not significantly different between years. The 2008 sampling was performed in later in the summer and fall, when water temperatures were much colder (Ottawa: 0-7.0°C, Mississippi: 0.6-10.0°C) than in 2009 sampling, which was performed in the spring and summer (Ottawa: 16.4-23.8°C,
Mississippi: 19.2-22.5°C) (Casselman and Marcogliese 2009, 2010).
In 2008, sampling was conducted late in the season because of the arrangement of contractual agreements. In that year, with the onset of cooler conditions, in late fall, fish distribution could have been affected. Fish in very shallow areas (too shallow to electrofish) that may have avoided detection during summer 2009 sampling, may have retreated to adjacent areas and depths in the fall of 2008, making them more susceptible to sampling (Borkholder and Parsons 2001; Wilberg et al. 2010).
Temporal variation of littoral zone fish community assemblages have been observed as a result of differences in species behaviour (schooling, feeding, activity level, etc.) (Tufescu 1994; Mayo and Jackson 2006; Reid and Mandrak 2009). Allen et al.
(1992) demonstrated that summer and late fall seine net sampling produced significantly greater efficiency than sampling during spring and fall seasons. Fish that have undergone ontogenetic shifts or migrated from colder water temperatures, may have displaced fish
79 from adjacent areas into the sampling strata that were used, causing them to become more susceptible to sampling (Alfredsen and Tesaker 2002; Reid and Mandrak 2009).
5.2 Species Richness and Diversity
Quantitative electrofishing favours the sampling of fish using shallow water habitat and likely under-represented species using deepwater habitat. The original protocol was designed to sample various habitats and provide a representative sample of fish communities to determine whether they were associated with eel abundance. Despite the greater fish abundance in 2008, there was significantly greater species richness and species diversity in 2009. Tufescu (1994) suggests that variation in seasonal fish communities results from two main features: (a) reductions in the total fish abundance, and (b) decreased dominance by individual species within a community (increasing evenness). Our results support Tufescu (1994), since our sample demonstrated a reduction in fish abundance and greater species evenness during the warm water sampling in 2009. Dominance by golden shiners and yellow perch (32% and 24% respectively) in 2008 reduced diversity and evenness.
In 2008, both fish species richness and species diversity in the Mississippi River system were significantly greater than in the Ottawa River system, while in 2009, no differences in richness or diversity were observed. When minnow species were removed from the analysis, a significant increase in species diversity was observed in the Ottawa
River between years. The dominance of golden shiners in the Ottawa River 2008 reduced species evenness (and SWI values); however, richness appeared to be affected by rare
80 species in the Ottawa River, while the species observed in the Mississippi River occurred more regularly.
5.3 Changes in Species Composition between Years
Species composition did not change statistically between years; however, a number of locations in the Ottawa River demonstrated considerable variability in species composition. The seasonal fish assemblages varied between years at the same locations.
In the Ottawa River, the trend appeared to be strongest in locations associated with the inflow of tributaries such as the mouth of the Madawaska River (Location 9) and the
Snye River inflow at Chats Falls (Location 6). Loadings of the principal components demonstrate that species composition varies considerably between years at these locations. Species composition demonstrates a predictable change along an upstream gradient in 2009, however there was no significant change observed in 2008. Rockbass, smallmouth bass, walleye and perch catches demonstrated a decrease in contribution to the fish community during the 2009 (summer) sampling season. Also, below the Carleton
Place Dam (Location 20) on the Mississippi River, brassy minnow (Hybognathus hankinsoni) were abundant in 2008, but absent in 2009.
Temporal shifts in habitat demonstrated by piscivorous species are well documented (Lyons and Kanehl 2002; Altena 2003; Cooke and Philipp 2009; Radabaugh et al. 2009; Bowlby and Hoyle 2011). Piscivorous fish concentrate in tributary mouths in cold water, since inflow areas often provide a source of prey such as brassy minnow.
Catches later in the season suggest that piscivorous fish may move downstream into river mouths, where prey is more abundant (Bowlby and Hoyle 2011; Radabaugh et al. 2009).
81 In a comparison of six above-dam and below-dam location pairings of shallow water assemblages, there was no significant influence of dams on species richness or diversity. No significant difference was observed for migratory species such as American eel and redhorse sucker (Moxostoma spp.). However, few individuals of these species were electrofished. It should be considered that three paired comparisons at varying distance may not accurately reflect the true above-dam and below-dam fish communities.
An increased sample size would more accurately depict the impact of dams.
Fish assemblages around the locations of comparison may be a result of sampling position relative to the dams. Locations were not selected with the intent of measuring above-dam and below-dam assemblages, and as a result locations were varying distances from the dam. Often locations were one or more kilometres from the dam itself. Had sampling been done closer to the dam, a more obvious association to the barrier might have been observed.
5.4 Effect of Dams on Water Velocity
The abundances of central mudminnow, silvery minnow, blacknose shiner and rock bass were positively correlated with sites immediately downstream of dams. It is likely that many rheotaxic species have been lost to fractionation and as a result, fish assemblages that are typically associated with areas of current have become rare or lost and were not present. Moxostoma spp. are commonly found in large streams and rivers and are widely distributed across southern Ontario (Scott and Crossman 1998), however, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has designated several Moxostoma species at risk. The silver redhorse (Moxostoma
82 anisurum), golden redhorse (Moxostoma erythrurum) and greater redhorse (Moxostoma valenciennesi) have recently (6/03/2012) been listed as “Mid priority candidates” for protection (COSEWIC 2012), all three of which are native to the Ottawa River system
(Scott and Crossman 1998).
Sites close to dams often had increased water velocity; however, a number of high-velocity sites were not associated with dams. This has created difficulties in determining the effects on rheotaxic species and species found in sites associated with dams. Rockbass, common carp and bluntnose minnow demonstrated trends of increased abundance with increased water velocity, while bluegill, brown bullhead and pumpkinseed demonstrated negative trends associated with velocity.
5.5 Effect of Physical Distance and Reach Length on Richness and Diversity
In the Ottawa River system, upstream of Lower Duck Island (Location 3) and throughout the Mississippi River system, fish species richness and diversity decreased upstream. Sampling intensity was lower downstream of Lower Duck Island and additional locations were added in the second year, however, excluded from the analysis.
Locations downstream of Lower Duck Island did not demonstrate this trend. Joy and
Death (2001) found that riverine ecosystems display an increase in diversity with distance downstream and away from their headwaters. Gehrke et al. (1999) determined that fish assemblages become increasingly fragmented with upstream distance and this effect is compounded by river barriers. The length of the river reach is fundamentally important in the prediction of species richness (Corbacho and Sánchez 2001). In 2008, the greatest species richness (15) observed in the Ottawa River immediately below Chaudière Falls at
83 Lower Duck Island (Site 4), which was the upper most location in the longest river reach
(116 km) that was sampled. The greatest observed richness (13) on the Mississippi River was observed immediately below Almonte Dam (Site 1), which was the second longest sampled reach (28 km) in the Mississippi River system. The South Nation River mouth
(Site 6) and Voyageur Provincial Park (Site 2) located in the Lac Dollard des Ormeaux reach in the Ottawa River system demonstrated the greatest species diversity (SWI=2.09 and 2.03 respectively). This increased species diversity might be related to increased velocity because the mouth of the South Nation River (Location 29, a tributary of the
Ottawa River) had the greatest water velocity in the river reach. Poff and Allan (1995) observed a decrease of specialist species and an increase of generalist species when flow was regulated. The River Continuum Concept (RCC) suggests that greater species diversity resulting from increased habitat heterogeneity and environmental stability is typical of lower river reaches (Vannote et al. 1980; Sedell et al. 1989).
Increased species richness is typically of the increased habitat size associated with lower river reaches. The Carillon Dam is located roughly 100 km downstream of Ottawa-
Hull and is the only barrier between the St. Lawrence River and the major urban centre.
The associated reach between Carillon dam and Chaudière Falls is the longest reach (100 km) along the sampled portion of the river system. In the Ottawa River 2009, four additional locations were added (locations 26-29). These four locations along with the existing three locations, sampled below Ottawa-Hull, were examined and a trend of increasing species richness and diversity with upstream proximity to the urban centre was observed. This trend may be a result of a variety of either independent or interacting factors, which decrease upstream from urban centres.
84 5.6 Anthropogenic Factors Affecting Richness and Diversity
Upstream of the urban centre of Ottawa-Hull, two potentially important factors change: (1) there may be a decrease in introduced species because there is less human and angling activity (Johnson et al. 2001; Strayer 2010) and (2) there is an increasing number of river barriers that prevent the passage of migratory species (Han et al. 2008a).
Bait bucket introductions are well documented throughout Ontario (Litvak and
Mandrak 1993; Mills et al. 1993; DiStefano et al. 2009) and the frequency of introductions are more likely to occur around urban centres with increased angling
(Johnson et al. 2001; Strayer 2010). It is difficult to confirm bait bucket introductions by anglers as many introduced species become naturalized and established as part of the fish community (Ruesink 2006). Increased species richness in the vicinity of urban areas may be attributed to a combination of the intentional and unintentional introduction of non- native species. Unauthorized game fish transfer (Rahel 2004), discarding of unwanted aquarium species (Rixon et al. 2005; Chang et al. 2009) and the dumping of angler bait buckets may contribute to increased species richness (Strayer 2010). Interbasin transfer of species may occur within a water body, introducing species to previously unoccupied reaches of the river system (Ludwig and Leitch 1996).
Dams that fragment waterways may limit the movement of indigenous migratory species (Reid et al. 2008) and may contribute to a loss of species richness and diversity.
Upstream of Chaudière Falls, the number of hydroelectric facilities increases, further inhibiting the passage of migratory species and posing a threat to both upstream and downstream migration (Schilt 2007). Species such as American eel and redhorse, which
85 may originally have been in greater abundance throughout the various river reaches, are now greatly reduced or even extirpated (Reid et al. 2008; Wozney et al. 2011).
Dams may contribute to the loss of rheotaxic species through the creation of large areas of impoundment water. This could reduce available habitat for species requiring fast-flowing, shallow water and reduce or eliminate those species that do not fare well in reservoir environments (Bowen et al. 2003; Schilt 2007). The alteration to any river drainage may contribute to species loss (Winston et al. 1991) and may facilitate the colonization of non-native species better adapted to reservoirs (Han et al. 2008a).
American shad were once present throughout much of the St. Lawrence and Ottawa River systems as far upstream as the City of Ottawa (Maltais et al. 2010). However, due to fractionation and river impoundment, American shad are now found only in low abundance below Carillion Dam during spawning (Maltais et al. 2010). Regardless, some fish appear to be capable of passing dams that have no facilitated passage, but this passage diminishes after one or two dams and may be another partial explanation for the trend of decreased diversity upstream.
5.7 Effect of Environmental Variables
In 2009, in the Mississippi River, conductivity decreased along an upstream gradient (r2 = 0.92, df = 8, p < 0.001) and demonstrated a correlation with species assemblages, but not species richness or diversity (there were insufficient data in 2008).
Species from all trophic levels were correlated with conductivity; however no discernable pattern in species assemblages could be determined through their association with conductivity. The relationship between conductivity and distance from river mouth
86 suggests that the continuous gradient model of the RCC may be capable of predicting conductivity gradients in smaller fragmented systems.
Water temperature was expected to be a primary factor influencing fish community assemblages (Jackson et al. 2001; Buisson et al. 2008; Costas et al. 2009;
Olden and Naiman 2010), however, there were no correlations observed. Water temperatures at the time of sampling were within the typical range for warm water environments and within the preferred temperature range of sampled species.
Although nutrient measurements were not taken as a component of the data collection, phosphorus may be an important component in shaping community composition in the Mississippi River. The Mississippi River is surrounded by agricultural land, where the application of fertilizers to increase terrestrial productivity is often practiced. An important component to agricultural fertilizer is phosphorous. During periods of heavy precipitation, loose soil and excess fertilizer is carried into the surrounding watershed. The RCC suggests that there is a predictable gradient of nutrient accumulation which increases towards at river bottoms. With increased nutrient availability in aquatic systems, increased aquatic primary productivity may have direct affects on species richness and diversity (Peterson et al. 1993; Rosso and Quiros 2009).
In 2008, there was significantly greater species richness and diversity in the Mississippi
River system, which may have been partially attributed to increased productivity resulting from agricultural runoff occurring later in the fall after crops have been harvested and soil compaction was loose. Nutrient rich agricultural runoff may increase the algae biomass available for primary consumers (cyprinid species), and production potential for the entire systems (Balayla et al. 2010).
87 A side effect of increased primary production and macrophyte growth is the potential for anoxic conditions. Anoxic conditions exist when oxygen reduction resulting from macrophyte decomposition exceeds biological oxygen demand. Although this may occur in any season, anoxia is most common in summer and winter, when nutrient or light may limit productivity and induce macrophyte mortality and decomposition
(Peterson et al. 1993). In winter, fish mortality that results from under ice anoxic conditions is referred to as winter kill (Greenbank 1945). These conditions may potentially exist in backwater eddies and shallow bays of large river systems and may contribute to the shaping of local fish assemblages (Balayla et al. 2010; Shuter et al.
2012).
88 CHAPTER 6
CONCLUSIONS AND SUMMARY
6.1 Conclusions and Summary
Intensive quantitative electrofishing facilitates a more complete estimate of local fish assemblages than many more common sampling methods. Using electrofishing to sample the shallow water fish communities of the lower Ottawa and Mississippi River systems, I examined the impacts of physical distance and environmental conditions and how they influence local fish assemblages. In the Ottawa River system, I observed a trend of decreasing species richness and diversity correlated with increasing upstream distance from the urban centre of Ottawa-Hull. Migratory (e.g. American eel) and rheotaxic species (e.g. redhorse species) were present throughout the Ottawa River system, including below-dam and above-dam locations; however, in the upper reaches of the
Ottawa River system lower American eel abundances were observed than in lower river reaches. Other variables such as temperature, conductivity, and water velocity appeared to have minimal affects on fish species richness and species diversity.
Species richness and diversity were greatest during the summer season sampling in both river systems, suggesting that temporal shifts in nearshore communities occur in early fall. While fish density appeared to be greater in late fall, variation in the data likely limited our statistical power. It appears that while richness and diversity decreased during the late fall, abundance increased as a result of schooling behaviour in cyprinid species.
These results suggest that based on the study objectives, the sampling methodology should consider the sample season during data collection.
89 6.2 Future Research Considerations
Species richness and diversity are important biological indicators of ecosystem stability and health. It is fundamentally important that monitoring projects balance the practical and financial limitations with the quality and quantity of the data (Bryant et al.
2004; Gerber et al. 2005). Quantitative electrofishing enables a balance between cost effectiveness and data quality. The data I used were collected with the intentions of sampling American eel and the fish community associated with American eel (Casselman and Marcogliese 2009, 2010). Increased resources (time and money), paired with a more randomized sampling approach would facilitate a more comprehensive representation of fish communities on large river systems.
Sampling locations intensively throughout the year, over a shorter time, would provide a more complete picture of the relationship between species and environment.
Increased effort at locations closer to barriers, particularly in the upper reaches, may reveal relationships between fish communities and river barriers that were not obvious at greater distances from the barriers.
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103 Appendix A
Scientific Species Codes, Family, Genus, Species and Species’ Common Names
104 Table A-1. Numeric species codes, Family, Genus and Species common names and scientific names for all species sampled on the Ottawa and Mississippi River systems.
Species Family Genus Species Code Petromyzontidae (Lampreys) Lampetra 11 American brook lamprey (Lampetra lamottei) Ichthyomyzon 13 silver lamprey (Ichthyomyzon unicuspis) Lepisosteidae (Gars) Lepisosteus 41 Longnose gar (Lepisosteus osseus) Amiidae (Bowfins) Amia 51 Bowfin (Amia calva) Esocidae (Pikes) Esox 131 Northern pike (Esox lucius) 132 Muskellunge (Esox masquinongy) Umbridae (Mudminnows) Umbra 141 Central mudminnow (Umbra limi) Hiodontidae (Mooneyes) Hiodon 152 Mooneye (Hiodon tergisus)
Catostomidae (Suckers) Carpiodes 161 Quillback (Carpiodes cyprinus) Catostomus 163 White sucker (Catostomus commersoni) Moxostoma 168 Redhorse, silver (Moxostoma anisurum) 171 Redhorse, shorthead (Moxostoma macrolepidotum) 172 Redhorse, greater (Moxostoma valenciennesi) 173 Redhorse, river (Moxostoma carinatum) Cyprinidae (Minnows) Cyprinus 186 Common carp (Cyprinus carpio) Hybognathus 189 Brassy minnow (Hybognathus hankinsoni) 190 Silvery minnow (Hybognathus nuchalis) Notemigonus 194 Golden shiner (Notemigonus crysoleucas) Notropis 196 Emerald shiner (Notropis atherinoides) 198 Common shiner (Notropis cornutus)
105 199 Blackchin shiner (Notropis heterodon) 200 Blacknose shiner (Notropis heterolepis) 201 Spottail shiner (Notropis hudsonius) 202 Rosyface shiner (Notropis rubellus) 206 Mimic shiner (Notropis volucellus) Pimephales 208 Bluntnose minnow (Pimephales notatus) Semotilus 213 Fallfish (Semotilus corporalis) Ictaluridae (Catfish) Ictalurus 232 Bullhead, yellow (Ictalurus natalis) 233 Bullhead, brown (Ictalurus nebulosus) 234 Channel catfish (Ictalurus punctatus) Anguillidae (Freshwater eels) Anguilla 251 American eel (Anguilla rostrata) Cyprinodontidae (Killifish) Fundulus 261 Banded killifish (Fundulus diaphanus) Gadidae (Cod) Lota 271 Burbot (Lota lota) Percopsidae (Trout-Perches) Percopsis 291 Trout-perch (Percopsis omiscomaycus) Centrarchidae (Sunfishes) Ambloplites 311 Rock bass (Ambloplites rupestris) Lepomis 313 Pumpkinseed (Lepomis gibbosus) 314 Bluegill (Lepomis macrochirus) Micropterus 316 Smallmouth Bass (Micropterus dolomieui) 317 Largemouth Bass (Micropterus salmoides) Pomoxis 319 Black Crappie (Pomoxis nigromaculatus) Percidae (Perches) Perca 331 Yellow perch (Perca flavescens) Sander 332 Sauger (Sander canadensis) 334 Walleye (Sander vitreus) Etheostoma 341 Johnny darter (Etheostoma nigrum) Percina 342 Logperch (Percina caprodes)
106 Atherinidae (Silversides) Labidesthes 361 Brook silverside (Labidesthes sicculus) Gobiidae (Gobies) Neogobius 366 Round goby (Neogobius melanostomus) Sciaenidae (Drum) Aplodinotus 371 Freshwater drum (Aplodinotus grunnies) Cottidae (Sculpins) Cottus 381 Mottled sculpin (Cottus bairdi)
107 Table A-2. Species abundance at each location in the Ottawa River system 2008 sampling.
Location Species 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 8.10 8.11 8.12 8.13 8.14 A. brook lamprey Silver lamprey 20 Longnose gar Bowfin 1 Northern pike 2 1 26 6 38 15 8 4 2 1 2 8 16 Muskellunge 1 2 1 2 1 1 Central mudminnow 8 Mooneye Quillback White sucker 5 1 1 2 4 29 1 2 Redhorse, silver 3 1 1 9 3 14 4 2 7 1 Redhorse, shorthead 4 1 3 Redhorse, greater Redhorse, river 2 Common carp Brassy minnow 3 1 43 2 Silvery minnow 2 7 12 Golden shiner 11 1 20 218 57 167 109 160 82 3801 Emerald shiner 13 4 29 Common shiner Blackchin shiner Blacknose shiner Spottail shiner 21 4 33 275 57 33 3 2 Rosyface shiner 6 242 Mimic shiner Bluntnose minnow 10 217 40 21 57 58 Fallfish 2 1 7 Bullhead, yellow Bullhead, brown 9 5 22 1 71 10 1 5 2 5
108 Channel catfish 1 1 American eel 1 1 Banded killifish 492 Burbot 2 3 1 Trout-perch Rockbass 5 35 13 2 20 45 14 385 10 18 19 10 Pumpkinseed 15 8 17 8 177 117 17 6 1 17 4 8 Bluegill 4 1 Smallmouth Bass 3 1 32 2 1 27 47 223 4 9 5 Largemouth Bass 4 12 4 3 10 4 22 2 3 1 Black Crappie 4 2 5 1 Yellow perch 60 180 541 201 38 577 60 182 656 14 11 25 1 413 Sauger 8 7 3 2 2 8 Walleye 2 8 10 6 1 4 7 13 46 7 7 3 3 12 Johnny darter 10 15 1 24 Logperch 2 50 7 37 19 41 1 11 Brook silverside 21 7 1 1 Round goby 1 Freshwater drum Mottled sculpin 2 4 1 5
109 Table A-3. Species abundance at each location in the Mississippi River system 2008 sampling
Location Species 8.15 8.16 8.17 8.18 8.19 8.20 8.21 8.22 8.23 8.24 A. brook lamprey Silver lamprey Longnose gar Bowfin Northern pike 14 33 15 37 19 38 23 9 4 8 Muskellunge 3 Central mudminnow 1 102 5 44 136 1 Mooneye Quillback White sucker 4 1 27 2 2 8 14 4 Redhorse, silver 16 2 1 Redhorse, shorthead 2 Redhorse, greater 1 Redhorse, river Common carp Brassy minnow 23 1152 Silvery minnow Golden shiner 646 739 176 93 26 1 328 45 59 9 Emerald shiner 2 Common shiner Blackchin shiner Blacknose shiner Spottail shiner Rosyface shiner Mimic shiner Bluntnose minnow 124 57 Fallfish 2 6 7 Bullhead, yellow 1 1 3 Bullhead, brown 19 29 7 19 21 128 25 6 1
110 Channel catfish American eel 2 Banded killifish 47 Burbot 1 24 9 Trout-perch Rockbass 32 132 138 125 114 63 13 7 17 41 Pumpkinseed 44 32 27 35 3 264 951 54 59 14 Bluegill 487 89 Smallmouth Bass 26 7 45 1 12 3 5 2 21 Largemouth Bass 9 2 17 23 1 1 32 12 2 6 Black Crappie 28 13 104 Yellow perch 405 624 69 181 10 99 134 428 162 Sauger 5 Walleye 15 10 5 1 2 1 8 2 6 26 Johnny darter 68 Logperch 16 23 Brook silverside 1 2 Round goby Freshwater drum Mottled sculpin
111 Table A-4. Species abundance at each location in the Ottawa River system 2009 sampling
Location Species 9.26 9.1 9.27 9.2 9.28 9.29 9.3 9.4 9.5 9.6 9.7 9.8 9.9 9.10 9.11 9.12 9.13 9.14 A. brook lamprey 1 18 Silver lamprey Longnose gar 20 2 4 1 1 1 1 4 1 3 Bowfin 1 Northern pike 13 7 5 2 9 13 8 4 17 4 1 2 7 5 5 Muskellunge 1 2 Central mudminnow Mooneye 8 1 Quillback 2 16 3 White sucker 1 2 1 1 4 Redhorse, silver 3 8 12 3 17 4 5 2 5 6 3 6 5 7 Redhorse, shorthead 1 1 5 Redhorse, greater Redhorse, river 4 Common carp 2 2 4 13 1 13 Brassy minnow 7 Silvery minnow 539 Golden shiner 37 79 153 16 125 43 18 104 111 54 28 16 18 4 79 110 Emerald shiner 11 Common shiner 77 Blackchin shiner 18 Blacknose shiner 75 Spottail shiner 234 19 85 81 47 535 41 12 31 1 242 Rosyface shiner 271 50 157 37 80 143 88 Mimic shiner 1 Bluntnose minnow 35 3 33 291 Fallfish 2 2 Bullhead, yellow Bullhead, brown 204 69 40 10 45 29 4 32 3 3 4 1
112 Channel catfish 9 1 13 1 1 1 1 1 1 American eel 19 4 1 3 1 1 1 Banded killifish Burbot 3 1 Trout-perch 14 Rockbass 37 17 17 1 3 22 17 2 9 40 11 243 24 11 2 42 22 Pumpkinseed 343 252 14 247 159 51 9 103 43 14 8 2 15 28 9 15 Bluegill 4 142 3 29 20 1 5 Smallmouth Bass 15 5 30 3 3 54 2 6 33 35 96 10 62 8 6 16 Largemouth Bass 9 15 38 11 13 12 3 3 11 1 2 1 2 3 2 Black Crappie 69 23 3 4 6 6 9 2 3 2 1 2 2 1 3 1 Yellow perch 385 442 323 164 454 459 539 214 75 101 64 112 87 59 47 85 59 192 Sauger 1 32 14 29 2 2 3 2 19 8 8 13 Walleye 2 4 12 14 2 9 6 1 3 5 4 5 11 11 1 7 6 Johnny darter 1 Logperch 3 14 1 2 239 2 56 4 38 165 6 3 Brook silverside 2 2 2 Round goby Freshwater drum 1 4 1 2 1 Mottled sculpin 1
113 Table A-5. Species abundance at each location in the Mississippi River system 2009 sampling
Location Species 9.15 9.16 9.17 9.18 9.19 9.20 9.21 9.22 9.23 9.24 A. brook lamprey Silver lamprey Longnose gar 2 Bowfin Northern pike 8 10 4 9 11 11 5 9 7 2 Muskellunge Central mudminnow 186 55 237 2 Mooneye Quillback White sucker 1 2 13 6 1 7 4 1 2 Redhorse, silver 4 2 7 1 Redhorse, shorthead 3 Redhorse, greater Redhorse, river Common carp 48 5 Brassy minnow Silvery minnow Golden shiner 42 58 29 4 89 16 25 178 60 Emerald shiner Common shiner 1 Blackchin shiner Blacknose shiner 134 455 77 Spottail shiner Rosyface shiner Mimic shiner Bluntnose minnow 1 15 3 7 Fallfish 9 12 Bullhead, yellow 1 5 6 26 Bullhead, brown 7 5 63 5 27 2 9 11
114 Channel catfish 1 American eel 2 Banded killifish 4 Burbot 5 11 4 3 1 Trout-perch Rockbass 19 31 143 117 161 58 4 14 78 68 Pumpkinseed 10 17 8 240 5 54 28 99 137 36 Bluegill 2 1 2 68 160 Smallmouth Bass 8 11 26 24 52 1 7 36 Largemouth Bass 4 15 11 51 3 5 18 10 25 14 Black Crappie 1 1 1 50 2 7 Yellow perch 81 108 10 167 2 1 26 105 689 326 Sauger 1 Walleye 2 7 2 1 1 1 2 6 14 Johnny darter Logperch 2 5 8 2 1 41 Brook silverside Round goby Freshwater drum Mottled sculpin
115 Appendix B
River Reaches and Sample Locations
116
Figure B-1. Ottawa River. Reach 1- Lac des Deux Montagnes. The reach extends from the St. Lawrence River to the Carillon Dam. Locations 26, 1 and 27.
117
Figure B-2. Ottawa River. Reach 2 – Lac Dollard des Ormeaux. This reach extends upstream from the Carillon Dam to Chaudière Falls. Locations 2, 28, 29 and 3.
118
Figure B-3. Ottawa River. Reach 3 – Lac Deschenes. This reach extends upstream from Chaudière Falls to Chat Falls. Locations 4-7.
119
Figure B-4. Ottawa River. Reach 4 – Lac des Chats. This reach extends upstream from Chat Falls Dam to the Chenaux Dam. Locations 9-14.
120
Figure B-5. Mississippi River. Reach 1 – Mississippi River Mouth upstream to Galatta Dam. Locations 15-16.
121
Figure B-6. Mississippi River. Reach 2 – Galatta Dam upstream to Almonte Dam. Location 17.
122
Figure B-7. Mississippi River. Reach 3 – Almonte Dam upstream to Appleton Dam. Location 18.
123
Figure B-8. Mississippi River. Reach 4 – Appleton Dam upstream to Carleton Place Dam. Locations 19-20.
124
Figure B-9. Mississippi River. Reach 5 – Carleton Place Dam upstream to High Falls Dam. Locations 21-24.
125 Appendix C
Supplementary Analysis
126 Table C-1. Individual species scores for first two axis of the principal component analysis for the Ottawa River.
Species Species Code Axis 1 Axis 2 Axis 3 Axis 4 American brook lamprey 11 -0.049 0.263 -0.104 0.258 Silver lamprey 13 -0.047 0.269 0.001 0.059 Longnose gar 41 -0.062 0.211 -0.069 -0.303 Bowfin 51 -0.044 -0.116 0.011 -0.039 Northern pike 131 -0.129 0.287 -0.213 -0.264 Muskellunge 132 -0.133 0.139 -0.110 0.133 Central mudminnow 141 -0.030 -0.158 -0.079 -0.106 Mooneye 152 -0.013 0.061 0.199 0.018 Quillback 161 -0.036 0.281 -0.136 -0.189 White sucker 163 0.964 -0.036 -0.066 0.028 Silver redhorse 168 -0.158 0.189 0.142 0.013 Shorthead redhorse 171 -0.086 0.230 -0.126 0.226 River redhorse 173 -0.052 0.047 0.087 0.203 Common carp 186 -0.054 0.204 -0.158 -0.214 Brassy minnow 189 -0.016 0.309 -0.115 -0.058 Silvery minnow 190 -0.020 -0.033 0.466 -0.405 Golden shiner 194 1.000 0.016 0.000 0.002 Emerald shiner 196 -0.066 0.202 0.043 0.013 Common shiner 198 -0.046 -0.167 -0.056 0.082 Blackchin shiner 199 -0.018 -0.038 0.467 -0.405 Blacknose shiner 200 -0.046 -0.148 -0.076 0.091 Spottail shiner 201 -0.012 -0.045 0.928 0.015 Rosyface shiner 202 -0.120 -0.192 -0.271 0.623 Mimic shiner 206 -0.030 0.242 -0.155 -0.163 Bluntnose minnow 208 -0.061 -0.222 0.068 0.186 Fallfish 213 0.053 -0.133 -0.212 0.660 Brown bullhead 233 -0.083 0.336 -0.255 -0.362 Channel catfish 234 -0.072 0.278 -0.082 -0.229 American eel 251 -0.061 0.232 -0.182 -0.267 Banded killifish 261 -0.046 -0.264 -0.191 0.627 Burbot 271 -0.057 0.213 0.222 0.222 Trout-perch 291 -0.041 -0.153 -0.025 0.016 Rock bass 311 -0.065 0.293 0.558 0.452 Pumpkinseed 313 -0.094 0.529 -0.357 -0.395 Bluegill 314 -0.044 0.337 -0.201 -0.162 Smallmouth bass 316 -0.077 0.212 0.490 0.428 Largemouth bass 317 -0.119 0.454 0.029 0.055 Black crappie 319 -0.079 0.353 -0.231 -0.278 Yellow perch 331 -0.174 0.977 0.017 0.075 Sauger 332 -0.116 0.089 0.207 -0.088 Walleye 334 -0.007 0.367 0.294 0.382 Johnny Darter 341 -0.084 0.270 -0.055 0.053 Logperch 342 -0.006 -0.134 0.159 0.159 Brook silverside 361 -0.061 0.405 -0.071 0.002 Round goby 366 -0.004 -0.030 -0.054 -0.027 Freshwater drum 371 -0.071 0.181 -0.047 -0.035 Mottled sculpin 381 0.104 -0.187 0.089 -0.044
127
Figure C-1 Principal component analysis of species composition at various locations in the Ottawa River system for 2008 (open circles) and 2009 (closed circles). All sample locations were included in the analysis. The first axis explains 82% and the second axis explains 8% of the variation in fish community.
128