Modeling Walleye (Sander Vitreus) Spawning Habitat Suitability and Reproductive Success in the Sandusky River (Ohio, USA) PDF Download
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Author: Daniel Adam Gillenwater
Publisher:
ISBN:
Category : Dam retirement
Languages : en
Pages : 284
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Abstract: Dam removal is becoming an increasingly popular tool for river restoration throughout the United States. One of the most controversial dam removal proposals in the Lake Erie Watershed involves the Ballville Dam on the Sandusky River (Ohio). The Sandusky River is one of the major spawning tributaries for Lake Erie walleye (Sander vitreus). However, the dam located at river kilometer 29, blocks the fish from reaching upstream gravel beds and forces them to spawn below the Ballville Dam. It has been suggested that removing the dam will increase walleye reproductive success and thus the returning spawning population. This work is divided into two separate studies that focus on different aspects of the impacts the Ballville Dam has on the walleye population in the Sandusky River. An existing ecological model of walleye spawning and early life history stages in the Sandusky River is validated using in-situ egg deposition and larval drift data collected during the 2003 and 2004 spawning seasons. The results indicate that the model results agree with field observations for a spawning population of 2000 to 5000 females. However, this number of females is insufficient to saturate the below-dam spawning grounds, and therefore no increase in egg deposition or larval production is noted for without-dam simulations. A GIS-based habitat suitability model of an area of the currently available spawning grounds in the Sandusky River was also created and validated. The model was able to give a reasonable indication of habitat suitability dynamics in the current spawning grounds. However, there was difficulty resolving velocities in complex areas of the channel. The results indicate that floods with discharges exceeding 100 m3/s can reduce the area of suitable habitat to almost zero. Reproductive success in a given year may therefore rely heavily on the length of the spawning season and the discharge patterns. The results of the two models offer new insight into the removal of the Ballville Dam. However, coupling the two systems (an ecological model and a high resolution habitat suitability model) would give the most complete assessment of the potential impacts of the removal of the Ballville Dam on the walleye population in the Sandusky River.
Author: Daniel Adam Gillenwater
Publisher:
ISBN:
Category : Dam retirement
Languages : en
Pages : 284
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Book Description
Abstract: Dam removal is becoming an increasingly popular tool for river restoration throughout the United States. One of the most controversial dam removal proposals in the Lake Erie Watershed involves the Ballville Dam on the Sandusky River (Ohio). The Sandusky River is one of the major spawning tributaries for Lake Erie walleye (Sander vitreus). However, the dam located at river kilometer 29, blocks the fish from reaching upstream gravel beds and forces them to spawn below the Ballville Dam. It has been suggested that removing the dam will increase walleye reproductive success and thus the returning spawning population. This work is divided into two separate studies that focus on different aspects of the impacts the Ballville Dam has on the walleye population in the Sandusky River. An existing ecological model of walleye spawning and early life history stages in the Sandusky River is validated using in-situ egg deposition and larval drift data collected during the 2003 and 2004 spawning seasons. The results indicate that the model results agree with field observations for a spawning population of 2000 to 5000 females. However, this number of females is insufficient to saturate the below-dam spawning grounds, and therefore no increase in egg deposition or larval production is noted for without-dam simulations. A GIS-based habitat suitability model of an area of the currently available spawning grounds in the Sandusky River was also created and validated. The model was able to give a reasonable indication of habitat suitability dynamics in the current spawning grounds. However, there was difficulty resolving velocities in complex areas of the channel. The results indicate that floods with discharges exceeding 100 m3/s can reduce the area of suitable habitat to almost zero. Reproductive success in a given year may therefore rely heavily on the length of the spawning season and the discharge patterns. The results of the two models offer new insight into the removal of the Ballville Dam. However, coupling the two systems (an ecological model and a high resolution habitat suitability model) would give the most complete assessment of the potential impacts of the removal of the Ballville Dam on the walleye population in the Sandusky River.
Author: Madison R. Myers
Publisher:
ISBN:
Category : Sandusky River (Ohio).
Languages : en
Pages : 0
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The Sandusky River, Ohio, is one of the major tributaries of Lake Erie that supports walleye (Sander vitreus) reproduction. The goal of this study was to assess spawning habitat in the Sandusky River following the removal of the Ballville Dam and to determine if walleye can access habitat that was previously unavailable by migrating past a series of ice control structures. To determine the quantity of spawning habitat, a Habitat Suitability Index was calculated from the mouth of the river in Muddy Creek Bay to the first low-head dam in Tiffin, Ohio. A fine scale model was created that encompassed the ice control structures area and swim speed comparisons were done to determine if the area was passable. This study shows that there is suitable spawning habitat for walleye upstream and downstream of the former Ballville Dam, and that walleye can migrate passed the ice control structure area during certain conditions.
Author: Thomas E. McMahon
Publisher:
ISBN:
Category : Aquatic biology
Languages : en
Pages : 56
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Author: Adam L. Thompson
Publisher:
ISBN:
Category : Habitat selection
Languages : en
Pages : 66
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Abstract: Understanding habitat selection in fish can reveal areas critical for a population's continuation in the ecosystem. In systems experiencing habitat alterations or reductions in population sizes, identifying habitat use takes on increased importance. To facilitate our understanding of potential factors limiting the success of walleye (Sander vitreus) in Sandusky Bay, Lake Erie, we combined walleye locations determined from radio telemetry with habitat predictor variables to model habitat use and reveal sex-specific patterns of habitat use throughout the spawning season (Chapter 2). Models revealed that the presence of preferred walleye spawning substrate, gravel and cobble, was an important predictor of walleye locations during the entire spawning season, and depth and distance from shore were important particularly prior to the spawn. In examining sex-specific patterns of habitat use, we discovered that males were more likely to occur over gravel and cobble substrates than females. We hypothesize that males establish position in these areas in anticipation of spawning females. Only a small proportion of walleye tagged in Sandusky Bay migrated to upstream spawning grounds (2 of 197; 1%). To confirm whether walleye spawning occurs in Sandusky Bay and to analyze how spawning substrate might affect egg deposition rates and viability, we compared eggs collected using spawning mats from gravel/cobble and sand/silt substrates (Chapter 3). Egg deposition and egg viability were not significantly different between substrates, and the majority of walleye eggs were collected from one site that contained gravel and cobble. The combined results of this investigation reveal that the Sandusky Bay is a spawning ground for walleye and that preferred spawning substrate is an important factor predicting the location of walleye during the spawn. Because the amount of spawning habitat in this system has declined by an estimated 92% during the past century, we recommend that conservation and restoration steps be taken to preserve this walleye spawning population.
Author: Michael T. Hamilton
Publisher:
ISBN:
Category : Walleye (Fish)
Languages : en
Pages : 114
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The objective of this project was to achieve an assessment of walleye (Sander vitreus) spawning through the collection of eggs and physico-chemical data in the Shenango River, from the Shenango River Lake extending upstream approximately 24 river kilometers. It is generally thought that successful spawning of walleye in Pennsylvania is nearly non-existent, but the research to support this is limited. The data collected during sampling included river depth, flow velocity, water temperature, dissolved oxygen, pH, and river substrate content. This data will provide a baseline for future studies of the Shenango River and similar fisheries. This information was compared with that of other studies on walleye spawning habitat to establish a Walleye Spawning Qualitative Habitat Evaluation Index (WSQHEI). Walleye spawning attempts by Shenango River Lake walleye in the Shenango River was confirmed by this study. The WSQHEI appeared unsuitable for predicting walleye spawning in the Shenango River. Physico-chemical data displayed minimal gradients, which limited the development and effectiveness of the WSQHEI. This occurred because sampling was restricted to areas conducive to walleye spawning based upon literature of known environmental variables. Although walleye spawning activity was unrelated to environmental conditions among sites, migration distance was negatively correlated with walleye spawning activity. Sampling in 2008 and 2009 indicated that spawning occurrence decreased as distance from Shenango River Lake increased. The WSQHEI could be useful for baseline assessments when little or no data are available about the walleye spawning activities in a lotic system.
Author: Andrew Peter Bade
Publisher:
ISBN:
Category : Aquatic sciences
Languages : en
Pages : 232
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Many migratory animals time reproduction using environmental cues (e.g., photoperiod) that signal favorable conditions for offspring (e.g., food availability). However, environmental change can decouple these cues from the conditions relevant to offspring success. In turn, variation in reproductive behaviors may be critical to population persistence in a changing environment. For example, while natal homing can lead to valuable local adaptations in a stable environment, straying to new breeding sites can buffer against environmental change. Among exploited species, knowledge of reproductive behavior, such as spawn timing (phenology) and spawning site selection, has proven useful to fisheries management by influencing angling dynamics, estimates of biological reference points, and stock delineations. Thus, a well-developed understanding of reproductive phenology, breeding site selection, and fishery dynamics could help agencies effectively conserve and manage fisheries in ecosystems experiencing environmental change. Accordingly, my dissertation research sought to better understand the reproductive behaviors and angling dynamics of Lake Erie’s walleye population. In collaboration with other researchers and agency biologists, I used acoustic telemetry, creel surveys, environmental monitoring data, and quantitative techniques to discern the spawning behaviors and angling dynamics of this population. We assessed the timing of residency in spawning sites, focusing on how environmental cues and individual characteristics drive observed variation (Chapter 2), developed a quantitative framework to estimate the frequencies of each potential spawning site selection strategy (Chapter 3), demonstrated sex based-differences in spawning behavior and male-biased walleye harvest during the spawning season (Chapter 4), and modeled the impact of fishery characteristics and angler behaviors on recreational catch outcomes (Chapter 5). Each chapter generated new insights to the benefit of fisheries management through advances in our understanding of reproductive ecology and angling dynamics. In Chapter 2, we found that the timing of residency in spawning sites differed between sexes and among spawning locations and was controlled by photoperiod and temperature. The varying responses to warming suggest that reproductive resilience is promoted by conserving local spawning populations and a broad age structure. The findings from Chapter 3 demonstrated that, although spawning site fidelity and annual spawning are common, apparent skipped spawning also occurs (~ 14% of observations). Accounting for this potential skipped spawning led to revised biological reference points, owing to adjusted estimates of spawning stock biomass. Additionally, although few walleye strayed, the pattern of straying indicated that some stocks mix heavily. In Chapter 4, we found strong evidence for sex-specific spawning behaviors, with males occupying spawning grounds longer than females, which helped explain male-biased walleye harvest on the spawning grounds. Lastly, in Chapter 5, modeling creel survey data showed that angler decisions influenced catch outcomes more than abundance of the targeted walleye population. The findings from this chapter can help anglers maximize their probability of fishing success, given desired catch outcomes. The improved understanding of Lake Erie walleye reproductive behavior, angling dynamics, and the relationships between them, should help agencies worldwide keep their valued fish populations sustainable in the face of continued environmental change.
Author: Jo Ann Banda
Publisher:
ISBN:
Category : Genetics, Population
Languages : en
Pages : 54
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The population genetic structure of three of the largest walleye spawning groups in Lake Erie is tested for consistency over time and space spanning 14 years, based on nine high-resolution nuclear DNA microsatellite loci. Previous genetic studies focused on a one-time genetic "snapshot", with an earlier study by our laboratory finding that the genetic structure of three Lake Erie spawning groups along the southern shore - Maumee River, Sandusky River, and Van Buren Bay reefs - appeared similar in 2003, whereas most other spawning groups across Lake Erie were genetically distinctive. The present study analyzes the stability of genetic similarity patterns within and among 726 walleye spawning at these three sites across years and age cohorts in 1995, 1998, 2003, 2007, and 2008. Genetic patterns are evaluated using pairwise FST analog and contingency tests, AMOVA partitioning, and Bayesian assignment tests. Results reveal overall year-to-year consistency in genetic structure of walleye spawning at the three sites, with some annual variation in the Van Buren Bay reef group. Greater genetic divergence from the other groups is detected in the Van Buren Bay spawning group, which reflects greater geographic separation. Walleye spawning in the Sandusky and Maumee Rivers are genetically distinguishable from each other when data from all years are combined, which suggests possible sample size effect (i.e., annual sample sizes likely were not large enough to detect their genetic differentiation). No significant differences occur among age cohorts, between the sexes, or among sampling dates within spawning runs. Results demonstrate the importance of sampling over several years of walleye spawning runs in order to resolve fine-scale genetic relationships within an open lake system.
Author: Matthew J. Sperry
Publisher:
ISBN:
Category : Bemidji, Lake (Minn.)
Languages : en
Pages : 84
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Radio telemetry, larval fish sampling, egg baskets, and scapnetting were utilized to determine walleye Sander vitreus spawning sites in Lake Bemidji, Minnesota, during the spring spawning periods of 2002 through 2004. Some walleye populations travel from their lake environments into rivers or streams to spawn, but Lake Bemidji walleyes appear to be lake spawners. No tracked walleyes were found in river habitats during the 2002 spawning season. Based on radio telemetry, six putative spawning areas were located: Rocky Point at Lake Bemidji State Park, northwestern shore of the north basin, weed beds (bulrush Scirpus spp.) on each side of the Mississippi River outlet on the east side of the lake, Diamond Point, and the ridge between Diamond Point and the outlet of the Mississippi River. The greatest concentration of spawning walleyes occurred along the ridge between Diamond Point and the outlet of the Mississippi River in relatively shallow water over more coarse substrate than is typically found in the lake. No walleye eggs were found in egg baskets placed in putative spawning areas during 2003, but one was found by scapnetting on the ridge off of Diamond Point during spring 2004. These methods were conducted in shallow waters less than 1.5 m deep. Spawning shoals may be relatively small and isolated in waters deeper than 1.5 m. further studies utilizing a combination of SCUBA or an underwater video camera and scapnetting should be conducted to pinpoint spawning sites in deeper waters. Based on the presence of adequate natural recruitment, the amount of walleye spawning habitat does not appear to be limiting. Thus, habitat enhancement is not recommended at this time.
Author: Joshua K. Raabe
Publisher:
ISBN:
Category : Fishery management
Languages : en
Pages : 364
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Author: Gina M. Rammer
Publisher:
ISBN:
Category : Fishery management
Languages : en
Pages : 152
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