Walleye Growth Research Articles

Growth and survival of age-0 walleye (Sander vitreus): interactions among walleye size, prey availability, predation, and abiotic factors

We examined the importance of prey availability, predation, and abiotic factors in determining growth and survival of age-0 walleye (Sander vitreus) across 15 Illinois reservoirs during 7 years. Multiple life stages were examined by stocking walleye at three different size groups: larval (6 mm total length (TL)), small (46 mm TL), and large (100 mm TL). Factors affecting growth and survival of walleye varied depending on walleye size. Growth of small and large walleye increased with benthic invertebrate density. Temperature had a positive effect on larval and small walleye growth but a negative effect on large walleye growth. Prey availability was an important factor for walleye survival across all size groups, whereas temperature affected only larval and large walleye. Juvenile centrarchid density had a negative effect on larval walleye survival, presumably caused by predation. Our best predictive models explained substantial variation in survival for larval (97%), small (57%), and large (83%) walleye. We also explained a high proportion of variation in growth of large (98%), small (55%), and larval (52%) walleye. Our study demonstrates the importance of examining multiple life stages to predict growth and survival and leads to a better understanding of walleye recruitment and recommendations for stocking strategies.

Evaluation of a Modified Bag Limit for Walleyes in Wisconsin: Effects of Decreased Angler Effort and Lake Selection

AbstractWe evaluated a modified daily bag limit for walleyes Sander vitreus to determine whether management goals were achieved. The modified bag limit consisted of no minimum length limit but allowed a daily harvest of only one walleye longer than 356 mm. The Wisconsin Department of Natural Resources implemented the single‐fish, 356‐mm regulation in 1997 on a number of lakes in northern Wisconsin that were previously subject to a 381‐mm minimum length limit. The intent of the regulation was to increase the harvest of smaller walleyes in order to increase growth, spawning stock abundance, and harvest rate in lakes characterized by high densities of slow‐growing walleyes. We examined the effects of the regulation in light of variables associated with walleye populations, the walleye fishery, and tribal harvest. All lakes included in our evaluation are located within the ceded territory of northern Wisconsin, where tribal harvest of walleyes, which is regulated differently than angler harvest, occurs annually. The daily bag limit for walleyes ranged between two and five, depending on the level of tribal harvest. Walleye fishery characteristics measured before 1997 (381‐mm limit) and after 1999 (single‐fish, 356‐mm limit) demonstrated an increased angler harvest rate and a decreased mean length of harvested walleyes. However, we found none of the desired changes in walleye population characteristics. In addition, we found no evidence that lakes that were changed to the single‐fish, 356‐mm regulation were characterized by slower growth than those that retained the 381‐mm regulation. The single‐fish, 356‐mm regulation requires increased harvest to achieve the desired changes to walleye population characteristics. Our results suggest that a significant decline in angler effort over time, in conjunction with the possibility that the lakes selected to receive the single‐fish, 356‐mm regulation did not exhibit particularly slow walleye growth, acted to offset increases in harvest rate and played a role in the general failure of this regulation to meet its goals.

Relationships among condition indices, feeding and growth of walleye in Lake Erie

Abstract Condition indices are often used as surrogates of fish health, growth, and feeding and to compare ecological well‐being among fish populations. In an effort to identify easily measured indices, growth and food consumption were compared with gonadal‐somatic index, liver‐somatic index (LSI), fat‐somatic index and relative weight (Wr) for ages 1–3 walleye, Sander vitreus (Mitchill), in Lake Erie from 1986 to 1988. The LSI and Wr were significantly correlated with growth rate or food consumption, but correlations were too small to be considered biologically meaningful. Furthermore, no consistent relationships between condition indices and growth or consumption were found among combinations of fish age and season. None of the indices are considered reliable surrogates for more laborious estimates of growth and food consumption for Lake Erie walleye. Significant relationships between Wr and relative abundance of key prey species warrant further investigation.

Interactions between Walleyes and Four Fish Species with Implications for Walleye Stocking

AbstractWe used a number of different data sets and four criteria to evaluate evidence of competition and predation between walleye Sander vitreus and northern pike Esox lucius, muskellunge E. masquinongy, smallmouth bass Micropterus dolomieu, and largemouth bass M. salmoides in northern Wisconsin lakes. The four criteria were as follows: (1) indices of population abundance were inversely related, (2) two species had shared resources or one species preyed on the other, (3) competition or predation was strong enough to produce a measurable effect, and (4) experimental manipulations produced results consistent with the hypothesis of competition or predation. Using these criteria, we identified which species interact most strongly with walleyes, determined the most likely mechanism for interaction (predation, competition, or both), and characterized the effects of walleye stocking on these species. Largemouth bass was the only species that strongly interacted with walleyes: (1) indices of largemouth bass and walleye population abundance were inversely related in lakes with self‐sustaining walleye populations; (2) the diet of largemouth bass included juvenile walleyes; (3) walleye growth was positively related to indices of largemouth bass abundance; and (4) survival of stocked walleyes was negatively related to indices of largemouth bass abundance, and indices of largemouth bass abundances increased as an index of walleye stocking intensity increased. A bioenergetics analysis of one lake that was stocked with 39,300 juvenile walleyes, but also has some natural reproduction of walleyes, suggested that the largemouth bass population could consume up to 82,500 juvenile walleyes per year. Our findings suggest that largemouth bass interact strongly with walleyes through predation, that they can limit the survival of stocked walleyes, and that walleye stocking can result in increased largemouth bass populations. Therefore, management goals seeking to simultaneously maximize largemouth bass and walleye populations may be unrealistic.

Angler Catch Rates and Catchability of Walleyes in Oneida Lake, New York

AbstractUnderstanding the relationship between anglers and fish is important to the management of angling fisheries. We compared angler catch rates estimated from creel surveys with (1) population density estimates of age‐3 and older walleyes Sander vitreus based on mark–recapture and (2) mean growth of walleyes aged 4–6 in Oneida Lake during 1957–1959, 1997, and 2002– 2003. We also compared walleye catchability to walleye population density. Angler catch rates were not related to walleye population density; however, by combining population density and walleye growth, we were able to explain 97% of the variability in angler catch rates, perhaps because growth rates were related to prey abundance. Catchability of walleyes decreased as population density increased. Consideration of these effects should improve our understanding of angler–fish dynamics and allow fishery managers to better predict the effects of management actions.

Can growth be used as a surrogate measure of walleye (Sander vitreus) abundance change?

We examined several models to determine the relative contributions of density-dependent and density-independent factors on walleye (Sander vitreus) growth in the ceded territory of Wisconsin from 1990 to 1999. We then used independent data from 2000 to determine how well each model predicted walleye growth and examined several models to determine if growth could be used to predict density. Adult density best predicted the mean size of age-3 males ( [Formula: see text]3m) and age-5 females ( [Formula: see text]5f). Density-independent measures of pH, the morphoedaphic index, maximum depth, and conductance had a positive influence on growth, while adult density negatively affected growth. The solely density-dependent models predicted [Formula: see text]3m and [Formula: see text]5f poorly in 2000. The addition of density-independent factors improved model predictions of [Formula: see text]3m and [Formula: see text]5f. Walleye growth did not predict adult walleye densities. Regional patterns in walleye growth were correlated with surrogate measures of lake productivity and to a lesser extent adult density. Density dependence had a relatively weak affect on growth patterns, suggesting that growth cannot be used as a surrogate method for monitoring abundance change.

A Comparison of Elastomer Marks and Fin Clips as Marking Techniques for Walleye

AbstractTwo marking techniques, fin removal and visible implant elastomer, were evaluated in walleye Sander vitreus. Although fin‐clipping is widely practiced, research results have been ambiguous as to whether the technique is harmful to fish over the long term. We attempted to determine over a 7‐year period whether elastomer marking might have significant benefits to growth and survival of walleye when compared with fish given a single fin clip. We also evaluated the long‐term detection rates of elastomer marks as well as their cost‐effectiveness. Each year for 5 years we marked and stocked an average of 8,000 extended‐growth walleye fingerlings in the lower Milwaukee River, Wisconsin, as part of a project to reintroduce walleyes to the Milwaukee River estuary. One‐half were given a single fin clip and one‐half were given an elastomer mark. Fin clips and elastomer colors were changed each year. Fish were recaptured the following year by means of electrofishing gear. We found no significant differences in survival or growth rates between the differentially marked fish. We also found that tag detection in recaptured fish over the long term was 82.5% for fish originally marked with elastomer. The cost associated with elastomer marking was US$0.40 per mark while the cost of fin clipping was $0.03 per mark. We concluded that a single fin clip was the more desirable technique for marking walleyes.

Spatial Patterns Emphasize the Importance of Coastal Zones as Nursery Areas for Larval Walleye in Western Lake Erie

Lake Erie walleye Sander vitreus exhibits significant interannual variability in year-class strength. Recent research revealed the importance of larval growth and survival rates in determining walleye year-class strength in western Lake Erie, indicating that spatial and temporal overlap of larvae with good habitat conditions (e.g., abundant prey, warm waters) promoted walleye growth and survival. To assess the spatial overlap between walleye larvae and habitat parameters (water depth, temperature, water clarity, prey density) in western Lake Erie, we evaluated the spatial distribution of walleye larvae and these habitat parameters with intensive sampling at 30 to 36 sites during spring 1994–1999. We analyzed spatial relationships among pelagic walleye larvae and various habitat attributes using a geographic information system and principal components analysis. Larval walleye density was consistently highest at nearshore sites during all years and showed a high degree of spatial overlap with high ichthyoplankton density, and warm water temperatures. Larval walleye density was negatively associated with water depth and water clarity. Two principal components represented 79.6% of the total variability in site attributes. Principle components analysis supported our spatial analysis by graphically separating sites into distinct groups based on larval walleye density and habitat attributes. These analyses indicated that similar relationships between larval distribution and habitat attributes occur each year, emphasizing the importance of nearshore coastal zones as nursery areas for walleye.

The Role of Density Dependence in Growth Patterns of Ceded Territory Walleye Populations of Northern Wisconsin: Effects of Changing Management Regimes

Abstract We assessed density-related changes in growth of walleye Sander vitreus in the ceded territory of northern Wisconsin from 1977 to 1999. We used asymptotic length (L ∞), growth rate near t 0 (ω), and body condition as measures of walleye growth to determine the relationship between growth and density. Among lakes, there was weak evidence of density-dependent growth: Adult density explained only 0–6% of the variability in the growth metrics. Within lakes, growth was density dependent, L ∞, ω, and body condition of walleyes changing with density for 69, 28, and 62% of the populations examined, respectively. Our results suggest that walleye growth was density dependent within individual lakes. However, growth was not coherently density dependent among lakes, which was possibly due to inherent differences in the productivity, surface area, forage base, landscape position, species composition, and management regime of lakes in the ceded territory. Densities of adult walleyes averaged 8.3 fish/ha and di...

Growth, ingestion rates and metabolic activity of walleye in lakes with and without lake herring

Growth efficiencies, ingestions rates and activity levels of walleye Sander vitreus were compared in lakes with and without lake herring Coregonus artedi. Yellow perch Perca flavescens were the main prey in lakes without lake herring. Walleye were sampled in September and October from 38 lakes in Ontario in 1998 and 1999, using multimesh monofilament gillnets. Ingestion rates were estimated from annual increments in somatic mercury and body mass, and the mercury content of yellow perch and lake herring. Walleye had higher growth efficiencies, and lower ingestion and activity rates in lakes with lake herring. Lake herring grow larger than yellow perch and therefore could provide more profitable prey for larger walleye. The results are consistent with optimal foraging theory that predicts that walleye feeding on optimal prey sizes should grow more efficiently, if the ratio of feeding benefit (energy) to cost (search and seizure) is a function of the ratio of predator and prey size.

Age Structure and Mortality of Walleyes in Kansas Reservoirs: Use of Mortality Caps to Establish Realistic Management Objectives

AbstractAge structure, total annual mortality, and mortality caps (maximum mortality thresholds established by managers) were investigated for walleye Sander vitreus (formerly Stizostedion vitreum) populations sampled from eight Kansas reservoirs during 1991–1999. We assessed age structure by examining the relative frequency of different ages in the population; total annual mortality of age‐2 and older walleyes was estimated by use of a weighted catch curve. To evaluate the utility of mortality caps, we modeled threshold values of mortality by varying growth rates and management objectives. Estimated mortality thresholds were then compared with observed growth and mortality rates. The maximum age of walleyes varied from 5 to 11 years across reservoirs. Age structure was dominated (≥72%) by walleyes age 3 and younger in all reservoirs, corresponding to ages that were not yet vulnerable to harvest. Total annual mortality rates varied from 40.7% to 59.5% across reservoirs and averaged 51.1% overall (SE = 2.3). Analysis of mortality caps indicated that a management objective of 500 mm for the mean length of walleyes harvested by anglers was realistic for all reservoirs with a 457‐mm minimum length limit but not for those with a 381‐mm minimum length limit. For a 500‐mm mean length objective to be realized for reservoirs with a 381‐mm length limit, managers must either reduce mortality rates (e.g., through restrictive harvest regulations) or increase growth of walleyes. When the assumed objective was to maintain the mean length of harvested walleyes at current levels, the observed annual mortality rates were below the mortality cap for all reservoirs except one. Mortality caps also provided insight on management objectives expressed in terms of proportional stock density (PSD). Results indicated that a PSD objective of 20–40 was realistic for most reservoirs. This study provides important walleye mortality information that can be used for monitoring or for inclusion into population models; these results can also be combined with those of other studies to investigate large‐scale differences in walleye mortality. Our analysis illustrates the utility of mortality caps for monitoring walleye populations and for establishing realistic management goals.

Consumption Dynamics of the Adult Piscivorous Fish Community in Spirit Lake, Iowa

AbstractAt Spirit Lake, one of Iowa's most important fisheries, walleye Sander vitreus (formerly Stizostedion vitreum) is one of the most popular species with anglers. Despite a century of walleye stocking and management in Spirit Lake, walleye growth rate, size structure, and angler harvest continue to decline. Our purpose was to determine the magnitude and dynamics of walleye population consumption relative to those of other piscivorous species in Spirit Lake, which would allow managers to judge the feasibility of increasing the abundance, growth rate, and size structure of the walleye population. We quantified food consumption by the adult piscivorous fish community in Spirit Lake over a 3‐year period. Data on population dynamics, diet, energy density, and water temperature from 1995 to 1997 were used in bioenergetics models to estimate total consumption by walleye, yellow perch Perca flavescens, smallmouth bass Micropterus dolomieu, largemouth bass Micropterus salmoides, black crappie Pomoxis nigromaculatus, and northern pike Esox lucius. Estimated annual consumption by the piscivorous community varied roughly fourfold, ranging from 154,752 kg in 1995 to 662,776 kg in 1997. Walleyes dominated total consumption, accounting for 68, 73, and 90% (1995–1997, respectively) of total food consumption. Walleyes were also the dominant consumers of fish, accounting for 76, 86, and 97% of piscivorous consumption; yellow perch followed, accounting for 16% of piscivorous consumption in 1995 and 12% in 1996. Yellow perch were the predominant fish prey species in all 3 years, accounting for 68, 52, and 36% of the total prey consumed. Natural reproduction is weak, so high walleye densities are maintained by intensive stocking. Walleye stocking drives piscivorous consumption in Spirit Lake, and yearly variation in the cannibalism of stocked walleye fry may be an important determinant of walleye year‐class strength and angler success. Reducing walleye stocking intensity, varying stocking intensity from year to year, and attempting to match stocking intensity with the abundance of prey species other than walleye may improve the walleye fishery in Spirit Lake.

Growth and Survival of Larval Walleyes in Response to Prey Availability

Although larval fish can be highly susceptible to changes in prey availability, the effects on growth and survival are difficult to examine in the field. In addition, previous studies often have examined these relationships only with zooplankton communities common to northern oligotrophic lakes. We used mesocosm and pond experiments to better understand the relationship between communities of larval walleye Sander vitreus (formerly Stizostedion vitreum) and zooplankton common to eutrophic midwestern USA reservoirs. Treatments of low, medium, and high crustacean zooplankton density (1–50 individuals/L) were created in mesocosms by filtering pond water. Treatments in ponds were created by adding copper sulfate to create low-density zooplankton ponds and adding liquid fertilizer to create high-density zooplankton ponds. Walleye growth rate (0.7–1.5 mm/d) increased with crustacean zooplankton density in both mesocosms and ponds. Densities necessary to maintain good growth were higher than previously observed at northern latitudes, probably due to lack of large-sized zooplankton. Survival increased with zooplankton density in the mesocosm experiments (11–37%) but not in the ponds. Walleye consumption of zooplankton increased with zooplankton density up to 20–30 individuals/L. At low zooplankton densities, larval walleyes fed more heavily on chironomid larvae. Our results demonstrate the importance of zooplankton abundance and size composition for survival and growth of larval walleyes.

Factors related to growth and survival of larval walleyes: implications for recruitment in a southern Great Plains reservoir

Larval fishes, limnological characteristics, and zooplankton populations were sampled from Glen Elder Reservoir, Kansas, during 1999–2001 to determine factors associated with growth and survival of larval walleyes ( Stizostedion vitreum). Ichthyoplankton populations were sampled weekly from April to June during all years using paired conical nets. Water temperature and zooplankton populations were sampled at each ichthyoplankton sampling site. Approximately, 70% of all larval fishes and 80% of the larval walleyes were sampled in the upper reservoir during all years. Cyprinidae and Centrarchidae were the only taxa that were more abundant in the main reservoir than the upper reservoir. Despite similarities in zooplankton abundance between years, recruitment of walleyes in 1999 was the lowest in nearly 20 years, while moderate year classes were produced in 2000 and 2001. During 1999, low, variable spring temperatures resulted in poor growth of larval walleyes. Poor growth of walleyes, coupled with high densities of larval gizzard shad ( Dorosoma cepedianum), resulted in poor recruitment during 1999. Walleyes grew faster in 2000 and 2001 and were able to consume larval gizzard shad resulting in moderate recruitment. These results suggest that abiotic conditions mediate biotic interactions and that both abiotic and biotic characteristics are important for regulating walleye recruitment dynamics.

Latitudinal Comparisons of Walleye Growth in North America and Factors Influencing Growth of Walleyes in Kansas Reservoirs

Abstract We compared the growth of walleyes Stizostedion vitreum in Kansas to that of other populations throughout North America and determined the effects of the abundance of gizzard shad Dorosoma cepedianum and temperature on the growth of walleyes in Kansas reservoirs. Age was estimated from scales and otoliths collected from walleyes (N = 2,072) sampled with gill nets from eight Kansas reservoirs during fall in 1991-1999. Age-0 gizzard shad abundance was indexed based on summer seining information, and temperature data were obtained from the National Oceanic and Atmospheric Administration. Parameter estimates of von Bertalanffy growth models indicated that the growth of walleyes in Kansas was more similar to that of southern latitude populations (e.g., Mississippi and Texas) than to that of northern (e.g., Manitoba, Minnesota and South Dakota) or middle latitude (e.g., Colorado and Iowa) populations. Northern and middle latitude populations had lower mean back-calculated lengths at age 1, lower growth...

Piscivory in Juvenile Walleyes: Relative Importance of Prey Species, Timing of Spawning of Prey Fish, and Density on Growth and Survival

We examined the effect of the timing of spawning by prey fish and the species of prey fish on the growth and survival of juvenile walleye Stizostedion vitreum. We expected that age-0 walleyes would grow more in ponds when stocked about the same time as the spawning of gizzard shad Dorosoma cepedianum than when stocked about 6 weeks after spawning. We found, however, that the timing of larval gizzard shad presence did not affect walleye growth or survival. Also contrary to our expectations, walleyes from ponds with bluegill Lepomis macrochirus grew more (by 9% in total length and 38% in mass) than those from ponds with gizzard shad. However, the density of gizzard shad was lower than that of bluegills, particularly after the first few weeks of the experiment. Bluegills remained within the gape limits of walleyes throughout the experiment, whereas gizzard shad outgrew their vulnerability to predation. Late-spawned gizzard shad remained vulnerable to walleye predation only slightly longer than did those from early spawned ponds. The survival of age-0 walleyes was unaffected by water temperature, the timing of spawning by prey fish, prey species, or density. Our results suggest that even though walleyes typically grow faster in systems with gizzard shad as prey than in those with bluegills, juvenile walleyes can still grow well in bluegill-dominated systems. In some systems, high densities of a less beneficial prey (e.g., abundant bluegills rather than less abundant gizzard shad) may overcome the growth differences of juvenile walleyes that would be expected based on the differences in prey species alone. A wide variation in individual walleye growth in our ponds, even within prey treatments, indicated the complexity of interactions among the factors affecting juvenile walleye growth.

Seasonal variation in condition, growth and food habits of walleye in a Great Plains reservoir and simulated effects of an altered thermal regime

Catch rates in gillnets and relative weight (Wr) of walleye Stizostedion vitreum, in Glen Elder Reservoir, Kansas, were lowest during the summer (June–August) and highest during the autumn (September–November). Approximately 80% of their annual growth in length and mass was attained during late summer and autumn. Growth was minimal during winter (January–February) and spring (March–May). The number of walleye with empty stomachs was highest during the summer. Invertebrates (Cladocera, Chironomidae) were common in walleye stomachs during the summer and spring, but contributed little to the ingested biomass. Gizzard shad Dorosoma cepedianum dominated walleye diets (per cent by mass) throughout the year. A bioenergetics model predicted that the proportion of maximum consumption (Pc) was highest during the autumn and was probably due to spatial overlap of walleye and gizzard shad once water temperatures were <22° C. The bioenergetics model predicted that walleye would lose up to 65% of their body mass during the summer if water temperature increased by 10% (as predicted by some global warming models). Growth during the autumn, winter and spring was enhanced up to 150% by increased temperatures. The results of this study indicate that lower condition, reduced consumption and slow growth are a generalized response of walleye to extreme temperatures. Elevated temperatures may have a net positive effect on walleye growth if they can survive the high thermal stress during summer.

Seasonal variation in condition, growth and food habits of walleye in a Great Plains reservoir and simulated effects of an altered thermal regime

Seasonal variation in condition, growth and food habits of walleye in a Great Plains reservoir and simulated effects of an altered thermal regime

A Review of Walleye Management in Texas with Emphasis on Meredith Reservoir

Management of walleyes Stizostedion vitreum in Texas, and Meredith Reservoir in particular, has a 35-year history of challenges addressed by fisheries managers. The first attempt at stocking walleyes in Texas in 1953 was unsuccessful, with no documented survival. Additional stocking in the mid-1960s resulted in some survival, particularly in Meredith Reservoir. Walleye survival and development of a fishery was highest in reservoirs where there was at least some natural reproduction. Through experimentation, it became economically feasible to develop and maintain walleye fisheries through massive fry stockings where survival was high but reproduction was limited. Evaluation of stocking success allowed adjustments in stocking procedures, that is, 1-d-old walleyes were stocked instead of 3- to 5-d-old fish. Growth of Meredith Reservoir age-1 walleyes was faster than that of northern (Iowa and New York) age-1 walleyes, although growth rates declined more rapidly as fish aged. Walleye movement and home range establishment in Meredith Reservoir were similar to that of walleyes in their native range. Texas biologists managed walleyes using only daily bag limits for the first 20 years. The first minimum length limit (407 mm) was implemented in 1987. The relative abundance of walleyes in Meredith Reservoir increased after implementation of the minimum length limit. Indications of stockpiling for fish smaller than the minimum length limit led to the implementation of a five-fish daily bag limit, with anglers being allowed to keep only two fish under 407 mm. Growth of Meredith Reservoir walleyes may be limited by environmental stressors or genetics related to the limited size of the founder population, so managers are currently trying to enhance the population's genetics through supplemental stocking of an additional walleye strain.

Use of Biochronology to Examine Interactions of Freshwater Drum, Walleye and Yellow Perch in the Red Lakes of Minnesota

Growth histories for freshwater drum, Aplodinotus grunniens, walleye, Stizostedion vitreum, and yellow perch, Perca flavescens, were constructed using calcified structures for the period 1947 through 1996 for the Red Lakes, Minnesota. Increased walleye growth and decreased yellow perch growth were observed over the period from 1983 to 1996, which are attributed to intensive fishing resulting in decreased intraspecific competition in walleye and increased intraspecific competition in yellow perch through release from predation. Strong year-classes of yellow perch were positively correlated with walleye growth (r=0.57, p-value=0.042). There was no evidence for interactions of walleye or yellow perch with freshwater drum. Freshwater drum growth (r=0.680, p-value=0.0001) was more highly correlated with temperature than were walleye (r=0.386, p-value=0.006) and yellow perch growth (r=0.303, p-value=0.036).