Toxicity of Chlorpyrifos Adsorbed on Humic Colloids to Larval Walleye ( Stizostedion vitreum )

2003 ◽  
Vol 45 (2) ◽  
pp. 258-263 ◽  
Author(s):  
T. A. Phillips ◽  
R. C. Summerfelt ◽  
J. Wu ◽  
D. A. Laird
Keyword(s):  
Stizostedion Vitreum

Environmental Factors Affecting the Strength of Walleye (Stizostedion vitreum vitreum) Year-Classes in Western Lake Erie, 1960–70

1975 ◽  
Vol 32 (10) ◽  
pp. 1733-1743 ◽  
Author(s):  
Wolf-Dieter N. Busch ◽  
Russell L. Scholl ◽  
Wilbur L. Hartman
Keyword(s):  
Water Level ◽  
Lake Erie ◽  
Stizostedion Vitreum ◽  
Low Oxygen ◽  
Brood Stock ◽  
Factors Affecting ◽  
Spawning Area ◽  
Western Lake ◽  
Class Strength ◽  
Western Lake Erie

Commercial production of walleyes (Stizostedion vitreum vitreum) from western Lake Erie declined from 5.9 million pounds in 1956 to 140,000 pounds by 1969. Since 1956, marked irregularity in year-class success has developed. Only four year-classes were considered good during 1959–70. The rate and regularity of water warming during the spring spawning and incubation periods in 1960–70 had a positive effect on the density of egg deposits and the resulting year-class strength. Rates of warming were not themselves detrimental, but rather the extended length of the incubation period in cool springs increased the exposure of eggs to such negative influences as dislodgment from the spawning reefs by strong current action generated by spring storms, or siltation and low oxygen tensions. The annual brood stock size had much less influence on year-class strength than did water temperature. Reproductive success was unrelated to fluctuations in size of suitable reef spawning area caused by changes in water level. Apparently the usable spawning area at any water level is more than adequate to serve the limited walleye brood stocks.

Year-Class Formation in the Walleye (Stizostedion vitreum vitreum) Population of Oneida Lake, New York, 1966–73

1976 ◽  
Vol 33 (4) ◽  
pp. 783-792 ◽  
Author(s):  
J. L. Forney
Keyword(s):  
New York ◽  
Class Size ◽  
Class Formation ◽  
Stizostedion Vitreum ◽  
Oneida Lake ◽  
Pelagic Larvae ◽  
Second Year ◽  
Alternate Prey

Abundance of eight successive year-classes of walleyes (Stizostedion vitreum vitreum) was measured at intervals from hatching into the second year. Each year-class arose from an initial stock of 12–18 billion eggs. Population of pelagic larvae was augmented in some years by the release of hatchery-reared larvae but the effect on year-class size was obscured by mortality after young became demersal. Decrease in number of fingerlings was attributed to predation by older walleyes. Intensity of predation was influenced by abundance of alternate prey and duration of cannibalism by growth of young walleyes. Five year-classes that were monitored through age 4 contributed 12,000–478,000 walleyes to the adult stock.

Mortality of First-Feeding Postlarval Walleye (Stizostedion vitreum) in Culture Ponds

1993 ◽  
Vol 50 (9) ◽  
pp. 1835-1843 ◽  
Author(s):  
Thomas A. Johnston ◽  
J. A. Mathias
Keyword(s):  
Critical Period ◽  
Mortality Rates ◽  
Predation Pressure ◽  
Stizostedion Vitreum ◽  
Exogenous Feeding ◽  
Natural Lakes ◽  
First Feeding ◽  
Zooplankton Density ◽  
Food Concentrations ◽  
Order Of Magnitude

We examined mortality rates of postlarval walleye (Stizostedion vitreum) at the onset of exogenous feeding in extensive culture ponds. Food concentrations (≥49 zooplankters∙L−1) were apparently sufficient to support successful first feeding, and no critical period of starvation mortality was evident at this stage of life. The highest observed mortality rates were associated with interspecific or intraspecific predation pressure. At low predation pressure, mean survival from stocking to the 12-mm stage was 87% in 1988 and 90% in 1989, and instantaneous mortality rates were an order of magnitude lower than those reported for postlarval walleye in natural lakes. Mortality rates calculated over the early postlarval period (stocking to 12 mm; 9–11 d) were similar to those calculated over the entire culture period (88–107 d) when predation pressure was low. At low predation pressure and 49–159 zooplankters∙L−1, there was no significant relationship between postlarval mortality rates and zooplankton density. The condition of first-feeding postlarvae captured from the pond with the lowest mean zooplankton density (49∙L−1) was significantly higher than that of postlarvae deprived of food for 48 h. Starvation is probably not a major cause of postlarval morality when zooplankton densities are ≥50∙L−1.

Comparison of Allozyme and Mitochondrial DNA Variation in Populations of Walleye, Stizostedion vitreum

1989 ◽  
Vol 46 (12) ◽  
pp. 2074-2084 ◽  
Author(s):  
Robert D. Ward ◽  
Neil Billington ◽  
Paul D. N. Hebert
Keyword(s):  
Mitochondrial Dna ◽  
Glacial Refugia ◽  
Divergence Times ◽  
Stizostedion Vitreum ◽  
Dna Variation ◽  
Mtdna Variation ◽  
Mtdna Haplotypes ◽  
Total Genetic Diversity ◽  
Allozyme Loci ◽  
Organelle Genes

Twelve populations of walleye (Stizostedion vitreum) from the Great Lakes and three populations from northern Manitoba were screened for allozyme and mitochondrial DNA (mtDNA) variation. Nine enzyme loci known to show genetic variation were screened in all fish: five of them (Prot-4, Prot-2, Mdh-3, Idh-1, Adh) showed appreciable polymorphism. MtDNA was examined in all fish using six endonucleases that detected polymorphic sites and a further 13 endonucleases that detected only monomorphic sites. Only one of the allozyme loci (Prot-4) showed evidence of geographic patterning of allele frequencies. By contrast, the mtDNA haplotypes showed clear geographic variation. The proportion of total genetic diversity attributable to population differentiation (Gst) was three to five times greater for mtDNA than for the allozymes. Gst values for organelle genes are expected on theoretical grounds to be greater than for nuclear genes, and this expected difference may be enhanced in walleye because of the likelihood that, in this species, male-mediated gene flow exceeds that of females. The distributions of mtDNA haplotypes and estimated divergence times are consistent with the derivation of extant walleye populations from three different glacial refugia.

Effect of Prey Density and Prey Size on Growth and Survival of Juvenile Walleye (Stizostedion vitreum vitreum)

1989 ◽  
Vol 46 (8) ◽  
pp. 1323-1328 ◽  
Author(s):  
Michael G. Fox
Keyword(s):  
Prey Density ◽  
Prey Availability ◽  
Food Limitation ◽  
Survival Rates ◽  
Stizostedion Vitreum ◽  
Growth And Survival ◽  
First Feeding ◽  
Length Increase ◽  
Prey Length ◽  
Chironomid Biomass

I investigated the influence of food availability on growth and survival of walleye (Stizostedion vitreum vitreum) fry stocked in six fertilized experimental ponds (density 40 fish∙m−3) and reared for 8 wk. Walleye fed largely on chironomid larvae and cyclopoid copepods in weeks 1 and 2, and chironomids thereafter. Prey choice and consumption were strongly influenced by chironomid biomass in the benthos, and to a lesser extent by zoo-plankton density. Weekly length increase of the populations and mean length in week 7 were significantly correlated with chironomid benthic biomass and mean prey length. Chironomid biomass and density of large zoo-plankton together explained 56% of the variation in the weekly population growth rate. Despite obvious food limitation in the second half of the experiment, pond survival rate was not significantly correlated with mean prey density, mean stomach fullness, or percentage of fish with empty stomachs. The results indicate that juvenile walleye growth can be regulated by the density and size of available prey. Prey availability apparently does not regulate short term juvenile walleye survival rates after the period around first feeding.

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