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.

Impact of environmental factors on survival of larval and juvenile Cape anchovy Engraulis encrasicolus (G.) in the southern Benguela upwelling region, determined from hatchdate distributions: implications for recruitment

2005 ◽  
Vol 56 (5) ◽  
pp. 561 ◽  
Author(s):  
M. R. Wilhelm ◽  
S. J. Painting ◽  
J. G. Field ◽  
M. Kerstan ◽  
M. D. Durholtz
Keyword(s):  
Electron Microscopy ◽  
Success Rate ◽  
Critical Period ◽  
Mortality Rates ◽  
Sea Surface ◽  
Planktonic Food ◽  
First Feeding ◽  
Benguela Upwelling ◽  
Scanning Electron ◽  
Age Estimates

March larval and May juvenile Cape anchovy of the unusually strong 1999/2000 year-class were collected off South Africa. Age estimates were obtained from daily increment counts on otoliths using light microscopy for March larvae (14–70 mm standard length, SL, n = 193, 92% success rate), and scanning electron microscopy for May juveniles (52–110 mm SL, n = 80, 22% success rate). Differences between March and May hatchdate distributions were related to the prevailing temperatures. March larval hatchdate distributions showed slight modes in October/November 1999 and January/February 2000, each a month later than May juvenile hatchdate distributions (September/October and November/December). Thus, mortality rates of larvae hatched after mid-December seem to have been higher. Large areas of warm water (19–26°C sea surface temperature) on the Agulhas Bank, mid-November 1999 to March 2000, indicated conditions conducive to spawning and reduced offshore advection of spawning products. A period of strong upwelling, March to May 2000, is likely to have increased availability of planktonic food for older larvae; also causing offshore dispersal of younger larvae and food patches required by these, possibly leading to starvation mortality of younger larvae during strong upwelling. The critical period thus seemed to be later than at first-feeding.

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.

Ontogeny of Feeding Behavior of First-Feeding Atlantic Salmon (Salmo salar)

1991 ◽  
Vol 48 (10) ◽  
pp. 1896-1904 ◽  
Author(s):  
David J. Coughlin
Keyword(s):  
Atlantic Salmon ◽  
Feeding Behavior ◽  
Salmo Salar ◽  
Exogenous Feeding ◽  
Feeding Mode ◽  
Atlantic Salmon Salmo Salar ◽  
First Feeding ◽  
Swimming Motion ◽  
In The Wild ◽  
Time To Learn

Feeding strikes of Atlantic salmon (Salmo salar) alevins preying upon Daphnia are described using videorecording of synchronous lateral and antero-ventral views. Based on examination of characteristics such as aiming inaccuracy and capture distance, it is demonstrated that feeding behavior significantly improves during the first 2 wk after initiation of exogenous feeding. With increasing experience, young salmon tend to capture prey more quickly and with greater accuracy. First-feeding alevins use a body-ram feeding mode, relying on their swimming motion to overtake and capture prey. After 7–10 d of feeding, the fish change to a suction feeding mode that effectively uses suction generated by expansion of the orobranchial chamber to pull in prey from a distance. Also, feeding behavior of alevins raised on a commercial salmon feed lags developmentally behind the behavior offish raised on live food. This lag time is short (2–3 d), indicating that despite reports to the contrary, hatchery-raised fish do not require a Song time to learn to capture prey effectively in the wild.

The Evolution of Age-Specific Mortality Rates in Drosophila melanogaster: Genetic Divergence Among Unselected Lines

Genetics ◽  
1999 ◽  
Vol 153 (2) ◽  
pp. 813-823 ◽  
Author(s):  
Scott D Pletcher ◽  
David Houle ◽  
James W Curtsinger
Keyword(s):  
Process Model ◽  
Mortality Rates ◽  
Mutational Bias ◽  
Spontaneous Mutations ◽  
Specific Effects ◽  
Specific Mortality ◽  
Age Dependent ◽  
Order Of Magnitude ◽  
Mutational Variance ◽  
New Mutations

AbstractAge-specific effects of spontaneous mutations on mortality rates in Drosophila are inferred from three large demographic experiments. Data were collected from inbred lines that were allowed to accumulate spontaneous mutations for 10, 19, and 47 generations. Estimates of age-specific mutational variance for mortality were based on data from all three experiments, totalling ∼225,000 flies, using a model developed for genetic analysis of age-dependent traits (the character process model). Both within- and among-generation analyses suggest that the input of genetic variance is greater for early life mortality rates than for mortality at older ages. In females, age-specific mutational variances ranged over an order of magnitude from 5.96 × 10-3 at 2 wk posteclosion to 0.02 × 10-3 at 7 wk. The male data show a similar pattern. Age-specific genetic variances were substantially less at generation 47 than at generation 19—an unexplained observation that is likely due to block effects. Mutational correlations among mortality rates at different ages tend to increase with the accumulation of new mutations. Comparison of the mutation-accumulation lines at generations 19 and 47 with their respective control lines suggests little age-specific mutational bias.

Recruitment dynamics of walleyes (Stizostedion vitreum) in Kansas reservoirs: generalities with natural systems and effects of a centrarchid predator

2003 ◽  
Vol 60 (7) ◽  
pp. 830-839 ◽  
Author(s):  
Michael C Quist ◽  
Christopher S Guy ◽  
James L Stephen
Keyword(s):  
Abiotic Factors ◽  
Water Clarity ◽  
Water Levels ◽  
Stizostedion Vitreum ◽  
Manipulative Experiment ◽  
Natural Systems ◽  
White Crappie ◽  
Zooplankton Density ◽  
Pomoxis Annularis ◽  
Biotic Effects

Knowledge of factors influencing recruitment dynamics of walleyes (Stizostedion vitreum) in different systems and regions is important for developing a better understanding of walleye ecology. Therefore, we investigated associations among walleye recruitment and climatic, water-level, and biotic characteristics in four Kansas reservoirs during 1985–1999. Walleye recruitment was positively related to spring storage ratios and temperatures and negatively associated with spring water levels and abundance of 130- to 199-mm white crappies (Pomoxis annularis). The influence of juvenile white crappie predation on larval walleyes was examined by conducting a manipulative experiment. Regardless of zooplankton density or water clarity, mortality of larval walleyes resulting from white crappie predation was over 90%. Based on our empirical and experimental results, we propose a biotic–abiotic confining hypothesis (BACH) to explain abiotic and biotic effects on walleye recruitment dynamics. Specifically, high variability in walleye recruitment was observed during years with low densities of 130- to 199-mm white crappies and likely resulted from the effects of abiotic factors. When white crappie abundance was high, walleye recruitment was low and exhibited little variability, suggesting that white crappies can have an overriding influence on walleye recruitment regardless of abiotic conditions.

scholarly journals Survival bottlenecks in the early ontogenesis of Atlantic herring (Clupea harengus, L.) in coastal lagoon spawning areas of the western Baltic Sea

2013 ◽  
Vol 71 (4) ◽  
pp. 982-990 ◽  
Author(s):  
Patrick Polte ◽  
Paul Kotterba ◽  
Cornelius Hammer ◽  
Tomas Gröhsler
Keyword(s):  
Baltic Sea ◽  
Critical Period ◽  
Developmental Stages ◽  
Early Stage ◽  
Larval Survival ◽  
Clupea Harengus ◽  
Research Progress ◽  
Larval Stages ◽  
First Feeding ◽  
Spawning Areas

Abstract Dominant drivers of larval survival are considered to include oceanographic dispersal, sea temperatures, and food availability in the phase of first-feeding. However, research progress on larval herring survival dynamics indicates that multiple factors might act on differing larval developmental stages. Hypothesizing that in inshore systems of the western Baltic Sea bottlenecks of herring development occur before the point of first-feeding, we analysed an extensive time-series of weekly abundances of early stage larvae in Greifswald Bay, an important spawning area for Western Baltic herring. Additionally, we investigated whether distinct hatching cohorts contribute differently to established survival indices on the level of (i) later larval stages in Greifswald Bay and (ii) 1+ group juveniles in the overall western Baltic Sea. Results revealed that abundances of the earliest larval stage explain 62% of the variability of later stage larvae and 61% of the variability of surviving juveniles, indicating pre-hatching survival bottlenecks. Hatching cohorts occurring later during the spawning season contribute most to the surviving year class. Earlier hatching cohorts were not found to result in significant amounts of growing larvae, indicating a bottleneck phase at the critical period when larvae start feeding.

scholarly journals Ctenophore population recruits entirely through larval reproduction in the central Baltic Sea

2012 ◽  
Vol 8 (5) ◽  
pp. 809-812 ◽  
Author(s):  
Cornelia Jaspers ◽  
Matilda Haraldsson ◽  
Sören Bolte ◽  
Thorsten B. H. Reusch ◽  
Uffe H. Thygesen ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Egg Production ◽  
Mortality Rates ◽  
Predation Pressure ◽  
Arctic Regions ◽  
Comb Jelly ◽  
High Predation ◽  
High Predation Pressure

The comb jelly Mertensia ovum, widely distributed in Arctic regions, has recently been discovered in the northern Baltic Sea. We show that M. ovum also exists in the central Baltic but that the population consists solely of small-sized larvae (less than 1.6 mm). Despite the absence of adults, eggs were abundant. Experiments revealed that the larvae were reproductively active. Egg production and anticipated mortality rates suggest a self-sustaining population. This is the first account of a ctenophore population entirely recruiting through larval reproduction (paedogenesis). We hypothesize that early reproduction is favoured over growth to compensate for high predation pressure.

scholarly journals Digestive enzyme system of larvae of different freshwater teleosts and its differentiation during the initial phase of exogenous feeding

2017 ◽  
Vol 62 (No. 10) ◽  
pp. 403-416 ◽  
Author(s):  
F. Lahnsteiner
Keyword(s):  
Digestive System ◽  
Enzyme System ◽  
Digestive Enzyme ◽  
Sander Lucioperca ◽  
Thymallus Thymallus ◽  
Exogenous Feeding ◽  
First Feeding ◽  
Histological Characteristics ◽  
Species Specific ◽  
Freshwater Teleosts

Activities of digestive enzymes and main histological characteristics of the intestine were investigated in larvae of three salmonid species (Coregonus maraena, C. atterensis, Thymallus thymallus), of burbot (Lota lota), and pikeperch (Sander lucioperca) at the onset of exogenous feeding (0 day degrees (°d)) and at 250°d thereafter. At the onset of exogenous feeding the activities of proteolytic, lipolytic, and carbohydrate splitting enzymes were detected in the intestines of all species. The enzymatic activities showed significant species specific differences indicating specializations in functionality and digestion ability. In C. atterensis and L. lota the activities of most enzymes were low in comparison to the other investigated species and therefore their digestive system was only poorly developed. In S. lucioperca it was moderately developed and in T. thymallus and C. maraena well-developed. After 250°d, the activities of the investigated enzymes changed in a very species specific way. Histologically, the intestines of the investigated species revealed no species specific differentiations at the onset of the first feeding with the exception of the absence of goblet cells in L. lota and C. atterensis. These differentiated after 250°d.

Daily Mortality Rates of Larval and Juvenile American Shad (Alosa sapidissima) in the Connecticut River with Changes in Year-Class Strength

1983 ◽  
Vol 40 (10) ◽  
pp. 1719-1728 ◽  
Author(s):  
V. Crecco ◽  
T. Savoy ◽  
L. Gunn
Keyword(s):  
Survival Rates ◽  
Mortality Rates ◽  
American Shad ◽  
Connecticut River ◽  
Alosa Sapidissima ◽  
Growth And Survival ◽  
Juvenile Mortality ◽  
First Feeding ◽  
Gompertz Equation ◽  
Class Strength

Age-specific growth and survival rates were estimated for larval and juvenile American shad (Alosa sapidissima) from the Connecticut River from 1979 to 1982. Relative indices (CPE) of year-class strength of juveniles determined from seine sampling in 1978–82 and 1966–73 are compared with resulting levels of adult recruitment. Length–age data for larval and juvenile American shad were determined from sagittal otoliths. Length increments among larval and juvenile shad followed an asymptotic pattern with age, both life stages being well described by the Gompertz equation. Larval survivorship curves from 1979 to 1982 were age specific, with mortality rates of 19.8–25.6%/d for first feeding larvae and 4.3–8.7%/d for larvae approaching metamorphosis. By contrast, juvenile mortality rates were much lower (1.8–2.0%/d) and more consistent among years. Juvenile indices of year-class strength from 1966 to 1973 were positively correlated (r = +0.92, df 7, P < 0.001) with recruitment levels of adult females 4–6 yr later, suggesting that year-class strength of shad is established prior to the juvenile stage.

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