Size Selection of Daphnia pulicaria by Yellow Perch (Perca flavescens) Fry in West Blue Lake, Manitoba

1972 ◽  
Vol 29 (12) ◽  
pp. 1761-1764 ◽  
Author(s):  
Brian Wong ◽  
F. J. Ward
Keyword(s):  
Energy Source ◽  
Body Size ◽  
Yellow Perch ◽  
Perca Flavescens ◽  
Daphnia Pulicaria ◽  
Body Depth ◽  
Blue Lake ◽  
Selection For ◽  
Initial Selection ◽  
Selection Of

Prior to mid-July, Daphnia pulicaria in yellow perch (Perca flavescens) fry stomachs were smaller than those in plankton collections but after this date mean lengths of D. pulicaria in stomachs and collections were similar indicating an initial selection for small D. pulicaria by the fish. The relation between D. pulicaria body depth and perch mouth gape width indicated that perch fry less than 18 mm long, a length attained in mid-July, could not readily ingest D. pulicaria with body depths greater than 0.7 mm (1.3 mm long). The heterogenic relation between growth in mouth and body size enabled perch fry in West Blue Lake to quickly utilize, as an energy source, the abundant D. pulicaria population.

Precision Micrometer Measurement of Mouth Gape of Larval Fish

1987 ◽  
Vol 44 (10) ◽  
pp. 1786-1791 ◽  
Author(s):  
Michael T. Arts ◽  
D. O. Evans
Keyword(s):  
Body Size ◽  
Yellow Perch ◽  
Larval Fish ◽  
Perca Flavescens ◽  
Data Capture ◽  
Coregonus Clupeaformis ◽  
Manual Method ◽  
Direct Data ◽  
Coregonus Artedii ◽  
Lake Herring

A precision micrometer device is described which standardizes measurement of mouth gape of larval fish and provides a greater degree of accuracy and speed than the conventional manual method. We compared gape measurements of larval lake whitefish (Coregonus clupeaformis) and lake herring (Coregonus artedii) using the gape micrometer versus the manual method. The micrometer measurements revealed a greater increase in gape with body length and resulted in a greater proportion of the variance in gape being explained, indicating that the gape micrometer is more sensitive and accurate than the manual method. Coefficient of variation of gape measurements on 238 larval yellow perch (Perca flavescens) decreased with body size from 0.5–4.0% at 0.8–1.2 cm standard length to 0.2–0.5% at 3.0 cm. The device has the added advantage that it could be adapted to connect to a microcomputer for direct data capture.

Unexploited Percid Populations of West Blue Lake, Manitoba, and their Interactions

1977 ◽  
Vol 34 (10) ◽  
pp. 1655-1669 ◽  
Author(s):  
J. R. M. Kelso ◽  
F. J. Ward
Keyword(s):  
Yellow Perch ◽  
Perca Flavescens ◽  
Growth Period ◽  
Older Individuals ◽  
Behavioral Differences ◽  
Food Items ◽  
Blue Lake ◽  
Early Fall ◽  
Summer Growth ◽  
Main Food Item

West Blue Lake, Manitoba, essentially unaffected by man, sustains populations of yellow perch, Perca flavescens, and walleye, Stizostedion vitreum vitreum, which interact in two fundamental ways: perch are a major source of energy for walleye and the two species share common food organisms.Perch adults, juveniles and fry generally contributed 80–90% of the energy required for the annual walleye production (340 kg) and, on the basis of conversion experiments, provided for at least 1.7 kg∙ha−1 of the observed production of 2.1 kg∙ha−1. The brief summer growth period, combined with moderate mortality, caused biomass to reach a maximum in early fall at which time production ceased.Although walleye utilized yellow perch as its basic energy supply, behavioral differences tended to offer protection to juvenile and adult perch. Walleye were active at night, whereas older perch w ere inactive. Age 0 perch, during their epilimnetic phase, on the other hand, were active at night and vulnerable to walleye predation providing at least 18% of the observed walleye production.Walleye and yellow perch shared the same food resources although at different times and to different degrees. This competition was most intense between walleye (> 25 cm) and adult perch (> 12 cm). A main food item shared was amphipods. Most other food items (sticklebacks, mayflies, crayfish) were also shared but none in equal proportions by the two percids.Neither of the percid species showed a preponderance of older individuals and both showed evidence of strong and weak year-classes — walleye to a greater degree. Also, for walleye at least, production was only 2.1 kg∙ha−1, and biomass appeared to be stable, approximately 900 kg. Growth for both species was less than most other percid communities and was restricted to a brief, ≈ 80 day, period. Key words: unexploited, yellow perch, walleye, feeding, behavior, production, population structure

Influence of Prey Abundance on Species and Size Selection by Young Yellow Perch (Perca flavescens)

1990 ◽  
Vol 47 (5) ◽  
pp. 882-887 ◽  
Author(s):  
John L. Confer ◽  
Edward L. Mills ◽  
Linda O'Bryan
Keyword(s):  
Nutritional Quality ◽  
Yellow Perch ◽  
Prey Selection ◽  
General Pattern ◽  
Perca Flavescens ◽  
Growth Efficiency ◽  
Oneida Lake ◽  
Selection For ◽  
Zooplankton Prey

Prey selection by young yellow perch (Perca flavescens) (22–62 mm TL) was measured during 11 experiments over two summers, 1982–83. For each experiment fish were offered different densities of the same mixture of zooplankton from Oneida Lake, NY. As density of prey increased, several measures of selectivity for Daphnia either remained unchanged or declined, while all measures of selectivity for calanoids and cyclopoids increased. At all densities small to mid-sized Daphnia were preferred to large Daphnia. Reanalyses of other studies suggests this may be the general pattern for young planktivores, despite the contrary predictions of several models of prey selection. For young planktivores, differences in the nutritional quality of zooplankton prey, including resultant growth efficiency and speed of digestion, can account for these results.

Daily Ration of Yellow Perch (Perca flavescens) from Lake Memphremagog, Quebec–Vermont, with a Comparison of Methods for In Situ Determinations

1978 ◽  
Vol 35 (12) ◽  
pp. 1597-1603 ◽  
Author(s):  
Brian S. Nakashima ◽  
William C. Leggett
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Yellow Perch ◽  
Diet Composition ◽  
Seasonal Pattern ◽  
Feeding Activity ◽  
Perca Flavescens ◽  
Complex Method ◽  
Daily Ration

In situ estimates of daily ration for yellow perch (Perca flavescens) range from a high of 5.5–6.7% body weight in July to a low of 2.2–2.4% body weight in October. The seasonal pattern corresponds well to known patterns of growth. Comparison of three methods for in situ determination of daily ration levels indicated the method outlined here and the more complex method of Thorpe yield similar results. The method of Keast and Welsh and derivatives of this method which correct for digestion between sampling periods give unreliable values that are 50% below the other two and, in general, are below maintenance ration levels. Diet composition and feeding activity varied seasonally and with body size. Key words: body size relationships, diet composition, seasonality

Sexual Differentiation and Use of Hormones to Control Sex in Yellow Perch (Perca flavescens)

1986 ◽  
Vol 43 (1) ◽  
pp. 26-35 ◽  
Author(s):  
Jeffrey A. Malison ◽  
Terrence B. Kayes ◽  
Cody D. Best ◽  
Clyde H. Amundson ◽  
Bernard C. Wentworth
Keyword(s):  
Body Size ◽  
Germ Cell ◽  
Sexual Differentiation ◽  
Yellow Perch ◽  
Perca Flavescens ◽  
Similar Treatment ◽  
Initial Onset ◽  
Sex Inversion ◽  
Distinguishing Features ◽  
Estradiol 17Β

Morphological and histologial studies demonstrated that estrogens and androgens affect sexual differentiation and can be used to control the phenotypic sex of yellow perch (Perca flavescens). Normal perch larvae of 5–10 mm total length (TL) had paired gonads with no sex-distinguishing features. In normal 16 mm TL perch, the gonads of females had fused into a single sac-shaped organ, while in males the gonads remained paired. Oogenesis had begun in most females of 35 mm TL. Spermatogenesis in males and vitellogenesis in females were first observed at 85 mm TL. Treatment (for 84 d) of perch (initially 20–35 mm TL) with estradiol-17β at 15–120 μg/g diet induced complete germ cell sex inversion in most males. Similar treatment with 17α-methyltestosterone at 1.5 to 60 μg/g diet induced spermatogenesis and the formation of ovotestes in females. Sperm collected from such ovotestes fertilized normal ova, and the resultant offspring were all female. Our findings indicate that in yellow perch: (1) differentiation of the somatic elements of the gonads precedes gametogenesis, (2) gametogenesis begins earlier in females than in males, (3) the attainment of a specific minimum body size (80–100 mm TL) is important to the initial onset of vitellogenesis and spermatogenesis, (4) both estrogens and androgens are probably involved in mediating sexual differentiation of germinal tissues and (5) females are the homogametic sex.

scholarly journals Foraging selectivity by larval yellow perch (Perca flavescens): implications for understanding recruitment in small and large lakes

2006 ◽  
Vol 63 (1) ◽  
pp. 28-42 ◽  
Author(s):  
Richard S Fulford ◽  
James A Rice ◽  
Thomas J Miller ◽  
Fred P Binkowski ◽  
John M Dettmers ◽  
...  
Keyword(s):  
Yellow Perch ◽  
Lake Michigan ◽  
Larval Growth ◽  
Perca Flavescens ◽  
Larval Survival ◽  
Large Lakes ◽  
Prey Composition ◽  
Foraging Decisions ◽  
Selection For ◽  
Relative Selectivity

Growth and survivorship of larval yellow perch (Perca flavescens) have been examined in many systems but can conclusions from well-studied perch populations in smaller lakes be applied to populations in meso-oceanic systems like Lake Michigan, USA? Laboratory experiments were conducted with yellow perch (hatch to 35 mm total length) to develop an empirical selectivity function based on Chesson's α to describe larval diet as a function of changes in prey community composition. This function was used in an individual-based foraging and growth model (IBM) to describe changes in foraging decisions resulting from changes in prey composition between different systems. Larval perch made three selective transitions during ontogeny. Initial positive selection for rotifers and the relative selectivity for cladocerans vs. copepods in late-stage larvae were both dependent on prey composition. Larvae exposed to prey assemblages differing only in composition had different diets. The empirically based IBM accurately predicted these dietary differences and resulting differences in larval growth and likelihood of starvation between systems at equal prey density. The importance of feeding behavior to larval survival will differ between Lake Michigan and smaller lakes, and these results are important for comparisons of recruitment dynamics between large and small systems.

scholarly journals Characteristics of Technical and Physical Fitness of Young Athletes in the Selection for Classes in the Basketball Section

2021 ◽  
Vol 2 (2 (340)) ◽  
pp. 252-259
Author(s):  
Serhii Shynkarov ◽  
Keyword(s):  
Biological Age ◽  
Small Scale ◽  
Sports Training ◽  
Social Psychological ◽  
Young Athletes ◽  
Basketball Players ◽  
Selection For ◽  
The Relationship ◽  
Initial Selection ◽  
Selection Of

The article reveals the essence of the content and basic theoretical principles of selection and sports training of young basketball players based on biological age, substantiates the need to take into account the biological age of young basketball players in sports training. The main features of the initial selection of young basketball players are identified, systematized and characterized. It is shown that the problem of selection of athletes is very multifaceted. It affects many aspects: social, psychological, pedagogical, philosophical and others. On some issues of selection there are more or less clear ideas from the theory, on others – they are still in the process of formation. The idea of the relationship between physical and technical fitness of young athletes in the selection for classes in the basketball section, their sports training in the training of young basketball players, taking into account the biological age, was expanded. A small-scale and quantitatively selective experiment was conducted, which provided an opportunity to solve the objectives of the study. The importance of using different methods and means of selection, the importance of this process to achieve high results in basketball give grounds for further scientifically sound search for a solution to this problem.

Body Size and Its Impact on Selection for Advanced Level Baseball Teams

2011 ◽  
Vol 4 (2) ◽  
pp. 89 ◽  
Author(s):  
Michael Cathey
Keyword(s):  
Body Size ◽  
Normal Population ◽  
Professional Baseball ◽  
Advanced Training ◽  
Baseball Players ◽  
Advanced Level ◽  
Selection For ◽  
Selection Of

The presentation is focused on the role that body size plays in the selection of pitchers at advanced levels. Previous studies have shown that players who are more biologically mature are more likely to be selected for advanced training or competition, especially near puberty (French, Spurgeon, & Nevett, 2007). At young ages, the tallest players tend to be assigned to play shortstop, first base, and pitcher (French, et al 2007). Professional baseball players are taller than the normal population, pitchers and first basemen are the tallest players (French & Spurgeon, 2010).

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