Feeding Interrelations Between Age-Groups of Pumpkinseed (Lepomis gibbosus) and Comparisons with Bluegill (L. macrochirus)

1978 ◽  
Vol 35 (1) ◽  
pp. 12-27 ◽  
Author(s):  
Allen Keast
Keyword(s):  
Key Words ◽  
Interspecific Competition ◽  
Intraspecific Competition ◽  
Spatial Ecology ◽  
Prey Size ◽  
Age Groups ◽  
Lepomis Gibbosus ◽  
Young Fish ◽  
Chironomid Larvae ◽  
Class Separation

Analysis of the stomachs of 2435 pumpkinseeds (Lepomis gibbosus) showed that the diet was made up largely of chironomid larvae, molluscs, isopods, with lesser quantities of amphipods, Trichoptera larvae, and Ephemeroptera nymphs. Cladocera were only important to the very young fish. Age-class separation, in terms of taxonomic and prey-size categories, was minor, although the diet changed somewhat with age. Quantification of the diet overlaps between year-classes (by Levins index) revealed overlap levels that were moderate to high, varying seasonally between 0.5 and 1.1. They were greatest in July when the diversity of available prey organisms fell and October when several size-classes simultaneously consumed isopods, then at a peak in biomass. The feeding and spatial ecology of the pumpkinseed was compared with that of a closely related congener, the bluegill (L. macrochirus). The two species and their equivalent year-classes separated out partially on diet (the bluegill consuming a greater proportion of Cladocera and Tnchoptera larvae; the pumpkinseed, molluscs and isopods), and partly on habitat and the height at which they foraged in the water column. Ecological overlap values between equivalent year-classes of the two species were moderate, 0.52–0.57 (Levins scale), on the basis of diet alone as well as when the habitat component was incorporated. It is suggested, however, that other differences serve to reduce these levels. Key words: feeding, year-class diets, sunfish, intraspecific competition, interspecific competition, prey invertebrates, Centrarchidae

Effect of Competition Between Two Freshwater Fishes on Prey Consumption and Abundance

1986 ◽  
Vol 43 (7) ◽  
pp. 1363-1372 ◽  
Author(s):  
John Mark Hanson ◽  
William C. Leggett
Keyword(s):  
Interspecific Competition ◽  
Intraspecific Competition ◽  
Littoral Zone ◽  
Yellow Perch ◽  
Perca Flavescens ◽  
Lepomis Gibbosus ◽  
Fish Biomass ◽  
Gut Fullness ◽  
Total Fish ◽  
Food Consumed

The effect of inter- and intraspecific competition on the type and quantity of food consumed by fish, and on the abundance of macroinvertebrate prey, was examined by manipulating densities of yellow perch (Perca flavescens) and pumpkinseed (Lepomis gibbosus) stocked into littoral zone enclosures at levels approximating 0.5, 1.0, and 2.0 times the measured total fish biomass on the littoral zone. In intraspecific competition experiments, neither species showed a change in the type of prey eaten (principally macroinvertebrates). The amount of food eaten by yellow perch reared at high (26 g/m2) densities was significantly depressed relative to that of perch reared at low (6.5 g/m2) and natural (13 g/m2) densities. There were no significant differences in the amount of food eaten by pumpkinseed at the three fish densities. The gut fullness of pumpkinseed reared at high densities, however, was biased to a significant but unknown degree by the inclusion of a nonfood item, macrophyte fragments, in the estimates. No other fish consumed macrophytes. In interspecific competition experiments, the gut fullness of yellow perch and pumpkinseed reared together (combined density 13 g/m2) did not differ from that of fish reared alone at low or natural densities. The diet (principally macroinvertebrates) of the superior competitor, pumpkinseed, did not change relative to that of pumpkinseed reared alone. The inferior competitor, yellow perch, exhibited a significant change in diet. Microcrustaceans (an energetically inferior food) comprised 30–53% of the diet (by weight) of yellow perch reared with pumpkinseed compared with < 1% of the diet of perch reared alone. Total macroinvertebrate biomass and abundance were unaffected by differences in fish biomass in the enclosures.

Interrelations Between Walleye (Stizostedion vitreum vitreum) and Smallmouth Bass (Micropterus dolomieui) in Four Northeastern Minnesota Lakes, 1948–69

1977 ◽  
Vol 34 (10) ◽  
pp. 1626-1632 ◽  
Author(s):  
Fritz H. Johnson ◽  
John G. Hale
Keyword(s):  
Habitat Use ◽  
Key Words ◽  
Interspecific Competition ◽  
Intraspecific Competition ◽  
Smallmouth Bass ◽  
Stizostedion Vitreum ◽  
Minnesota Lakes ◽  
Micropterus Dolomieui ◽  
Main Factor ◽  
Spawning Sites

Smallmouth bass (Micropterus dolomieui) introduced from 1945 to 1948 into four rocky, infertile northeastern Minnesota lakes with established walleye (Stizostedion vitreum vitreum) populations reached maximum abundance in 9–15 yr and then declined to low numbers within 2–4 yr. In three, walleyes declined as the bass increased and in the fourth there was a simultaneous rise of walleye and bass followed by increased abundance of walleye with the decline of bass. Interspecific competition for spawning sites, shoal habitat, or food did not appear to be factors in the fluctuations in abundance. Growth of both species was density-dependent implying that intraspecific competition may have been the main factor. Also, predation of young walleye by bass may have been a factor in failure of walleye year-classes. Key words: Percidae, species interrelations, Stizostedion, Micropterus, competition, diet, populations fluctuations, habitat use, density

Experimental and Field Evidence for Inter- and Intraspecific Competition in Two Freshwater Fishes

1985 ◽  
Vol 42 (2) ◽  
pp. 280-286 ◽  
Author(s):  
John Mark Hanson ◽  
William C. Leggett
Keyword(s):  
Interspecific Competition ◽  
Weight Change ◽  
Intraspecific Competition ◽  
Littoral Zone ◽  
Yellow Perch ◽  
Lepomis Gibbosus ◽  
Field Evidence ◽  
Behavioural Interactions ◽  
Natural Density ◽  
Growth Changes

Direct evidence for intra- and interspecific competition in fishes was obtained by manipulating populations of yellow perch (Perca flavescens) and pumpkinseed (Lepomis gibbosus) stocked into littoral zone enclosures. Stocking densities were above, below, and equal to measured littoral zone fish biomass. There were no significant differences in mean percent weight change at given densities among repeated experiments (each of 14-d duration). In experiments testing for intraspecific competition, all fish reared at low density gained weight, all fish reared at high density lost weight, and mean weight change at natural density did not differ from 0.0. In experiments testing for interspecific competition, growth of pumpkinseed did not differ from growth of pumpkinseed reared alone at equivalent densities whereas growth of yellow perch was depressed relative to growth of yellow perch reared alone at equivalent densities. These growth changes did not result from behavioural interactions. We conclude that (a) inter- and intraspecific competition for food is significant at natural fish densities and (b) pumpkinseed are superior to perch when competing for food. A marked reduction in yellow perch growth in Lake Memphremagog between 1972 and 1983, coincident with a major increase in pumpkinseed abundance, is consistent with these findings and our interpretations.

scholarly journals GLUCOSE CONSUMPTION AND LACTIC ACID PRODUCTION BY ERYTHROCYTES FROM DOUBLE-MUSCLED CATTLE

1982 ◽  
Vol 62 (3) ◽  
pp. 751-757 ◽  
Author(s):  
J. A. BASARAB ◽  
R. T. BERG ◽  
J. R. THOMPSON
Keyword(s):  
Lactic Acid ◽  
Key Words ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Age Groups ◽  
Phenotypic Expression ◽  
Glucose Consumption ◽  
Molar Ratio ◽  
Breed Group

The in vitro glucose consumption and lactic acid production by erythrocytes from 20 cattle of a Beef Synthetic (SY) breed group and 25 cattle of a double-muscled (DM) breed group were determined. There were three age groups and two sexes within each breed group. Animals within the DM breed group were categorized as either phenotypically normal- to moderate-muscled (DM carriers) or extreme-muscled (extreme DM) based on the phenotypic expression of the double-muscling trait and on their breeding history. Both DM phenotypes had higher (P < 0.01) erythrocyte glucose consumption and lactic acid production than normal-muscled, noncarrier cattle of the SY breed group. Extreme DM cattle were not different (P > 0.05) in either their erythrocyte glucose consumption or lactic acid production compared with DM carriers. No difference (P > 0.05) due to breed or phenotype was observed in the molar ratio of lactic acid produced to glucose consumed by erythrocytes. These results suggest that carriers of the Double Muscled Syndrome, regardless of phenotypic expression of the double-muscling trait, have a higher rate of erythrocyte glycolysis than normal cattle. Key words: Cattle, double muscled, erythrocyte, glucose, lactic acid

Jules Verne’s ‘Around the World in 80 Days’: Multilingualism, Multiculturalism and Symbols

2021 ◽  
Vol 2021 ii (15) ◽  
pp. 146-182
Author(s):  
Haroula Hatzimihail ◽  
Ioannis Pantelidis
Keyword(s):  
Key Words ◽  
Age Groups ◽  
Literary Work ◽  
Point Of View ◽  
Social Classes ◽  
Jules Verne ◽  
The World ◽  
Semiotic Systems ◽  
Points Of View ◽  
Different Cultures

In this announcement, the various –linguistic and non-linguistic- symbols used in the literary work 'Around the world in 80 days', written by Jules Verne, are examined from an intertemporal and contemporary point of view. The references through these points of view, in matters of multiculturalism and multilingualism, are becoming classical in nature: they concern the necessity of the applied ability to communicate between individuals who belong to different social classes and age groups, speak the same or different languages, come from different cultures, with rights and obligations in their various areas of life, etc. Key-words: linguistics, multilingualism, multiculturalism, semiotics, semiotic systems, symbols

Prophylaxis of genital prolapse in women in the late postpartum period

2018 ◽  
pp. 31-33
Author(s):  
S.I. Zhuk ◽  
◽  
E.A. Budchenko ◽  
Keyword(s):  
Connective Tissue ◽  
Pelvic Floor ◽  
Key Words ◽  
Postpartum Period ◽  
Age Groups ◽  
Clinical Manifestations ◽  
Genital Prolapse ◽  
Degrees Of Severity ◽  
Female Genital ◽  
Vaginal Cones

The article describes genital prolapse as a pathology of female genital organs. The factors leading to the occurrence of genital prolapse in women of different age groups are presented. Clinical manifestations and mechanisms of their occurrence are substantiated. Considered variants of treatment of women with genital prolapse of various degrees of severity. Illumination of the data of our research of the method of prophylaxis of genital prolapse in the late postpartum period with the help of Corelax vaginal cones. Key words: genital prolapse, rectocele, pelvic floor, connective tissue, vaginal cones.

STUDENTS' ATTITUDE TO SCHOOL SCIENCE: COMPARATIVE RESEARCH IN LATVIA, BELARUS, FINLAND AND SWEDEN

2012 ◽  
Vol 9 (1) ◽  
pp. 18-28
Author(s):  
Janis Gedrovics ◽  
Dagnija Cedere ◽  
Eila Jeronen ◽  
Ingvar Wäreborn ◽  
Elena Vasilevskaya
Keyword(s):  
Key Words ◽  
Comparative Research ◽  
Positive Attitude ◽  
Age Groups ◽  
School Science ◽  
Nordic Countries ◽  
Research School ◽  
Future Career

The number of students characterized as science enthusiasts in all countries and age groups does not exceed 20 %, except Belarus with 34%. The number of students character-ized as science negationists is average of 41% in Belarus and 55% in Latvia, 70% in Sweden and 76 % in Finland, decreased from the form 7 to 12. Students in Latvia and Belarus demonstrated a higher positive value practically in all 16 statements. The Belarusian students had a considerably more positive attitude to school science compared to the Latvian students, and the Finnish students - compared to the Swe-dish ones. For the students from Latvia and Belarus, school science plays an important role in developing their knowledge of nature and health, and in the choice of their future career. However, the number of students who see themselves working in the field of science is small both in post-socialistic and Nordic countries. Key words: attitude, carrier, comparative research, school science.

Competition betweenElymus elymoidesandTaeniatherum caput-medusae

Weed Science ◽  
1999 ◽  
Vol 47 (6) ◽  
pp. 720-728 ◽  
Author(s):  
David W. Clausnitzer ◽  
Michael M. Borman ◽  
Douglas E. Johnson
Keyword(s):  
Soil Moisture ◽  
Interspecific Competition ◽  
Seed Production ◽  
Intraspecific Competition ◽  
Field Experiments ◽  
Block Design ◽  
Low Oxygen ◽  
Competitive Effects ◽  
Growing Seasons ◽  
Randomized Block Design

Two field experiments were conducted from 1993–1994 through 1995–1996 growing seasons in Harney County, OR, to determine the relative competitive abilities ofElymus elymoides(squirreltail) a native perennial range grass, andTaeniatherum caput-medusae(medusahead), an exotic annual grass weed. The 1993–1994 growing season was very dry, 1994–1995 was dry, and 1995–1996 was wetter than average. One experiment tested seedlings vs. seedlings in each of three seasons. The second experiment tested seedlings plus second- and third-year establishedE. elymoidesplants vs. 77caput-medusaeover 2 yr. Biomass, seed production, and soil moisture utilization 15, 30, 45, and 60 cm deep by the two species were measured. A randomized block design with factorial arrangement was used, with 25 2.25-m2plots per block. Initial seeding densities of each species were 0, 10, 74, 550, and 4,074 seeds m−2in all combinations of density. In the seedling vs. seedling experiment, intraspecific competition by 77caput-medusaeon itself was always significant (P ≤ 0.10) for both biomass and seed production. Interspecific competition byE. elymoidesseedlings onT. caput-medusaebiomass and seed production was not significant (P ≥ 0.10) in 2 of 3 yr and was always less than intraspecific competition by 77caput-medusae. Only 0.4% ofE. elymoidesseed germinated, and no seed was produced in the very dry first year, but 84% of remaining seed was viable for the next year, which had better moisture conditions for germination and establishment. Interspecific competition affected (P ≤ 0.10)E. elymoidesseedling biomass and seed production throughout the study. Intraspecific competition affected (P ≤ 0.10) seedlingE. elymoidesseed production in the dry year but not in the wetter than average year. In the matureE. elymoidesexperiment, intraspecific competition byT. caput-medusaeon weight and seed production per plant was greater than interspecific competition fromE. elymoides. Seedling/matureE. elymoidesreducedT. caput-medusaeweight per plant in the dry year but the effect was not biologically significant. Larger, matureEelymoidesplants produced 600 to 3,000 seeds per plant during the wet year; neither intra- nor interspecific competition was a factor.Taeniatherum caput-medusaewas better able to access deeper soil moisture and was more aggressive at extracting soil moisture than wereE. elymoidesseedlings in the wet year. Cold soils and low oxygen due to wet soils may have restrictedE. elymoidesseedling root activity. MatureE. elymoidesplants did not appear restricted by cold soils or low oxygen. Established second- and third-yearE. elymoidesplants were able to compete for soil moisture down to 45 cm. The generally greater interspecific competitive effects ofT. caput-medusaeonE. elymoidesthan vice versa suggested that it will be difficult to establish anE. elymoidesstand in an existingT. caput-medusaecommunity without first suppressingT. caput-medusae. IndividualE. elymoidesplants did establish and were productive with and withoutT. caput-medusaecompetition.

Life cycle and diet of Zygonyx iris insignis (Insecta: Odonata: Anisoptera) in Hong Kong running waters

1986 ◽  
Vol 2 (1) ◽  
pp. 73-85 ◽  
Author(s):  
David Dudgeon ◽  
Christina Y. M. Wat
Keyword(s):  
Hong Kong ◽  
Prey Size ◽  
Generalist Predator ◽  
Running Waters ◽  
Wet Season ◽  
Chironomid Larvae ◽  
Tropical Asia ◽  
Larval Recruitment ◽  
Food Items ◽  
Selection Of

ABSTRACTZygonix iris is widespread in tropical Asia, and larvae are sprawlers/clingers on rock surfaces in fast-flowing streams and rivers. In the Lam Tsuen River, Hong Kong, this species is univoltine; emergence occurs prior to the summer monsoon and larval recruitment during the wet season. Studies on larval dietary composition in four habitats indicated that Z. iris is a generalist predator, consuming epibenthic prey taxa in proportion to their abundance in the environment. Larval Chironomidae (Diptera) and Baetis (Ephemeroptera) were the commonest food items at all sites and there was little consistent evidence of preference for individual taxa. Larger Z. iris larvae tended to consume more prey taxa than did smaller larvae, and Baetis prey size was positively correlated with predator size. No size selection of chironomid larvae was apparent. Despite its unusual larval habit, Z. iris is a generalist feeder resembling lotic and lentic temperate-zone Odonata.

scholarly journals Population dynamics and feeding ecology of the invasive Caucasian dwarf goby, Knipowitschia caucasica, in a freshwater habitat in Ukraine

2020 ◽  
pp. 26
Author(s):  
Alexander Didenko ◽  
Igor Buzevych ◽  
Yuriy Volikov ◽  
Svitlana Kruzhylina ◽  
Alexander Gurbyk
Keyword(s):  
Population Dynamics ◽  
Littoral Zone ◽  
Diet Composition ◽  
Sampling Site ◽  
Age Groups ◽  
Stomach Contents ◽  
Seasonal Fluctuations ◽  
Chironomid Larvae ◽  
High Diversity ◽  
Two Age Groups

Population dynamics and feeding patterns of invasive Knipowitschia caucasica were studied in the littoral zone of the lower Stugna River. The abundances of this goby showed significant inter-annual and seasonal fluctuations. The studied population of K. caucasica was represented by two age groups (0 and I). Fish die after their first breeding season. In total, 58 prey items were identified in the diet of K. caucasica at the sampling site. The most abundant prey were copepods and cladocerans, while the most frequently encountered prey were copepods and chironomid larvae. Copepods were represented mainly by Cyclopoidae. Cladocerans included 21 taxa, among which the most abundant were Diaphanosoma sp., Acroperus harpae, and Disparalona rostrata; chironomids included 22 taxa, among which the most abundant was Cricotopus sylvestris. The diet composition showed seasonal dynamics, where copepods predominated in January to April and in August-September, chironomid larvae were especially important in May to July, while cladocerans were most important in November-December. The relatively high diversity of both phytophilous and open-bottom-dwelling prey organisms in the stomach contents of K. caucasica indicates that this species fed on a large variety of benthic habitats including among macrophytes and open areas.

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