Dorsal Light Response as an Index of Prey Preference in Bluegill (Lepomis macrochirus)

1975 ◽  
Vol 32 (10) ◽  
pp. 1860-1863 ◽  
Author(s):  
Gary L. Vinyard ◽  
W. John O’brien
Keyword(s):  
Lepomis Macrochirus ◽  
Light Response ◽  
Prey Preference ◽  
Planktivorous Fish ◽  
Experimental Conditions ◽  
Comparison Of Results ◽  
Prey Length ◽  
Actual Selection ◽  
Selection Of

An apparatus utilizing the variation in the dorsal light response of sight-feeding planktivorous fish when exposed to prey of various lengths, was used to measure the predator’s interest in particular prey. Comparison of results with actual selection of prey by fish under experimental conditions confirms the importance of prey length in determining the preference of these predators.

Prey Location Volume of a Planktivorous Fish: A New Measure of Prey Vulnerability

1981 ◽  
Vol 38 (10) ◽  
pp. 1264-1270 ◽  
Author(s):  
Chris Luecke ◽  
W. John O'Brien
Keyword(s):  
Dimensional Space ◽  
Lepomis Macrochirus ◽  
Three Dimensional ◽  
Planktivorous Fish ◽  
Water Volume ◽  
Distance Measurements ◽  
Experimental Conditions ◽  
Reactive Distance ◽  
Prey Location ◽  
Three Dimensional Space

The probability that bluegills (sunfish) (Lepomis macrochirus) will locate prey varies with distance and position of the prey in three-dimensional space. Location ability is greatest in the hemisphere directly ahead of the fish. The probability that bluegills will locate prey declines steadily when prey are placed to the side, behind, or directly above or below the fish. Bluegills could locate prey farthest when placed slightly to the side of the area directly in front of the fish. Under all experimental conditions, fish could locate prey, at least some of the time, at distances considerably farther than suggested by reported reactive distance measurements, indicating that the water volume searched by bluegills has generally been underestimated.Key words: planktivorous fish, zooplankton, reactive distance, location volume, predator search

Examination of direct daytime predation by Coregonus artedi on Bythotrephes longimanus in Harp Lake, Ontario, Canada: no evidence for the refuge hypothesis

2009 ◽  
Vol 66 (3) ◽  
pp. 449-459 ◽  
Author(s):  
Joelle D. Young ◽  
Ellis R. Loew ◽  
Norman D. Yan
Keyword(s):  
Cold Water ◽  
Lake Ontario ◽  
Planktivorous Fish ◽  
Bythotrephes Longimanus ◽  
Death Rates ◽  
Direct Observations ◽  
Coregonus Artedi ◽  
Selection Of ◽  
Gill Netting ◽  
Harp Lake

Since its introduction to Harp Lake, Ontario, Canada, summer abundance of the cladoceran zooplanktivore Bythotrephes longimanus has fluctuated substantially both among and within years. The principal planktivorous fish in Harp Lake is the cold-water Coregonus artedi (cisco). Previous studies hypothesized that Bythotrephes abundance was affected by the thickness of an ephemeral, dark, daytime refuge from cisco that potentially established at the bottom of the metalimnion. During summer of 2003, we estimated peak daytime refuge thickness by simulating light energy visible to cisco and found it was always negative and did not correlate with Bythotrephes death rates. Direct observations using gill-netting and acoustical methods suggested that cisco had frequent metalimnetic forays. Additionally, including years 2000–2004, the previous correlation between mean Bythotrephes abundance and refuge thickness no longer held. The refuge hypothesis appears to fail, as the amount of metalimnetic illumination was always above the level at which cisco reaction distance to prey is maximal. Selection of Bythotrephes by cisco instead appeared to increase once Bythotrephes became abundant, remaining consistent and nontrivial even after Bythotrephes population declined.

scholarly journals Intrinsic Prey Preference and Selection of the Giant Gartersnake: A Threatened Predator in a Nonnative Prey-Dominated Community

2020 ◽  
Vol 11 (1) ◽  
pp. 164-173
Author(s):  
Julia S.M. Ersan ◽  
Brian J. Halstead ◽  
Erica L. Wildy ◽  
Michael L. Casazza ◽  
Glenn D. Wylie
Keyword(s):  
Exotic Species ◽  
Native Species ◽  
Prey Selection ◽  
Central Valley ◽  
Prey Preference ◽  
Live Prey ◽  
Species Of Conservation Concern ◽  
Conservation Concern ◽  
Behavioral Trials ◽  
Selection Of

Abstract The introduction of exotic species into an environment can introduce great change in the trophic dynamics of native species. This is of even greater concern if the native species is of conservation concern. The giant gartersnake, Thamnophis gigas, an endemic predator of the Central Valley of California and a species of conservation concern at the state and federal levels, has declined as a result of conversion of its once vast wetland habitat to agriculture. Another anthropogenic factor contributing to this snake's changing ecology is the introduction of nonnative prey into the species' habitats. These introductions have resulted in a prey community that is almost completely composed of exotic species and have potential for considerable effects. In order to assess prey preference and selection we performed three sets of behavioral trials on naïve neonates. We examined 1) neonate prey preference in response to olfactory cues of prepared prey extracts, 2) neonate consumption of different live prey items presented simultaneously; and 3) terrestrial feeding behavior and/or latency to successful attack. Results from the olfactory study suggest that native Sierran treefrogs, Pseudacris sierra, are preferred by neonates. Results from consumption trials suggest that neonates are more likely to select frog species than fish species. This is the first study that we are aware of that examines prey selection of this threatened species and serves to inform its conservation and management.

Design Optimization Procedure for Amorphous Core Distribution Transformers

2012 ◽  
Vol 721 ◽  
pp. 159-164
Author(s):  
Eleftherios I. Amoiralis ◽  
Marina A. Tsili ◽  
Antonios Kladas
Keyword(s):  
Energy Efficiency ◽  
Amorphous Alloy ◽  
Design Optimization ◽  
Optimization Procedure ◽  
Significant Benefit ◽  
Design Practice ◽  
Comparison Of Results ◽  
Distribution Transformers ◽  
Installation Cost ◽  
Selection Of

The paper presents a design optimization procedure appropriate for distribution transformers with amorphous alloy cores. Several considerations and the main differences from the design practice of conventional transformers are presented and discussed in detail. Moreover, comparison of results present the significant benefit in the transformer energy efficiency by the selection of amorphous alloy core, despite its initial higher installation cost.

Expert System for EPMA

1999 ◽  
Vol 5 (S2) ◽  
pp. 592-593
Author(s):  
C. Fournier ◽  
C. Merlet ◽  
P.F. Staub ◽  
O. Dugne
Keyword(s):  
Quantitative Analysis ◽  
Expert System ◽  
Reasonable Accuracy ◽  
Experimental Conditions ◽  
Sample Composition ◽  
Starting Point ◽  
Accuracy Of Results ◽  
Short Time ◽  
And Control ◽  
Selection Of

Analysis parameters for an electron microprobe are numerous, and the accuracy of the quantitative analysis is very sensitive to the selection of these experimental conditions. The expert system intends to optimize the choice of each analysis parameter as well as to automate the phases of a quantitative analysis on all kinds of materials. To summarise, the aim of the expert system is to simplify the procedures, improve the accuracy of results and control the analysis time. The figure 1 illustrates the various stages of the expert system.The starting point of the expert system is an interactive questionnaire concerning the sample,( ie, what is already known), and about the expectations on the analysis,( ie, the accuracy of the results and/or the duration of the analysis required by the operator). Then, the expert system performs a semi-quantitative analysis on the sample. Based on the acquisition of a wavelength qualitative spectrum, this method is a way to obtain the sample composition in a short time with the advantages of the WDS system, and with a reasonable accuracy.

Utilizing ultrafiltration to remove alkaline phosphatase from clinical analyzer water

2006 ◽  
Vol 44 (5) ◽  
Author(s):  
Julien Bôle ◽  
Stéphane Mabic
Keyword(s):  
Alkaline Phosphatase ◽  
Water Samples ◽  
Bacterial Contamination ◽  
Pure Water ◽  
Experimental Conditions ◽  
Enzyme Immunoassays ◽  
Selection Of

AbstractAlkaline phosphatase (ALP) conjugated to antibodies is often used in enzyme immunoassays (EIAs). These assays are notably sensitive to experimental conditions. A possible source of interference is bacterial ALP, which is released when bacterial contamination occurs in clinical analyzers. Preliminary experiments led to the selection of a detection kit, ALP source, and specific types of tubes for collecting water samples and performing assays. The release of ALP from various strains of bacteria identified in pure water was demonstrated (10–30×10

On Sex Variations in Excitation Process Composition

1929 ◽  
Vol 75 (311) ◽  
pp. 693-696
Author(s):  
W. Burridge
Keyword(s):  
Excitation Process ◽  
Experimental Conditions ◽  
Process Composition ◽  
Selection Of

Physiologists, when experimenting with the frog, customarily make selection of one sex. This, being done to ensure constancy of experimental conditions, presumes the possible existence of a sexual modification of results—a presumption I find justified, for, having over many years simply selected the frog of largest size, which one day was male and another female, I can record the following variations of results according to sex.

scholarly journals The impact of adding front-of-package sodium content labels to grocery products: an experimental study

2012 ◽  
Vol 16 (3) ◽  
pp. 383-391 ◽  
Author(s):  
Samantha Goodman ◽  
David Hammond ◽  
Rhona Hanning ◽  
Judy Sheeshka
Keyword(s):  
Sodium Content ◽  
Control Group ◽  
Traffic Light ◽  
Experimental Conditions ◽  
Low Sodium ◽  
Numeric Information ◽  
Grocery Products ◽  
The Impact ◽  
Selection Of ◽  
Colour Coding

AbstractObjectiveCanadians consume approximately twice the daily Adequate Intake of sodium. The present study examined the efficacy of four types of front-of-package (FOP) sodium labels at influencing consumers’ selection of products low v. high in sodium.DesignParticipants were randomly assigned to one of five experimental conditions: (i) control condition with no FOP label; (ii) basic numeric FOP label; (iii) numeric FOP label with ‘high’ and ‘low’ sodium content descriptors; (iv) detailed Traffic Light (TL) label with colour coding, content descriptors and numeric information; and (v) simple TL label with no numeric information. Participants were shown pairs of grocery products that varied in sodium content and told they could choose a free sample. Selection of the low-sodium v. the high-sodium product was the primary behavioural outcome, in addition to ratings of effectiveness, understanding, liking and believability.SettingWaterloo, Ontario, Canada.SubjectsAdults (n 430) aged ≥18 years, recruited from community settings.ResultsParticipants in the three FOP conditions with ‘high/low’ sodium content descriptors were significantly more likely to choose the lower-sodium product compared with the control group. The detailed TL label was ranked most effective at helping participants select low-sodium products, and was rated significantly higher than other formats in liking, understanding and believability. Product selection did not differ significantly across sociodemographic groups.ConclusionsFOP labels that include content descriptors may be more effective in helping consumers to select lower-sodium products. TL labels, which incorporate content descriptors and colour coding, should be considered for future FOP labelling initiatives.

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