effects of school size of neon tetras on their response to the presence of a zebra fish
DESCRIPTION
Effects of school size of neon tetras on their response to the presence of a zebra fish. Kelsey and Jenna. Purpose of the experiment. Look at schooling behaviour in neon tetras in the presence of a predator, measured in terms of distance from a predator. Overview. Background Information - PowerPoint PPT PresentationTRANSCRIPT
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Effects of school size of neon tetras on their response to the presence of a zebra fish
Kelsey and Jenna
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Purpose of the experiment
Look at schooling behaviour in neon tetras in the presence of a predator, measured in terms of
distance from a predator
![Page 3: Effects of school size of neon tetras on their response to the presence of a zebra fish](https://reader035.vdocument.in/reader035/viewer/2022062813/5681649c550346895dd67e7f/html5/thumbnails/3.jpg)
Overview
• Background Information• Hypothesis • Materials• Methods• Results • Discussion• Conclusions
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Background Information
• Schooling: anti-predator strategy– Predator confusion– More fish reduces
individual’s chance of attack
– More energy invested in feeding and mating
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Background information
Neon Tetras (Cheirodon innessi)– Small, bright, vulnerable to
predation
Zebra fish (Danio rerio)- Aggressive- Territorial
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Background Information
• Neon tetras display schooling behaviour• Zheng et. al.– Presence of unfamiliar object– Increase in school size, decrease in timidity• Darting• Time between feeding
• Sloman et. al.– Presence of aggressive fish– Increase in schooling
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Hypothesis
The neon tetras would remain further away from the zebra fish when the neon tetras were present in a small school compared to a large
group
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Materials
• Dip net• Aquarium• 500mL Jar• Neon tetras• Zebra fish
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Materials
• The Aquarium:
1 2 3 4
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Materials
• The Aquarium:
Water temperature maintained at 20⁰C
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Methods
• Neon tetras placed in aquarium– School sizes: 2 and 8– Acclimation period of 3
minutes• Jar containing a zebra fish
added in section 4
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Methods
• Scan sampling – Neon tetras in each section recorded every 30
seconds– Total of 15 minutes– 10 replicates for each school size– Control• Empty jar• 5 replicates for each school size
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Results
• Small school:
1 2 3 40
10
20
30
40
50
60
controlexperimental
Section of Aquarium
Perc
ent N
eon
Tetr
as (%
)
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Results• Small school: – Chi-square analysis• Experimental: X2(3)= 52.4, p< 0.05• Control: X2(3)= 38.3, p< 0.05• Significant preference for section 3
– Mann-Whitney U• p >0.9999• Insignificant difference between control and experimental
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Results
• Large school:
1 2 3 40
10
20
30
40
50
60
controlexperimental
Section of Aquarium
Perc
ent N
eon
Tetr
as (%
)
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Results• Large school: – Chi-square analysis• Experimental: X2(3)= 45.3, p< 0.05• Control: X2(3)= 12.0, p< 0.05• Significant preference for section 3
– Mann-Whitney U• p =0.8857• Insignificant difference between control and experimental
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Discussion
• Due to insignificant difference between control and experimental, hypothesis could not be accepted or rejected
• Jar was seen as a novel object– Saxby et. al. • Higher prevalence of darting in presence of unfamiliar
object when in small schools
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Discussion
• Predator did not cause neon tetras to stay away
• Possible reasons:– Wanted to school with the zebra fish– Zebra fish was not threatening enough• Zebra fish normally school• Separation by the jar
– Curiosity of the neon tetras
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Discussion
• Future avenues of research:– Looking at darting behaviour– Use a more aggressive species• Ex: Angelfish
– Using a model predator– Trials without the jar – Collecting more data
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Conclusions• No significant difference in the response to
the empty jar versus the predator• Neon tetras were attracted to the jar, despite
the size of the school• Future improvements to the data collection
could provide more useful results