Schooling of Fish: Advantages and Disadvantages of the Buddy System - PowerPoint Presentation

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Schooling of Fish: Advantages and Disadvantages of the Buddy System

Taylor Drexinger

Lena Finkel

David Quinn

Caroline Wilkinson Slide2

Background

Schooling vs. Shoaling

How fish school

Both advantages and disadvantagesSlide3

Relevance

Impact on surrounding species

Impact on surrounding environmentSlide4

What Fish School

Clupeomorpha

Barracuda

Larvae

Some sharks (hammerheads)

Ostariophysi Slide5

Advantage-Social

When separated from the school, the individuals become skittish and aggressive

Lower

respiration

rate when fish in groups

Synchronized actions Slide6

Advantage-Reproductive

Easier to find mate

Decreases chance of larval predation

Initiation of schooling from environmental factors after morphological evolution Slide7

Advantage-Foraging

More eyes to seek prey

Copepods and herring Slide8

Advantage-Hydrodynamic

Schooling placement is not random

Draft off of each other

Back and forth tail movement “wagging” Slide9

Advantage-Predator avoidance

Reduce probability of capture

Reduced ease of capture

Improved detection of predatory threatsSlide10

How does schooling decrease risk of predation?

1/N Hypothesis

Confusion Hypothesis

Predator Satiation Hypothesis

Predator DetectionSlide11

1/n Hypothesis

Based on a simple mathematical model

P = 1/n

Where a schooling fish’s probability of being consumed by a predator (P) is function of the size of the school (n)

Obviously a gross simplification (basic form assumes predators only consume one prey item per feeding)

Nevertheless, useful in describing the basic theoretical relationship between school size and risk of predation.Slide12

Confusion Hypothesis

Schooling may allow fish to exploit perceptual bottlenecks within a predator’s nervous system, by overwhelming its ability to process visual and auditory signals.

Predators unable to isolate/maintain focus on individual prey

results in “relay race” effect, in which predator follows a prey target for a short time before diverting its attention to a different target… overall predation reduced as attacker constantly pursues new prey targets with little success.

In theory the confusion effect on predator should increase with relative school size of the preySlide13

Confusion Hypothesis

Vs.

Works on humans too!Slide14

Predator Satiation Hypothesis

There is a maximum amount of prey an individual predator can consume during an individual feeding

By synchronizing behaviors amoung large groups of individuals, prey fishes can exploit the inability of predators to consume more than a set amount of prey… ensures the survival of the remaining fish

The Predator Satiation Hypothesis may explain the synchronized and social behavior of wide range of other organisms throughout the biological worldSlide15

Synchronous Emergence of Adult Mayflies from Larval StageSlide16

Synchronous Acorn Production Among Adjacent Oak TreesSlide17

Mass Nesting in Sea TurtlesSlide18

Predator Detection Hypothesis

Larger schools… wider collective field of vision

One hole: schooling obscures vision of individuals located near the interior of the group

Possible association with alarm substances to provide net advantage…. See OstariophysiSlide19

Disadvantages – Ease of Predation

Easy for underwater predators to spot because of size

Birds can easily spot large bait balls near the surface

Normally attracts a lot of birds, not just one

Cannot effectively hide in reefs or underwater structures

Move around constantly due to resource demands

More chances to run into prey

Whale’s size negate most anti-predator measuresSlide20

Disadvantages – Concentration of Pollution

Very similar to aquaculture disadvantages

Disease spread quick due to proximity

Waste is concentrated

One sick fish can put the entire school at risk

One fish gets out of rhythm

Loses main anti-predator behavior caused by synchronous movements

Predators can begin to pick off the schoolSlide21

Disadvantages – Use of Resources

Must move on quickly to new food sources

Food found during foraging used up quickly due to sheer number of fish

Can get very little food depending on orientation in the schoolUse large amounts of dissolved oxygenSlide22

Predator Adaptations

Adopted their own schooling behavior

Will yield very high returns especially for predators in front of the pack

Sailfish, Dolphins

Force schools into shallow or cluttered waters

Mass synchronous movement greatly hindered

Specific adaptations

Spinner Shark, Sailfish, Swordfish, Thresher SharkSlide23

Still, certain questions remain unanswered…

…What aspects of a predatory stimulus actually elicit a behavioral/defensive response?

…How do schooling patterns change in response to a predatory attack?

…Who shot Biggie Smalls?Slide24

ConservationQuantitative analysis of fish schooling can lead to

better commercial fishing practices

information on environmental demands for large schools

Better understanding for efficient aquaculture of schooling fishesResources demand (ex. Oxygen levels)Need for Waste RemovalCombating diseases Slide25

Future Research

Windmills!Slide26

Summary

Advantages

Disadvantages

HypothesesSlide27

Evaluation of Sources

Valid conclusions

Experimental data

Dated in some cases Slide28

References

Barber, I., & Huntingford, F. A. (1996). Parasite infection alters schooling behaviour: deviant positioning of helminth-infected minnows in conspecific groups. 

Proceedings of the Royal Society of London. Series B: Biological Sciences

, 263

(1374), 1095-1102.

Bertrand, A., Barbieri, M. A., Gerlotto, F., Leiva, F., & Córdova, J. (2006). Determinism and plasticity of fish schooling behaviour as exemplified by the South Pacific jack mackerel Trachurus murphyi. 

Marine Ecology Progress Series

, 

311

, 145-156.

Eggers, D. M. (1976). Theoretical effect of schooling by planktivorous fish predators on rate of prey consumption. 

Journal of the Fisheries Board of Canada

, 

33

(9), 1964-1971.

Major, P. F. (1978). Predator-prey interactions in two schooling fishes,< i> Caranx ignobilis</i> and< i> Stolephorus purpureus</i>. 

Animal Behaviour

, 

26

, 760-777.

Ryer, C.H., and B.L. Olla. 1991. Information transfer and the facilitation and inhibition of feeding in a schooling fish. Environmental Biology of Fishes 30.3: 317-323.

Abrahams, M., Colgan, P. 1985. Risk of predation, hydrodynamic efficiency, and their influence on school structure. Environmental Biology of Fishes. 13.3: 195-202.

 Partridge, B., Pitcher, T., Culler, M., Wilson, J. 1980. The three-dimensional structure of fish schools. Behavioral Ecology and Sociobiology. 6.4:277-288. Slide29

References

 Kils, U. 1992. The esSCOPE and dynIMAGE: Microscale tools for in situ studies of predator-prey interactions. Arch Hydrobiol Beih 36: 83-96.

 Moyle, P.B., Cech, J.J. 2003. Fishes, An introduction to Ichthyology. 5

th

Ed. Benjamin Cummings.

Hunter, J.R., Coyne, K.M. 1982. The onset of schooling in northern anchovy larvae, Engraulis mordax. CalCOFI 23: 246-251.

Landa, J.T. 1998. Bioeconomics of schooling fishes: selfish fish, quasi-free riders, and other fishy tales. Environmental Biology of Fishes. 53.4:353-364.

 Alexander, R.M. 2004. Hitching a lift hydrodynamically- in swimming, flying and cycling. Journal of Biology. 3.2:7.

Weiner, Jon. "Ideas for Wind Farming."

California Institution of Technology News

. CalTech University, 17 May 2012. Web. 25 Nov. 2012. <http://www.caltech.edu/content/schooling-fish-offer-new-ideas-wind-farming>.

Images

http://www.sharkattackfile.net/species.htm#spinner

http://www.extremescience.com/sailfish.htm

http://dsc.discovery.com/sharks/shark-pictures/pelagic-thresher-shark.html

http://natural-wild-life.blogspot.com/2011/09/barracuda.html

http://digital-art-gallery.com/photo/gallery/birds

http://www.eaglewingtours.com/016_WhalesandWild/2719_EagleWingWhal.html

http://science.kqed.org/quest/2010/09/13/back-to-school-for-sardines/