FishSchooling: Difference between revisions
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In general, fish prefer larger schools to smaller schools.<ref name="behavior"></ref> Larger schools react more quickly to predators, and tend to be more stable. <ref name="cognition"></ref> Predators are also more confused when attacking larger schools: as long as the school remains intact, predators will focus first on one individual, then another, etc. <ref name="behavior"></ref> Predators have lower rates of capture when they attack large schools or shoals than when they attack smaller groups of fish. <ref name="behavior"></ref> | In general, fish prefer larger schools to smaller schools.<ref name="behavior"></ref> Larger schools react more quickly to predators, and tend to be more stable. <ref name="cognition"></ref> Predators are also more confused when attacking larger schools: as long as the school remains intact, predators will focus first on one individual, then another, etc. <ref name="behavior"></ref> Predators have lower rates of capture when they attack large schools or shoals than when they attack smaller groups of fish. <ref name="behavior"></ref> | ||
However, competition for resources prevents schools from growing too large.<ref name="behavior"></ref> When foraging, fish will split up into smaller groups if | However, competition for resources prevents schools from growing too large.<ref name="behavior"></ref> When foraging, fish will split up into smaller groups if food sources are scattered.<ref name="behavior"></ref> Schools that are too large also tend to fractionate due to internal dynamics: fish picking up on different environmental factors are less willing to compromise, and communication tends to be stunted in too-massive groups.<ref name="cognition"></ref> | ||
Relative positions within a school are determined by both social dynamics and environmental factors, and fish often change positions in the school in response to internal or external stimuli. <ref name="cognition"></ref><ref name="behavior"></ref> Fish exhibit a relative preference for positions at the front of the school when deprived of food: although fish at the front of the school are more likely to be attacked by predators, they also have an advantage when foraging for food. <ref name="behavior"></ref> However, when fish are alerted to the presence of a predator they are more likely to gather to the center of the school, where they are less likely to be caught by predators.<ref name="behavior"></ref> | Relative positions within a school are determined by both social dynamics and environmental factors, and fish often change positions in the school in response to internal or external stimuli. <ref name="cognition"></ref><ref name="behavior"></ref> Fish exhibit a relative preference for positions at the front of the school when deprived of food: although fish at the front of the school are more likely to be attacked by predators, they also have an advantage when foraging for food. <ref name="behavior"></ref> However, when fish are alerted to the presence of a predator they are more likely to gather to the center of the school, where they are less likely to be caught by predators.<ref name="behavior"></ref> |
Revision as of 22:56, 20 April 2014
Fish Schooling
Schooling is a social behavior in which fish align and stay close to one another as members of a group. [1] Many animals live in groups, but unlike most such groups (herds of deer, for example) a school of fish has a consistent geometric orientation. Fish in a school swim parallel to each other, are evenly spaced, and move in almost perfect synchronization.[2] Seen in this way, a school of fish can resemble a single fluid organism. This geometric synchronization distinguishes schooling from another common behavior, shoaling, in which fish loosely group together; however, the two are often used interchangeably.[3]
Which Fish School?
Schooling behavior occurs in both saltwater and freshwater environments.[4] Schooling tendencies vary from species to species. Some fish spend their entire lives in schools, some school occasionally, some only shoal , and a few species neither school nor shoal.[2] Schooling tendencies also vary by situation: individuals that show little interest in joining a school are much more likely to school when exposed to a predator or to a chemical alarm signal. [3] Some fish form short-term schools for spawning (reproductive) and migratory events. [5] Fish often form schools in order to forage more effectively over long distances; and predatory fish (such as sharks and barracudas) occasionally hunt in groups. [3][4]
Structure of Fish Schools
Schooling fish begin to form schools soon after hatching. [2] Schooling behavior seems to be limited by fry size: fry under a certain size or level of development will not school.[2] As fry grow larger, they become more and more inclined to follow other fry for longer periods of time, eventually forming parallel groups swimming in tandem.[2]
Most fish schools are intragenerational, even in fish that school or shoal only occasionally.[2] The reason for this is that fish tend to prefer to swim with fish of a similar size and fish that swim at a similar speed, factors linked to age in fish. [3] [4] Fish have a reason for preferring homogenous schools: predators are more likely to prey on a fish that "sticks out" from the rest of the group. [3] For the same reason, fish also tend to school with fish of the same species; but a small fish will choose to school with small fish of a different species rather than large fish of the same species.[3] Another reason for fish to avoid schooling with fish larger than themselves is that larger fish can out-compete smaller fish when foraging.[3]
In general, fish prefer larger schools to smaller schools.[3] Larger schools react more quickly to predators, and tend to be more stable. [4] Predators are also more confused when attacking larger schools: as long as the school remains intact, predators will focus first on one individual, then another, etc. [3] Predators have lower rates of capture when they attack large schools or shoals than when they attack smaller groups of fish. [3]
However, competition for resources prevents schools from growing too large.[3] When foraging, fish will split up into smaller groups if food sources are scattered.[3] Schools that are too large also tend to fractionate due to internal dynamics: fish picking up on different environmental factors are less willing to compromise, and communication tends to be stunted in too-massive groups.[4]
Relative positions within a school are determined by both social dynamics and environmental factors, and fish often change positions in the school in response to internal or external stimuli. [4][3] Fish exhibit a relative preference for positions at the front of the school when deprived of food: although fish at the front of the school are more likely to be attacked by predators, they also have an advantage when foraging for food. [3] However, when fish are alerted to the presence of a predator they are more likely to gather to the center of the school, where they are less likely to be caught by predators.[3]
- foraging behavior
- group size
- limited by resources available, competition
- movement in a fish school
Why fish school
- Predator avoidance
- Difficulty of tracking movement of a single fish
- Decreased vulnerability to predators
- increased warning system- see predators more quickly, react
- mention co-evolutionary results of this- predator behavior when confronted with a school
- Cooperation
- predatory fish sometimes hunt in groups
- Foraging
- fish forage and find food more effectively in a group
- information sharing
- mention experiment in tank, when new fish learned from other fish to move out of shady area at feeding times, even though no food was distributed
- Hydrodynamics
- Schooling can make it easier for fish to change direction, move more quickly
- examples and explanation
- Mating events and social behavior in fishes
- describe
- examples
How fish school
- Visual determination
- Lateral Line System
- Define Lateral Line System, physiological
- Explain
- Mention that some fish can school even when blinded- though probably only in laboratory setting
- Hormonal signals
- Basis of chemical signaling
Works Cited
- ↑ Grunbaum, Daniel. 1998. “Schooling as a strategy for taxis in a noisy environment”. Evolutionary Ecology[Internet]. http://download.springer.com/static/pdf/768/art%253A10.1023%252FA%253A1006574607845.pdf?auth66=1393865989_f7f8646a3e3802005dc2b710fadb8179&ext=.pdf
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Shaw, Evelyn. 1962. “The Schooling of Fishes”. Scientific American[Internet].http://www.nature.com/scientificamerican/journal/v206/n6/pdf/scientificamerican0662-128.pdf
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 3.14 Reebs, S. 2001.Fish Behavior in the Aquarium and in the Wild. Ithaca, N.Y.: Cornell University Press; 252 p.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Brown C,Laland K,Krause J. 2006.Fish Cognition and Behavior. Oxford, U.K. Blackwell Publishing Ltd.; 328 p.
- ↑ Deloach, N. 1999.Reef Fish Behavior: Florida, Caribbean, Bahamas. Verona, Italy.: New World Publications, Inc.; 343 p.