The structure of schools of giant bluefin tuna in Cape Cod Bay

Partridge, Brian L.; Johansson, Jonas; Kalish, John M.

doi:10.1007/bf00692374

Cited by 106 publications

(102 citation statements)

References 23 publications

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“…Regardless of the school size, these are characterized by in-line configurations, described in the literature as phalanx (8) or soldier (17). This type of swimming pattern is observed, for instance, for hunting/predatory bluefin tunas in the Atlantic Ocean (18). We also note that the typical nearestneighbor distance (NND) is smaller than in the schools swimming at low velocity.…”

Section: Resultsmentioning

confidence: 54%

Simple phalanx pattern leads to energy saving in cohesive fish schooling

Ashraf

Bradshaw

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

141

145

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The question of how individuals in a population organize when living in groups arises for systems as different as a swarm of microorganisms or a flock of seagulls. The different patterns for moving collectively involve a wide spectrum of reasons, such as evading predators or optimizing food prospection. Also, the schooling pattern has often been associated with an advantage in terms of energy consumption. In this study, we use a popular aquarium fish, the red nose tetra fish, Hemigrammus bleheri, which is known to swim in highly cohesive groups, to analyze the schooling dynamics. In our experiments, fish swim in a shallow-water tunnel with controlled velocity, and stereoscopic video recordings are used to track the 3D positions of each individual in a school, as well as their tail-beating kinematics. Challenging the widespread idea of fish favoring a diamond pattern to swim more efficiently [Weihs D (1973) Nature 241:290-291], we observe that when fish are forced to swim fast-well above their free-swimming typical velocity, and hence in a situation where efficient swimming would be favored-the most frequent configuration is the "phalanx" or "soldier" formation, with all individuals swimming side by side. We explain this observation by considering the advantages of tail-beating synchronization between neighbors, which we have also characterized. Most importantly, we show that schooling is advantageous as compared with swimming alone from an energy-efficiency perspective.fish swimming | collective dynamics | pattern formation | synchronization | energy efficiency T he dynamics of animal groups is driven by many different factors, such as foraging, social life, or survival instinct against predators (1). The collective movements are built from local interactions between the individuals constituting the group (2, 3). Apart from behavioral aspects, the benefit from schooling has often been associated with group optimization in terms of hydrodynamic resistance (4). A fish school represents a typical case of such cohesive and collaborative complex systems. The fluid dynamical mechanisms influencing the motion of fish in a school have been described in essence in the early study of Weihs (5). He demonstrated, using a 2D model, that if each fish maintains a specific position within the school, forming a diamond pattern, the hydrodynamic interactions will globally improve the swimming performance. The basic idea is that fish in a school optimize swimming by interacting constructively with the vortices shed by the local leading individuals; such constructive interactions require a precise synchronization between fish. This study has been followed by an extensive number of studies modeling or simulating fish school swimming configurations to validate Weihs' hypothesis (6-8). It has been shown that by following this strategy, fish could improve their efficiency by ∼20% (8, 9). However, the idea that a beneficial situation in terms of swimming power can be achieved for the group by maintaining a specific complex pattern remai...

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Section: Resultsmentioning

confidence: 54%

Simple phalanx pattern leads to energy saving in cohesive fish schooling

Ashraf

Bradshaw

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

141

145

View full text Add to dashboard Cite

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“…Eschmeyer et al 1983, Partridge et al 1983, Krause et al 2000, the energetic advantages of such behaviour are still relatively unexplored, particularly in fish that swim using MPF swimming. This study demonstrates a significant reduction in the pectoral fin beat frequency of trailing labriform fish swimming in a school, compared to solitary and leading individuals.…”

Section: Discussionmentioning

confidence: 99%

Kinematics and energetic benefits of schooling in the labriform fish, striped surfperch Embiotoca lateralis

Johansen¹,

Vaknin²,

Steffensen³

et al. 2010

Mar. Ecol. Prog. Ser.

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“…Grey dashed curve: averaged nearest neighbour distribution of 100 randomly chosen flocks in the model. Dashed line: expected value for a random isotropic system, where the probability to find any bearing angle is the same for all angles P random (cos(u)) ¼ wake from others [41,68]. As to the hypothesis of optimal vision through the swarm, no specific bearing angle has been suggested.…”

Section: The Angle To the Nearest Neighbour The 'Bearing Angle'mentioning

confidence: 99%

Schools of fish and flocks of birds: their shape and internal structure by self-organization

2012

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Models of self-organization have proved useful in revealing what processes may underlie characteristics of swarms. In this study, we review model-based explanations for aspects of the shape and internal structure of groups of fish and of birds travelling undisturbed (without predator threat). Our models attribute specific collective traits to locomotory properties. Fish slow down to avoid collisions and swim at a constant depth, whereas birds fly at low variability of speed and lose altitude during turning. In both the models of fish and birds, the 'bearing angle' to the nearest neighbour emerges as a side-effect of the 'blind angle' behind individuals and when group size becomes larger, temporary subgroups may increase the complexity of group shape and internal structure. We discuss evidence for model-based predictions and provide a list of new predictions to be tested empirically.

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The structure of schools of giant bluefin tuna in Cape Cod Bay

Cited by 106 publications

References 23 publications

Simple phalanx pattern leads to energy saving in cohesive fish schooling

Simple phalanx pattern leads to energy saving in cohesive fish schooling

Kinematics and energetic benefits of schooling in the labriform fish, striped surfperch Embiotoca lateralis

Schools of fish and flocks of birds: their shape and internal structure by self-organization

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