Risk of predation, hydrodynamic efficiency and their influence on school structure

Abrahams, Mark V.; Colgan, Patrick W.

doi:10.1007/bf00000931

Cited by 98 publications

(58 citation statements)

References 13 publications

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“…In all cases, fish swim around midheight of the channel. The schools, nonetheless, do have a 3D structure, which supports the observations reported in the literature where a slight spreading of the school pattern in the third dimension permits enlargement of the visual field of each member of the school (19)(20)(21). Considering the horizontal positions, in Fig.…”

Section: Resultssupporting

confidence: 88%

Simple phalanx pattern leads to energy saving in cohesive fish schooling

Ashraf

Bradshaw

et al. 2017

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

129

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: Resultssupporting

confidence: 88%

Simple phalanx pattern leads to energy saving in cohesive fish schooling

Ashraf

Bradshaw

et al. 2017

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

129

145

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“…Positional benefits are also a function of group shape (29,30). The food-finding advantage to the vanguard individual is diluted as the group switches from an oblate ellipsoid to a sphere to a flat forward surface.…”

Section: The Paradox Of Individualitymentioning

confidence: 99%

Complexity, Pattern, and Evolutionary Trade-Offs in Animal Aggregation

Parrish

Edelstein‐Keshet

1999

Science

1,057

745

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“…Breder 1965, 1976Belyayev & Zuyev 1969, Lissaman & Schollenberger 1970, Weihs 1973, Higdon & Corrsin 1978, Badgerow & Hainsworth 1981, Hummel 1983, Kshatriya & Blake 1992 while empirical quantifications are rare. Only few studies have measured oxygen consumption rate (Parker 1973, Abrahams & Colgan 1985, Fish 1994, Herskin & Steffensen 1998, heart rate (Weimerskirch ABSTRACT: Cetacean mother-calf dyads demonstrate formation locomotion that may provide hydrodynamic and/or social benefits. For example, echelon position (calf in close proximity of its mother's mid-lateral flank) enables calves to increase swim performance at reduced locomotor effort compared to periods of solitary swimming.…”

Section: Introductionmentioning

confidence: 99%