Schooling behaviour of small pelagic fish: phenotypic expression of independent stimuli
| Type | Article | ||||||||
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| Date | 2007-03 | ||||||||
| Language | English | ||||||||
| Author(s) | Brehmer Patrice1, 6, Gerlotto François2, Laurent Charline1, Cotel Pascal3, Achury Alina4, Samb Birane5 | ||||||||
| Affiliation(s) | 1 : Ctr Rech Halieut Mediterraneenne & Trop, IRD, IFREMER, F-34203 Sete, France. 2 : Inst Mar Peru, Inst Rech Dev, La Punta, Callao, Peru. 3 : Inst Rech Dev, St Clotilde 97490, Reunion. 4 : Fdn La Salle, Estac Invest Marinas Isla Margarita, Punta De Piedras 6318, Venezuela. 5 : Ctr Rech Oceanog Dakar Thiaroye, Inst Senegalais Rech Agron, Dakar Thiaroye, Senegal. |
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| Source | Marine Ecology Progress Series (0171-8630) (Inter-Research), 2007-03 , Vol. 334 , P. 263-272 | ||||||||
| WOS© Times Cited | 24 | ||||||||
| Keyword(s) | Small pelagic fish, Schooling, Phenotypic expression, In situ observations, Echo type, Diel cycle, Behaviour | ||||||||
| Abstract | We compared echo sounder measurements of fish schools on Venezuelan and Senegalese coastal shelves. In both areas Sardinella aurita was the predominant aggregative species; the stocks are known to be genetically independent. Persistent school typology is described by analysing 7 acoustic surveys in Venezuela and comparing with pioneer observations in Senegal. The echo types encountered in both countries were comparable, with S. aurita and their associated species having comparable schooling behaviour. School morphology appears to be more related to species than to global characteristics of their ecosystems, as fish school descriptors were similar for both stocks. Nevertheless, S. aurita may adopt different school morphologies. Differentiation between day and night fish schools was mainly due to morphological variables, as determined by fractal dimension. Echo types were different between day and night in both Venezuela and Senegal. This analysis shows that several independent parameters can influence school morphology. However, although schooling behaviour is temporally highly variable, it shows several constant, typical 2D morphological structures, i.e. echo types. The observation of small pelagic fish schools occurring during the night is not unusual according to the literature, although a strict diurnal schooling behaviour, with scattering during the night, is often reported. Schooling behaviour appears to be a phenotypic expression depending on biotic and abiotic stimuli, intrinsic characteristics and motivation. | ||||||||
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