Size structure and feeding dynamics in estuarine clupeoid fish schools: field evidence for the school trap hypothesis
Maes, J.; Ollevier, F.P. (2002). Size structure and feeding dynamics in estuarine clupeoid fish schools: field evidence for the school trap hypothesis. Aquat. Living Resour. 15(4): 211-216. dx.doi.org/10.1016/S0990-7440(02)01181-6 In: Aquatic Living Resources = Ressources Vivantes Aquatiques. Elsevier: Montrouge. ISSN 0990-7440; e-ISSN 1765-2952, more |  |
| Keywords | Behaviour > Feeding behaviour
Behaviour > Social behaviour > Schooling behaviour
Clupea harengus Linnaeus, 1758 [WoRMS]; Clupea harengus Linnaeus, 1758 [WoRMS]; Sprattus sprattus (Linnaeus, 1758) [WoRMS]; Sprattus sprattus (Linnaeus, 1758) [WoRMS]
ANE, Belgium [Marine Regions]
Marine/Coastal; Brackish water | | Author keywords | schooling behaviour; school trap hypothesis; diet composition; niche overlap; size-assortativeness; Clupea harengus; Sprattus sprattus |
| Abstract | An analysis of 273 samples taken at the filter screens of an estuarine power plant cooling water intake showed that herring and sprat were strongly associated with each other and formed mixed species schools. Herring-dominated schools were typically larger, more frequent and contained larger-sized individuals than schools dominated by sprat. The mean body length of both herring and sprat was biased as a function of their relative importance in the school suggesting that the fish schools were assorted by size. However, switching to a fish school dominated by the other species increased the individual body length variation relative to the group average. Diets of both species overlapped strongly but the feeding rate of sprat was significantly lower than that of herring. Our results suggest that during estuarine residency young sprat suffer the consequences of the school trap, possibly to profit from reduced predation risks in herring schools. |
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