Why do shallow-water predators migrate? Strategic models and empirical evidence from an estuarine mysid
Speirs, D.; Lawrie, S.; Raffaelli, D.; Gurney, W.; Emes, C. (2002). Why do shallow-water predators migrate? Strategic models and empirical evidence from an estuarine mysid. J. Exp. Mar. Biol. Ecol. 280(1-2): 13-31. http://dx.doi.org/10.1016/S0022-0981(02)00363-5 In: Journal of Experimental Marine Biology and Ecology. Elsevier: New York. ISSN 0022-0981; e-ISSN 1879-1697, more |  |
| Keywords | Aquatic communities > Plankton > Zooplankton
Aquatic organisms > Estuarine organisms
Aquatic organisms > Heterotrophic organisms > Predators
Behaviour > Migrations
Behaviour > Migrations > Feeding migrations
Behaviour > Migrations > Vertical migrations
Behaviour > Orientation behaviour
Behaviour > Protective behaviour
Behavioural responses
Dispersion
Ecological zonation
Environmental factors
Environments > Aquatic environment > Marine environment > Intertidal environment
Motion > Water motion > Circulation > Water circulation > Shelf dynamics > Estuarine dynamics
Motion > Water motion > Water currents
Motion > Water motion > Water currents > Tidal currents
Taxa > Species > Migratory species
Transport processes > Diffusion
Velocity > Current velocity
Mysida [WoRMS]; Neomysis integer (Leach, 1814) [WoRMS]
Brackish water |
| Authors | | Top | - Speirs, D.
- Lawrie, S.
- Raffaelli, D., more
| | |
| Abstract | We investigated factors potentially affecting tidal migrations over the littoral zone by invertebrate predators via a combination of strategic modelling, field observations and laboratory experiments using the mysid Neomysis integer. The models predict the distribution of individuals over the immersed intertidal region under the three different scenarios of diffusive movement, movement up a gradient of prey abundance, and movement towards a specific water depth. We reject the diffusive spread hypothesis since the predicted changes in spatial patterns are qualitatively inconsistent with those of density estimates over the tidal cycle in the field. The foraging hypothesis was consistent with the field samples only if there was a consistent upshore food gradient. Gut contents analysis showed meiofaunal prey were rare, but that organic detritus was the main dietary component. Sediment samples indicated some evidence of an organic matter gradient, but in the laboratory, Neomysis showed no preference for sediment with high organic content. We therefore rejected the foraging hypothesis. The depth-seeking model was not rejected, but laboratory experiments involving responses to various predators of Neomysis provided only weak evidence that depth-seeking was a result of predator avoidance. We hypothesise that the proximate mechanism is most likely to involve behavioural responses to flow conditions. |
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