Quantifying Tidal Movements of the Shore Crab <Emphasis Type="Italic">Carcinus maenas</Emphasis> on to Complex Epibenthic Bivalve Habitats |
| |
| Authors: | Andreas M Waser Rob Dekker Johannes IJ Witte Niamh McSweeney Bruno J Ens Jaap van der Meer |
| |
| Institution: | 1.Department of Coastal Systems,NIOZ Royal Netherlands Institute for Sea Research and Utrecht University,Den Burg,The Netherlands;2.Department of Animal Ecology,VU University Amsterdam,Amsterdam,The Netherlands;3.Sovon Dutch Centre for Field Ornithology,Den Burg,The Netherlands |
| |
| Abstract: | Many subtidal predators undertake regular tidal migrations into intertidal areas in order to access abundant prey. One of the most productive habitats in soft bottom intertidal systems is formed by beds of epibenthic bivalves such as blue mussels (Mytilus edulis) and Pacific oysters (Crassostrea gigas). In the Dutch Wadden Sea, these bivalves might face substantial predation pressure by the shore crab (Carcinus maenas), which increased considerably in numbers during the last 20 years. However, the quantification of this species on bivalve beds is challenging, since most methods common for quantifying animal abundance in marine habitats cannot be used. This study investigated the potential of two methods to quantify the abundance of C. maenas on 14 epibenthic bivalve beds across the Dutch Wadden Sea. The use of the number of crabs migrating from subtidal towards intertidal areas as a proxy of abundance on bivalve beds yielded unreliable results. In contrast, crabs caught with traps on the beds were correlated with the abundance assessed on the surrounding bare flats by beam trawl and therefore provided usable results. The estimates, however, were only reliable for crabs exceeding 35 mm in carapace width (CW). The application of these estimates indicated that crab abundances on bivalve beds were influenced by the biogenic structure. Beds dominated by oysters attracted many large crabs (> 50-mm CW), whereas abundances of medium-sized crabs (35–50-mm CW) showed no relationship to the oyster occurrence. The combination of traps and trawls is capable of quantifying crab abundance on bivalve beds, which offers the possibility to study biotic processes such as predator-prey interactions in these complex structures in more detail. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
