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Comparing quality of estuarine and nearshore intertidal habitats for Carcinus maenas

Amaral, Valter, Cabral, Henrique N., Jenkins, Stuart, Hawkins, Stephen and Paula, José (2009) Comparing quality of estuarine and nearshore intertidal habitats for Carcinus maenas Estuarine, Coastal and Shelf Science, 83, (2), pp. 219-226. (doi:10.1016/j.ecss.2009.03.029).

Record type: Article


Estuarine and nearshore marine areas are vital habitats for several fish and benthic invertebrates. The shore crab Carcinus maenas (Crustacea: Brachyura: Portunidae) inhabits a variety of coastal, estuarine and lagoon habitats. At low tide, habitat structural complexity may be most important for crabs in the intertidal, providing refuge from predation and desiccation. The quality of different vegetated and nonvegetated estuarine and rocky shore habitats in SW Portugal and SW England was evaluated for intertidal C. maenas populations. We estimated population density, size–structure, and potential growth (RNA/DNA ratios) to investigate habitat quality. Vegetated estuarine habitats supported higher crab densities, than nonvegetated estuarine and rocky shore habitats. Investigation of population size–structure revealed that all habitats seem important recruitment and nursery areas although estuarine habitats in SW Portugal appeared to support higher densities of new recruits than equivalent habitats in SW England. Significant variation was found in RNA/DNA ratios among habitats. Ratios were highest in the rocky shore suggesting a high quality habitat where growth potential is high. We speculate that competition from other top-predators (Pachygrapsus spp.) rather than low habitat quality may limit the occurrence of C. maenas in intertidal rocky shore habitats in SW Portugal. In estuarine environments RNA/DNA ratios were significantly higher in the vegetated than in the nonvegetated estuarine habitats in SW Portugal but not in SW England, suggesting geographic differences in the extent to which highly structure habitats represent high quality. Our results challenge the current paradigm that structured habitats are necessarily those of higher quality for C. maenas.

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Published date: 20 June 2009
Keywords: green crab, density, nucleic acid, physiological condition, population structure, SW Portugal, SW England


Local EPrints ID: 187857
ISSN: 0272-7714
PURE UUID: dd6154d8-f579-483c-aa3c-6d097631e42d

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Date deposited: 18 May 2011 14:49
Last modified: 18 Jul 2017 11:43

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Author: Valter Amaral
Author: Henrique N. Cabral
Author: Stuart Jenkins
Author: Stephen Hawkins
Author: José Paula

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