Journal of the Marine Biological Association of the UK

Research Article

Rare predation by the intertidal crab Pachygrapsus marmoratus on the limpet Patella depressa

Ana  Silva a1a2, Diana  Boaventura a1a2c1, Augusto  Flores a1a2, Pedro  Ré a1a2 and Stephen J.  Hawkins a3a4
a1 Laboratório Marítimo da Guia/IMAR—Faculdade de Ciências da Universidade de Lisboa, Estrada do Guincho, 2750-374 Cascais, Portugal
a2 Escola Superior de Educação João de Deus, Avenida Álvares Cabral, 1269-094 Lisboa, Portugal
a3 Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK
a4 Division of Biodiversity and Ecology, School of Biological Sciences, Biomedical Sciences Building, University of Southampton, Southampton, SO16 7PX, UK

Article author query
silva a   [PubMed][Google Scholar] 
boaventura d   [PubMed][Google Scholar] 
flores a   [PubMed][Google Scholar] 
re p   [PubMed][Google Scholar] 
hawkins sj   [PubMed][Google Scholar] 


The predatory effects of Pachygrapsus marmoratus on populations of the intertidal limpet Patella depressa were analysed on rocky shores located on the central coast of Portugal. Nocturnal observations on crab feeding behaviour were conducted and experimental exclusion cages were set in the substratum to assess density effects on limpets. The results indicated that although crabs feed on adult limpets the predatory level was minimal. Crabs used consistent tactics to detach limpets from the substratum but the majority of the attacks were unsuccessful, possibly due to morphological and behavioural adaptations of limpets. An alternative recruitment hypothesis is advanced to explain non-significant differences between experimental treatments and a possible predatory role on shaping levels of recruitment on lower levels of the shore is considered.

(Received March 21 2003)
(Accepted February 5 2004)

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