Predation on the rocky shores of Patagonia, Argentina
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Rocky intertidal communities of Argentinean Patagonia are exposed to harsh physical conditions caused by dry, strong southern trade winds (mean speed 45 km h-1, gusts up to 140 km h-1) that result in intense desiccation of intertidal organisms. Predator distributions in these communities were evaluated from April 2003 to December 2004 at two exposed headlands and six protected bays in Cabo dos Bahias (44°50′S, 65°40′W). Crabs and sea stars dominated the predator assemblage, with occasional scavenger snails and fish also present. During low tide, predators were never found in the open but were always associated with shelter (primarily within mussel beds and coralline algae), suggesting a strong predator dependency on foundation species to buffer them from physical stress. Few predators (mostly crabs) emerged from shelter at high tide. Unlike the larger predators found on Chilean rocky shores, invertebrate predators in this system are diminutive, generally < 2 cm. The lone exception was the newly discovered invasive green crab,Carcinus mamas. Feeding trials, gut content analyses, and visual surveys indicated that native predators feed primarily on small, soft-bodied prey.C. mamas fed on slow-moving and sessile animals, including the super abundant musselPerumytilus purpuratus, with much greater voracity than native predators. Because native intertidal organisms are dependent on mussel beds and coralline algae for shelter from desiccation, successful invasion ofC. mamas may lead to a significant decrease in native diversity by consuming foundation species. This study represents a preliminary survey of predator distributions and feeding habits on the rocky shores of Argentinean Patagonia and provides important baseline data to evaluate trophic linkages and predatory effects on Patagonian rocky shores.
KeywordsRocky Shore Green Crab Experimental Marine Biology Foundation Species Intertidal Level
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- Camacho, H. H. 1979. Descriptión geológica de la hoja 47h-48g, Bahía Camarones, Provincia del Chubut. Boletín No. 153. Servicio Geológico Nacional, Buenos Aires, Argentina.Google Scholar
- Clarke, K. R. andR. M. Warwick. 2001. Change in Marine Communities: An Approach to Statistical Analysis and Interpretation, 2nd edition. PRIMER-E, Plymouth, U.K.Google Scholar
- Dayton, P. K. andR. R. Hessler. 1972. Role of biological disturbance in maintaining diversity in the deep sea.Deep-Sea Research 19:199–208.Google Scholar
- Duffy, J. E. andM. E. Hay. 2000. The ecology and evolution of marine consumer-prey interactions, p. 131–157.In M. D. Bertness, S. D. Gaines, and M. E. Hay (eds.), Marine Community Ecology. Sinauer Associates, Inc. Publishers, Sunderland, Massachusetts.Google Scholar
- Hunt, H. L. andR. E. Scheibling. 1998. Effects of whelk(Nucella lapillus (L.)) predation on mussel(Mytilus trossulus (Gould),M. edulis (L.)) assemblages in tidepools and on emergent rock on a wave-exposed rocky shore in Nova Scotia, Canada.Journal of Experimental Marine Biology and Ecology 226:87–113.CrossRefGoogle Scholar
- Layman, C. A. andB. R Silliman. 2002. Preliminary survey and diet analysis of juvenile fishes of an estuarine creek on Andros Island, Bahamas.Bulletin of Marine Science 70:199–210.Google Scholar
- Olivier, S., A. Escofet, P. Penchaszadeh, andJ. M. Orensanz. 1972. Estudios ecológicos de la region estuarial de Mar Chiquita (Bs.As., Argentina):II. Relaciones tróficas interespe-cíficas.Anales de la Sociedad Científica Argentina 194:89–104.Google Scholar
- Scelzo, M. A. andV. Lichtscheinde Bastida. 1978. Desarrollo larval y metamorfosis del cangrejoCyrtograpsus altimanus Rathbum, 1914 (Brachyura, Grapsidae) en laboratorio, con observaciones sobre la ecología de la especie.Physis 38:103–126.Google Scholar
- Spivak, E. D. 1997. Cangrejos estuariales del Atlántico sudoccidental (25°-41°S) (Crustacea: Decapoda: Brachyura).Investigaciones Marinas 25:105–120.Google Scholar
- Walton, W. C., C. MacKinnon, L. F. Rodriguez, C. Proctor, andG. M. Ruiz. 2002. Effect of an invasive crab upon a marine fishery: Green crab,Carcinus maenas, predation upon a venerid clam,Katelysia scalarina in Tasmania (Australia).Journal of Experimental Marine Biology and Ecology 272:171–189.CrossRefGoogle Scholar
- Zar, J. H. 1999. Biostatistical Analysis, 4th edition. Prentice Hall, Inc, Englewood Cliffs, New Jersey.Google Scholar