Abstract

TESO, S. Valeria et al. Do native grazers from Patagonia, Argentina, consume the invasive kelp Undaria pinnatifida?. Rev. Mus. Argent. Cienc. Nat. [online]. 2009, vol.11, n.1, pp.7-14. ISSN 1853-0400.

The invasive kelp Undaria pinnatifida (Phaeophyceae, Laminariales) was first reported in Golfo Nuevo in 1992 and since then it has spread widely over more than 170 km, all along the northern Patagonian coast, Argentina. Field observations in the region have indicated the potential role of invertebrate grazers, like the sea urchins Arbacia dufresnii and Pseudechinus magellanicus and the gastropod Tegula patagonica, in controlling algal density. Laboratory experiments were conducted to ascertain whether, and if so, to what extent these grazers actually feed on the algae. The studied sea urchins fed on the alga, whereas the snail scraped off biofouling adhered to its surface. Higher densities of grazers were observed on the kelp during summer and might be attributed to increasing in metabolism with increasing temperature, and degradation of blades and sporophylls, which possibly increase their palatability.

Keywords : Arbacia dufresnii; Feeding behavior; Grazing; Invasive species; Pseudechinus magellanicus; Tegula patagonica.

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