Vegetative propagation of the carrageenophytic red alga Gigartina skottsbergii Setchell et Gardner: Indoor and field experiments María C. Hernández-González a, ⁎ , Alejandro H. Buschmann a , Marcos Cifuentes a , Juan A. Correa b , Renato Westermeier c a Centro de Investigación i∼mar, Departamento de Acuicultura y Recursos Acuáticos. Universidad de Los Lagos, Casilla 557, Puerto Montt, Chile b Departamento de Ecología and Center for Advanced Studies in Ecology and Biodiversity, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114, Santiago, Chile c Instituto de Acuicultura, Universidad Austral de Chile, Casilla 1327, Puerto Montt, Chile Received 28 February 2005; received in revised form 3 February 2006; accepted 12 April 2006 Abstract The carrageenophytic red alga Gigartina skottsbergii presents several biological constraints for its cultivation such as restricted temporal availability and high spore mortalities that affect the development of its mass cultivation. For this reason, research to develop alternative propagation methods has been undertaken. Previous laboratory studies demonstrated that manipulating temperature, light and nutrients could enhance healing and regeneration of this seaweed. In this study nursery and field experiments were undertaken to establish the possibility to regrow G. skottsbergii in conditions similar to those applied in mass cultivation practices. Frond fragments and rhizoids were tested as alternative ways to obtain new plants. Our results indicate that regeneration occurs in the field, and can be managed in nursery conditions. The addition of a nitrogen source enhances the growth from 0.6 to 1.0% d - 1 of the healed fragments and the use of a photon flux density above 50 μmol m - 2 s - 1 increases the growth rate but decrease the survival of the explants. Explants can be transferred to field conditions and grow at similar rates to those registered in the nursery (0.5% d - 1 ). It is also possible to propagate rhizoids of G. skottsbergii and it seems that the attachment of a frond portion to the substratum, enhanced its survival and regeneration capacity. Finally, this study demonstrated that rhizoids attached to rocks can regenerate complete plants in nature, a feature which could be a useful for developing a sustainable harvesting methodology. © 2006 Elsevier B.V. All rights reserved. Keywords: Cultivation; Chile; Gigartina skottsbergii; Propagation methodology; Regeneration 1. Introduction Gigartina skottsbergii is a high-quality carrageeno- phytic alga whose annual harvesting in Chile during 1997 reached, together with Sarcothalia crispata (Rhodophyta), over 31,000 metric tons with a value of US $ 2020 per dry ton (Sernap, 2002). The value of other carrageenophytes such a Mazzaella laminarioides (US $ 921 per dry ton) is lower creating a high demand for G. skottsbergii. The amount of biomass removed from wild stocks seems to be causing serious negative effects on the long-term sustainability of this resource (Buschmann et al., 1999a). However, in spite of the economic importance of this species, the limited knowledge on its biology still prevents the establishment of adequate management policies or the implementation of large- scale cultivation. Aquaculture xx (2006) xxx – xxx + MODEL AQUA-627388; No of Pages 9 www.elsevier.com/locate/aqua-online ⁎ Corresponding author. Fax: +56 65 322418. E-mail address: mhernand@ulagos.cl (M.C. Hernández-González). 0044-8486/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.aquaculture.2006.04.048 ARTICLE IN PRESS Please cite this article as: Hernández-González, M.C. et al. Vegetative propagation of the carrageenophytic red alga Gigartina skottsbergii Setchell et Gardner: Indoor and field experiments. Aquaculture (2006), doi:10.1016/j.aquaculture.2006.04.048