Substantial amounts of Macrocystis and Lessonia are traditionally harvested and exported from Chile as raw material for alginate. Because of intense mari culture of abalone (Haliotis ssp.), herbivorous mol luscs that feed on brown kelps, pressure on local populations of Macrocystis and Lessonia has in creased to critical levels within the past 5 years, strongly supporting e¡orts to produce algae maricul tured biomass. Here, we present our results on the de velopment of new techniques for large scale kelp mariculture in Chile. We have abandoned the tradi tional technique of direct spore seeding onto inocula tion lines. Instead, we used gametophyte cultures that were manipulated to enter gametogenesis and to produce synchronous batches of 10 4 10 5 embryos.Juvenile sporophytes were cultured under perma nent aeration and agitation, £oating unattached in contamination free glass bottles up to 10 L, plexiglass cylinders and 800 L greenhouse tanks. When hold fast initials were formed at a size of 8 cm, the sporo phytes were spliced into Nylon rope fragments and transferred to the sea. Twelve months after initiation of gametogenesis in the laboratory, Macrocystis pyrifera attained14 m length and 80 kg fresh weight m À1 line in the sea. For Lessonia trabeculata 6 months after gametogenesis initiation, 0.25 kg fresh weight m À1was attained in the sea.

The red alga Chondracanthus chamissoi (Gigartinales) is endemic to the southern-central region of South America. In the Pacific Ocean, it is distributed from northcentral Peru to Chiloe Island. This species is of economic importance because it is edible and used for carrageenan production. The tetrasporophyte phase was grown in the laboratory, obtaining male and female gametophytes that were incubated under different photoperiod, pH, salinity and temperature conditions. These gametophytes developed and generated reproductive structures that led to in vitro maturation. Subsequently, fertilisation occurred and formation of cystocarps was observed. Finally, carpospores were released and the formation of sporophytes completed the life history of this species under laboratory conditions. Reproductive phase growth rates were recorded for each of the different culture conditions used. Sporophytes reached the highest daily growth rate (22%), while gametophyte's daily growth rate was slower (9%). This research confirms, in vitro, the assumption that C. chamissoi has a sexual triphasic life history Polysiphonia type with isomorphic gametophytes and tetrasporophytes. The development of the complete life history took 20 months in the laboratory.

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