Algal Research 15 (2016) 9–23 Contents lists available at ScienceDirect Algal Research journal homepage: www.elsevier.com/locate/algal Review article Mariculture of the Asian kelp Undaria pinnatifida and the native kelp Saccharina latissima along the Atlantic coast of Southern Europe: An overview César Peteiro a,⁎, Noemí Sánchez b,c, Brezo Martínez d a Instituto Español de Oceanografía (IEO), Centro Oceanográfico de Santander, Santander, Spain b Universitat de Girona (UdG), Facultat de Ciències, Girona, Spain c Santander, Spain d Universidad Rey Juan Carlos (URJC), Escuela Superior de Ciencias Experimentales y Tecnología, Mostoles, Madrid, Spain article info abstract Article history: Kelps are one of the most economically and ecologically important groups of seaweeds in the world. Most kelps Received 25 September 2015 are confined to cold temperate regions, and northern Spain is the southern distribution limit of many species in Received in revised form 4 December 2015 Europe. As the supply from wild harvest cannot meet increasing current and future demands, methods to Accepted 22 January 2016 successfully cultivate kelp species are needed. This review integrates key points about mariculture of kelp species Available online xxxx from different cultivation trials conducted along the Atlantic coast of southern Europe, and more specifically about Undaria pinnatifida (wakame) and Saccharina latissima (sugar kombu) along the northern Spanish coast. Keywords: Kelp mariculture It focuses on the following topics: (1) effects of hydrodynamic conditions on culture grounds in coastal bays in Saccharina latissima order to identify optimal locations for culture of both kelp species; (2) suitability of different raft culture systems Southern Europe in sheltered and more exposed environments; (3) identification of the most suitable time frame for the maricul- Spanish experiences ture of both kelps and its relationship with environmental factors; and (4) different methods for open-sea Undaria pinnatifida cultivation of S. latissima based on practices traditionally employed in Asian Saccharina farming. Finally, (5) this paper discusses the development of mariculture of the introduced kelp, U. pinnatifida,inrelationtothe native kelp, S. latissima, both from economic and environmental perspectives. Overall, the information reported here contributes to the knowledge necessary for the successful mariculture of these and other kelps on a commercial basis in this and other areas of Europe. © 2016 Elsevier B.V. All rights reserved. Contents 1. Introduction............................................................... 10 2. Methodsanddatasources........................................................ 10 3. Hydrodynamicconditionsforcultivation.................................................. 11 3.1. Determiningthequantityandqualityoftheyield........................................... 11 3.2. Suitabilityofdifferentraftculturesystems.............................................. 12 4. Timeframesforcultivation........................................................ 13 4.1. Outplantingandharvestingtime.................................................. 13 4.2. Keyenvironmentalfactorsaffectingcultivation............................................ 14 5. Methodsforcultivation.......................................................... 17 6. Introducedvs.nativespeciesincultivation................................................. 17 6.1. Economicissues.......................................................... 17 6.2. Environmentalissues....................................................... 18 7. Conclusions............................................................... 20 Acknowledgments.............................................................. 20 ⁎ Corresponding author at: Instituto Español de Oceanografía (IEO), Centro Oceanográfico de Santander, Planta de Cultivo de Algas “El Bocal”, Barrio Corbanera s/n. (Monte), 39012 Santander, Spain. E-mail address: [email protected] (C. Peteiro). http://dx.doi.org/10.1016/j.algal.2016.01.012 2211-9264/© 2016 Elsevier B.V. All rights reserved. 10 C. Peteiro et al. / Algal Research 15 (2016) 9–23 AppendixA. Supplementarydata.......................................................20 References..................................................................20 1. Introduction required for the successful mariculture of U. pinnatifida and S. latissima on the northern Spanish coast. Kelps constitute an economically and ecologically important group of seaweeds that are used mainly as human food and as a source of 2. Methods and data sources alginate for a wide range of industries (textile, food, paper, cosmetic, and pharmaceutical). However, kelps also have many other commercial Gametophyte stock cultures (germplasm collection) from the applications, such as feed for aquaculture and animal husbandry, Spanish Institute of Oceanography (IEO) in Santander were used to agricultural fertilizers, feedstock for biofuel production, and medicinal produce seedlings of U. pinnatifida and S. latissima. These gametophyte purposes [1,2]. In addition, these large algae play important roles cultures were derived from zoospores released from sporophytes culti- as ecosystem engineers and/or foundation species (kelp forest), provid- vated in Galicia and along the Cantabrian coast of Spain (Northern ing habitat, protection, and food for numerous organisms in coastal Spain). The original parents were collected from wild populations of ecosystems [3,4]. U. pinnatifida in Gijón (Asturias) in 1996 and Lorbe (Galicia) in 2001 The commercial kelps Undaria (wakame) and Saccharina (kombu) or from natural populations of S. latissima in Cambados (Galicia) in were traditionally collected in eastern Asia from wild stocks, but this 1996 and Oleiros (Galicia) in 2001. The sporophytes originating from practice has been replaced to a great extent by mariculture. World aqua- Iberian populations have been actively bred by successive inbreeding culture production of wakame and kombu currently accounts for more and directional selection since 1996, in order to obtain cultivars or than 95% of total production [2,5]. In contrast to Asia, kelp species in strains with strong growth, high-quality morphological traits and high Europe are still wild harvested for industrial purposes, although natural tolerance to high temperature [15]. Note that the Asian kelp resources are limited [1,2] and populations have declined in recent U. pinnatifida was accidentally introduced in Spain on the Atlantic years due to climate change [6–8]. Mariculture of kelp species has gen- coast of Galicia in 1988 and that it has spread widely since then [16]. erated great interest in recent years, as it may lead to increased produc- Spore suspensions and gametophyte cultures were obtained using the tion for commercial uses and potential applications in integrated methodology developed by Perez et al. [17,18]. Seedlings attached to multitrophic aquaculture (IMTA); in turn, it may help protect the kelp strings were produced from crossing of gametophytic clones of the forest from overharvesting [9–12]. IEO collection with high similarity according to the protocols described Most kelps are confined to northern temperate regions with in previous studies [9,19]. relatively cold water, and the Iberian Peninsula (northern Spain and Open-sea cultivation trials for U. pinnatifida and S. latissima were Portugal) represents the southern distribution limit of many species in conducted at two different locations in an enclosed coastal bay off A Europe [13]. The introduced kelp Undaria pinnatifida (wakame) and Coruña, (Galicia), and trials were also conducted for S. latissima in an the native kelp Saccharina latissima (sugar kombu) are two of the open-sea coastal region off Santander (Cantabria); all sites lie off the most valuable seaweeds in northern Spain due to their high demand Atlantic coast of northern Spain. The farms in Galicia consist of a shel- and economic value. The retail prices of wakame and sugar kombu are tered site and a moderately exposed site with current velocities no approximately 61–66 and 40–49 euros per kg dry weight of useful greater than 12 cm s−1 and 27 cm s−1, respectively [20,21]. The farm blade, respectively, in markets whose goods are intended for human in Cantabria is an exposed site with currents ranging from 48 to consumption, which is their principal use today [14]. As the supply 92 cm s−1 [22]. Pilot-scale floating rafts with horizontal ropes (long- from wild harvest cannot meet increasing current and future demands, line) or hanging ropes (garland and vertical types) were used for culti- mariculture of these kelp species is currently a growing enterprise. vation trials in the sea (summarized in Fig. 1). The purpose of this paper is to review kelp mariculture based on The information presented here integrates and summarizes results experience gained and research developed from commercial-scale culti- gained from different culturing experiments carried out at a pilot scale vation trials along the Atlantic coast of northern Spain. This review at these farm sites [9,19,23–31]. The summarized data of cultivation focuses on describing the following: (1) the effects of hydrodynamic trials with U. pinnatifida and S. latissima along the northern Spanish conditions on kelp culture grounds in coastal bays to identify optimal coast are presented in Supplementary Tables 1 and 2 (Appendix A. Sup- locations for the cultivation of U. pinnatifida and S. latissima, (2) the suit- plementary data).