- 1 - Underwater eco-tourism routes – a case study in Central Algarve, Portugal Rangel M.O., Gonçalves, JMS., Almeida, C., Afonso, C., Costa, C., Erzini, K., Oliveira, F., Monteiro, P.; Ribeiro, J., Veiga, P. Abstract — The goal of this w ork was to describe a touristically sustainable use of the Central Algarve National Underw ater Ecological Reserve (REN). For this purpose five underw ater routes were developed at well know n beaches. The fauna, flora and geographic features of the underw ater areas to a depth of 7m w ere scientifically described. For the touristic routes, basic snorkelling equipment should be available freely for every interested person, along w ith acrylic plates to take underw ater for route interpretation. The defined routes have an easy/medium level of difficulty and a high level of interest. Plates describing local probable fauna, flora and other interesting features are placed in specific sites along the routes to enhance them and make them more appealing. In the end, tourists are invited to fill up a questionnaire so that researchers can understand and correct all the unachieved objectives, and improve them for the next beach season. The routes of Praia dos Arrifes is described here as an example. Keywords — eco-tourism, underw ater eco-tourism, underw ater routes, underw ater w alk. ——————————  —————————— 1 I NTRODUCTION he use of coastal areas for human pleasure has always been a concern for scientific and management communities, leading to obvious conflict between choices of recreational uses and natural preservation options [1], [2], [3]. A new tendency for the promotion of sustainable eco-tourism, as an alternative to mass tourism, is increasing, but market tendencies continue to dictate touristic rules [4]. Nowadays there is the need for sustainable planning in coastal management in order to avoid adverse impacts not only on the preservation of nature, but also on market and tourist plans. As [5] reports, eco-tourism presents itself as an alternative to classic mass tourism, as a guarantee to ecosystem preservation and valorisation of local cultures and economies. As recognised by Agenda 21, ecotourism is a potential tool for sustainable development, particularly in fragile environments (like the protected ones), relieving pressure from traditional tourism, such as pollution and destruction of biodiversity [6]. Regarding the choices and preferences of tourist divers in Marine Protected Areas (MPAs), [7] clearly states that divers prefer reductions in the level of site use to allow the implementation of conservation and education measures that can lead to a scenario of restricted underwater defined routes in marine protected zones. Central Algarve, including Albufeira’s county (the study area) was considered a National Underwater Ecological Reserve (REN) in June 1995. This classification implies special management procedures from the shore to the 30m bathymetric mark. To date, no measures have been taken to preserve and enhance sustainable underwater tourism in this popular Portuguese mass sand and beach tourism area. The Portuguese underwater REN zone covers a considerable area, in comparison with the terrestrial zone. But, as reported by [8], the systematic scientific study and data analysis of this extended area is still in the early stages, and only a global approach, considering both geologic and biologic factors, associated with an understanding of coastal biological communities, especially habitats and vulnerable or endangered species, can lead to integrated tools and the sustainable management of our natural patrimony. The mapping and characterization of the marine communities of the REN of the Central Algarve has been carried out through the RENSUB project since 2003 by the Coastal Fisheries Research Group (CFRG) of the Center of Marine Sciences (CCMAR). This project is financed by Regional Development and Coordination Commission of the Algarve (CCDR - Algarve) and provides the tools that allow the definition of underwater routes, with accurate scientific information on the fauna, flora and their geographic location. The selected routes characterized here represent an attempt to reduce mass tourism and to provide eco-tourism facilities and T