The Cape Verde Archipelago is composed of ten islands (and thirteen islets), located 750 km off Senegal (west coast of Africa), between 15-17ºN and 22-25ºW. Tourism is the country’s main source of income and of socioeconomic development for several of the islands. Tourism in the Archipelago has a close relationship with marine-related activities, due to the warm weather, sandy beaches, clear water and high diversity of marine species. Cape Verde was visited by 539,621 tourists in 2014 [1], with 41.5% visiting Sal Island, the main tourist area, followed by Boavista Island with 32.9% of the total number of visitors to the Archipelago [2]. Diving is one of the fastest growing industries [3] and, worldwide, there are over 25,000,000 PADI individual divers [4], with an increase of 66.1% between 1996 and 2010 [5] and the business activity supporting scuba diving tourists has become an important tourism sector stimulating a billion dollar global industry [6]. Even though there are no statistical data covering Cape Verde’s diving industry, there are six dive centres currently operating in Santa Maria Bay, Sal Island [7], which constitute an increased human pressure on local reefs - both natural and artificial - further aggravated by the scarce scientific literature on the impact of tourism on marine coastal areas [8] which, despite being an increasing concern for the scientific community [9, 10] remains largely unknown [11, 12].

Several studies have reported how diving activity can affect marine biodiversity: damage may come to benthic marine organisms, such as corals – soft and hard –, sponges, ascidians and large bryozoans, through the direct (physical contact) or indirect (raised sediments) action of divers [13-16]. Fish too can be disturbed, and their natural behaviour changed (e.g. during mating) due to selective search by divers (e.g. cryptic species) [17, 18]. Scientific information on local fish assemblages, however, is very limited, consisting mostly of inventories of species found in the area [19-23]. This is particularly worrisome given the biological richness and singularity of Cape Verde, with almost half of the total cryptobenthic fish species on the archipelago’s waters comprising endemic species [24] and being listed in the top 10 coral reef biodiversity hotspots in the world, but also in the top eight of threatened centres of endemism [25]. Such a scenario - biological richness and singularity, general unawareness and consequential threats by human activity - led a private diving operator (Manta Diving Centre, Sal Island, Cape Verde) to put forward, with the support of the Ministry of Environment and Marine Resources of Cape Verde, a project to deploy artificial reefs in Cape Verde coastal waters [26] to satisfy the demand for ’non-natural’ habitats [27] and promote environmental awareness among divers using “soft” management tools (i.e. education and interpretation) instead of “hard” management tools such as restrictions or visitors’ fees [28] (Fig. 1).

Fig. (1). Map of the Baía de Santa Maria, Sal Island, Cabo Verde with diving sites marked. Três Grutas and Tchuklassa represent natural reefs, Sargo and Kwarcit are artificial reefs (deployed vessels).

Divers are open minded and eager to learn about the dive sites visited. They tend to look for information and support regarding the dive in general [29] and environmental education must be included in diving activities through “pre-diving environmental briefings” [29, 30]. Education is advocated as an advisable method for reducing environment damage caused by divers [29, 31], but to be truly effective it should be adapted to each diving site, the socio-demographic characteristics of the divers, their previous knowledge about the environment and their learning capacity [29].

Underwater routes are perceived as an effective way to improve biodiversity awareness among divers’ community [32] and have been used to enhance environmental awareness [33, 34] and to reduce scuba-diver impacts on the environment [12, 31, 35, 36], by constraining divers to certain areas [37, 38], as well as to provide information along the path [12].

For the purpose of this study, the book Sob os Mares de Cabo Verde - Diving Into Adventure and an Underwater Species Identification Guide were published. Additionally, four Underwater Diving Routes were proposed for popular scuba diving sites off Santa Maria Bay (Sal Island, Cape Verde): “Kwarcit” and “Sargo”, the artificial reefs off Santa Maria Bay and two natural reefs within the area, “3 Grutas” and “Tchuklassa”.

A growing number of publications in recent years have highlighted many issues and concerns relevant to scuba diving tourism but little research has included the scuba diving industry, host communities or efforts towards sustainability [39]. Scuba diving tourism is an economically important industry as evidenced by the increasing number of other locations promoting their marine resources in efforts to become scuba diving destinations and Cape Verde aspires to follow popular, ‘must dive’ places widely promoted in social and other media such as Koh Tao in Thailand, Layang Layang and Sipadan in Malaysia, and the Great Barrier Reef, Australia and Sharm El Sheikh - Red Sea, Egypt, among others [25, 40, 41]. In this study, a survey was carried out to provide some preliminary data for Sal Island, Cape Verde, on the socio-economic profile of divers, their perceptions about the environmental awareness of the local area and potential uses of the produced tools for environmental awareness.

In order to ensure the sustainability of scuba diving tourism in the future, it is imperative to consider certain factors: the issues which may improve the dive experience; the industry’s search for commercial profit out of the same experiences; the local community’s needs and priorities; the overall necessity to preserve and protect the marine environments in which such activities take place. The conciliation of all these different, complex and at times contradictory goals presents a challenge to the several stakeholders who utilise, manage and value the marine environments in question [62-64].

Preferences for marine biodiversity may vary according to different cultural backgrounds [65]. However, a higher value is attributed to visiting a place where there is a strong conservation culture. The origin of the diving tourists may vary according to the destination, but certain patterns can be found, especially regarding tropical destinations [66-68], perhaps due to the pristine waters and higher biodiversity of marine species [69]. The need for a reinforced ecological management of the coastal areas where diving is practiced [8, 14, 15, 70] should include measures to maintain ecosystem equilibrium and increase visitors’ environmental awareness [71].

Several authors highlighted the importance of socio-demographic studies for defining diver motivations and perceptions towards several aspects of the activity and better address environmental awareness and education programs [16, 70, 72, 73].

Most of the surveyed divers were Portuguese, probably due to the fact that Portuguese tourists are among the four main nationalities visiting the Islands [1] and, as perceived by the authors, being a Portuguese owned diving center tends to attract more Portuguese divers.

As observed in most other diver surveys [32, 33, 72, 74-78] male divers are the majority, most have a college degree, and professional and technical occupations such doctors, teachers, and engineers. In fact, it was observed that diving is mostly practiced by individuals with a high level of formal education [8]. Similar results have been observed in other surveys [75, 79]. Nevertheless, more than half of respondents claim that diving has low or no impact in the marine ecosystems and only 41% are aware of the vulnerability of the marine ecossistem.

With almost half of the diver population with ages above 41 years and 77% hosted in four or more stars hotels, it is clear that diving is mostly practiced by people who are economically well off, as suggested by Musa et al. [80].

The vast majority of the interviewed divers were inexperienced, with less than 50 dives and many of them were experiencing diving as part of a holiday or once-only activity [81]. Similar results were obtained by Rangel [32] for south Portuguese coast divers. Given that more experienced divers (measured in number of dives) caused less impact on the system [16], divers’ profiling should be evaluated and adjusted prior to the educational programs.

Understand if teaching environmental education can, in fact, influence the way people behave in practice is fundamental [82]. Addressing environmental problems by placing youngsters in natural, undisturbed places can act as a powerful environmental education tool [82], and the marine environment can be used as an “outdoor laboratory”, where the diving operator provides in situ biological and ecological information to visitors [83].

The sustainability of scuba dive tourism requires not only the conservative use of natural and social resources, but also economic viability of all stakeholders, community integration and the provision of satisfying diving experiences [84]. Sal Island, having multiple artificial and natural reefs contributing to conservation and socio-economic purposes [85], seems to be in the right path to achieve a good position among the world's leading scuba diving hotspots. In fact, 95% of the respondents would recommend a dive trip to Sal Island to friends and family, indicating a high level of diving satisfaction.

When it comes to the interaction between diving and social and environmental issues, Sal Island’s case does not differ much from those of Belize in the Caribbean [86], Mozambique, in East Africa [87] and Palau, in the Pacific [68, 88] since in all cases fishing and agriculture coexist with scuba diving tourism. However, given the predominance of the dive tourism industry in Sal Island over other industries, both land and marine-based, which is not discernible in the previously referred cases, there has been an increasingly high competition between several tourism operating businesses, resulting in irresponsible management practices (M. T. Oliveira, pers. Observ.). Hence the suggestion by the present study of a new paradigm for the management of Sal Island as a reef-based dive tourism destination, one that integrates the concepts of Sustainable Tourism Development (STD) - important for the establishment of development guidelines - and Integrated Coastal Management (ICM) - essential for the practice of a sustainable management effort [89, 90]. These conceptual frameworks draw inspiration from the principles present in Agenda 21, devised at the Rio Earth Summit in 1992 [91] and are meant to represent a new step towards the solution for increasing constraints in coastal zones and offer a better answer to the growing pressures from tourism development [92-96]. The implementation of STD and ICM approaches opens the way for a more integrated management framework for Sal Island’s dive tourism, one which can be practised with the contemplation of multiple domains, such as scientific management integration, spatial integration and stakeholder integration. These key factors of ‘integration’ in the management of dive tourism must not be separately considered, but rather taken as overlapping and interacting with one another (Fig. 9). Leadership can prove vital in helping the host community engage in a series of adaptive management opportunities, besides encouraging participation and inclusion, thus benefiting the diving industry. The Leadership class should also address and foment some main factors of development, needed for a healthy management of the sector:

1. The complementarity of natural and social sciences, which would monitor the impact of the activity on both the natural resources explored and the local host community, as well as the relation between these two;
2. The development of a community-oriented tourism;
3. Voluntary management which, if coordinated with education and good governance, can ensure a long-term viability of the dive tourism industry [84].

Fig. (9). Illustrative diagram for the management of scuba dive tourism. Adapted from Pearce [97] and Wongthong & Harvey [84].

The vast majority of our surveyed divers claim that the Species ID field guide and the Diving routes guide had contributed to improving their diving experience and provided a better understanding of marine biodiversity of the dive site and would recommend them to their friends and family. The same was observed for the dive briefing, where 87% strongly agreed that this is a powerful tool to improve environmental awareness. Barker & Roberts [30] and Camp & Fraser [98] advocated on-board “environmental briefings”, provided immediately before diving, thereby ensuring a pleasant and safe experience, while simultaneously effectively promoting an increase in environmental awareness. These pre-diving briefings are highly effective at reducing divers’ contact with the surroundings, since they emphasize the importance of buoyancy control and careful action, important educational tools, resulting in an increase in environmental awareness and, thus, reduction of diver damage [16, 17, 28, 29, 99].

Marine environmental sustainability is a critical global issue which, nonetheless, has the potential to be a strategic business opportunity for host communities and the scuba diving tourism industry that seeks to attract tourists to a destination.

In this study, Sal Island’s divers can be classified as promoters of the diving sites visited and related products, as they seemed to enjoy their experience with the environmental tools designed for them, namely the Species ID field guide, Diving routes guide and the Environmental diving briefing. Moreover, these tools appear to have increased the diver’s environmental awareness and were considered an effective way to increase environmental education and knowledge, but also to improve divers experience within the dive site.

This study was a 1^st approach to better understand the diving industry in Cape Verde. A theoretical approach that incorporates human and social dimensions into the management of the said industry in Sal, through the implementation of ICM and STD in a more integrative way is proposed. Nonetheless, future research is needed to better understand this industry in a more holistic manner, identifying the concerns of each separate stakeholder, as well as the interactions between them, improving the management and planning processes currently in practice, reviewing present issues and elaborating solutions. All this is of core importance in allowing the decision-making processes to modify and adapt management models and principles, such as ICM and STD, to best serve the local conditions, thus attaining a more efficient and sustainable management of the dive tourism industry off Sal Island.