**5. Discussion**

The theoretical implication of this study lies in presenting a comprehensive understanding of factors influencing an SDI. More specifically, the model uses destination primary and secondary images, motivations, cultural background of tourists, and sociodemographic characteristics to explain the perception of SDI. Those variables are crucial in fully understanding the perception of SDI. This means that destination marketing organizations should adjust their strategies to di fferent market segments, attending to the mentioned variables. As far as we are aware, no other researchers have investigated this relationship prior to us.

The more intense the previous experience (primary image) in the destination, the more likely are travelers to have an SDI. This study further suggests that a key determinant of SDI is a destination secondary image. Thus, destination marketing organizations should consider these findings when designing their marketing strategies. The secondary image of a destination could be a ffected by destinations and the companies operating in the sector through various sources of information such as magazines, tour operators, travel agencies, social media, and so on [80]. DMOs must be able to design strategies in which an image of a sustainable destination is projected since, according to the results of our study, the information that the tourist receives through these sources will influence their perception of a sustainable destination and, consequently, their decision of whether to visit the destination. Those results are in line with the study of Lian and Yu (2019) [81], who highlighted the influence of online information sources in the decision to travel.

Furthermore, the results sugges<sup>t</sup> that three motivational factors ("Fashion, Fun, and Friends", "Sun, Beach, Relax, and Family", and "Sports and Nature") are statistically significant for SDI. Whilst we had hypothesized that a traveler's motivation to know new and di fferent places and to escape from the daily routine would have a positive e ffect on the SDI, our findings have revealed that this is not supported. Therefore, destination marketing organizations should project the SDI according to tourists' motivations [33,82]. Thus, the content used to promote the SDI should be adapted to match tourism motivations. In this way, the possible congruence that exists between the message and the specific motivations of the target market could determine better results [45]. Either way, developing a professional social command centre in charge of managing the social content of the destination seems to be an interesting strategy to foster SDI.

Our findings also sugges<sup>t</sup> that the cultural background of a tourist is an important factor determining SDI. More specifically, our findings reveal that national culture influences the way tourists from di fferent countries interpret sustainability and its fundamental role on the sustainability image of tourism destination formation [30]. This sheds lights on the usefulness of using the nationality as a segmentation criterion, helping marketers to tier customers. DMOs should pay special attention to the markets of The Netherlands, Austria, and Luxembourg, since they are those that have a lower probability of perceiving the destination as sustainable. In markets such as Russia, Spain, Portugal, and Italy, e fforts must be aimed at maintaining or even improving the SDI. This is in accordance with the Almeida-Santana et al. (2018) [45] study, which suggests nationality as being a relevant factor when seeking to comprehensively understand the behavior of travelers when choosing their holiday destination.

Furthermore, the results also determined that age and level of studies determine SDI. The results show, in line with Baloglu and McCleary (1999) [31] and Calantone et al. (1989) [65], that the older a person is, the more likely they are to perceive SDI. The negative relationship between the mean study levels expressed by the tourists and SDI is demonstrated. Destination marketing organizations should consider those results in order to better design their marketing strategies. Younger tourists have a lower perception of a sustainable destination, so marketing campaigns aimed at this younger segmen<sup>t</sup> should place greater emphasis on the projection of a sustainable destination image. The same approach could be applied to the segmen<sup>t</sup> with a high level of studies.

Finally, some limitations of this research are given. This study considers SDI only in respect to the Canary Islands. However, it could be applied to other destinations. SDI could also be further analyzed, with introduction to the model of other factors influencing SDI.
