not have had the same opportunity as more established divers to visit the site.
Hence, visits per year of diving experience allows for the effects of differing opportunities to dive to be taken into account while allowing a longer time period also to be included in the analysis.
Travel costs included the cost of the dive package, transport costs to the dive site from the diver's home (i.e. includes international travel costs where relevant), accommodation and other related expenditure.
As different packages included different numbers of dives, the cost was normalised to an average cost per dive. As expected, the frequency of trips per year of experience decreases with the estimated travel costs (Fig. 1). Information on the importance of the dive to the overall visit was also included, and this was used to further scale the travel cost [20]. Diver income information was