There is growing interest in tourism programmes that involve tourists in biodiversity observation and monitoring to support conservation programmes. The largest single specialist sector at present is probably bird-watching. In marine-based wildlife tourism, scuba-diving represents an important specialist sector. The specialist sector which appears to show the highest revenue potential is sport hunting, where very large licence fees can be charged under some circumstances. It must also be recognized that these fees and taxes can also be used as measures to regulate the level of access to concerned sites and biological resources. In addition, the prospect of their continued revenue generation provides a direct incentive for the maintenance of the populations or ecosystems. One potential negative aspect of specialist tourism, however, can be the relatively low level of local community involvement since relatively few local people will be involved as specialist guides or park managers.