Whale-watching is a global tourism industry whose annual revenue exceeds two billion dollars. Australia is a key player in this industry, especially on the east and west coast where humpback whales migrate each year between their breeding and feeding grounds. However, the global whale-watching industry faces uncertainty from changing whale migration patterns, with whales progressively ‘arriving’ at the traditional whale-watching areas earlier than in previous years/decades. If the whale-watching industry cannot evolve with these changing dynamics then the arrival of the whales might be missed resulting in a potential loss of revenue. This social-ecological issue has suddenly been exacerbated by the disruption to tourism caused by the global pandemic COVID-19. In this study, we use a systems modelling framework, which combines qualitative and quantitative processes, to evaluate the social-ecological system behaviour of the whale-watching industry. We apply this systems approach to the Gold Coast, one of Australia's premier tourist destinations and home to a vibrant whale-watching industry. The outcome of this systems assessment is that the efficacy of the whale-watching industry is affected through determinants of both supply (ability to respond to changes in whale behaviour) and demand (attractiveness of whale-watching). Furthermore, the recovery time of all tourism after COVID-19 will take years if not decades.