Compliance is a key feature for the management of non-consumptive wildlife viewing, as it can link management measures to performance and aid in developing recommendations that promote sustainable practices. Whale watching is a prominent wildlife viewing industry that is steadily rising in demand around the world. Managing vessel-cetacean encounters and operator behaviour (both commercial and recreational) is key to limiting impacts on cetaceans, yet the scale of regulatory compliance is often poor or unknown. Although efforts exist to regulate whale watching, challenges arise for the assessment of compliance in marine environments, as they are inherently spatially vast, lack physical boundaries, and can involve mobile stressors (i.e. vessels) and species. Chapter 1 reviews the shift in paradigms from consumptive to non-consumptive activities and highlights challenges for those tasked with managing the growing wildlife tourism industry, and in particular, whale watching. After reviewing a suite of measures prevalent around the world, this chapter then focuses on the Salish Sea’s approach to managing whale watching. This area epitomizes a major whale watching hub and displays complex, multi-jurisdictional and constantly evolving measures. Due to a lack of knowledge in this region, Chapter 2 shifts from theory to practice and assesses regulatory compliance with marine mammal distance regulations from 2018 to 2019 in the Salish Sea. Although compliance was nearly 80%, key drivers including vessel and species type were found to significantly influence non-compliance. Recreational vessels were non-compliant 41.9% of the time and 74.2% of non-compliant encounters occurred around killer whales across both years. The findings of the study demonstrate that case-specific investigation of compliance is necessary as each region is unique in its approach to management. Lastly, recommendations are proposed that can benefit marine managers and policymakers to enhance the performance of measures and subsequently minimize risk to cetaceans. / Graduate