California sea lion (Zalophus californianus) and Steller sea lion (Eumetopias jubatus) interactions with vessels in Pacific Rim National Park Reserve: Implications for marine mammal viewing management (British Columbia)

Sea lion viewing is an integral component of whale watching trips in the Broken Group Islands (BGI), Pacific Rim National Park Reserve (PRNPR). Pinniped viewing has become a management concern in PRNPR and viewing guidelines have been created to prevent potential disturbance by vessels. Effective management of sea lion viewing requires understanding how sea lions react to vessels and subsequently mitigating aspects of vessel activity that cause disturbance. The objective of this study was to evaluate the effectiveness of the Park's Pinniped Viewing Guidelines (PVG) in preventing sea lion disturbance. This was done by determining the kind and level of behavioural response California and Steller sea lions had to vessel activity in comparison to behaviours exhibited in the absence of vessels. Vessel approaches were controlled for predetermined measures of distance, speed, vessel types and numbers. Analysis included comparing behavioural responses during vessel interactions with behavioural states during scans. Significant change in behaviour was tested for each category of distance, speed, vessel type and number. A total of 160 scan and interaction pairs were sampled during 38 days over two seasons. Thirty-nine (24%) of vessel interactions resulted in disturbance. Variance in behaviours was significant for vessel approaches within 0-25 m (n=79; 38%); vessels approaching 'fast' (n=17; 47%); for motorized vessels under 5 tons (n=107; 30%), and for both 1-vessel (n=113; 23%) and 2-vessel (n=18; 39%) interactions. The results of this research demonstrate that PRNPR's PVG are effective in minimizing sea lion disturbance in the BGI when vessel operators follow the prescribed approach distance and speed guidelines. Recommendations regarding viewing by various vessel types and numbers are given, as well as suggestions for increasing understanding of sea lion behaviour.