1 SC/62/WW3 Research consistent with the IWC Large-scale Whale- watch Experiment (LaWE): assessing effects of human activity on spinner dolphins in resting bays in Hawai‘i and the effectiveness of time-area closures as a proposed mitigation tool JULIAN A. TYNE 1 , LARS BEJDER 1 , DAVID W. JOHNSTON 2 AND DAVID LUSSEAU 3 1 Centre for Fish and Fisheries Research, Cetacean Research Unit, School of Biological Sciences and Biotechnology, Murdoch University, South Street, Murdoch, WA 6150 Australia 2 Division of Marine Science and Conservation, Duke University, North Carolina 3 University of Aberdeen, Institute of Biological and Environmental sciences, Tillydrone Avenue, Aberdeen AB24 2TZ, U.K. Corresponding author: j.tyne@murdoch.edu.au ABSTRACT Due to growing concerns about the potential negative impacts of nature-based tourism on Hawaiian spinner dolphins, the U.S. National Oceanic and Atmospheric Administration (NOAA) is developing management plans to reduce the exposure of resting spinner dolphins to human activity in Hawaiian waters. One potential management approach under consideration by NOAA focuses on time-area closures to reduce the number and intensity of interactions between humans and dolphins during critical rest periods in particular bays. To investigate the efficacy of this approach, significant research is required to assess how spinner dolphins respond to time-area closures. The conceptual framework for this study follows a Before-After-Control-Impact (BACI) design where the local abundance, distribution and behaviour of spinner dolphins in five resting bays will be assessed before and after the implementation of time-area closures. Specifically, time-area closures will be introduced in four dolphin resting bays (each with varying levels of human activity) while the fifth bay (control) will remain open. At present, the timing of closures has not been determined, but these would not be implemented until a full year of pre-closure data collection has been completed. The data will be collected during field seasons lasting six months per year over three-four years. We highlight this study as a possible candidate project for inclusion in the IWC Large-scale Whale-watch Experiment (LaWE) initiative as it incorporates many facets that the LaWE initiative strives to achieve. INTRODUCTION At present, it is unclear how human interactions may affect Hawaiian spinner dolphins (Stenella longirostris). Emergent research is showing that cetacean-based tourism has the potential to cause biologically significant impacts on targeted dolphin communities (Bejder et al. 2006, Lusseau et al. 2006a, Lusseau et al. 2006b). In Hawai‘i, the dolphin-based tourism industry has grown rapidly in recent years (Hu et al. 2009). Recent studies (Danil et al. 2005, Courbis 2007, Delfour 2007, Courbis & Timmel 2009) suggest that resting periods for spinner dolphins in Hawai‘i may be interrupted or truncated by exposure to human activity; although, no conclusions regarding possible population-level effects could be made. Limited quantitative data are currently available to assess potentially biological significant impacts of tourism activities on targeted animals in Hawai‘i. Hawaiian spinner dolphins have predictable, daily movement patterns of foraging offshore at night and returning to inshore sheltered bays to rest during the day (Norris et al 1994; Courbis and Timmel 2009). This consistent movement pattern may render them particularly vulnerable to disturbance because of their reliance on a limited area of sheltered waters to rest, socialise and avoid predators. Considering that the impacts of tourism on dolphins have been documented in locations of substantially less tourism pressure, it seems likely that similar impacts are occurring in Hawai‘i. Specific concerns in regards to human-spinner dolphin interactions include: changes to dolphin behavioural budgets, energetic deficits, reduced vigilance for predators, truncated rest periods, alteration of social interactions with conspecifics, inadequate recovery from day-time disturbances with a concomitant reduction in nocturnal foraging efficiency and displacement of dolphins from prime habitat to less optimal habitat with a concomitant increase in predation risk.