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This paper explores the suitability of community-based conservation measures to complement a proposed command-and-control approach for two multi-user bays with spinner dolphins in Hawai`i, USA, which have considerable dolphin watching tourist activities and human–dolphin interactions. The paper uses Ostrom's common-pool resource theory as an analytical lens, with an assessment of the attributes of the resource and the user(s) to explore questions of governance and sustainability. In Hawai`i, spinner dolphins move predictably from offshore overnight feeding grounds into shallow bays for daytime rest, interacting frequently with humans using these bays for tourism and other social, recreational, and subsistence purposes. To reduce the current negative interactions with dolphins, managers are seeking to implement a command-and-control approach, namely time–area closures. Our analysis indicates that viewing the bay as a resource with tourism as one of many human demands, instead of specifically focusing on dolphins, reflects an ecosystem-based approach and acknowledges complex management demands. We found that while unrealistic to expect community-based conservation to spontaneously emerge here, cultivating some of Ostrom's attributes among stakeholders might lead to a more productive set of institutional arrangements that would benefit the dolphin population, with the methodology used potentially leading to a global management model. [ABSTRACT FROM PUBLISHER]

Reliable population estimates are critical to implement effective management strategies. The Hawai’i Island spinner dolphin (Stenella longirostris) is a genetically distinct stock that displays a rigid daily behavioural pattern, foraging offshore at night and resting in sheltered bays during the day. Consequently, they are exposed to frequent human interactions and disturbance. We estimated population parameters of this spinner dolphin stock using a systematic sampling design and capture–recapture models. From September 2010 to August 2011, boat-based photo-identification surveys were undertaken monthly over 132 days (>1,150 hours of effort; >100,000 dorsal fin images) in the four main resting bays along the Kona Coast, Hawai’i Island. All images were graded according to photographic quality and distinctiveness. Over 32,000 images were included in the analyses, from which 607 distinctive individuals were catalogued and 214 were highly distinctive. Two independent estimates of the proportion of highly distinctive individuals in the population were not significantly different (p = 0.68). Individual heterogeneity and time variation in capture probabilities were strongly indicated for these data; therefore capture–recapture models allowing for these variations were used. The estimated annual apparent survival rate (product of true survival and permanent emigration) was 0.97 SE±0.05. Open and closed capture–recapture models for the highly distinctive individuals photographed at least once each month produced similar abundance estimates. An estimate of 221±4.3 SE highly distinctive spinner dolphins, resulted in a total abundance of 631±60.1 SE, (95% CI 524–761) spinner dolphins in the Hawai’i Island stock, which is lower than previous estimates. When this abundance estimate is considered alongside the rigid daily behavioural pattern, genetic distinctiveness, and the ease of human access to spinner dolphins in their preferred resting habitats, this Hawai’i Island stock is likely more vulnerable to negative impacts from human disturbance than previously believed. [ABSTRACT FROM AUTHOR]