Network analysis has recently been used to delve into the dynamics of cetacean sociality. Few studies, however, have addressed how habitat shape influences sociality, specifically how linear water bodies constrain the space where individuals might interact. We utilized network and spatiotemporal analyses to investigate association patterns and community structure in a bottlenose dolphin population in a linear estuarine system, the Indian River Lagoon (IRL), Florida. Using sighting histories from a multiyear photo-identification study we examined association patterns for 185 individuals collected over a 6.5 yr period (2002)(2003)(2004)(2005)(2006)(2007)(2008). The population was highly differentiated (S = 0.723) and organized into six distinct social communities (Q = 0.544), spread in an overlapping pattern along the linear system. Social organization differed between communities, with some displaying highly interconnected networks and others comprising loosely affiliated individuals with more ephemeral associations. Temporal patterns indicated short-term associations were a significant feature of the fission-fusion dynamics of this population. Spatial analyses revealed that social structure was shaped by an individual's ranging patterns and by social processes including preference and avoidance behavior. Finally, we found that habitat "narrowness" may be a major driving force behind the sociality observed.

Bottlenose dolphins (Tursiops truncatus) in northern New Zealand range widely and their coastal distribution increases their risk of exposure to a variety of threats. Marine protected areas (MPAs) are increasingly used to protect species but there is a paucity of studies examining their efficacy. In the Bay of Islands, New Zealand (35°14'S, 174°06'E), dolphin distribution and habitat use patterns were examined between two time periods: 1996–2000 and 2007–2010. In addition, dolphin use of tourism exclusion zones designed to protect the dolphins were assessed. Spatial distribution was analysed using kernel densities and Mantel tests. Broad‐scale distribution patterns remained constant between the two periods but fine‐scale dolphin distribution patterns shifted considerably. The exclusion zones that were established based on results from the 1996–2000 study were rarely used in 2007–2010, and therefore no longer provided dolphins protection from tourism. This research demonstrates the plasticity in dolphin habitat use patterns through time and the importance of re‐evaluating the efficacy of static protected areas, especially for wide‐ranging species. Copyright © 2014 John Wiley & Sons, Ltd.

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Background While cetaceans have been extensively studied around the world, nocturnal movements and habitat use have been largely unaddressed for most populations. We used satellite telemetry to examine the nocturnal movements and habitat use of four bottlenose dolphins (Tursiops truncatus) from a well-studied population in a complex estuary along the east coast of Florida. This also enabled us to explore the utility of satellite tracking on an apex predator within a very narrow and convoluted ecosystem. Our objectives were to evaluate (1) nocturnal home ranges and how individual dolphins moved within them, (2) nocturnal utilization of habitats surrounding ocean inlets, (3) nocturnal movements outside of the population’s known range (i.e., the study area), and (4) nocturnal use of select environmental variables. Results Satellite tags were active between 129 and 140 days (136 ± 4.99) during nocturnal hours (summer/fall 2012), yielding 3.3 ± 1.4 high-quality transmissions per night. Results indicated substantial individual variation among the four tagged dolphins, with home ranges varying in length from 53.9 to 83.6 km (x̅ = 71.9 ± 12.9). Binomial tests and MaxEnt models revealed some dolphins preferred habitats surrounding inlets, seagrass habitats, and various water depths, while other dolphins avoided these areas. All dolphins, however, showed substantial movement (x̅ = 5.8 ± 7.4 km) outside of the study area, including travel into rivers/canals and the adjoining ocean (6.0–8.6% and 0.8–2.9% of locations per dolphin, respectively). Conclusions This study was the first to utilize satellite telemetry on Indian River Lagoon dolphins and provided the first detailed insights into the nocturnal movements and habitat use of this population. Our findings suggest that while individual dolphin home ranges may overlap, they use different foraging strategies, feed on different prey, and/or exhibit intraspecific resource partitioning. In contrast with a prior study, all tagged dolphins showed considerable movement into the adjoining ocean and freshwater sources. This suggests this population has a much larger range than previously thought, which is important to consider for future research and conservation efforts.