Background noise can interfere with the detection and discrimination of crucial signals among members of a species. Here we investigate the vocal behaviour in the presence and absence of whale-watcher boat traffic of three social groups (pods) of killer whales (Orcinus orca) living in the nearshore waters of Washington state. We find longer call durations in the presence of boats for all three pods, but only in recent recordings made following a period of increasing boat traffic. This result indicates that these whales adjust their behaviour to compensate for anthropogenic noise once it reaches a threshold level.

Multitarget tracking (MTT) refers to the problem of jointly estimating the number of targets and their states or trajectories from noisy sensor measurements. MTT has a long history spanning over 50 years, with a plethora of applications in many fields of study. While numerous techniques have been developed, the three most widely used approaches to MTT are the joint probabilistic data association filter (JPDAF), multiple hypothesis tracking (MHT), and random finite set (RFS). The JPDAF and MHT have been widely used for more than two decades, while the RFS‐based MTT algorithms have received a great deal of attention during the last decade. In this article, we provide an overview of MTT and succinct summaries of popular state‐of‐the‐art MTT algorithms.

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A diverse range of marine wildlife species respond to dynamic environments and patchy resources with variations in their distribution pattern. For many cetacean species, highly structured social systems add to the complexity of modeling distribution patterns and understanding the effects on population viability. Southern resident killer whales Orcinus orca are comprised of 3 distinct, yet cohesive, matrilineally related social groups called pods, and recent population declines have prompted conservation actions in the US and Canada, including listings as an endangered species. Habitat protection is a major component of each listing, yet little is known about pod-specific core areas or patterns of space use for this population. Using 6 yr of sighting information within the inshore waters of Washington and British Columbia, we modeled pod-specific summer distribution and measured relative variation in the density of sightings on a uniform spatial grid. Our results indicate that the pods exhibit complex, non-uniform summer space-use patterns. Although some regions are used in common by all pods, some areas are used almost exclusively by individual pods or certain combinations of pods, indicating specialization to particular areas. Our results indicate that pod groups display variable patterns of space use; therefore, each pod may experience unique habitat conditions or exposure to potential risk factors. This result is highly relevant when considering podspecific mortality rates and the relative contribution of each pod to overall population trends. Our analyses highlight important areas of conservation, and provide the necessary description for podfocused conservation initiatives.

They are most abundant in nearshore temperate waters but also occur, at lower densities, in tropical, subtropical, and offshore waters (Mead & Brownell 2005, Ford 2014). Eastern North Pacific stocks of killer whales tend to be highly social animals that occur primarily in stable matriarchal social groups or pods that range in size from 2 to dozens of animals (Bigg et al. 1990, Parsons et al. 2009). Temporary groups as large as several hundred individuals, called superpods, form occasionally (Bigg et al. 1990, Parsons et al. 2009, Ford 2014). In the Northeast Pacific, 3 distinct ecotypes of killer whales are recognized: resident, tran