Publications by authors named "Ari S Friedlaender"

The field of marine mammal conservation has dramatically benefited from the rapid advancement of methods to assess the reproductive physiology of individuals and populations from steroid hormones isolated from minimally invasive skin-blubber biopsy samples. Historically, this vital information was only available from complete anatomical and physiological investigations of samples collected during commercial or indigenous whaling. Humpback whales () are a migratory, cosmopolitan species that reproduce in warm, low-latitude breeding grounds.

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Studying sound production at different developmental stages can provide insight into the processes involved in vocal ontogeny. Humpback whales (Megaptera novaeangliae) are a known vocal learning species, but their vocal development is poorly understood. While studies of humpback whale calves in the early stages of their lives on the breeding grounds and migration routes exist, little is known about the behavior of these immature, dependent animals by the time they reach the feeding grounds.

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Southern hemisphere blue () and fin () whales are the largest predators in the Southern Ocean, with similarities in morphology and distribution. Yet, understanding of their life history and foraging is limited due to current low abundances and limited ecological data. To address these gaps, historic Antarctic blue ( = 5) and fin ( = 5) whale baleen plates, collected in 1947-1948 and recently rediscovered in the Smithsonian National Museum of Natural History, were analyzed for bulk (δC and δN) stable isotopes.

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Southern hemisphere humpback whale (Megaptera novaeangliae, SHHW) breeding populations follow a high-fidelity Antarctic krill (Euphausia superba) diet while feeding in distinct sectors of the Southern Ocean. Their capital breeding life history requires predictable ecosystem productivity to fuel migration and migration-related behaviours. It is therefore postulated that populations feeding in areas subject to the strongest climate change impacts are more likely to show the first signs of a departure from a high-fidelity krill diet.

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Article Synopsis
  • - The study investigates stable isotope analysis (SIA) of humpback whale biopsies to explore differences in isotope ratios, focusing on how demographic factors like pregnancy and biopsy location affect the results.
  • - Results show significant variability in carbon isotope ratios (δC) within the same whale, while nitrogen isotope ratios (δN) remained more consistent; pregnancy status notably reduced both δC and δN levels in females.
  • - The findings suggest that both internal (like pregnancy) and external factors can influence isotopic signatures, highlighting the importance of considering individual variability in ecological research.
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Acoustic recording tags provide fine-scale data linking acoustic signalling with individual behaviour; however, when an animal is in a group, it is challenging to tease apart calls of conspecifics and identify which individuals produce each call. This, in turn, prohibits a robust assessment of individual acoustic behaviour including call rates and silent periods, call bout production within and between individuals, and caller location. To overcome this challenge, we simultaneously instrumented small groups of humpback whales on a western North Atlantic feeding ground with sound and movement recording tags.

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Suction-cup-attached biologging tags have led to major advances in our understanding of large whale behaviour. Getting close enough to a whale at sea to safely attach a tag is a major limiting factor when deploying these systems. Here we present an uncrewed aerial system (UAS)-based tagging technique for free-swimming large whales and provide data on efficacy from field testing on blue () and fin () whales.

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The krill surplus hypothesis of unlimited prey resources available for Antarctic predators due to commercial whaling in the 20th century has remained largely untested since the 1970s. Rapid warming of the Western Antarctic Peninsula (WAP) over the past 50 years has resulted in decreased seasonal ice cover and a reduction of krill. The latter is being exacerbated by a commercial krill fishery in the region.

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Article Synopsis
  • Lunge feeding is a unique, energetically demanding feeding mechanism found in rorqual whales, requiring precise movements and timing during foraging.
  • The study utilized multi-sensor tags and UAS footage to analyze how body size affects lunge feeding characteristics, such as speed and deceleration, for various whale species.
  • Results indicated that despite the expected lower foraging efficiency at higher speeds, maximum foraging speeds remained consistently high across different body sizes, revealing a positive correlation between body size and foraging efficiency.
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Empirical metabolic rate and oxygen consumption estimates for free-ranging whales have been limited to counting respiratory events at the surface. Because these observations were limited and generally viewed from afar, variability in respiratory properties was unknown and oxygen consumption estimates assumed constant breath-to-breath tidal volume and oxygen uptake. However, evidence suggests that cetaceans in human care vary tidal volume and breathing frequency to meet aerobic demand, which would significantly impact energetic estimates if the findings held in free-ranging species.

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Article Synopsis
  • Whales, despite being massive, are active predators that need to be agile to capture smaller prey, leading to the development of unique movement strategies that require significant energy and mechanical power.
  • Research on seven baleen whale species shows that as whale size increases, their maneuvering performance, such as acceleration and agility, decreases, meaning larger whales are generally less agile than smaller ones.
  • However, larger whales adapt their behaviors to cope with their size, employing maneuvers that enhance their capability, indicating that they have evolved specific physical traits to optimize their movement despite their bulk.
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Sex-specific phenotypic differences are widespread throughout the animal kingdom. Reproductive advantages provided by trait differences come at a cost. Here, we link sex-specific foraging strategies to trade-offs between foraging reward and mortality risk in sexually dimorphic northern elephant seals ().

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Nursing influences growth rate and overall health of mammals; however, the behavior is difficult to study in wild cetaceans because it occurs below the surface and can thus be misidentified from surface observations. Nursing has been observed in humpback whales on the breeding and calving grounds, but the behavior remains unstudied on the feeding grounds. We instrumented three dependent calves (four total deployments) with combined video and 3D-accelerometer data loggers (CATS) on two United States feeding grounds to document nursing events.

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The scale dependence of locomotor factors has long been studied in comparative biomechanics, but remains poorly understood for animals at the upper extremes of body size. Rorqual baleen whales include the largest animals, but we lack basic kinematic data about their movements and behavior below the ocean surface. Here, we combined morphometrics from aerial drone photogrammetry, whale-borne inertial sensing tag data and hydrodynamic modeling to study the locomotion of five rorqual species.

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The distributions of migratory species in the ocean span local, national and international jurisdictions. Across these ecologically interconnected regions, migratory marine species interact with anthropogenic stressors throughout their lives. Migratory connectivity, the geographical linking of individuals and populations throughout their migratory cycles, influences how spatial and temporal dynamics of stressors affect migratory animals and scale up to influence population abundance, distribution and species persistence.

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Climate-induced range overlap can result in novel interactions between similar species and potentially lead to competitive exclusion. The West Antarctic Peninsula (WAP) is one of the most rapidly warming regions on Earth and is experiencing a poleward climate migration from a polar to subpolar environment. This has resulted in a range expansion of the ice-intolerant gentoo penguins () and a coincident decrease in ice-obligate Adélie penguins () near Palmer Station, Anvers Island, WAP.

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Background: Matching animal movement with the behaviors that shape life history requires a rigorous connection between the observed patterns of space use and inferred behavioral states. As animal-borne dataloggers capture a greater diversity and frequency of three dimensional movements, we can increase the complexity of movement models describing animal behavior. One challenge in combining data streams is the different spatial and temporal frequency of observations.

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