Seasonal activity levels of a farm-island population of striated caracaras (Phalcoboenus australis) in the Falkland Islands

Harrington KJ, Fahlbusch JA, Langrock R, Therrien J-F, Houtz JL, McDonald BI. Seasonal activity levels of a farm-island population of striated caracaras (Phalcoboenus australis) in the Falkland Islands. Animal Biotelemetry. 2020;8(1): 27

From individual responses to population effects : integrating a decade of multidisciplinary research on blue whales and sonar

Funding: Office of Naval Research (GrantNumber(s): N00014-19-1-2464).As ecosystems transform under climate change and expanding human activities, multidisciplinary integration of empirical research, conceptual frameworks and modelling methods is required to predict, monitor and manage the cascading effects on wildlife populations. For example, exposure to anthropogenic noise can lead to changes in the behaviour and physiology of individual marine mammals, but management is complicated by uncertainties on the long-term effects at a population level. We build on a decade of diverse efforts to demonstrate the strengths of integrating research on multiple stressors for assessing population-level effects. Using the case study of blue whales exposed to military sonar in the eastern north Pacific, we model how behavioural responses and environmental effects induced by climate change affect female survival and reproductive success. Environmental changes were predicted to severely affect vital rates, while the current regime of sonar activities was not. Simulated disturbance had a stronger effect on reproductive success than adult survival, as predicted by life-history theory. We show that information on prey resources is critical for robust predictions, as are data on baseline behavioural patterns, energy budgets, body condition and contextual responses to noise. These results will support effective management of the interactions between sonar operations and blue whales in the study area, while providing pragmatic guidance for future data collection to reduce key uncertainties. Our study provides important lessons for the successful integration of multidisciplinary research to inform the assessment of the effects of noise and other anthropogenic stressors on marine predator populations in the context of a changing environment.Publisher PDFPeer reviewe

Predator-scale spatial analysis of intra-patch prey distribution reveals the energetic drivers of rorqual whale super-group formation

Animals are distributed relative to the resources they rely upon, often scaling in abundance relative to available resources. Yet, in heterogeneously distributed environments, describing resource availability at relevant spatial scales remains a challenge in ecology, inhibiting understanding of predator distribution and foraging decisions. We investigated the foraging behaviour of two species of rorqual whales within spatially limited and numerically extraordinary super-aggregations in two oceans. We additionally described the lognormal distribution of prey data at species-specific spatial scales that matched the predator's unique lunge-feeding strategy. Here we show that both humpback whales off South Africa's west coast and blue whales off the US west coast perform more lunges per unit time within these aggregations than when foraging individually, and that the biomass within gulp-sized parcels was on average higher and more tightly distributed within super-group-associated prey patches, facilitating greater energy intake per feeding event as well as increased feeding rates. Prey analysis at predator-specific spatial scales revealed a stronger association of super-groups with patches containing relatively high geometric mean biomass and low geometric standard deviations than with arithmetic mean biomass, suggesting that the foraging decisions of rorqual whales may be more influenced by the distribution of high-biomass portions of a patch than total biomass. The hierarchical distribution of prey in spatially restricted, temporally transient, super-group-associated patches demonstrated high biomass and less variable distributions that facilitated what are likely near-minimum intervals between feeding events. Combining increased biomass with increased foraging rates implied that overall intake rates of whales foraging within super-groups were approximately double those of whales foraging in other environments. Locating large, high-quality prey patches via the detection of aggregation hotspots may be an important aspect of rorqual whale foraging, one that may have been suppressed when population sizes were anthropogenically reduced in the 20th century to critical lows.Office of Naval Research, Stanford University, South African Department of the Environment, Forestry and Fisheries National Science Foundation.http://wileyonlinelibrary.com/journal/fec2022-01-25hj2021Zoology and Entomolog

Scaling of maneuvering performance in baleen whales: larger whales outperform expectations

Despite their enormous size, whales make their living as voracious predators. To catch their much smaller, more maneuverable prey, they have developed several unique locomotor strategies that require high energetic input, high mechanical power output and a surprising degree of agility. To better understand how body size affects maneuverability at the largest scale, we used bio-logging data, aerial photogrammetry and a high-throughput approach to quantify the maneuvering performance of seven species of free-swimming baleen whale. We found that as body size increases, absolute maneuvering performance decreases: larger whales use lower accelerations and perform slower pitch-changes, rolls and turns than smaller species. We also found that baleen whales exhibit positive allometry of maneuvering performance: relative to their body size, larger whales use higher accelerations, and perform faster pitch-changes, rolls and certain types of turns than smaller species. However, not all maneuvers were impacted by body size in the same way, and we found that larger whales behaviorally adjust for their decreased agility by using turns that they can perform more effectively. The positive allometry of maneuvering performance suggests that large whales have compensated for their increased body size by evolving more effective control surfaces and by preferentially selecting maneuvers that play to their strengths.We thank the crews of many research vessels including the R/V John Martin, R/V Fluke, ARSV Laurence M. Gould, R/V Sanna, M/V Antonie, M/V Northern Song, the Cascadia Research Collective and the Shallow Marine Surveys Group; in particular, we thank John Douglas, Andrew Bell, Shaun Tomlinson, Steve Cartwright, Tony D'Aoust, Dennis Rogers, Kelly Newton, Heather Riley, Gina Rousa and Mark Rousa. We also thank Brandon L. Southall, Alison K. Stimpert and Stacy L. DeRuiter for their role in collecting data as part of the SOCAL-BRS project. We thank Matt S. Savoca, Julian Dale and Danuta M. Wisniewska for assistance with data collection. Finally, we thank John H. Kennedy, Michael A. Thompson and the NSF Office of Polar Programs.Ye

Context-dependent variability in the predicted daily energetic costs of disturbance for blue whales

Funding: This study was supported by the Office of Naval Research (ONR) [grant number N00014–19-1-2464: “BRS4PCoD:Integrating the results of Behavioral Response Studies intomodels of the Population Consequences of Disturbance”]. J.A.G., D.E.C. and J.A.F. were supported by the National Science Foundation (Division of Integrative Organismal Systems) [grant number 1656691], ONR Young Investigator Program [grant number N000141612477], ONR Defense University Research Instrumentation Program [grant number N000141612546] and Stanford University’s Terman and Bass Fellowships. The SOCAL-BRS project was supported by the US Navy’s Chief of Naval Operations Environmental Readiness Division, the US Navy’s Living Marine Resources Program and the Marine Mammal Program of the Office of Naval Research.Assessing the long-term consequences of sub-lethal anthropogenic disturbance on wildlife populations requires integrating data on fine-scale individual behavior and physiology into spatially and temporally broader, population-level inference. A typical behavioral response to disturbance is the cessation of foraging, which can be translated into a common metric of energetic cost. However, this necessitates detailed empirical information on baseline movements, activity budgets, feeding rates and energy intake, as well as the probability of an individual responding to the disturbance-inducing stressor within different exposure contexts. Here, we integrated data from blue whales (Balaenoptera musculus) experimentally exposed to military active sonar signals with fine-scale measurements of baseline behavior over multiple days or weeks obtained from accelerometry loggers, telemetry tracking and prey sampling. Specifically, we developed daily simulations of movement, feeding behavior and exposure to localized sonar events of increasing duration and intensity and predicted the effects of this disturbance source on the daily energy intake of an individual. Activity budgets and movements were highly variable in space and time and among individuals, resulting in large variability in predicted energetic intake and costs. In half of our simulations, an individual’s energy intake was unaffected by the simulated source. However, some individuals lost their entire daily energy intake under brief or weak exposure scenarios. Given this large variation, population-level models will have to assess the consequences of the entire distribution of energetic costs, rather than only consider single summary statistics. The shape of the exposure-response functions also strongly influenced predictions, reinforcing the need for contextually explicit experiments and improved mechanistic understanding of the processes driving behavioral and physiological responses to disturbance. This study presents a robust approach for integrating different types of empirical information to assess the effects of disturbance at spatio-temporal and ecological scales that are relevant to management and conservation.Publisher PDFPeer reviewe

Animal-borne metrics enable acoustic detection of blue whale migration

Supplemental Information can be found online at https://doi.org/10.1016/j.cub.2020.08.105.The article of record as published may be located at http://dx.doi.org/10.1016/j.cub.2020.08.105Linking individual and population scales is fundamental to many concepts in ecology [1], including migration [2, 3]. This behavior is a critical [4] yet increasingly threatened [5] part of the life history of diverse organisms. Research on migratory behavior is constrained by observational scale [2], limiting ecological understanding and precise management of migratory populations in expansive, inaccessible marine ecosystems [6]. This knowledge gap is magnified for dispersed oceanic predators such as endangered blue whales (Balaenoptera musculus). As capital breeders, blue whales migrate vast distances annually between foraging and breeding grounds, and their population fitness depends on synchrony of migration with phenology of prey populations [7, 8]. Despite previous studies of individual-level blue whale vocal behavior via bio-logging [9, 10] and population-level acoustic presence via passive acoustic monitoring [11], detection of the life history transition from foraging to migration remains challenging. Here, we integrate direct high-resolution measures of individual behavior and continuous broad-scale acoustic monitoring of regional song production (Figure 1A) to identify an acoustic signature of the transition from foraging to migration in the Northeast Pacific population. We find that foraging blue whales sing primarily at night, whereas migratory whales sing primarily during the day. The ability to acoustically detect population-level transitions in behavior provides a tool to more comprehensively study the life history, fitness, and plasticity of population behavior in a dispersed, capital breeding population. Real-time detection of this behavioral signal can also inform dynamic management efforts [12] to mitigate anthropogenic threats to this endangered population [13, 14]).W.K.O. is supported by the National Science Foundation Graduate Research Fellowship Program (NSFGRFP) and as a David and Lucile Packard Foundation Stanford Graduate Fellow. The NSF funded installation and maintenance of the MARS cabled observatory through awards 0739828 and 1114794. Hydrophone recording through MARS was supported by the Monterey Bay Aquarium Research Institute, through a grant from the David and Lucile Packard Foundation. Thanks to C. Dawe, D. French, K. Heller, P. McGill, and the crew of the R/V Rachel Carson for design, deployment, and maintenance of the MARS hydrophone hardware system and to D. Cline and P. McGill for the decimated PAM data used in this study. Tagging efforts were funded by National Science Foundation Integrative Organismal Systems (NSF IOS) grant 1656691, Office of Naval Research (ONR) grants N00014-13-1-0772 and N00014-14-1-0414, and Office of Naval Research/Living Marine Resources (ONR/LMR) grants N39430-16-C-1853 and N39430-15-C-1692. Additional funding for 2019 field efforts was provided by the California Ocean Alliance. Thank you to the crew of the R/V John Martin for support in the 2017 and 2018 tagging efforts. Thank you also to M. Chapman, M. Savoca, and three anonymous reviewers for comments that improved this manuscript

Supplemental Tables and Figures from Submesoscale coupling of krill and whales revealed by aggregative Lagrangian coherent structures

Additional tables and figures referenced in the main text of the manuscript

Supplemental Methods from Submesoscale coupling of krill and whales revealed by aggregative Lagrangian coherent structures

A knitted R-Markdown PDF file that contains all of the code used in the analysis for this manuscript

Social exploitation of extensive, ephemeral, environmentally controlled prey patches by supergroups of rorqual whales

Large groups of animals aggregate around resource hotspots, with group size often influenced by the heterogeneity of the environment. In most cases, the foraging success of individuals within groups is interdependent, scaling either constructively or destructively with group size. Here we used biologging tags, acoustic prey mapping, passive acoustic recording of social cues and remote sensing of surface currents to investigate an alternative scenario in which large, dense aggregations of southeast Atlantic humpback whales, Megaptera novaeangliae, and northeast Pacific blue whales, Balaenoptera musculus, were each associated with ephemeral krill aggregations large enough such that their availability to predators appeared to be influenced more by environmental features than by consumption, implying independence of group size and consumption rates. We found that the temporal scale and spatial extent of oceanographic drivers were consistent with the temporal scale and locations of predator aggregations, and additionally found that groups formed above bathymetric features known to promote zooplankton concentration. Additionally, we found calling behaviour counter-indicative of competition: blue whale foraging calls were anomalously high during observed aggregation time periods, suggesting signalling behaviour that could alert conspecifics to the location of high-quality resources. Modelled results suggest that the use of social information reduces the time required for individuals to discover and exploit high-quality resources, allowing for more efficient foraging without apparent costs to the caller. Thus, rorqual whales foraging in these environments appear to exhibit a social foraging strategy whereby a behaviour with negligible individual costs (signalling) provides information that enhances group foraging efficiency. The population density dependence of this social foraging strategy may help explain why some rorqual species were at first slow to recover from human exploitation, but have since increased more rapidly.NSF IOS, ONR YIP, Stanford University’s Terman and Bass Fellowships, and funding from the South African Department of the Environment, Forestry and Fisheries.http://www.elsevier.com/locate/anbehavhj2022Zoology and Entomolog