Towards a Wearer-Centred Framework for Animal Biotelemetry

The emerging discipline of Animal-Computer Interaction (ACI) aims to understand the relation between animals and technology in naturalistic settings, to design technology that can support animals in different contexts and to develop user-centred research methods and frameworks that enable animals to take part in the design process as legitimate contributors [11]. Given existing interspecies differences and communication barriers, measuring the behaviour of animals involved in ACI research can be instrumental to achieving any or all of these aims, as a way of gauging the animals’ patterns, needs and preferences. Indeed, measuring behaviour is a common practice among ACI researchers, who take various approaches to this task [5,15,17,24]. In this respect, the use of biotelemetry devices such as VHF tags and GPS trackers, or bio-logging and environmental sensors has a significant potential [22]. At the same time, biotelemetry has been used for many years in many areas of biological research. Biotelemetry is used to improve the quality of physiological and behavioural data collected from animals and in an attempt to reduce researchers’ intrusion in the animals’ habitat [2]. However, there is evidence that carrying biotelemetry tags may influence the bearer’s physiology and behaviour [20]. Such impacts interfere with the validity of recorded data [14] and the welfare of individual animal wearers [1,3,13]. Neither of these effects are compatible with the animal-centred perspective advocated by ACI, on both scientific and ethical grounds. Our analysis of current body-attached device design and biotelemetry-enabled studies points to a general lack of wearer-centred perspective. To address these issues, we have developed a framework to inform the design of wearer-centred biotelemetry interventions, in order to support the implementation of animal-centred research methodologies and design solutions in ACI and other disciplines

Intrinsic and extrinsic factors drive ontogeny of early-life at-sea behaviour in a marine top predator

Young animals must learn to forage effectively to survive the transition from parental provisioning to independent feeding. Rapid development of successful foraging strategies is particularly important for capital breeders that do not receive parental guidance after weaning. The intrinsic and extrinsic drivers of variation in ontogeny of foraging are poorly understood for many species. Grey seals (Halichoerus grypus) are typical capital breeders; pups are abandoned on the natal site after a brief suckling phase, and must develop foraging skills without external input. We collected location and dive data from recently-weaned grey seal pups from two regions of the United Kingdom (the North Sea and the Celtic and Irish Seas) using animal-borne telemetry devices during their first months of independence at sea. Dive duration, depth, bottom time, and benthic diving increased over the first 40 days. The shape and magnitude of changes differed between regions. Females consistently had longer bottom times, and in the Celtic and Irish Seas they used shallower water than males. Regional sex differences suggest that extrinsic factors, such as water depth, contribute to behavioural sexual segregation. We recommend that conservation strategies consider movements of young naïve animals in addition to those of adults to account for developmental behavioural changes

Wild animals' biologging through machine learning models

In recent decades the biodiversity crisis has been characterised by a decline and extinction of many animal species worldwide. To aid in understanding the threats and causes of this demise, conservation scientists rely on remote assessments. Innovation in technology in the form of microelectromechanical systems (MEMs) has brought about great leaps forward in understanding of animal life. The MEMs are now readily available to ecologists for remotely monitoring the activities of wild animals. Since the advent of electronic tags, methods such as biologging are being increasingly applied to the study of animal ecology, providing information unattainable through other techniques. In this paper, we discuss a few relevant instances of biologging studies. We present an overview on biologging research area, describing the evolution of acquisition of behavioural information and the improvement provided by tags. In second part we will review some common data analysis techniques used to identify daily activity of animals

Minimizing the impact of biologging devices: Using computational fluid dynamics for optimizing tag design and positioning

1. Biologgingdevicesareusedubiquitouslyacrossvertebratetaxainstudiesofmove- ment and behavioural ecology to record data from organisms without the need for direct observation. Despite the dramatic increase in the sophistication of this technology, progress in reducing the impact of these devices to animals is less obvi- ous, notwithstanding the implications for animal welfare. Existing guidelines focus on tag weight (e.g. the ‘5% rule’), ignoring aero/hydrodynamic forces in aerial and aquatic organisms, which can be considerable. Designing tags to minimize such im- pact for animals moving in fluid environments is not trivial, as the impact depends on the position of the tag on the animal, as well as its shape and dimensions.2. Wedemonstratethecapabilitiesofcomputationalfluiddynamics(CFD)modelling to optimize the design and positioning of biologgers on marine animals, using the grey seal (Halichoerus grypus) as a model species. Specifically, we investigate the effects of (a) tag form, (b) tag size, and (c) tag position and quantify the impact under frontal hydrodynamic forces, as encountered by seals swimming at sea.3. By comparing a conventional versus a streamlined tag, we show that the former can induce up to 22% larger drag for a swimming seal; to match the drag of the streamlined tag, the conventional tag would have to be reduced in size by 50%. For the conventional tag, the drag induced can differ by up to 11% depending on the position along the seal's body, whereas for the streamlined tag this difference amounts to only 5%.4. We conclude by showing how the CFD simulation approach can be used to opti- mize tag design to reduce drag for aerial and aquatic species, including issues such as the impact of lateral currents (unexplored until now). We also provide a step‐ by‐step guide to facilitate the implementation of CFD in biologging tag design

First insights Into the fine-scale movements of the Sandbar Shark, Carcharhinus plumbeus

The expanding use of biologging tags in studies of shark movement provides an opportunity to elucidate the context and drivers of fine-scale movement patterns of these predators. In May 2017, we deployed high-resolution biologging tags on four mature female sandbar sharks Carcharhinus plumbeus at Ningaloo Reef for durations ranging between 13 and 25.5 h. Pressure and tri-axial motion sensors within these tags enabled the calculation of dive geometry, swimming kinematics and path tortuosity at fine spatial scales (m-km) and concurrent validation of these behaviors from video recordings. Sandbar sharks oscillated through the water column at shallow dive angles, with gliding behavior observed in the descent phase for all sharks. Continual V-shaped oscillatory movements were occasionally interspersed by U-shaped dives that predominately occurred around dusk. The bottom phase of these U-shaped dives likely occurred on the seabed, with dead-reckoning revealing a highly tortuous, circling track. By combining these fine-scale behavioral observations with existing ecological knowledge of sandbar habitat and diet, we argue that these U-shaped dives are likely to be a strategy for bentho-pelagic foraging. Comparing the diving geometry of sandbar sharks with those of other shark species reveals common patterns in oscillatory swimming. Collectively, the fine-scale movement patterns of sandbar sharks reported here are consistent with results of previous biologging studies that emphasize the role of cost-efficient foraging in sharks

Estratégias de forrageio de aves marinhas tropicais no arquipélago dos Abrolhos

Estratégias de forrageio de aves marinhas tropicais no arquipélago dos Abrolhos: As aves marinhas são central-place foragers durante a época de reprodução, o que reforça a competição ao redor da colônia, especialmente em ambientes oligotróficos, como os oceanos tropicais. Em resposta, as aves marinhas desenvolveram estratégias de forrageio, tais como estratégia de alimentação bimodal e/ou uso diferencial de recursos entre os sexos para evitar competição intraespecífica. Nas últimas décadas, as ferramentas de biologging proporcionaram importantes avanços na ecologia do movimento das aves marinhas. Por exemplo, a partir de conjuntos de dados obtidos com os receptores do Sistema Global de Navegação por Satélite (GNSS) é possível obter informações detalhadas e precisas sobre as viagens de alimentação das aves marinhas e segmentar as trajetórias para identificar comportamentos no tempo e no espaço usando ferramentas estatísticas, como os Modelos de Cadeias Ocultas de Markov (HMM). Os sistemas de posicionamento combinados com sensores de pressão fornecem informações sobre distribuição tridimensional, o que é particularmente útil para o estudo de estratégias de forrageio de aves marinhas mergulhadoras. Além disso, o uso de isótopos estáveis em carbono e nitrogênio fornece informações sobre a dieta das aves marinhas, estimando, por exemplo, um nicho isotópico bidimensional como um substituto do nicho trófico. Portanto, este estudo teve como objetivo caracterizar as estratégias de forrageio da ave marinha tropical rabo-de-palha-de-bico-vermelho Phaethon aethereus Linnaeus, 1758 (Aves: Phaethontiformes: Phaethontidae) em um espaço tridimensional e avaliar as diferenças no uso do espaço e dos recursos alimentares entre viagens curtas e longas, assim como as diferenças entre os sexos. Este estudo foi estruturado em dois capítulos: o primeiro apresenta uma avaliação do desempenho do HMM usando dispositivos GNSS e sensores de pressão para identificar áreas de forrageio quando são usadas baixas frequências de amostragem (ou seja, 1 localização a cada 15 min); e o segundo capítulo focalizou a aplicação de tais descobertas combinadas a isótopos estáveis para avaliar diferenças intersexuais em estratégias de forrageio dos rabo-de-palha-de-bico-vermelhos. A partir disto, demonstramos que o uso dos HMM a partir de dados somente de GPS é uma abordagem adequada para inferir áreas de forrageio a nível populacional, mesmo quando são usadas baixas frequências de amostragem. Além disso, este estudo evidenciou que os rabo-de-palha-de-bico-vermelhos realizam viagens bimodais de forrageio com duração de três dias e duas horas, mas não apresentam segregação sexual em relação ao uso do espaço e dieta durante a época de reprodução. Portanto, o presente estudo forneceu informações sobre a aplicabilidade de modelos de espaço-estado para segmentação de trajetórias em espécies de aves marinhas de baixa massa corporal que realizam longas viagens de forrageio e, portanto, precisam ser equipadas com equipamentos leves, com baixas frequências de amostragem. Finalmente, os resultados mostraram uma estratégia bimodal de forrageio e uma sobreposição intersexual quase completa de áreas de forrageio e aspectos dietéticos dos rabo-de-palha- de-bico-vermelho ao redor do arquipélago dos Abrolhos, onde está localizada a maior colônia das espécies no sudoeste do Oceano Atlântico.Foraging strategies of tropical seabirds in the Abrolhos archipelago: Seabirds are central-place foragers during the breeding season which reinforces competition around the colony, especially in oligotrophic environments such as the tropical oceans. In response, seabirds developed foraging strategies, such as bimodal foraging strategy and/or differential resource use between sexes to avoid intraspecific competition. In recent decades, biologging tools have provided important advances in the movement ecology of seabirds. For example, from datasets obtained with Global Navigation Satellite System (GNSS) receivers it is possible to obtain detailed and accurate information about seabird foraging trips and to segment trajectories to identify behaviors in time and space using statistical tools, such as Hidden Markov Models (HMM). Positioning systems combined to pressure sensors provide information on three-dimensional distribution, which is particularly useful for studying foraging strategies of diving seabirds. In addition, the use of carbon and nitrogen stable isotopes provides information on the diet of seabirds by estimating, for instance, a bi-dimensional isotopic niche as a proxy of the trophic niche. Therefore, this study aimed to characterize the foraging strategies of the strictly marine red-billed tropicbird Phaethon aethereus Linnaeus, 1758 (Aves: Phaethontiformes: Phaethontidae) in a three- dimensional space and to assess differences in space and food resource use between short and long trips as well as differences between sexes. This study was structured in two chapters: the first presents an evaluation of the HMM performance using GNSS-only devices and pressure sensors to identify foraging areas when low sampling frequency (i.e. 1 fix each 15 min) are used; and the second chapter focused on applying such findings combined to stable isotopes to assess intersexual differences in foraging strategies of red-billed tropicbirds. From this, we demonstrated that HMM from GPS-only data is a suitable approach for inferring foraging areas at the population level even when low sampling frequencies are used. In addition, this study evidenced that red-billed tropicbirds perform bimodal foraging trips lasting three days and two hours, but do not present sexual segregation regarding space use and diet during the breeding season. Therefore, the present study provided information on the applicability of state space models for segmentation of trajectories in seabird species of low body mass which perform long foraging trips and thus need to be equipped with lightweight loggers set with low sampling frequencies. Finally, the findings indicate a bimodal foraging strategy and an almost complete intersexual overlapping of foraging areas and dietary aspects of red-billed tropicbirds around the Abrolhos archipelago, where the biggest colony of the species in the southwestern Atlantic Ocean is located