From physiology to physics: are we recognizing the flexibility of biologging tools?

Abstract

The remote measurement of data from free-ranging animals has been termed 'biologging' and in recent years this relatively small set of tools has been instrumental in addressing remarkably diverse questions -from 'how will tuna respond to climate change?' to 'why are whales big?'. While a single biologging dataset can have the potential to test hypotheses spanning physiology, ecology, evolution and theoretical physics, explicit illustrations of this flexibility are scarce and this has arguably hindered the full realization of the power of biologging tools. Here we present a small set of examples from studies that have collected data on two parameters widespread in biologging research (depth and acceleration), but that have interpreted their data in the context of extremely diverse phenomena: from tests of biomechanical and diving-optimality models to identifications of feeding events, Lévy flight foraging strategies and expanding oxygen minimum zones. We use these examples to highlight the remarkable flexibility of biologging tools, and identify several mechanisms that may enhance the scope and dissemination of future biologging research programs.KEY WORDS: Acoustic telemetry, Energetics, Hypoxia, Logger, Penguin, Scaling, Seal, Shark, Stroke frequency, Temperature IntroductionThe collective term 'biologging' has been coined to describe a process by which researchers gain information (typically position, behavior, movement or physiological status) from an animal remotely (see Glossary). Its value with aquatic animals has been highlighted repeatedly (Cooke et al., 2004; Metcalfe et al., 2012;Rutz and Hays, 2009), and in recent years, the diversity of biologging applications has expanded dramatically. In contrast, the suite of parameters recorded by biologging devices has expanded at a much slower pace. While temperature, pressure (depth), heart rate, location and acceleration have been measured in aquatic animals for decades, recent studies have seen these few parameters address remarkably diverse phenomena (Fig. 1). The same type of device that is used to estimate an animal's daily energy budget [e.g. accelerometers (Halsey et al., 2009)] is also used to help explain why diving mammals attain larger sizes than fish (e.g. ). An instrument that reveals preferences for dissolved oxygen levels [e.g. a depth sensor (Stramma et al., 2012)] also provides evidence of Lévy flight foraging strategies (e.g. Humphries et al., 2010). The advantages and disadvantages of using a specific biologging sensor for addressing a particular problem have been thoroughly considered, and are reviewed elsewhere [e.g. in the context of ecology (Cooke et al., 2004), energy expenditure (Halsey et al., 2008) and conservation physiology (Metcalfe et al., 2012)]. Less well recognized, however (or perhaps simply less well documented), is how the collection of a dataset on a single biologging parameter can potentially facilitate insights spanning physiology, ecology, evolution and theoretical physics. While hypothesis-driven research is...

Thermal limitation of performance and biogeography in a free-ranging ectotherm: insights from accelerometry

“…Other biologging devices allow identification of such behaviours, but represent a variety of trade-offs [e.g. size, battery life and the need to retrieve devices (Payne et al, 2014)]. Future biologging research on thermal performance should aim to increase understanding of the mechanisms underlying thermal performance curves in wild animals, and a variety of tools are available for this pursuit.…”

“…Biologging approaches have emerged as powerful tools for addressing remarkably diverse objectives (Payne et al, 2014), and accelerometers in particular hold significant potential for examining thermal performance curves in free-ranging ectotherms. Despite this potential, we are not aware of any studies that have used biologging to test for thermal performance curves in the activity levels of freeranging ectotherms.…”

First autonomous recording of in situ dissolved oxygen from free-ranging fish

“…Advances in biologging and biotelemetry technologies have enhanced our understanding of the ecology of marine animals and have been central to identifying how oceanographic features influence their distribution and behavior [1][2][3]. Given the changes in ocean conditions that are predicted to occur in coming decades, understanding the interplay between physical and biological phenomena is becoming increasingly important [3,4].…”

“…Given the changes in ocean conditions that are predicted to occur in coming decades, understanding the interplay between physical and biological phenomena is becoming increasingly important [3,4]. Data obtained from biologging devices (tags) attached to free-ranging animals have the significant advantage that they are recorded at a scale and resolution that are pertinent to and contemporaneous with the movement and behavior of the tagged animal [2,5].…”

“…Data obtained from biologging devices (tags) attached to free-ranging animals have the significant advantage that they are recorded at a scale and resolution that are pertinent to and contemporaneous with the movement and behavior of the tagged animal [2,5]. Moreover, data collected by modern biologging sensors are often equivalent to industry standards for environmental sampling [2,3,5].…”