Geology topics

George V. Lauder

Publications and source records attributed to George V. Lauder.

3 recordsLinked to original sources

USGS2026

Fish locomotor dynamics quantified using multiple inertial measurement units

Animals exhibit a diversity of locomotor behaviours that vary with body shape, ontogeny, motivation and environment. Documenting these behaviours often relies on recording videos of animals in controlled conditions displaying stereotyped behaviours. By contrast, animal-borne motion sensing data loggers can document diverse behaviours of animals in their natural environment. Traditionally, one data logger is used to infer body dynamics; however, a single location presents an incomplete picture of body movement. Here, we deploy multiple independent inertial measurement units on individual fish to study within-body dynamics and assess the accuracy of this approach compared to traditional video methods. Using a combination of robotic and animal experiments, we accurately measure the timing, direction and magnitude of movement of multiple locations along the body and can recreate accurate three-dimensional midline kinematics without video data. Furthermore, we show that with as few as two data loggers, parameters such as propulsive wavelength can be calculated, even during high-intensity behaviours. Using multiple data loggers has the potential to provide unbiased spatio-temporal estimates of fish kinematics, allowing kinematic studies to be extended to new species, new habitats and a diversity of natural fish locomotor behaviours beyond those traditionally studied in laboratory settings.

Royal Society Open Science↗

USGS2022

Fish-inspired segment models for undulatory swimming

Many aquatic animals swim by undulatory body movements and understanding the diversity of these movements could unlock the potential for designing better underwater robots. Here, we analyzed the steady swimming kinematics of a diverse group of fish species to investigate whether their undulatory movements can be represented using a series of interconnected multi-segment models, and if so, to identify the key factors driving the segment configuration of the models. Our results show that the steady swimming kinematics of fishes can be described successfully using parsimonious models, 83% of which had fewer than five segments. In these models, the anterior segments were significantly longer than the posterior segments, and there was a direct link between segment configuration and swimming kinematics, body shape, and Reynolds number. The models representing eel-like fishes with elongated bodies and fishes swimming at high Reynolds numbers had more segments and less segment length variability along the body than the models representing other fishes. These fishes recruited their anterior bodies to a greater extent, initiating the undulatory wave more anteriorly. Two shape parameters, related to axial and overall body thickness, predicted segment configuration with moderate to high success rate. We found that head morphology was a good predictor of its segment length. While there was a large variation in head segments, the length of tail segments was similar across all models. Given that fishes exhibited variable caudal fin shapes, the consistency of tail segments could be a result of an evolutionary constraint tuned for high propulsive efficiency. The bio-inspired multi-segment models presented in this study highlight the key bending points along the body and can be used to decide on the placement of actuators in fish-inspired robots, to model hydrodynamic forces in theoretical and computational studies, or for predicting muscle activation patterns during swimming.

Bioinspiration & Biomimetics↗

USGS2022

Applied aspects of locomotion and biomechanics

Locomotion is the act and process of moving from place to place, which is fundamental to the life history of all mobile organisms. While the field of biomechanics encompasses the study of the physical constraints of what animals are capable of, ecological contexts require an integrated view that includes ecology and behavior. This chapter provides an overview of some of the areas where locomotion and biomechanics of fish movement interface with the rapidly evolving changes that humans impose on aquatic environments. These changes include fundamental alterations to the environment such as altered flows, fragmentation of riverine habitats, and invasive species, but also direct interactions that occur with capture fisheries. We explore each of these areas, considering both challenges and opportunities informed by the study of locomotion and biomechanics, emphasizing how this field can contribute to conservation of fishes in the Anthropocene. We then turn to technology, where important advances are aiding in our understanding of fish movement. In some cases those advances have themselves led to novel technologies, where biomimetic robots and related devices offer novel opportunities, both for conservation and for other pursuits.

Book chapter↗