RESEARCH THEMES
Research in the Di Santo Lab aims to make fundamental advances in our understanding of fish locomotor performance across their life history and evolutionary diversity and to apply those discoveries to reveal their relationship to changing environmental conditions. This interdisciplinary research incorporates a wide range of methodologies, including biomechanical, physiological, and robotic approaches as well as rearing experiments and artificial intelligence. We have established collaborative teams with engineers, computer scientists, and anatomists to leverage biological data for the study of fish locomotor diversity, underwater propulsion, and the development of efficient artificial swimmers and computational models for experimental testing.
Climate change and comparative physiology
A major focus of research in the lab is quantifying the impact of climate-related stressors, such as warming, hypoxia, and acidification, on the overall physiological performance of organisms during different locomotor behaviors. Recent investigations have specifically delved into the influence of local adaptation, ontogeny, and acclimatization on locomotor performance. By integrating ecophysiological tools and climate projections, we aim to elucidate the underlying mechanisms and implications of residing in changing environments. While a significant portion of our work has concentrated on benthic elasmobranchs, particularly skates, we have now extended our investigations to include several fish species, including silversides, smelt, stickleback, damselfish, catfish, and zebrafish. Through these studies, we seek to quantify the consequences of climate change on collective motion across multiple generations.
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We also analyze specimens from Natural History Collections to quantify skeletal morphology and mineralization through CT scans of forage fish collected over the span of the last 200 years. By examining potential changes in morphology, we aim to uncover the long-term environmental and sea chemistry patterns and models. The insights gained from the examination of specimens, in conjunction with experimental data, will contribute to the development of a robust theoretical framework for projecting realistic responses of fishes to climate change. The analysis of specimens from natural history collections plays a pivotal role in enhancing our understanding and prediction of the impacts of climate change on organisms.
Fish locomotion and biomechanics
We conduct extensive research on various forms of fish locomotion, including swimming, maneuvering, collective movement, and even walking. Our approach involves a combination of automated and manual tracking methods to analyze the kinematics of the body and fins. Additionally, we employ simulations, robotics, and energetics to enhance our understanding of complex locomotor behaviors. One of the exciting aspects of our work is the diverse range of fish species we investigate. To date, we have examined over 90 species of freshwater, brackish, and marine fishes. This breadth allows us to gain insights into locomotion strategies across different habitats and environments. Our primary objective is to identify how fishes modulate their body and fins to optimize speed, efficiency, and stability in the face of disturbances. By shedding light on these aspects, we contribute to the broader understanding of fish locomotion and potentially inspire innovative solutions for various engineering and biological applications.
Walking fishes
The transition from water to land represents a significant milestone in vertebrate evolution, necessitating substantial anatomical, physiological, and behavioral changes to enable fishes to transition from swimming to walking on land. Surprisingly, walking behavior has also been observed in fully aquatic fish species, such as sharks, skates, and frogfishes. Despite the documentation of underwater walking in several species, the purpose behind this behavior remains unclear. To shed light on this question, our team is currently investigating underwater walking performance. We employ a multidisciplinary approach that combines anatomical studies, biomechanics, respirometry, and the use of robotic models. Through these methods, we aim to unravel the principles governing underwater walking in fishes. This project is currently funded by the Human Frontier Science Program and it is conducted at the Marine Biological Laboratory.
Bio-inspired robotics
We integrate biological data with robotic and computational models to gain insights into the mechanics of both steady and unsteady locomotion in solitary and schooling fishes. Through collaborations with engineers and computer scientists, we have developed several robotic platforms. One of our team's notable achievements is the creation of a bio-hybrid ray, which demonstrates remarkable navigation abilities in response to light stimuli. Additionally, our bass-bot features flexible modular fins, enabling us to delve deeper into the study of unsteady locomotion. Furthermore, our team has successfully developed a tuna-bot, which serves as a platform to investigate energetic efficiency and achieve high speeds. To witness the remarkable swimming capabilities of the cyborg-skate, watch the video here.
Funding
Current work in the Di Santo Lab is funded by:
The Human Frontier Science Program
The University of California, San Diego
