New research at Georgia Aquarium helps conserve endangered beluga whales in Alaska
Metabolic and caloric measurements show belugas have big caloric needs to maintain their cold-water lifestyle
ATLANTA – New data provided by studying the beluga whales at Georgia Aquarium helps close a key information gap about how much food these whales need to thrive. The information will inform important management decisions for their counterparts in Alaska’s Cook Inlet, which are protected under the U.S. Endangered Species Act (ESA).
A new study released in the Journal of Experimental Biology, led by Terrie M. Williams, Director of the Integrative Carnivore EcoPhysiology Lab, with her graduate student Jason John at the University of California-Santa Cruz in partnership with Georgia Aquarium, reveals that the whales’ unique metabolism and elevated caloric needs may limit their ability to escape from potential human disturbances.
The Cook Inlet beluga population was listed as endangered in 2008 due to a decline from over-harvesting by Alaska’s native hunters. But despite a cessation in whaling and other efforts to help the population recover, their numbers have not increased, and it is unknown why.
Difficulty collecting this type of data on belugas in the wild has made it hard for scientists to identify why they have failed to recover from excessive harvest. This study, which started in 2018, was a collaboration between U.C. Santa Cruz and Georgia Aquarium with the Alaska Region of NOAA Fisheries, which has management authority for Cook Inlet belugas. Scientists collected data about energy output from the aquarium’s one adult male and two adult female belugas while resting in metabolic domes, during submerged swimming, and when diving for food.
“We are losing large wild species all over the world,” said Williams. “One way that we might be able to prevent wholesale extinctions is to do the basic science that allows us to predict what these animals need to live in this crazy, changing world.”
“This study is one element we can do here to create a better understanding of how these animals take in and use energy,” said Dennis Christen, Georgia Aquarium’s Senior Director, Mammals and Birds. “That’s a measurement that’s nearly impossible to get in the wild. By understanding their metabolism, we can get an understanding of what they have to feed on in the wild and whether it is enough.”
“Taking these baseline measurements – which are the gold standard for conservation modeling – helps us to understand how these whales are built,” Williams explained. “There aren’t many facilities like Georgia Aquarium that have the capabilities and research mindset to conduct this type of research.”
Georgia Aquarium scientists prepared the belugas for the study over a six-month period, using positive reinforcement and operant conditioning techniques to measure their resting and active metabolic rates in different states. Open flow respirometry was used to measure oxygen consumption using a plexiglass dome for the animals to breathe in, and accelerometers were used to measure movement and swim stroke rates in the water.
Data gleaned from this research will help create predictive energy models to evaluate the potential impact of human activities on beluga whales, and a close relative, Arctic narwhals.
The metabolic study conducted by this collaboration is helping to inform measures to ensure Cook Inlet belugas have adequate resources to fuel their caloric needs. Under the ESA, any action that is funded or permitted by the federal government that has the potential to impact a threatened or endangered species must be reviewed. This includes activities like oil and gas exploration and development, marine construction, and commercial fishing. This review includes mitigations to reduce impacts on ESA species. Obtaining a baseline on the calorie needs of Cook Inlet belugas will help inform these mitigations to reduce the effects of these activities on Cook Inlet belugas.
“Wild belugas typically use the calories from ingesting fish to fuel growth, activity, maintaining their health and reproducing,” said Williams. “With increased human disturbance, calories will have to be diverted to respond to perceived threats. Such energy imbalance cannot be sustained for long periods without negative consequences.”
“The whales at Georgia Aquarium are ambassadors for their species. Getting the opportunity to participate in a research study like this one means a lot,” said Katie Flammer, associate curator, Mammals and Birds. “These animals, and our training team, are helping beluga whales globally.”
To learn more about Georgia Aquarium’s conservation work, click here.
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ABOUT THE JOSEPH M. LONG MARINE LABORATORY/UC-SANTA CRUZ
The Joseph M. Long Marine Laboratory (LML) provides a state-of-the-art home for interdisciplinary research and teaching on marine life, coastal conservation, climate change impacts and other marine and coastal science issues. LML is world-renowned for innovative research in coastal ecology, marine vertebrates and invertebrates, and marine mammal studies in the lab and field, including physiology, sensory reception, behavior and bioacoustics.
ABOUT GEORGIA AQUARIUM
Georgia Aquarium is a leading 501(c)(3) non-profit organization located in Atlanta, Ga. that is Humane Certified by American Humane and accredited by the Alliance of Marine Mammal Parks and Aquariums and the Association of Zoos and Aquariums. Georgia Aquarium is committed to working on behalf of all marine life through education, preservation, exceptional animal care, and research across the globe. Georgia Aquarium continues its mission each day to inspire, educate, and entertain its millions of guests about the aquatic biodiversity throughout the world through its engaging exhibits and tens of thousands of animals across its eight major galleries.
Media Contact:
Paige Hale / Georgia Aquarium / Phale@georgiaaquarium.org
JOURNAL
Journal of Experimental Biology
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Animals
ARTICLE TITLE
Marine mammal metabolic measures help save species
ARTICLE PUBLICATION DATE
13-Mar-2024
National Korea Maritime & Ocean University researchers develop a new control method that optimizes autonomous ship navigation
The novel method accounts for the dynamic conditions in a real sea that affect the maneuvering performance of autonomous ships
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THIS INNOVATIVE CONTROL METHOD ACCOUNTS FOR THE WAVE LOADS PRESENT IN REAL SEA CONDITIONS THAT AFFECT THE MANOEUVRING PERFORMANCE OF AUTONOMOUS SHIPS, PROVIDING AN OPTIMIZED CONTROLLER FOR TIME-EFFICIENT NAVIGATION.
view moreCREDIT: DAEJEONG KIM FROM KOREA MARITIME & OCEAN UNIVERSITY
The study of ship manoeuvring at sea has long been the central focus of the shipping industry. With the rapid advancements in remote control, communication technologies and artificial intelligence, the concept of Maritime Autonomous Surface Ships (MASS) has emerged as a promising solution for autonomous marine navigation. This shift highlights the growing need for optimal control models for autonomous ship manoeuvring.
Designing a control system for time-efficient ship manoeuvring is one of the most difficult challenges in autonomous ship control. While many studies have investigated this problem and proposed various control methods, including Model Predictive Control (MPC), most have focused on control in calm waters, which do not represent real operating conditions. At sea, ships are continuously affected by different external loads, with loads from sea waves being the most significant factor affecting manoeuvring performance.
To address this gap, a team of researchers, led by Assistant Professor Daejeong Kim from the Division of Navigation Convergence Studies at the Korea Maritime & Ocean University in South Korea, designed a novel time-optimal control method for MASS. “Our control model accounts for various forces that act on the ship, enabling MASS to better navigate and track targets in dynamic sea conditions,” says Dr. Kim. Their study was made available online on January 05, 2024, and published in Volume 293 of the journal Ocean Engineering on February 01, 2024.
At the heart of this innovative control system is a comprehensive mathematical ship model that accounts for various forces in the sea, including wave loads, acting on key parts of a ship such as the hull, propellers, and rudders. However, this model cannot be directly used to optimise the manoeuvring time. For this, the researchers developed a novel time optimisation model that transforms the mathematical model from a temporal formulation to a spatial one. This successfully optimises the manoeuvring time.
These two models were integrated into a nonlinear MPC controller to achieve time-optimal control. They tested this controller by simulating a real ship model navigating in the sea with different wave loads. Additionally, for effective course planning and tracking researchers proposed three control strategies: Strategy A excluded wave loads during both the planning and tracking stages, serving as a reference; Strategy B included wave loads only in the planning stage, and Strategy C included wave loads in both stages, measuring their influence on both propulsion and steering.
Experiments revealed that wave loads increased the expected manoeuvring time on both strategies B and C. Comparing the two strategies, the researchers found strategy B to be simpler with lower performance than strategy C, with the latter being more reliable. However, strategy C places an additional burden on the controller by including wave load prediction in the planning stage.
“Our method enhances the efficiency and safety of autonomous vessel operations and potentially reduces shipping costs and carbon emissions, benefiting various sectors of the economy,” remarks Dr. Kim, highlighting the potential of this study. “Overall, our study addresses a critical gap in autonomous ship manoeuvring which could contribute to the development of a more technologically advanced maritime industry.”
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Reference
Title of original paper: Time-optimal control of ship manoeuvring under wave loads
Journal: Ocean Engineering
DOI: https://doi.org/10.1016/j.oceaneng.2023.116627
About National Korea Maritime & Ocean University
South Korea’s most prestigious university for maritime studies, transportation science and engineering, the National Korea Maritime & Ocean University is located on an island in Busan. The university was established in 1945 and since then has merged with other universities to currently being the only post-secondary institution that specializes in maritime sciences and engineering. It has four colleges that offer both undergraduate and graduate courses.
To know more, visit: http://www.kmou.ac.kr/english/main.do
About the author
Daejeong Kim is currently an Assistant Professor in the Division of Navigation Convergence Studies at the National Korea Maritime & Ocean University. His research interests cover a wide spectrum, including conducting CFD simulations for ship manoeuvrability, motions, and resistance in waves. Additionally, he explores the performance of ship path-following and collision avoidance at sea. He has also actively contributed to various domestic R&D projects related to Maritime Autonomous Surface Ships (MASS).
JOURNAL
Ocean Engineering
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Time-optimal control of ship manoeuvring under wave loads
ARTICLE PUBLICATION DATE
5-Jan-2024
COI STATEMENT
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ming Zhang reports financial support was provided by National Natural Science Foundation of China.
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