Study uncovers neural mechanisms underlying foraging behavior in freely moving animals

RICE UNIVERSITY

 

IMAGE: 

VALENTIN DRAGOI PROFESSOR OF ELECTRICAL AND COMPUTER ENGINEERING AT RICE UNIVERSITY, PROFESSOR OF NEUROSCIENCE AT WEILL CORNELL MEDICAL COLLEGE AND SCIENTIFIC DIRECTOR OF THE METHODIST/RICE CENTER FOR NEURAL SYSTEMS RESTORATION.
 

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CREDIT: (PHOTO BY JEFF FITLOW/RICE UNIVERSITY)

HOUSTON – (April 19, 2024) – While foraging, animals including humans and monkeys are continuously making decisions about where to search for food and when to move among possible sources of sustenance.

“Foraging behavior is something we perform daily when we go to the grocery store to pick up food, and we make choices based on the degree of reward each choice provides. It’s a classical problem common to every species on the planet,” said Valentin Dragoi, professor of electrical and computer engineering at Rice, professor of neuroscience at Weill Cornell Medical College and scientific director of the Methodist/Rice Center for Neural Systems Restoration.

In a paper published in Nature Neuroscience, Dragoi and collaborators investigate the brain processes involved in searching for food.

“In this study, we describe the use of a new integrated wireless system for recording brain activity in the frontal areas of their brain and for oculomotor and behavioral tracking. We examine in real time how this ubiquitous task of foraging unfolds, which is something we naturally perform every day,” Dragoi said.

Macaques are a genus of monkeys native to Asia, North Africa and Southern Europe (Gibraltar). They most often eat fruit, seeds and other plant-based food. “We study macaques,” Dragoi said, “because foraging is a natural behavior and the macaque brain is quite similar to the human brain in terms of organization and function.”

Until now, it was difficult to examine the neural basis of foraging in naturalistic environments because previous approaches relied on restrained animals performing trial-based foraging tasks. Dragoi and his research partners allowed unrestrained macaques to freely interact with reward options while wirelessly recording neural activity in their prefrontal cortex.

“Animals decided when and where to forage based on whether their predictions of reward were fulfilled or violated. The predictions were not based exclusively on a history of reward delivery, but also on the understanding that waiting longer improves the chance of reward,” Dragoi said.

The results indicate that foraging strategies are based on a cortical model of reward dynamics as animals freely explore their environment.

“We learned that we can predict choices even in complex situations by simply reading out the responses of dozens of neurons in the frontal lobe. This can potentially move in the direction of prosthetic devices to influence or bias choice, even noninvasively. More fundamentally, it allows us to understand how the brain works when engaged in this natural behavior,” Dragoi said.

Next, the Dragoi lab will combine foraging in a social context and record from two animals simultaneously while they cooperate to seek food as a reward. This is a daunting technical challenge but Dragoi believes he and his research partners are close to achieving such goals. This may enable a solution to the challenge of cortical implants to assist patients with brain dysfunction and enable their behavioral decisions.

The lead author of the article is Neda Shahidi, a former Ph.D. student in Dragoi’s lab, currently group leader at Georg-Elias-Müller-Institute for Psychology, Georg August-Universität, Göttingen. The co-authors, in addition to Dragoi, are Melissa Franch, postdoctoral research fellow in neuroscience, Baylor College of Medicine; Arun Parajuli, data scientist at the University of Texas Health Science Center, Houston; Paul Schrater, professor of computer science and engineering at the University of Minnesota; Anthony Wright, professor of neurobiology and anatomy, McGovern Medical School, Houston; Assistant Professor, Electrical and Computer Engineering; Assistant Professor of Neuroscience, Baylor College of Medicine; Xaq Pitkow, assistant professor of ECE at Rice and assistant professor of neuroscience at Baylor College of Medicine.

The research was supported in part by the National Institutes of Health (5U01NS094368), The Robert and Janice McNair Foundation and DFG (CRC1528). The content in this press release is solely the responsibility of the authors and does not necessarily represent the official views of the NIH and other listed funders.

⎯ by Patrick Kurp, science writer at the Rice University George R. Brown School of Engineering

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This news release can be found online at news.rice.edu.

Follow Rice News and Media Relations via Twitter @RiceUNews.

Peer-reviewed paper:

Population coding of strategic variables during foraging in freely moving macaques | Nature Neuroscience | DOI: 10.1038/s41593-024-01575-w

Authors: Neda Shahidi, Melissa Franch, Arun Parajuli, Paul Schrater, Anthony Wright, Xaq Pitkow and Valentin Dragoi

https://www.nature.com/articles/s41593-024-01575-w

Image downloads:

https://news-network.rice.edu/news/files/2024/04/240208_Dragoi_Fitlow_019-457ce01a4c12c800.jpg
CAPTION: Valentin Dragoi professor of electrical and computer engineering at Rice University, professor of neuroscience at Weill Cornell Medical College and scientific director of the Methodist/Rice Center for Neural Systems Restoration. (Photo by Jeff Fitlow/Rice University)

About Rice:

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation’s top 20 universities by U.S. News & World Report. Rice has highly respected schools of architecture, business, continuing studies, engineering, humanities, music, natural sciences and social sciences and is home to the Baker Institute for Public Policy. With 4,574 undergraduates and 3,982 graduate students, Rice’s undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction, No. 2 for best-run colleges and No. 12 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger’s Personal Finance.

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JOURNAL

Nature Neuroscience

DOI

10.1038/s41593-024-01575-w 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Population coding of strategic variables during foraging in freely moving macaques

 

Lemur’s lament: When one vulnerable species stalks another

WASHINGTON UNIVERSITY IN ST. LOUIS

 

IMAGE: 

DIADEMED SIFAKA

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CREDIT: ONJA RAMILIJAONA

What can be done when one threatened animal kills another? Scientists studying critically endangered lemurs in Madagascar confronted this difficult reality when they witnessed attacks on lemurs by another vulnerable species, a carnivore called a fosa.

This dynamic can be particularly complex when the predation occurs in an isolated or poor-quality habitat, according to research from Washington University in St. Louis and the University of Antananarivo in Madagascar.

In the new paper published in Ecology and Evolution, researchers describe how they were observing small groups of critically endangered diademed sifaka lemurs (Propithecus diadema) at Betampona Strict Nature Reserve when the predator struck.

“We were conducting our daily behavioral observations when we came across a very unusual sight — a predation attempt by a fosa, which is the biggest predator in Madagascar,” said WashU’s Giovanna Bonadonna, a postdoctoral research associate in biological anthropology in Arts & Sciences and the study’s co-first author.

“What we saw was very rare,” Bondadonna said. “There are other small carnivores in Madagascar, but they are not big enough to be able to prey upon an adult diademed sifaka because they are among the biggest lemurs. There are not so many predators that could actually get them.”

With slender bodies and long tails, fosas (or fossas, Crytoprocta ferox) have many cat-like features. They are great climbers and are sometimes compared to small cougars, though they are actually part of the weasel family.

The fosa is categorized as vulnerable by the International Union for Conservation of Nature and Natural Resources, and is at risk of extinction, as are almost all of its lemur prey. Fosas also eat other small animals such as birds and rodents.

But they’re rarely caught in the act. Fosas are stealthy hunters. Researchers have mostly determined what fosas eat by examining bones and other evidence left behind in scat.

“We noticed that a female diademed sifaka that we were following after the first attack didn’t run away very far,” said Onja Ramilijaona, a PhD candidate at the University of Antananarivo and the other co-first author of the paper. “Instead she stayed still and remained vigilant, looking at the fosa.”

Ramilijaona also documented the later discovery of the remains of another diademed sifaka, presumed to have been killed by a fosa because of the condition of the remains and because of the way that branches had been broken in the area. Signs indicated a struggle in the trees.

The researchers also described other instances over a period of 19 months of observation when fosas appeared to stalk lemurs but were unsuccessful in bringing one down as food.

The impact of predation — combined with low reproductive rates and potentially high inbreeding of the lemur population of Betampona — could affect the survival of this species at this site, researchers said.

Created in 1927, Betampona was Madagascar’s first protected reserve and comprises about 22 square kilometers (about 5,400 acres) of rainforest on the east coast, surrounded by agricultural land. While the land itself is protected, this forest’s relatively small size and isolation mean that it can be difficult for plants and animals to continue to breed and survive at Betampona.

“Although Betampona is one of the best protected reserves in Madagascar, its isolation from other viable forests with lemur populations has created a predicament in which the critically endangered lemurs cannot engage in typical dispersal patterns, leading to genetic and demographic isolation,” said Lisa Kelley, executive director of the Saint Louis Zoo Wildcare Institute. “The need to study these populations for a possible genetic management study became clear several years back, once there were indications that there were few infant births and even fewer infant survivals.”

The impact of predation — combined with low reproductive rates and potentially high inbreeding of the lemur population of Betampona — could affect the survival of this species at this site. (Photo: Onja Ramilijaona)

The Saint Louis Zoo and the Missouri Botanical Garden have conducted work at Betampona since the 1980s with the Madagascar Flora and Fauna Group, an international nonprofit, non-governmental organization that enables institutions to collaborate for the united purpose of conserving Madagascar’s biodiversity. Washington University, the Saint Louis Zoo and the Missouri Botanical Garden are also partners in the Living Earth Collaborative. This particular effort is part of a larger project in Madagascar made possible with funding from the Living Earth Collaborative and the Eric P. and Evelyn E. Newman Charitable Foundation.

“These most recent observations of fosa attacks are especially troubling, as the observation of predation attacks, especially by the elusive fosa, are very rare,” Kelley said.

“It leads to questions of why the fosa are so bold to predate on lemurs in front of humans, and whether the fosa leave Betampona to hunt elsewhere and then return, or whether they are targeting the lemurs within the reserve,” she said. “It is an incredible scenario in which you have a vulnerable species potentially over-predating on several critically endangered species.”

Senior authors on the study include Krista Milich and Emily Wroblewski, both assistant professors in the Department of Anthropology in Arts & Sciences at Washington University.

“This population of diademed sifakas is already in bad shape,” Bonadonna said. “There is a huge predation pressure that was underestimated until we did this behavioral study. We were able to highlight inbreeding and other factors that may be behind the fact that this population cannot thrive at Betampona.

“It’s not that the fosa is the bad guy,” Bonadonna said. “It’s also in need of conservation. This study really highlights how complicated it can be. Human activities lead to changes in dynamics within ecosystems, having cascading effects beyond even what people realize. Despite the effort to conserve one species, it’s really the ecosystem and the balance of that ecosystem that is at stake once the habitat is compromised.”

Diademed sifaka, a critically endangered lemur in Madagascar.

CREDIT

Onja Ramilijaona

JOURNAL

Ecology and Evolution

DOI

10.1002/ece3.11248 

METHOD OF RESEARCH

Observational study

ARTICLE TITLE

Response of diademed sifaka (Propithecus diadema) to fosa (Cryptoprocta ferox) predation in the Betampona Strict Nature Reserve, Madagascar

ARTICLE PUBLICATION DATE

19-Apr-2024

 

Surf clams off the coast of Virginia reappear – and rebound

Rutgers scientists point to improved environmental conditions as possible reason

RUTGERS UNIVERSITY

 

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MEMBERS OF A RUTGERS UNIVERSITY RESEARCH TEAM COLLECT SURFCLAMS FOR A STUDY.

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CREDIT: D. MUNROE/RUTGERS UNIVERSITY

The Atlantic surfclam, an economically valuable species that is the main ingredient in clam chowder and fried clam strips, has returned to Virginia waters in a big way, reversing a die-off that started more than two decades ago.

In a comprehensive study of surfclams collected from an area about 45 miles due east from the mouth of the Chesapeake Bay, Rutgers scientists found the population to be thriving and growing. A likely reason could be that environmental conditions improved, and another possibility is that the clams adapted, the scientists said. The report, published in the science journal Estuaries and Coasts, details the characteristics of a population of healthy-size surfclams of different ages living just under the surface of the sandy ocean bottom.

And it’s all a bit of a surprise.

“It’s unexpected and it’s good news,” said Daphne Munroe, an associate professor in the Department of Marine and Coastal Sciences in the Rutgers School of Environmental and Biological Sciences, and an author of the study. “They disappeared some time ago – we thought they were gone. But we found there were more clams there than we thought we were going to see. And they are flourishing.”

Surfclams started disappearing from waters off the coast of Virginia in the late 1990s, affected by warming water, Munroe said. By the turn of the 21st century, there were too few present to justify fishing in those waters.

One day in 2021, Munroe received a phone call from one of her fishing partners with whom she often collaborates.

“He said, ‘Daphne, do you know I’ve got five boats working out of Cape Charles [off Virginia’s Eastern Shore] right now? They’re catching surfclams and we’re putting them on trucks,’” Munroe said.

She added, “And I said, ‘What is that? What are they doing? How is that possible?’”

The refrigerated trucks carting seafood were headed to Port Norris, N.J., she was told, the location of one of the main surfclam processing plants on the East Coast. Munroe works out of the New Jersey Agricultural Experiment Station’s Haskin Shellfish Research Laboratory in Port Norris, just around the corner from the processor.

“I told him: ‘I have to see those clams. That’s crazy.’”

Munroe, an expert in the dynamics of coastal and marine ecosystems, examined the surfclams and a new research study was born. She secured funding from the National Science Foundation-funded Science Center for Marine Fisheries that enabled Munroe to hire a Michigan State undergraduate, Brynne Wisner, as an intern. Wisner, who would lead the collection, preparation and measurement of the clams, became first author on the study.

The Atlantic surfclam – its shell well-known to beachcombers in the northeastern U.S. – is one of the most common species of bivalves in the western Atlantic Ocean. Surfclams can live 40 years and grow their shells up to 8 or 9 inches long.

While its habitat ranges from the Gulf of St. Lawrence in Canada to Cape Hatteras in North Carolina, the surfclam’s primary population lives off the coast of New Jersey. There, the relatively shallow Northeast U.S. Continental Shelf provides an ideal, vast breeding habitat, extending for about 100 miles before a falloff to the canyons of the deep ocean. The animals also thrive in the Cold Pool, a band of cold near-bottom water that streams through the lower regions of this section of the New York-New Jersey Bight.

The researchers used the New Jersey surfclam population, perfectly located in the middle of the species range, as a standard of comparison in the study. From the samples collected from Virginia waters, scientists recorded the ages of each surfclam shell (as with trees, the successive rings on the shells equate to years lived), its size, rate of growth and whether the surfclam contained a generous portion of meat. They also collected tissue samples for genetic analysis.

“The clams in the southern range are in good shape,” Munroe said. “They are still young, and growing as we would expect.”

The study found multiple generations of surfclams in the animals collected, a sign of a healthy, expanding population.

“The finding suggests that environmental conditions may have improved for surfclams in the south, or that this population has acclimated to altered conditions,” Munroe said.

Understanding the population of surfclams at the southern edge of their range can help researchers better understand shifts in the ranges of species and possible adaptation and recovery, Munroe said.

The genetic analysis indicated that, among the population of the surfclam species, Spisula solidissima solidissima, a smaller subspecies better known for favoring warmer climates, Spisula solidissima similis, was also found living there.

Further research, Munroe said, will investigate the possibility of mating between these species. This phenomenon, known as subspecies hybridization, can be an important path for species to adapt to a changing environment.

In addition to Munroe and Wisner, other Rutgers scientists on the study included Ximing Guo, a distinguished professor in the Department of Marine and Coastal Sciences; Zhenwei Wang, a doctoral student; and Ailey Sheehan, a lab technician, all with the Haskin Shellfish Research Laboratory.

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JOURNAL

Estuaries and Coasts

DOI

10.1007/s12237-023-01281-z 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animal tissue samples

ARTICLE TITLE

Genetics, Age Demographics, and Shell Size of Atlantic Surfclams from the Southern Edge of Their Range

Warming of Antarctic deep-sea waters contribute to sea level rise in North Atlantic, study finds

UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF MARINE, ATMOSPHERIC, AND EARTH SCIENCE

 

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INFOGRAPHIC HIGHLIGHTS THE AREA OF STUDY AND FINDINGS OF THE  ABYSSAL LIMB OF THE ATLANTIC MERIDIONAL OVERTURNING CIRCULATION (AMOC)

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CREDIT: NICOLE BOZKURT, UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF MARINE, ATMOSPHERIC, AND EARTH SCIENCE.

Analysis of mooring observations and hydrographic data suggest the Atlantic Meridional Overturning Circulation deep water limb in the North Atlantic has weakened. Two decades of continual observations provide a greater understanding of the Earth’s climate regulating system.

A new study published in the journal Nature Geoscience led by scientists at University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, and the National Oceanic and Atmospheric Administration’s Atlantic Oceanographic and Meteorological Laboratory, found that human-induced environmental changes around Antarctica are contributing to sea level rise in the North Atlantic.

The research team analyzed two decades of deep sea oceanographic data collected by observational mooring programs to show that a critical piece of Earth’s global system of ocean currents in the North Atlantic has weakened by about 12 percent over the past two decades.

“Although these regions are tens of thousands of miles away from each other and abyssal areas are a few miles below the ocean surface, our results reinforce the notion that even the most remote areas of the world's oceans are not untouched by human activity,” said the study’s lead author Tiago Biló, an assistant scientist at the Rosenstiel School’s NOAA Cooperative Institute for Marine and Atmospheric Studies.

As part of the NOAA-funded project DeepT (Innovative analysis of deep and abyssal temperatures from bottom-moored instrument), the scientists analyzed data from several observational programs to study changes over time in a cold, dense, and deep water mass located at depths greater than 4,000 meters (2.5 miles) below the ocean surface that flow from the Southern Ocean northward and eventually upwells to shallower depths in other parts of the global ocean such as the North Atlantic.

This shrinking deep-ocean branch — that scientists call the abyssal limb – is part of the Atlantic Meridional Overturning Circulation (AMOC), a three-dimensional system of ocean currents that act as a “conveyer belt” to distribute heat, nutrients, and carbon dioxide across the world’s oceans.

This near-bottom branch is comprised of Antarctic bottom water, which forms from the cooling of seawater in the Southern Ocean around Antarctica during winter months. Among the different formation mechanisms of this bottom water, perhaps the most important is the so-called brine rejection, a process that occurs when salty water freezes.  As sea ice forms, it releases salt into the surrounding water, increasing its density. This dense water sinks to the ocean floor, creating a cold, dense water layer that spreads northward to fill all three ocean basins – the Indian, Pacific, and Atlantic oceans. During the 21st century, the researchers observed that the flow of this Antarctic layer across 16°N latitude in the Atlantic had slowed down, reducing the inflow of cold waters to higher latitudes, and leading to warming of waters in the deep ocean.

“The areas affected by this warming spans thousands of miles in the north-south and east-west directions between 4,000- and 6,000-meters of depth,” said William Johns, a co-author and professor of ocean sciences at the Rosenstiel School. “As a result, there is a significant increase in the abyssal ocean heat content, contributing to local sea level rise due to the thermal expansion of the water.”

“Our observational analysis matches what the numerical models have predicted—human activity could potentially impose circulation changes on the entire ocean,” said Biló. “This analysis was only possible because of the decades of collective planning and efforts by multiple oceanographic institutions worldwide.”

The study, titled “Weakening of the Atlantic Meridional Overturning Circulation Abyssal Limb in the North Atlantic,” was published in the April 19 issue of the journal Nature Geoscience. The study’s authors include: Tiago Biló, William Johns from the Rosenstiel School; Renellys Perez and Shenfu Dong from NOAA’s Atlantic Oceanographic and Meteorological Laboratory, and Torsten Kanzow from the Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research in Germany.

The research was supported by NOAA’s Global Ocean Monitoring and Observing program (100007298); NOAA’s Climate Program Office, Climate Observations and Monitoring, and Climate Variability and Predictability programs (NOFO NOAA-OAR-CPO-2021-2006389), U.S. National Science Foundation (grants OCE-1332978 and OCE-1926008), the European Union’s Horizon 2020 Research and Innovation Program (grant 821001 (SO-CHIC), and the Deutsche Forschungsgemeinschaft German Research Foundation project number 274762653), with additional NOAA Atlantic Oceanographic and Meteorological Laboratory support.

About the University of Miami

The University of Miami is a private research university and academic health system with a distinct geographic capacity to connect institutions, individuals, and ideas across the hemisphere and around the world. The University’s vibrant and diverse academic community comprises 12 schools and colleges serving more than 17,000 undergraduate and graduate students in more than 180 majors and programs. Located within one of the most dynamic and multicultural cities in the world, the University is building new bridges across geographic, cultural, and intellectual borders, bringing a passion for scholarly excellence, a spirit of innovation, a respect for including and elevating diverse voices, and a commitment to tackling the challenges facing our world. Founded in the 1940’s, the Rosenstiel School of Marine, Atmospheric, and Earth Science has grown into one of the world’s premier marine and atmospheric research institutions. Offering dynamic interdisciplinary academics, the Rosenstiel School is dedicated to helping communities to better understand the planet, participating in the establishment of environmental policies, and aiding in the improvement of society and quality of life. www.earth.miami.edu.

 

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JOURNAL

Nature Geoscience

METHOD OF RESEARCH

Data/statistical analysis

ARTICLE TITLE

Weakening of the Atlantic Meridional Overturning Circulation Abyssal Limb in the North Atlantic

ARTICLE PUBLICATION DATE

19-Apr-2024

 

Baby sharks prefer being closer to shore, show scientists

Young great white sharks gather in nurseries close to shore, perhaps to avoid predators

FRONTIERS

 

VIDEO: 

JUVENILE GREAT WHITE SHARKS AGGREGATING IN WARM, SHALLOW WATERS 

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CREDIT: PATRICK REX

Remember #BabyShark? And no, this was not the very catchy song for kids that took the internet by storm. Earlier this year, social media was abuzz with stunning footage of a newborn great white shark, captured by a flying drone.

Now, marine scientists have shown for the first time that juvenile great white sharks select warm and shallow waters to aggregate within one kilometer from the shore. These results, published in Frontiers in Marine Science, are important for conservation of great white sharks – especially as ocean temperatures increase due to climate change – and for protecting the public from negative shark encounters.

Nurseries off central California

Baby great white sharks (‘pups’) don’t receive any maternal care after birth. In the studied population off Padaro Beach near Santa Barbara in central California, pups and juveniles gather in ‘nurseries’, unaccompanied by adults.

“This is one of the largest and most detailed studies of its kind. Because around Padaro Beach, large numbers of juveniles share near-shore habitats, we could learn how environmental conditions influence their movements,” said senior author Dr Christopher Lowe, a professor at California State University. 

“You rarely see great white sharks exhibiting this kind of nursery behavior in other locations.”

In 2020 and 2021, Lowe and his team used darts to tag a total of 22 juveniles with sensor-transmitters. These were females and males aged between one and six years old. Great white sharks can live for up to 40 to 70 years.

The sensor-transmitters measured local water pressure and temperature in real time, and tracked each juvenile’s position by sending acoustic ‘pings’ into an array of receivers, spread out over approximately 5.5 sq km along the shoreline. These methods had been approved by the university’s Animal Care and Use Committee and California’s Department of Fish and Wildlife.

Tracking was halted during the winter months, when juveniles temporarily left for offshore waters. The researchers gathered further data on the temperature distribution throughout the local water column with an autonomous underwater vehicle. They then used artificial intelligence to train a 3D model of the juveniles’ temperature and depth preferences.

The results showed that the juveniles dived to the greatest depths around dawn and dusk, when they were likely foraging on skates, rays, schooling fish, and other small bony fish. They moved closest to the surface – between zero and four meters deep – in the afternoon when the sun was hottest, possibly to increase their body temperature.

First author Emily Spurgeon, a former master’s student and current research technician in Lowe’s team, said: “We showed that juveniles directly altered their vertical position in the water column to stay between 16 and 22 °C, and if possible between 20 and 22 °C. This may be their optimum to maximize growth efficiency within the nursery.”

Preference for shallow waters

The results showed that the temperature distribution in these waters is ever changeable, which means that juveniles have to be constantly on the move to remain within this optimal range.

The authors concluded that juvenile great white sharks spend most of their time in much shallower water than adults. The latter were rarely observed in the nursery.

The results also showed that the temperature distribution across three dimensions strongly impacted the horizontal distribution of the juveniles, which spread out at greater depths when seafloor temperatures were higher, and moved closer together towards the surface when deeper water was cooler.

What the researchers don’t yet know is what benefits pups and juveniles get from gathering in nurseries in the first place. One advantage might be to avoid predators.

“Our results show that water temperature is a key factor that draws juveniles to the studied area. However, there are many locations across the California coast that share similar environmental conditions, so temperature isn’t the whole story. Future experiments will look at individual relationships, for example to see if some individuals move among nurseries in tandem,” said Spurgeon.

  

First author Emily Spurgeon tagging a juvenile great white shark

CREDIT

Patrick Rex

Juvenile great white shark viewed from the unmanned underwater autonomous vehicle

CREDIT

Emily Spurgeon

Tagging a juvenile great white shark

CREDIT

Patrick Rex

Juvenile great white shark viewed from a boat

CREDIT

Emily Spurgeon

JOURNAL

Frontiers in Marine Science

DOI

10.3389/fmars.2024.1290769 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

COI STATEMENT

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest

 

Japan Plans Next Generation Containership for Zero Emissions and Efficiency

Imoto looks to leverages its expertise in feeders to develop a next generation hybrid containership (Imoto)

PUBLISHED APR 19, 2024 9:02 PM BY THE MARITIME EXECUTIVE

 

 

A Japanese consortium made up of coastal shipping company Imoto Lines and marine software company Marindows is launching a government-backed effort to develop a next-generation containership. Plans call not only for the vessel to address decarbonization with the ability to operate emissions-free, but also to address the emerging challenges due to the lack of seafarers in Japan. The companies have scheduled the completion of the vessel for January 2027.

Imoto, which is a leading operator of coastal feeder ships, reports the designs for the new vessel feature a hybrid operational capability centered on batteries. The vessel will be able to use containerized batteries that can be swapped out to extend its efficiency. They expect to power the vessel with three 20-foot battery containers with an assumed 2000kWh power capacity. It will employ a standardized and modularized universal plug-in hybrid powertrain.

The vessel will also be equipped to use shore power while on dock both to power its operations and to recharge. Using two 360kW engines, the vessel is expected to have a speed of 12.5 knots. Its maximum range in hybrid operations will be 2,700 miles while using just the three containerized batters it will have a range of 180 miles. It will also be designed for the future installation of low-environment impact technologies such as hydrogen fuel or the use of bio or synthetic fuel.

Plans call for the containership to have a capacity of 200 TEU. It is projected to be 499 gross tons with an overall length of 265 feet (81 meters) and a beam of 44 feet (13.5 meters). Miura Shipbuilding in Saiki City will build the vessel.

 

The hybrid containership will be designed for zero-emission operations and to address the growing shortage of seafarers 

 

The ship will be deployed on the route between Kobe and Hiroshima. It will also operate as a demonstration project supported by the Ministry of Environment’s Carbon Neutral Technology Research and Development Program.

In addition to addressing the challenges of zero-emission operations, Imoto points to the challenges of a shortage of seafarers and skilled mariners to operate vessels. The government has highlighted in the past the anticipated challenges as the Japanese population ages.

Working with Marindows they plan to develop standardized operations that will be supported by a shore operations center meaning the vessel will require fewer people and less skills and experience to operate. They report systems will be modularized and standardized for ease of operation.

One of the five goals of the project is to improve the work environment for crewmembers while also enhancing productivity per crewmember. They believe it will be possible to create a vessel that will have the same expenses as existing ships and can be environmentally friendly while costing basically the same as existing ships. 

They believe mass production will maximize the financial efficiency of the vessel for operators. Modularization will also permit them to protect from obsolesce by creating the ability to replace individual systems as new technologies are commercialized.