Nutritional stress and warming seas threaten Hawaiʻi’s last false killer whales

University of Hawaii at Manoa

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Aerial view of two false killer whales near Hawaiian Islands

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Credit: Pacific Whale Foundation

A seven-year collaborative study has revealed alarming fluctuations in the health of Hawaiʻi’s endangered insular false killer whales, with some individuals losing nearly a quarter of their body weight in just a few months. Published today in Endangered Species Research, the findings provide the first quantitative evidence that nutritional stress and environmental shifts may be driving the decline of this iconic population, which now numbers fewer than 140 individuals.

The research—a partnership between the Pacific Whale Foundation (PWF), the Marine Mammal Research Program (MMRP) at UH Mānoa Hawaiʻi Institute of Marine Biology, and the Okinawa Churashima Foundation—utilized high-resolution drone photogrammetry to track 68 whales (roughly half the remaining population) between 2019 and 2025.

Rapid Declines and Climate Links 

The study documented extreme physiological shifts, including one individual that lost an estimated 28% of its body mass—approximately 500 pounds—over a 10-week period. Researchers also found that the population’s overall Body Condition Index hit a record low in 2020. This decline coincided with a severe marine heatwave and the largest single-year population drop in recent history, suggesting that rising ocean temperatures are directly impacting the whales' ability to maintain necessary energy reserves.

 

“This study is a critical step in understanding whether prey limitation is driving the extinction risk for these whales,” explains Jens Currie, Chief Scientist at PWF, MMRP PhD candidate, and lead author of the study. “Our findings suggest that many individuals are living on a thin metabolic margin. We are now examining how competition with fisheries for high-energy prey like ‘ahi (yellowfin tuna) and mahimahi may be forcing these whales into a state of chronic nutritional stress.”

Mapping Health Across the Archipelago 

The research highlights that health is not distributed equally across the population. Whales in "Cluster 1," known for traveling broad distances across the islands, showed significant variability in their physical condition. This suggests that the high energetic cost of moving long distances to find prey may be taking a heavier physical toll on certain social groups than others.

To ensure the highest level of accuracy, the research team validated their drone measurements against 3D scans of whales in human care at the Okinawa Churashima Foundation in Japan. This calibration provided the foundational data needed to convert aerial images into precise weight and volume estimates, confirming that the study’s measurements are accurate to within 3%.

“This level of precision allows us to pinpoint exactly when and where these whales are struggling, which is key for directing conservation efforts,” notes Lars Bejder, MMRP Director, HIMB Professor, and co-author of the study. 

“This partnership shows how research facilities throughout the Pacific ocean can play a meaningful role in global conservation,” says Nozomi Kobayashi, Chief Research Scientist at the Okinawa Churashima Foundation Research Institute. “Using precise 3D scans from animals in our care to support the recovery of endangered populations in Hawaiʻi is both powerful and inspiring.”

A Cultural and Ecological Loss

The whales found in Hawaiʻi are a distinct, island-resident population adapted to the region’s coastal ecosystems and dependent on these waters for survival. They represent one of the smallest and most endangered whale populations in the United States, where the loss of even a few animals can have consequences for the entire population.

The loss of these apex predators resonates beyond biology. “Hawaiian culture has been losing many kūpuna, elders who carry the libraries of knowledge in cultural practices,” shares Kaʻapuni, Cultural Advisor at PWF. “Losing our native population of false killer whales removes even more knowledge from our islands and our history. We cannot afford to lose any more pieces of Hawaiʻi.” 

Next Steps: A Foundation for Survival

Whales and dolphins today face multiple stressors, including climate change, entanglement in fishing gear, and pollution. Ensuring that false killer whales have enough food can help improve their resilience to these pressures. False killer whales in Hawaiʻi feed on large pelagic fish such as mahi-mahi, ono, aku, and ʻahi—species that are also favored by humans and targeted by fisheries. Understanding whether prey limitations are contributing to the population’s decline is a critical next step in their conservation.

“That is why this work is so important,” emphasizes Bejder. “These findings highlight the need to better understand the energetic requirements of these whales and how external stressors may be affecting them.”

As the population continues to decline at an average rate of 3.5% per year, this study represents a milestone: the first comprehensive effort to track the body mass and physical condition of individuals within Hawaiʻi’s endangered false killer whale population. Establishing this baseline is a critical turning point for management. Future studies built upon this foundational data will be the key to identifying shifting health trends in real-time, allowing for the robust management of pelagic fish stocks and the informed policy decisions necessary for the species’ long-term survival.

 

A false killer whale suspended above the water, after launching its prey high into the air

 

Credit

Pacific Whale Foundation

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Journal

Endangered Species Research

DOI

10.3354/esr01505 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Body condition differs among social clusters and across years in endangered false killer whales in Hawai‘i

 

Study reveals high sedimentation risk in small reservoirs worldwide

Chinese Academy of Sciences Headquarters

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Regular sediment flushing at Xiaolangdi Reservoir helps maintain storage capacity.

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Credit: Photo by DONG Baohua

Reservoirs around the world are losing storage capacity at an average rate of 7.3 percent per decade—disproportionately affecting small reservoirs, which together provide water to billions of people.

The data come from a study published in Nature Sustainability on June 5, which offers the clearest global assessment of reservoir sedimentation to date.

In the study, led by Prof. SONG Chunqiao of the Nanjing Institute of Geography and Limnology (NIGLAS) of the Chinese Academy of Sciences, the researchers developed the Global REservoir Inventory (GREI), combining remote sensing, geospatial data, and engineering records to identify more than 550,000 reservoirs worldwide. Over 95 percent of these reservoirs are smaller than one square kilometer—a category largely absent from previous assessments.

“This study provides the first high-resolution global assessment of reservoir sedimentation that fully incorporates small reservoirs,” said LIU Kai, first author of the study and a researcher at NIGLAS.

Reservoirs are essential infrastructure for flood control, irrigation, water supply, and hydropower generation. However, sediment trapped behind dams gradually reduces usable storage capacity, weakening reservoir functionality and threatening long-term water security. Reduced downstream sediment transport may also alter river morphology and intensify risks such as delta subsidence, coastal erosion, and ecosystem degradation.

Using field-based sedimentation observations from more than 6,000 reservoirs and a physics-guided machine learning framework, the team found that nearly one in five reservoirs already faces rapid storage loss. Small reservoirs are particularly vulnerable, especially in dryland regions such as the southwestern United States, the Middle East, and western Australia.

The study also identifies 16 global sedimentation hotspots, many of which overlap with major irrigated agricultural regions and water-scarce drylands.

The researchers found that around one-quarter of global irrigated land, affecting more than 2 billion people, is exposed to elevated sedimentation risk, raising concerns for long-term water and food security. Without effective intervention, the study estimates that more than half of global reservoirs could experience functional degradation by 2060.

“Reservoir sedimentation deserves greater attention as a growing challenge to long-term water, food, and energy security,” Prof. SONG said. “More sustainable reservoir management will be essential for supporting human well-being and advancing global sustainable development.”

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Journal

Nature Sustainability

DOI

10.1038/s41893-026-01859-y 

Article Title

Global patterns of reservoir sedimentation and overlooked risks in small reservoirs

Article Publication Date

5-Jun-2026

 

Are wading bird populations in urban estuaries in decline?

Wiley

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Urban estuaries can support thriving ecosystems despite bustling human activity. Noting that bird populations can serve as a key indicator of environmental health, researchers recently investigated trends in the New York–New Jersey Harbor, home to the largest breeding population of colonial nesting wading birds (herons, egrets, ibises) in the northeastern United States.

In NYC Bird Alliance’s study, which is published in Conservation Science and Practice, data spanning 22 years showed that the overall population of these wading birds has declined by 27%, faster than average declines across North American birds. Though populations of Great Egret and Snowy Egret increased over time, Black-crowned Night Heron—the most abundant in the harbor and an important environmental indicator species—declined by 55%. Alarmingly, the researchers estimated that the Night Heron could be lost from the region as soon as 2037 if no conservation action is taken.

“Conservation action works, and our discovery of this decline while this bird is still plentiful will allow us to prevent their local extinction. As a top predator that connects to every corner of the harbor ecosystem, the Black-crowned Night Heron is a modern day ‘canary in the coal mine’ telling us something important about the health of our estuary,” said corresponding author Dustin Partridge, PhD, of the NYC Bird Alliance. “Healthier waterways brought nesting wading birds back to our city 50 years ago, and the same investment can keep the Black-crowned Night Heron here too—while improving the lives of all New Yorkers connected to our harbor.”

URL upon publication: https://onlinelibrary.wiley.com/doi/10.1111/csp2.70316

 

Additional Information
NOTE: The information contained in this release is protected by copyright. Please include journal attribution in all coverage. For more information or to obtain a PDF of any study, please contact: Sara Henning-Stout, newsroom@wiley.com.

About the Journal
Conservation Science and Practice focuses on publishing papers related to the science, policy, planning, and practical aspects of conserving biological diversity. Our journal covers a range of topics, from practical experiences to theoretical advancements. We highlight studies that link findings to conservation outcomes, assessing both successful and unsuccessful strategies. Our journal welcomes studies with direct implications and actionable recommendations for improving biodiversity conservation, even if they are based on specific case studies or established methods without broader applicability.

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Journal

Conservation Science and Practice

DOI

10.1111/csp2.70316 

Article Title

Steep declines of colonial wading birds in northeastern North America's largest breeding population

Article Publication Date

3-Jun-2026

 

From Amazon pastures to suburban lawns and groomed bodies: Anthropologist’s new book explores the meanings of plants and hair

University of California - Santa Barbara

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Jeffrey Hoelle's book "Cultivated"

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Credit: UC Santa Barbara

Cultivated lawns, cleared cattle pastures and carefully groomed hair all reflect a shared cultural logic, according to a new book by UC Santa Barbara anthropology professor Jeffrey Hoelle.

In “Cultivated: Plants, Hair, and the Aesthetic of Control” (Yale, 2026), Hoelle explores how people shape both landscapes and bodies through practices tied to cleanliness, order and control. The book draws from research in the Brazilian Amazon as well as urban and suburban landscapes in Brazil and the United States, following what Hoelle calls the “imprint of cultivation.”    

“It examines this relationship between how people shape plants and hair, and how the two are connected in an overarching aesthetic of control,” said Hoelle. “The way these two ‘covers’ are managed is similar in the emphasis on straight lines or geometric shapes, and people consistently read clean-cut bodies and lawns in similar ways.”  

The project grew out of Hoelle’s research on ranching and deforestation at the edge of the Amazon rainforest in Brazil, where he has worked since 2007. After studying the expansion of cattle raising for his first book, he became interested in the symbolic meanings attached to cultivated landscapes. 

“I walked to interviews to ask people about how they used their land. I was focused on the upcoming interview, but I slowly noticed that the people from the local community who accompanied me were always commenting on the state of the pasture while we walked,” he said. “They might say it was ‘clean’ or ‘dirty,’ based on how it looked.      

“I gradually realized these observations of pasture were connected to the character of the people who owned the land,” Hoelle continued. “The farm with the clean pasture was linked to a hard worker, while ‘dirty’ overgrown pastures created concern and criticism — what was wrong with the person who lives here? Were they sick? Lazy? Dead?”

In frontier Amazonia, the “clean” pasture tells everyone that a hard worker lives in that house, but it also shows they are contributing to a larger project of bringing progress to the forests they see as unproductive and wild.  

Hoelle never intended to study the body, he said, but he noticed that people were evaluated in similar ways, based on their control over hair. “Like the plants on the land, the hair on the body was also described using similar terms. I began to see hair and plants as ‘covers’ that both grow, fall out, sprout up and otherwise behave naturally,” he said.      

People recognize the hair-plants connection, he added, giving examples like “stubble,” “cornrows” and “tendrils.” “We use similar tools and procedures to manage them, creating similar imprints, such as straight edges, uniform density, symmetry or removal. Even when the intention is to create a ‘natural’ look, it is necessary to show that a cover has been shaped in some way by a person for it to be considered cultivated.”

Extending the study to the body required thinking about the ethical issues surrounding sensitive and highly personal topics of hair and the body. Hoelle interviewed barbers and beauty experts, but did not ask people about their own hair or observe any procedures.  

Thinking about where hair was on the body and what society defined as the padrão (the dominant standard or pattern) in Brazil revealed general expectations for the groomed body, he explained. It also made clear that women and Afro-Brazilians faced greater scrutiny and baseline standards for grooming body and head hair. 

As Hoelle details in his book, many Americans are already familiar with famed Brazilian beauty exports, the Brazilian wax and the Brazilian blowout. These popular procedures remove pubic hair and straighten or smooth textured or curly hair, respectively. “These and many other beauty procedures associated with a good appearance are influenced by standards of beauty that paint naturally occurring covers of women and Afro-Brazilians as undesirable forms that must be ‘improved,’” he said. 

When Hoelle returned from fieldwork in Brazil, he thought he could focus on writing, but he could not help but see the imprint of cultivation. “It looked a little different,” he said, “but the same emphasis on shaping covers in human spaces was there, as was the reading of the landscape and assigning values to people. 

“These things I observed about plants and hair in Brazil helped me see that the imprint of cultivation extended beyond the boundaries of what I considered the field, and so did the broader system of thought that equates control over covers with virtue,” Hoelle continued.

“This forced me to reconsider external critiques of Amazonian land use and the ways people from outside of the U.S. might find our land uses irrational. While Brazilian farmers clear land to produce food, lawns are the largest irrigated crops in the U.S., consuming massive resources without yielding sustenance. Yet, Americans face immense pressure to maintain them as a symbol of character.”As Hoelle notes, a perfect lawn might reflect hard work, but it could just as easily mean someone paid a landscaper, or that a serial killer lives inside. Ultimately, the link between outward appearance and inner character can be deceptive, whether applied to lawns or hair.

For Hoelle, questioning inherited assumptions about order, cleanliness and control is increasingly important to conversations about sustainability and equality.

“If we’re trying to move toward a more sustainable and just world, then it’s necessary to really question these assumptions,” he said. “We have to understand the system of thought that is inherited and confront it. With plants, how might we move toward relations that are less domineering? And with the body, this is more about being able to decide what is right for you. As one woman in Brazil put it, they just want to be able to have the freedom to decide where and how hair will grow on their own body, like a white man, without all the pressure or assumptions that something is wrong with them.” 

Rather than treating environmental destruction as a problem that exists somewhere else, the book draws parallels between the Amazon frontier and the cultivated landscapes of the U.S.

“This is a similar system of thought that transcends these frontiers,” Hoelle said. “If we believe in sustainability and equality, we have to come to terms with these covers that grow out there, but also on us.”

 

Disgust may contribute to improper waste disposal

University of Gothenburg

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Jacob Sohlberg, political scientist at University of Gothenburg 

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Credit: Photo: Emelie Asplund

A common explanation for why waste management sometimes fails is that carelessness breeds more carelessness. Now, research from the University of Gothenburg shows that dirty waste disposal rooms can evoke feelings of disgust that increase the risk of people disposing of their waste incorrectly.

Previous research has mainly explained littering through social norms — people do what others do. However, studies also show that people’s behavior in public environments is shaped not only by rules and norms but also by emotions and sensory impressions.

“If a waste disposal room is dirty and unpleasant, it does not always help that there are functioning systems for recycling and waste management. People who are sensitive to disgust simply do not want to spend time there, and this increases the risk of improper waste disposal,” says political scientist Jacob Sohlberg.

Littering is a major problem in disadvantaged areas
In the study, he and Senior Professor Peter Esaiasson investigated how sensitivity to disgust affects people’s waste disposal behavior. The research builds on their previous findings showing that littering is a particularly serious problem in disadvantaged neighborhoods.

“In fact, residents in disadvantaged areas consider littering to be just as serious a problem as unemployment and crime, which are two more widely recognized challenges,” says Jacob Sohlberg.

The researchers formulated three hypotheses:

1. Dirty waste disposal environments lead to more improper waste disposal. 
2. People who are easily disgusted are more likely to dispose of waste incorrectly. 
3. The effect of dirty environments is stronger among people with high sensitivity to disgust. 

To investigate this, the researchers conducted three separate studies in socioeconomically disadvantaged residential areas in Sweden, Finland, and Denmark.

In the first study, the researchers collaborated with a municipal housing company in Gothenburg. Over a three-week period, two waste stations were cleaned especially carefully every day, while eight others served as a control group. The researchers documented the amount of incorrectly disposed waste before and after the intervention.

“At the cleaned stations, littering clearly decreased, while the control stations looked much the same as before,” says Jacob Sohlberg.

Disgust sensitivity was measured
In the second study, an experiment was conducted with more than 300 residents in a disadvantaged area of Gothenburg. Participants were shown images of either a clean or a dirty waste station and answered questions about how they would act if they needed to use them. At the same time, their sensitivity to disgust was measured through questions about things such as mold, dog feces, and cockroaches.

“People who saw the dirty waste station were significantly less likely to say they would open the hatch and dispose of their waste correctly. In that study, the effect was particularly strong among individuals with high sensitivity to disgust.”

The third study built on the same experimental design but was conducted online with more than one thousand participants living in disadvantaged areas in Sweden, Finland, and Denmark. Here too, the researchers found strong evidence that dirty environments directly increased the risk of improper waste disposal.

Several positive effects of well-maintained waste disposal rooms
Taken together, the results suggest that municipalities and housing companies can reduce littering by keeping waste disposal areas clean and well maintained. At the societal level, this may have several positive consequences.

“In addition to improving the environment and quality of life in residential areas, it will probably also become easier to maintain order when an area is perceived as clean and well cared for. From a broader societal perspective, it is therefore important that waste and recycling are handled properly,” says Jacob Sohlberg.

 

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Journal

Journal of Environmental Psychology

DOI

10.1016/j.jenvp.2026.103057 

Method of Research

Case study

Subject of Research

Not applicable

Article Title

How Disgust Sensitivity Shapes Waste Disposal Behavior in Everyday Public Environments: Experimental and Difference-in-Differences Studies in the Nordic Countries

Italian Bill On Nuclear Energy Progressing Through Parliament

June 5, 2026 
By World Nuclear News

Italy’s lower house of parliament, the Chamber of Deputies, has approved a bill presented by Prime Minister Giorgia Meloni’s government paving the way for the country’s return to the use of nuclear energy.

In October last year, Italy’s Council of Ministers, at a meeting chaired by Meloni, approved for final consideration a bill delegating responsibility for the reintroduction of nuclear energy in the country to the government. The bill empowers the government to comprehensively regulate the introduction of ‘sustainable’ nuclear power, within the framework of European decarbonisation policies by 2050 and energy security objectives. The mandate includes, among other things, the development of a National Programme for Sustainable Nuclear Power, the establishment of an independent Nuclear Safety Authority, the strengthening of scientific and industrial research, the development of new skills, and the implementation of information and awareness campaigns.

The bill has now been passed by the Chamber of Deputies with 155 votes in favour, 86 against and eight abstentions.

The bill now goes to the upper house, the Senate, where the government expects the legislation to get final approval before the summer recess at the end of July. The implementing legislative decrees must be adopted within 12 months of the law’s entry into force.


Italy operated a total of four nuclear power plants starting in the early 1960s but decided to phase out nuclear power in a referendum that followed the 1986 Chernobyl accident. It closed its last two operating plants, Caorso and Trino Vercellese, in 1990.

In late March 2011, following the Fukushima Daiichi accident, the Italian government approved a moratorium of at least one year on construction of nuclear power plants in the country, which had been looking to restart its long-abandoned nuclear programme. In a poll held in June of that year, 94% of voters rejected the construction of any new nuclear reactors in Italy.

Since then, public opinion has become more favourable towards nuclear energy in the country and in May 2023, the Italian Parliament approved a motion to urge the government to consider incorporating nuclear power into the country’s energy mix. In September of that year, the first meeting was held of the National Platform for Sustainable Nuclear Power, set up by the government to define a time frame for the possible resumption of nuclear energy in Italy and identify opportunities for the country’s industrial chain already operating in the sector.