Atlantic nurse sharks show faster growth patterns in Biscayne Bay than nearby Bimini, Bahamas

University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science

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A juvenile nurse shark is gently restrained for measurements and sampling.

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Credit: Shark Research and Conservation Program, University of Miami Rosenstiel School.

A new study based on long-term monitoring data demonstrates significant differences in growth between nurse sharks off the coast of Miami and those living just across the Gulf Stream.

A new study from the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science shows that juvenile Atlantic nurse sharks (Ginglymostoma cirratum) grow more rapidly as juveniles and reach smaller maximum sizes than nurse sharks in Bimini, Bahamas—locations so close that these populations have historically been assumed to be the same.

Evidence from long-term fisheries-independent monitoring by the Shark Research and Conservation Program at the Rosenstiel School shows Biscayne Bay is an important nursery habitat for numerous species of shark. 

“Despite human degradation of Biscayne Bay, our data suggests it remains critical habitat for many species of juvenile shark, providing essential resources and protection from predation early in life,” said John Hlavin, Ph.D. student in the Abess Center for Ecosystem Science and Policy and lead author on the study. 

“Using data from nurse sharks captured more than once between 2017 and 2025, we were able to assess their growth rates and estimate the size of habitats they rely on based on the distance between initial and final capture,” said Emily Yeager, co-author of the study and a doctoral candidate in the Department of Environmental Science and Policy at the Rosenstiel School. “We found significant differences that show more rapid growth at smaller sizes in Biscayne Bay compared to the Bahamas.”

The study found that juvenile nurse sharks in Biscayne Bay likely rely on small home ranges while young, which increase in size as they grow, and that their growth rates and maximum size are distinct from nearby nurse sharks in the Bahamas. 

“These differences are likely to be driven by variances in access to resources, suggesting that resource availability may be more limited in Bimini, or that juveniles in Bimini may face greater competition from abundant juvenile lemon sharks that share those habitats,” said Catherine Macdonald, Ph.D., an associate professor in the Department of Environmental Science and Policy, and the director of the Shark Research and Conservation Program.  “These groups may show these significant differences as a result of greater resource availability and/or historic fishing pressure, which has been shown to select for faster growth and smaller maximum sizes.” 

Because South Florida includes extensive recreational fisheries and a historic fishery targeting nurse sharks for their skin and liver oil, there may be genetic differences in nurse shark populations in Florida that explain the observed differences.

The authors emphasize the importance of long-term monitoring that can provide these kinds of data sets. 

“Conducting studies of life-history traits across different habitats within a region can help us better understand how local variation might affect traits that are essential for science-based fisheries management,” added Hlavin. This is especially important for species like nurse sharks that are threatened by poorly managed or unmanaged fisheries in many parts of their range.”

The research was supported by the University of Miami’s Abess Center Fellowship, Florida Sea Grant–Guy Harvey Foundation,  and the National Science Foundation Graduate Research Fellowship 

The study, titled “Is the seagrass greener on the other side? Faster growth in Biscayne Bay, Florida’s nurse sharks (Ginglymostoma cirratum) compared to neighboring conspecifics of Bimini, The Bahamas” was published in the journal Environmental Biology of Fishes on December 18, 2025. The authors include John Hlavin*1,2,3,4, Emily Yeager1,2,3,4, Christine Martin1,2,3,4, Christopher Will1,2, Nicholas Perni2, Christian Pankow1,2, and Catherine Macdonald1,2,3

¹ Shark Research and Conservation Program, University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, ² Field School Scientific Training, ³ Department of Environmental Science and Policy, University of Miami, ⁴ Abess Center for Ecosystem Science and Policy, University of Miami

About the University of Miami and Rosenstiel School of Marine, Atmospheric and Earth Science

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 academic community comprises 12 schools and colleges serving more than 19,000 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, and a commitment to tackling the challenges facing our world. The University of Miami is a member of the prestigious Association of American Universities (AAU).

 Founded in 1943, the Rosenstiel School of Marine, Atmospheric, and Earth Science is one of the world’s premier research institutions in the continental United States. The School’s basic and applied research programs seek to improve understanding and prediction of Earth’s geological, oceanic, and atmospheric systems by focusing on four key pillars:

*Saving lives through better forecasting of extreme weather and seismic events. 

*Feeding the world by developing sustainable wild fisheries and aquaculture programs. 

*Unlocking ocean secrets through research on climate, weather, energy and medicine. 

*Preserving marine species, including endangered sharks and other fish, as well as protecting and restoring threatened coral reefs. www.earth.miami.edu.

 

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Journal

Environmental Biology of Fishes

DOI

10.1007/s10641-025-01784-7 

Method of Research

Data/statistical analysis

Subject of Research

Animals

Article Title

Is the seagrass greener on the other side? Faster growth in Biscayne Bay, Florida’s nurse sharks (Ginglymostoma cirratum) compared to neighboring conspecifics of Bimini, The Bahamas

 

Tests uncover unexpected humpback sensitivity to high-frequency noise

University of Queensland hearing tests conducted across kilometres of ocean off the Australian coast show humpback whales react to higher frequency sounds than expected.

Associate Professor Rebecca Dunlop from UQ’s School of the Environment said the discovery has implications for the mitigation of noise-related human activity along whale migration routes.

“Until our studies, estimates of humpback hearing sensitivity were inferred based on the anatomy of their ears,” Dr Dunlop said.

“In a series of experiments off the Sunshine Coast, we exposed whales to upsweep sounds at a range of frequencies.

“We looked for changes such as slowing their swimming or turning towards or away from the sound as an indication they’d heard it.

“Against a background of natural noise, we confirmed that the humpbacks’ best hearing range largely overlaps with the estimates from anatomical models.

“But their responses at 22 kHz provided the first direct evidence humpbacks are highly sensitive to higher frequencies at the upper end of the human hearing range.

“They are more sensitive at these higher frequencies than the anatomical models predicted.

“This finding is significant because baleen whale species – which includes humpbacks – had previously been considered low-frequency hearing specialists.

“Our experiments also showed their ability to hear quiet signals within natural ocean noise matched data from hearing tests on captive toothed whales, indicating our study in a wild setting was able to mimic hearing experiments in a controlled environment.”

The UQ team conducted the hearing tests across 4 whale migration seasons, 2021-2024.

In a process called behavioural observation audiometry (BOA), frequency-modulated upsweeps were broadcast from a boat positioned in the path of a migrating whale group but too far away to be heard.

As the group approached and came within hearing range, observers watched for deviations in the whale’s course or a change in speed and/or dive behaviour to indicate the sound was heard.

This was repeated for 8 to 10 different groups before the frequency of the upsweeps was changed, and the whole process repeated.

“The whales typically responded by temporarily slowing down or speeding up and turning away to avoid the source vessel and this behavioural change-point was noted,” Dr Dunlop said.

“Sometimes this was followed by heading directly towards the vessel and circling it or resuming their original course, so we know the experiments were a minor but important disruption to their behaviour.”

The results have been displayed in a graph called an audiogram, which shows how sensitive the animal is to each frequency.

For these experiments, the most sensitive whale group for each frequency was used to produce the first data-driven audiogram for humpback whales. It shows their hearing range extends from at least 80 Hz at the low end to 22 kHz at the high end.

“With better understanding of humpback hearing, we can better protect them and minimise human interference on their lives,” Dr Dunlop said.

The research has been published in a research paper in Communications Biology and a research paper in Current Biology and work was conducted under relevant permits and animal ethics approvals.

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Journal

Current Biology

DOI

10.1016/j.cub.2025.11.068 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

A predicted humpback whale hearing curve based on modified behavioral observation audiometry data

Article Publication Date

29-Jan-2026

PROVING MAHA WRONG, AGAIN

Paracetamol and ibuprofen safe in first year of life

A new landmark study supports the safety of the common painkillers paracetamol and ibuprofen in the first year of life, and finds no link to eczema or bronchiolitis, a common respiratory illness.

University of Auckland

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A new landmark study supports the safety of the common painkillers paracetamol and ibuprofen in the first year of life, and finds no link to eczema or bronchiolitis, a common respiratory illness.

Previous research suggested a potential link between paracetamol use in the first year of life and later eczema, asthma and other diseases.

“Our study found that paracetamol and ibuprofen are incredibly safe to use in young children,” says lead researcher Professor Stuart Dalziel, Cure Kids Chair of Child Health Research at Waipapa Taumata Rau, University of Auckland, and Paediatrician at Starship Children’s Hospital.

Dalziel says paracetamol and ibuprofen are the most common medicines prescribed or bought over the counter for babies worldwide.

“These results give parents and health professionals high confidence to continue to use these important medications.”

Almost 4,000 babies across New Zealand participated from birth, with half randomised to ensure their parents provided paracetamol and half to ensure their parents  provided ibuprofen when the infants required medication for fever or pain relief in the first year of life.

The researchers asked parents at regular intervals whether their children had eczema or asthma symptoms, or bronchiolitis. They also checked prescribing and hospital records.

The results for the first year of data have now been analysed and published in the leading journal The Lancet Child & Adolescent Health.

Eczema affected about 16 percent of babies given paracetamol and 15 percent of those given ibuprofen. Bronchiolitis occurred in about five percent of babies in both groups. These differences were not significant. Serious side effects were rare, and none was caused by the medications.

The study found no association between either medication and eczema or bronchiolitis and confirmed that both drugs were safe to use.

It is the first randomised controlled trial – considered the gold standard for research – to address this question.

This paper is part of a longer project dubbed the ‘Paracetamol and Ibuprofen in the Primary Prevention of Asthma in Tamariki (PIPPA Tamariki) study’.

PIPPA Tamariki is the largest trial ever conducted in children in New Zealand, and participants are being followed from birth to age six.

The researchers will soon publish findings on the same children at age three, and later at age six.

The long-term objective of the study is to test whether there are any links between paracetamol and specific conditions that can only be accurately diagnosed once children reach school age.

“We know that two‑thirds of children who are wheezy at age three years don’t develop asthma by age six,” says Dalziel.

“Thus we need to wait until school age to ultimately test if paracetamol in the first year of life causes asthma.”

Similarly, developmental disorders such as autism and attention deficit hyperactivity disorder (ADHD) are more accurately diagnosed as children get older.

Lead author Dr Eunicia Tan, a senior lecturer at the University of Auckland and emergency physician at Middlemore Hospital, says, “Ultimately, the study will provide important evidence regarding the link between paracetamol use and asthma, eczema, hay fever, and developmental disorders, such as autism and ADHD.”

The study was funded by the Health Research Council of New Zealand and Cure Kids and run by the University of Auckland and the Medical Research Institute of New Zealand, Wellington.

Media contacts
Professor Stuart Dalziel, Cure Kids Chair of Child Health Research, Faculty of Medical and Health Sciences, Waipapa Taumata Rau, University of Auckland
E: s.dalziel@auckland.ac.nz

Dr Eunicia Tan, senior lecturer, Faculty of Medical and Health Sciences, Waipapa Taumata Rau, University of Auckland and emergency physician at Middlemore Hospital
M: 021 487 771
E: Eunicia.Tan@middlemore.co.nz

Jodi Yeats, media adviser, Faculty of Medical and Health Sciences, Waipapa Taumata Rau, University of Auckland
M: +64 27 202 6372
E: jodi.yeats@auckland.ac.nz

 

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Journal

The Lancet Child & Adolescent Health

DOI

10.1016/S2352-4642(25)00341-4 

Method of Research

Randomized controlled/clinical trial

Subject of Research

People

Article Title

Paracetamol versus ibuprofen as required for fever or pain in the first year of life and the risk of eczema and bronchiolitis at age 1 year in New Zealand (PIPPA Tamariki): a multicentre, parallel-group,

Article Publication Date

22-Jan-2026

Major US tobacco brands flouting platform + federal policies to restrict young people’s access to their content on Instagram

Violations include lax/missing age verification, sponsorship disclosure, and health warnings

BMJ Group

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Leading US tobacco brands are flouting platform and federal marketing policies designed to restrict young people’s access to their content on the popular social media platform Instagram, indicates research published online in the journal Tobacco Control.

 

Violations include lax or missing age verification, disclosure on brand-influencer relationships, and health warnings, the findings show.

 

In 2024, around 2.25 million middle and high school students reported having used a tobacco or nicotine product in the past 30 days. That’s nearly 550,000 fewer than in 2023, but still leaves millions of teen nicotine users, underscoring the ongoing need for policy and prevention efforts, emphasise the researchers.

 

Most existing research on tobacco-related social media data has summarised themes, content types, and the prevalence of pro-tobacco messaging, note the researchers. But few studies have assessed compliance with specific federal or platform level marketing policies designed to restrict young people’s access to such content, they add.

 

To plug this knowledge gap, the researchers retrospectively collected 1654 Instagram posts relating to e-cigarettes, cigarettes, and nicotine pouches, and posted between October 2022 and the end of September 2024.

 

These were collected from the main pages and tagged sections of 6 leading tobacco brand accounts, based on market share data and consumer reviews: Vuse; Lost Mary; ZYN; Velo; Lucky Strike; and Winston.

 

The posts were analysed and coded for compliance with Instagram, Federal Trade Commission (FTC), and US Food and Drug Administration (FDA) marketing policies, including age verification, financial disclosure for influencers/celebrities with at least 10,000 followers, presence of required health warnings (‘contains nicotine’, for example), and restricted URL links.

 

To test Instagram’s age-gating policy, one of the researchers created a new Instagram account registered to a fictitious user under the age of 21. Instagram requires users to enter a birth date during account setup, which determines access to age-restricted content.

 

The researcher then systematically clicked on the associated URL link. Posts that were accessible without age verification were recorded as non-compliant.

 

Instagram also prohibits content or posts that directly sell, link to, or facilitate access to branded tobacco products.To evaluate this policy, coders reviewed the account profile

associated with each post and coded it for the presence of URL links to affiliate pages, products, and services. The percentage of posts with account profiles that contained such URL links, indicating non-compliance, was recorded.

 

The analysis revealed major gaps in enforcement. Over two thirds (69.5%;1148) of the posts contained URL links to commercial tobacco websites. Unrestricted access to tobacco content was observed among nearly half (47%; 772) of the posts, which came from 2 brands: Lucky Strike and Lost Mary.

 

“This is particularly concerning given that Lost Mary has been shown to use marketing tactics in their Instagram posts that may be appealing to youth (eg, featuring flavoured products and use of bright colours),” note the researchers.

 

Influencers or celebrities appeared in nearly 1 in 5 (19%; 317) posts, of which nearly 42% (132) didn’t disclose a financial relationship between the brand and the influencer or celebrity. These posts received the highest average number of likes (115).

 

Influencers or celebrities who partnered with Vuse and Velo inconsistently disclosed their financial relationship across multiple posts; and 88% (278) of influencer or celebrity-related posts contained URL links.

 

Nearly three quarters (73%;1200) of posts carried a health warning label, but only just over 41% (683) carried an age warning label. Only a few posts related to unsubstantiated health claims (less than 1%; 15).

 

The researchers acknowledge that the findings relate to data collected during a specific time frame and for 6 brands only. The findings may therefore not apply to subsequent periods of time, other brands, or other social media platforms. Nor were the researchers able to confirm if an actual financial relationship existed between an influencer’s account and a brand.

 

But they point out: “Despite platform-specific policies restricting access to promotional tobacco content and prohibiting direct sales, posts contained links to commercial tobacco websites, suggesting inconsistent enforcement of Instagram’s age-gating and commerce policies.

 

“Federal policies require transparency in advertising, including in influencer-brand partnerships, yet influencer-related posts lacked proper FTC-mandated disclosures of financial relationships.

 

“Additionally, compliance with FDA regulations on health warnings was inconsistent, as a portion of posts failed to contain the required nicotine addiction warnings.”

 

They add: “Taken together, these findings highlight ongoing concerns regarding tobacco posts on Instagram, compliance with existing policies, and the potential impact of these posts on shaping youth pro-tobacco-related attitudes and behaviours.”

 

And they conclude: “These findings underscore the need for tobacco control policies to regulate direct promotions and address the role of marketing tactics that contribute to youth tobacco normalisation.”

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Journal

Tobacco Control

DOI

10.1136/tc-2025-059609 

Method of Research

Observational study

Article Title

Evaluating policy compliance among leading tobacco brands on Instagram

Article Publication Date

27-Jan-2026