Science
How little plastic does it take to kill marine animals? Scientists have answers
Ocean plastic kills sea creatures. It can obstruct, perforate or twist their airways and gastrointestinal tracts.
Now new research shows it takes just 6 pieces of ingested rubber the size of a pencil eraser to kill most sea birds.
For marine mammals, 29 pieces of any kind of plastic — hard, soft, rubber or fishing equipment — is often lethal.
It’s the first time researchers have quantified how much and what kind of plastic — soft, hard, rubber or fishing debris — is needed to kill a bird, marine mammal or a turtle.
“Seeing the particularly small thresholds for rubber and seabirds, for example, that just six pieces of rubber, each smaller on average than the size of a pea was enough to kill 90% of sea birds that ingested it. … That was particularly surprising to me,” said Erin Murphy, a researcher with the group Ocean Conservancy and the department of ecology and evolution at the University of Toronto.
The sea birds were less sensitive to hard plastic: It would take 25 pieces of the pea-sized hard plastic pieces to ensure a 90% chance of dying.
Murphy and her colleagues from the University of Tasmania, in Australia, the Commonwealth Scientific and Industrial Research Organization, also from Australia, and the Federal University of Alagoas, in Brazil, published their study Monday in the journal Proceedings of the National Academies of Science.
For decades, researchers have been documenting death by plastic in marine animals. They have reported it in the gastrointestinal tracts of nearly 1,300 marine species — including every species of sea turtle, and in every family of seabird and marine mammal.
The team analyzed data from 10,412 published necropsies, or animal autopsy reports. Of the animals studied, 1,306 were sea turtles, representing all seven species of the animal; 1,537 were seabirds representing 57 species; and 7,569 were marine mammals across 31 species.
They found that 35% of the dead seabirds, 12% of marine mammals and 47% of sea turtles examined had ingested plastic. Seabirds seemed to be particularly sensitive to rubber. For marine mammals, soft plastics — such as plastic bags — and fishing debris was most harmful. For sea turtles, it was hard and soft plastics that were the most lethal.
“This was severe trauma or damage to the GI tract, or blockage of the stomach or intestines from plastic … and so these were physical harms that you could see, that you could see in the gut of these animals, and that were reported by scientists,” Murphy said in describing the reports.
The paper did not look at other ways plastic can kill marine animals — strangulation, entanglement and drowning.
Nor did it look at malnutrition or toxicity caused by eating plastic.
“So, this is likely an underestimate of the impacts of ingestion, and it’s definitely an underestimate of the lethality of plastics more broadly,” Murphy said.
Nearly half the animals in their analysis were threatened or endangered species.
More than 12 million tons of plastic enters the world’s oceans every year, according to several environmental and industry reports. That’s a garbage truck’s worth dumped every minute.
According to the United Nations, that number is expected to triple in the next 20 years.
“I find this piece a brilliant contribution to the field,” said Greg Merrill, a researcher with the Duke University Marine Lab, who did not participate in the study.
“We have thousands of examples of marine animals ingesting plastic debris. But for a number of reasons, eg. lack of data, difficulty of conducting laboratory-based experiments, and ethical considerations, risk assessments are really challenging to conduct,” he said in an email.
Such assessments are crucial for linking plastic ingestion to mortality, because “once we know some of those thresholds, they can help policy makers make informed decisions,” Merrill said.
And that’s what Murphy said she and her co-authors are hoping for: That lawmakers and others can use this information to reduce plastic, by crafting regulations to ban or reduce plastics, such as plastic bag or balloon bans, and encouraging small, local events such as beach cleanups.
“The science is clear: We need to reduce the amount of plastic that we’re producing and we need to improve collection and recycling to clean up what’s already out there,” said Murphy.
This year, in international talks on limiting plastic pollution, oil- and gas-producing countries succeeded in preventing language that would reduce the amount of plastics produced.
Science
What’s in a Name? For These Snails, Legal Protection
The sun had barely risen over the Pacific Ocean when a small motorboat carrying a team of Indigenous artisans and Mexican biologists dropped anchor in a rocky cove near Bahías de Huatulco.
Mauro Habacuc Avendaño Luis, one of the craftsmen, was the first to wade to shore. With an agility belying his age, he struck out over the boulders exposed by low tide. Crouching on a slippery ledge pounded by surf, he reached inside a crevice between two rocks. There, lodged among the urchins, was a snail with a knobby gray shell the size of a walnut. The sight might not dazzle tourists who travel here to see humpback whales, but for Mr. Avendaño, 85, these drab little mollusks represent a way of life.
Marine snails in the genus Plicopurpura are sacred to the Mixtec people of Pinotepa de Don Luis, a small town in southwestern Oaxaca. Men like Mr. Avendaño have been sustainably “milking” them for radiant purple dye for at least 1,500 years. The color suffuses Mixtec textiles and spiritual beliefs. Called tixinda, it symbolizes fertility and death, as well as mythic ties between lunar cycles, women and the sea.
The future of these traditions — and the fate of the snails — are uncertain. The mollusks are subject to intense poaching pressure despite federal protections intended to protect them. Fishermen break them (and the other mollusks they eat) open and sell the meat to local restaurants. Tourists who comb the beaches pluck snails off the rocks and toss them aside.
A severe earthquake in 2020 thrust formerly submerged parts of their habitat above sea level, fatally tossing other mollusks in the snail’s food web to the air, and making once inaccessible places more available to poachers.
Decades ago, dense clusters of snails the size of doorknobs were easy to find, according to Mr. Avendaño. “Full of snails,” he said, sweeping a calloused, violet-stained hand across the coves. Now, most of the snails he finds are small, just over an inch, and yield only a few milliliters of dye.
Science
Video: This Parrot Has No Beak, But Is at the Top of the Pecking Order
new video loaded: This Parrot Has No Beak, But Is at the Top of the Pecking Order
By Meg Felling and Carl Zimmer
April 20, 2026
Science
Contributor: Focus on the real causes of the shortage in hormone treatments
For months now, menopausal women across the U.S. have been unable to fill prescriptions for the estradiol patch, a long-established and safe hormone treatment. The news media has whipped up a frenzy over this scarcity, warning of a long-lasting nationwide shortage. The problem is real — but the explanations in the media coverage miss the mark. Real solutions depend on an accurate understanding of the causes.
Reporters, pharmaceutical companies and even some doctors have blamed women for causing the shortage, saying they were inspired by a “menopause moment” that has driven unprecedented demand. Such framing does a dangerous disservice to essential health advocacy.
In this narrative, there has been unprecedented demand, and it is explained in part by the Food and Drug Administration’s recent removal of the “black-box warning” from estradiol patches’ packaging. That inaccurate (and, quite frankly, terrifying) label had been required since a 2002 announcement overstated the link between certain menopause hormone treatments and breast cancer. Right-sizing and rewording the warning was long overdue. But the trouble with this narrative is that even after the black-box warning was removed, there has not been unprecedented demand.
Around 40% of menopausal women were prescribed hormone treatments in some form before the 2002 announcement. Use plummeted in its aftermath, dipping to less than 5% in 2020 and just 1.8% in 2024. According to the most recent data, the number has now settled back at the 5% mark. Unprecedented? Hardly. Modest at best.
Nor is estradiol a new or complex drug; the patch formulation has existed for decades, and generic versions are widely manufactured. There is no exotic ingredient, no rare supply chain dependency, no fluke that explains why women are suddenly being told their pharmacy is out of stock month after month.
The story is far more an indictment of the broken insurance industry: market concentration, perverse incentives and the consequences of allowing insurance companies to own the pharmacy benefit managers that effectively control drug access for the majority of users. Three companies — CVS Caremark, Express Scripts and OptumRx — manage 79% of all prescription drug claims in the United States. Those companies are wholly owned subsidiaries of three insurance behemoths: CVS Health, Cigna and UnitedHealth Group, respectively. This means that the same corporation that sells you your insurance plan also decides which drugs get covered, at what price, and whether your pharmacy can stock them. This is called vertical integration. In another era, we might have called it a cartel. The resulting problems are not unique to hormone treatments; they have affected widely used medications including blood thinners, inhalers and antibiotics. When a low-cost generic such as estradiol — a medication with no blockbuster profit margins and no patent protection — runs into friction in this system, the friction is not random. It is structural. Every decision in that chain is filtered through the same corporate profit motive. And when the drug in question is an off-patent estradiol patch that has negligible profit margins because of generic competition but requires logistical investment to keep consistently in stock? The math on “how much does this company care about ensuring access” is not complicated.
Unfortunately, there is little financial incentive to ensure smooth, consistent access. There is, however, significant financial incentive to steer patients toward branded alternatives, or simply to let supply tighten — because the companies aren’t losing much profit if sales of that product dwindle. This is not a conspiracy theory: The Federal Trade Commission noted this dynamic in a report that documented how pharmacy benefit managers’ practices inflate costs, reduce competition and harm patient access, particularly for independent pharmacies and for generic drugs.
Any claim that the estradiol patch shortage is meaningfully caused by more women now demanding hormone treatments is a distraction. It is also misogyny, pure and simple, to imply that the solution to the shortage is for women’s health advocates to dial it down and for women to temper their expectations. The scarcity of estradiol patches is the outcome of a broken system refusing to provide adequate supply.
Meanwhile, there are a few strategies to cope.
- Ask your prescriber about alternatives. Estradiol is available in multiple formulations, including gel, spray, cream, oral tablet, vaginal ring and weekly transdermal patch, which is a different product from the twice-weekly patch and may be more consistently available depending on manufacturer and region.
- Consider an online pharmacy. Many are doing a good job locating and filling these prescriptions from outside the pharmacy benefit manager system.
- Call ahead. Patch shortages are inconsistent across regions and distributors. A call to pharmacies in your area, or a broader geographic radius if you’re able, can locate stock that your regular pharmacy doesn’t have.
- Consider a compounding pharmacy. These sources can sometimes meet needs when commercially manufactured products are inaccessible. The hormones used are the same FDA-regulated bulk ingredients.
Beyond those Band-Aid solutions, more Americans need to fight for systemic change. The FTC report exists because Congress asked for it and committed to legislation that will address at least some of the problems. The FDA took action to change the labeling on estrogen in the face of citizen and medical experts’ pressure; it should do more now to demand transparency from patch manufacturers.
Most importantly, it is on all of us to call out the cracks in the current system. Instead of repeating “there’s a patch shortage” or a “surge in demand,” say that a shockingly small minority of menopausal women still even get hormonal treatments prescribed at all, and three drug companies control the vast majority of claims in this country. Those are the real problems that need real solutions.
Jennifer Weiss-Wolf, the executive director of the Birnbaum Women’s Leadership Center at New York University School of Law, is the author of the forthcoming book “When in Menopause: A User’s Manual & Citizen’s Guide.” Suzanne Gilberg, an obstetrician and gynecologist in Los Angeles, is the author of “Menopause Bootcamp.”
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