How Little Plastic Can Kill Marine Wildlife? A Study of 10,000 Necropsies Reveals a Disturbing Answer
A few pieces of plastic floating in the ocean may not look particularly threatening.
A bottle cap.
A torn shopping bag.
A piece of balloon.
A fragment of rubber.
Some discarded fishing line.
Compared with a whale, turtle, or seabird, these objects can seem almost insignificant.
But a major analysis of more than 10,000 marine-animal necropsies has revealed just how misleading that intuition can be.
For an Atlantic puffin, researchers estimated that ingesting less than three sugar cubes' worth of plastic was associated with a 90% probability of death from plastic ingestion.
For a loggerhead sea turtle, the corresponding volume was only a little more than two baseballs.
For a harbor porpoise, it was approximately one soccer ball.
At the 50% mortality threshold, the amounts were even smaller:
less than one sugar cube for a puffin,
less than half a baseball for a loggerhead turtle,
and less than one-sixth of a soccer ball for a harbor porpoise.
These comparisons do not mean that one particular soccer ball tossed into the ocean will automatically kill a porpoise.
They are illustrations derived from a statistical model that relates the volume of macroplastic inside an animal's gastrointestinal tract to the probability that plastic caused its death.
Still, the message from the research is unsettlingly clear:
Marine animals do not necessarily need to consume stomachs full of garbage before plastic becomes deadly.
Sometimes the dangerous amount is surprisingly small.
The Study Examined 10,412 Dead Marine Animals
The research was published in Proceedings of the National Academy of Sciences under the title:
“A quantitative risk assessment framework for mortality due to macroplastic ingestion in seabirds, marine mammals, and sea turtles.”
The team included researchers from Ocean Conservancy, the University of Toronto, the University of Tasmania, CSIRO Environment, and the Federal University of Alagoas in Brazil.
Researchers compiled necropsy data from around the world involving:
1,537 seabirds representing 57 species
1,306 sea turtles representing all seven living sea-turtle species
and
7,569 marine mammals representing 31 species.
Altogether:
10,412 animals.
For each usable case, researchers needed information about both:
the animal's cause of death,
and
the plastic found inside its gastrointestinal tract.
They then used statistical modeling to estimate how mortality risk changed with the amount and type of plastic an animal had consumed.
It is one of the most comprehensive attempts yet to answer a deceptively simple question:
How much swallowed plastic becomes dangerous?
Plastic Was Already Inside Thousands of the Animals
The analysis also demonstrated how widespread ingestion has become.
Among the animals examined:
47% of sea turtles had ingested plastic.
35% of seabirds had ingested plastic.
12% of marine mammals had ingested plastic.
Across the entire dataset, about 21.5% of the animals contained plastic.
But an important scientific distinction is necessary here.
These were not randomly selected healthy animals swimming throughout the world's oceans.
They were necropsied animals drawn largely from stranding networks, published studies, and mortality databases.
Therefore, the percentages should not be interpreted to mean exactly 47% of every living sea turtle worldwide currently contains plastic.
They describe the animals represented in this large mortality dataset.
Even with that limitation, however, the results show that plastic ingestion appears across an extraordinary range of marine wildlife.
The paper notes that plastic ingestion has now been documented in nearly 1,300 marine species, including every sea-turtle species and representatives from all seabird and marine-mammal families.
How Plastic Actually Kills an Animal
Plastic is often discussed as though its danger comes mainly from toxic chemicals.
For large pieces of plastic, the immediate mechanism can be brutally mechanical.
Macroplastic can cause:
intestinal obstruction
perforation
torsion
internal injury
and ultimately:
starvation or death.
Imagine swallowing an object that cannot be digested and cannot move successfully through the gastrointestinal tract.
It may lodge somewhere.
Food stops passing.
Gas and fluids accumulate.
The intestinal wall can become damaged.
Sharp material may penetrate tissue.
Blood supply can be compromised.
Or the animal's stomach may remain physically occupied by material containing no nutrition.
The animal can effectively feel full while slowly starving.
That is why even a quantity that looks small beside the animal's overall body size can become catastrophic.
The important comparison is not:
plastic versus whole animal.
It is:
plastic versus the diameter, flexibility, and anatomy of the digestive system through which it must pass.
Imrul
For a Puffin, Less Than Three Sugar Cubes Can Mean Extreme Risk
Perhaps the most striking result involves seabirds.
Researchers used the Atlantic puffin—roughly 28 centimeters, or 11 inches, long—as an illustrative example.
For a bird of that size, the modeled plastic volume associated with a 90% probability of plastic-induced mortality was less than the volume of three ordinary sugar cubes.
At approximately the 50% mortality threshold:
less than one sugar cube's volume was enough.
Think about that.
A bird may cross enormous expanses of ocean, survive storms, dive for fish, escape predators, and navigate across hundreds or thousands of miles—
yet a handful of synthetic debris small enough to fit inside a teaspoon can create an extreme mortality risk.
And some materials were even more dangerous than the overall plastic-volume comparison suggests.
Six Tiny Pieces of Rubber Could Be Enough
When the researchers separated plastics by material type, synthetic rubber emerged as particularly dangerous for seabirds.
The analysis estimated that only six pieces of rubber, each smaller than a pea, could correspond to a 90% probability of mortality in seabirds.
That matters because rubber debris can enter oceans through many routes.
Fragments can originate from:
balloons,
consumer products,
industrial materials,
and other synthetic rubber goods.
Small size does not necessarily make debris safer.
An object's danger depends partly on:
shape,
rigidity,
ability to pass through the gut,
and where it becomes lodged.
The study found that rubber and hard plastics presented especially high risks for seabirds.
Why Do Seabirds Eat Plastic?
A seabird does not know what plastic is.
It evolved in oceans where floating objects historically tended to have biological significance.
Some plastic fragments resemble prey.
Others become coated with marine organisms.
Plastic can also acquire chemical odors associated with productive feeding areas.
A bird searching rapidly for food at sea must make decisions under conditions where rejecting every suspicious object could also mean missing actual prey.
Evolution prepared these animals for:
fish,
crustaceans,
squid,
and other natural food.
It did not prepare them for billions of pieces of durable synthetic material introduced into the environment over only a few human generations.
Plastic becomes what biologists sometimes describe as an evolutionary trap:
a novel human-made stimulus triggering behavior that once helped an animal survive but now exposes it to danger.
Sea Turtles Face a Different Plastic Threat
Sea turtles encounter different types of debris and have different digestive anatomy.
In the study's dataset, 47% of necropsied sea turtles contained plastic, the highest rate among the three major groups examined.
Researchers estimated that for an animal approximately the size of a loggerhead turtle—about 90 centimeters long—slightly more than two baseballs' worth of plastic corresponded to a 90% probability of plastic-induced mortality.
At the 50% threshold, the volume fell to less than half a baseball.
Again, these are modeled equivalents.
They do not mean scientists fed turtles baseball-sized amounts of plastic.
Researchers derived the relationship from animals that had already died and had been necropsied.
That approach was necessary for obvious ethical reasons.
Plastic Bags Can Look Like Food
Sea turtles are especially vulnerable to soft plastics.
A floating shopping bag can move through the water in ways that resemble a jellyfish.
For a turtle that has evolved over millions of years to recognize gelatinous prey, the difference may not be obvious.
Once swallowed, flexible plastic creates problems of its own.
It can fold.
Twist.
Stretch.
Block sections of the gastrointestinal tract.
Or combine with other debris into larger masses.
The study identified hard and soft plastics as particularly dangerous to sea turtles.
Among turtles that had consumed plastic in the dataset, researchers reported exposure to several categories:
69% had eaten soft plastic,
58% fishing debris,
42% hard plastic,
with smaller proportions containing foam, rubber, or synthetic cloth. Individual animals could contain more than one category.
Bigger Animals Are Not Immune
One might assume marine mammals are simply too large to be seriously affected by ordinary plastic garbage.
A whale is enormous.
A dolphin is powerful.
A porpoise can weigh tens of kilograms.
Surely a plastic bag or piece of fishing line is insignificant?
The necropsy data say otherwise.
For a harbor porpoise approximately 1.5 meters long, researchers estimated that roughly a soccer ball's volume of plastic corresponded to a 90% mortality probability.
At the 50% threshold, it was less than one-sixth of a soccer ball.
And marine mammals faced one especially dangerous category:
discarded fishing gear.
Fishing Gear Was Particularly Dangerous to Marine Mammals
Among marine mammals that contained plastic, approximately 72% had ingested fishing debris.
That includes materials such as:
fishing line,
rope,
and pieces of net.
Fishing gear differs from an ordinary smooth plastic fragment.
It is long.
Flexible.
Strong.
Difficult to break.
And capable of becoming tangled internally.
The study identified soft plastic and fishing debris as the plastic categories posing the greatest mortality risks to marine mammals.
For sperm whales specifically, the researchers' modeling suggested that around 28 pieces of fishing debris, each smaller than a tennis ball, could correspond to a 90% mortality probability.
The study dataset even included dramatic individual cases.
Researchers discussing the work described an albatross found with an entire plastic bottle in its digestive tract and a sperm whale whose gastrointestinal obstruction involved fragments from a bucket.
These sound extraordinary.
Unfortunately, they exist within a much larger pattern.
The Number of Pieces Is Not the Whole Story
One of the most important improvements in the study was that researchers did not simply count plastic pieces.
That would be misleading.
Consider two animals:
Animal A swallows 30 microscopic-looking fragments.
Animal B swallows one large plastic bag.
Simply saying Animal A swallowed “30 times more plastic” would obviously be wrong.
So researchers examined both:
number of pieces
and
plastic volume relative to animal body length.
Across all plastic types combined, a 90% mortality probability corresponded to approximately:
23 pieces in seabirds
29 pieces in marine mammals
and
405 pieces in sea turtles, with the turtle estimate slightly lower for juveniles.
Those numbers initially make turtles appear more resistant.
But piece counts disguise enormous variation in size.
Hundreds of tiny fragments may occupy less space than one large bag or length of rope.
That is why the sugar-cube and ball-volume comparisons are useful.
They give humans a more intuitive sense of the physical burden involved.
Different Plastics Behave Differently Inside an Animal
The research strongly challenges another simplistic idea:
all plastic is equally dangerous.
It is not.
The paper grouped macroplastic into four broad categories:
hard plastic
soft plastic
rubber
and
fishing debris.
The highest-risk materials differed by animal group.
Seabirds
Rubber and hard plastics were particularly dangerous.
Sea turtles
Hard and soft plastics produced the greatest risk.
Marine mammals
Soft plastics and fishing debris were especially dangerous.
That makes biological sense.
Different objects fail to move through digestive systems in different ways.
A rigid shard can puncture tissue.
A flexible bag can block a passage.
A rope can twist or tangle.
Rubber may lodge where another object would pass.
Simply reporting the mass of “plastic” therefore leaves out information that can determine whether an individual survives.
What Does “90% Chance of Death” Actually Mean?
This point deserves careful explanation.
The scientists were not identifying a universal lethal dose comparable to a laboratory toxicology experiment.
They did not feed known amounts of plastic to animals and observe how many died.
Instead, they used necropsy records where:
the amount of plastic was known,
and
whether plastic contributed to death was known.
They then fitted a statistical model to estimate the relationship between gastrointestinal plastic load and mortality probability.
So when we say:
“three sugar cubes' worth can kill a puffin,”
the more technically accurate meaning is:
For a seabird approximately the size of an Atlantic puffin, the model associated that plastic volume with about a 90% probability of mortality attributed to plastic ingestion.
That distinction may sound academic.
It is important.
A specific bird could potentially survive more.
Another bird could die from less.
There Is No Completely Safe Number of Pieces
This also means the study should not be interpreted backward.
A threshold associated with 50% or 90% mortality does not imply that anything below it is harmless.
A single object can sometimes be deadly if it:
punctures the gut,
blocks a critical location,
or becomes dangerously entangled internally.
The researchers emphasize that macroplastic mortality often depends on discrete events rather than the simple cumulative-dose relationship familiar from chemical toxicology.
One badly shaped object in the wrong place can matter more than many smaller fragments.
The thresholds describe probability.
They do not establish a “safe allowance” of ocean plastic.
The Study Was About Macroplastic, Not Microplastics
Another crucial limitation is frequently lost in social-media summaries.
This research examined macroplastic—pieces 5 millimeters or larger.
It did not attempt to establish lethal thresholds for microplastics.
That means its findings should not be used to say:
“Scientists discovered exactly how much microplastic kills a whale.”
They did not.
Microplastics represent a different research problem involving potential effects such as:
inflammation,
chemical exposure,
feeding disruption,
and other chronic or sublethal impacts.
The PNAS study dealt primarily with the more immediate physical danger of larger swallowed debris.
Entanglement Wasn't Included Either
Plastic harms marine wildlife in ways that do not require swallowing it.
An animal can become wrapped in:
nets,
fishing line,
ropes,
packing bands,
or other debris.
Entanglement can prevent swimming.
Restrict feeding.
Cut deeply into tissue.
Cause infection.
Prevent animals from surfacing to breathe.
Or exhaust them until they drown.
The 2025 analysis was specifically designed to estimate mortality from plastic ingestion.
It did not count all the additional deaths or injuries caused by entanglement, nor did it quantify every potential sublethal effect of plastics.
The mortality thresholds therefore describe only one part of the larger plastic-pollution problem.
Not Every Animal Containing Plastic Died Because of Plastic
This is another distinction that responsible reporting must preserve.
Thirty-five percent of seabirds in the dataset had consumed plastic.
That does not mean plastic killed 35%.
The paper estimated plastic-attributed deaths in:
1.6% of all seabirds in the dataset
0.7% of marine mammals
and
4.4% of sea turtles.
An animal can contain plastic and die from something unrelated.
Disease.
Predation.
Ship strike.
Fishing interaction.
Trauma.
Starvation from another cause.
The researchers specifically needed cause-of-death information to distinguish ingestion from mere presence.
That is what makes their analysis much more useful than simply counting how many animals had debris inside them.
Nearly Half of Plastic-Exposed Animals Were Threatened Species
There was another troubling conservation finding.
Nearly half of the animals that had ingested plastic belonged to species listed by the IUCN as near threatened, vulnerable, endangered, or critically endangered.
For a common species with millions of individuals, losing one animal is tragic but unlikely to threaten population survival.
For an endangered species, additional preventable mortality has greater consequences.
Plastic pollution does not occur in isolation.
The same species may already be coping with:
climate change,
habitat degradation,
overfishing,
bycatch,
ship strikes,
disease,
and loss of breeding grounds.
Plastic becomes another pressure placed on animals that may already have little ecological margin left.
Why a Small Amount Can Be Such a Big Problem
The phrase “three sugar cubes” initially sounds absurdly small.
But imagine placing three solid cubes into the digestive tract of an animal whose entire body is only about 11 inches long.
Now imagine that those cubes:
cannot dissolve,
may have sharp edges,
may fold into obstructive shapes,
provide zero nutrition,
and may remain inside for extended periods.
The scale changes immediately.
Likewise, two baseballs are tiny compared with the body of a human.
But if two baseball-sized masses became trapped inside the human gastrointestinal tract, nobody would describe that as a trivial amount.
The problem is not that plastic somehow becomes chemically superpowered inside wildlife.
It is that digestive anatomy has physical limits.
Plastic Pollution Is an Evolutionarily New Threat
Life has had millions of years to adapt to many natural hazards.
Predators.
Storms.
Toxins.
Parasites.
Food shortages.
Plastic is different.
Large-scale commercial plastic production is essentially a phenomenon of the last several generations.
Evolution has had almost no time to adapt.
A turtle cannot develop an instinctive understanding that:
translucent polyethylene ≠ jellyfish.
A seabird cannot know that a colorful floating fragment has no nutritional value.
A whale cannot recognize every discarded rope as dangerous before swallowing prey around it.
Human manufacturing created an environmental material faster than wildlife could possibly evolve defenses against it.
More Than 11 Million Metric Tons Enter the Ocean Each Year
The scale of exposure makes the mortality thresholds particularly concerning.
Widely used estimates indicate that approximately 11 million metric tons of plastic enter the ocean each year from land-based sources, with substantially larger flows possible in future decades without intervention.
Most individual pieces will never encounter an animal.
But at ocean scale, the number of opportunities becomes enormous.
A bag that escapes a waste system can travel through:
storm drains,
rivers,
estuaries,
coastal currents,
and eventually open ocean.
Fishing gear can remain in marine environments long after it has been lost or abandoned.
Plastic does not need to remain intact either.
Sunlight and physical weathering can fragment larger objects into smaller pieces.
The result is not simply a floating garbage patch.
It is debris distributed through multiple ocean habitats where animals feed.
Cleanup Helps—but Prevention Matters More
The study has an unusually practical implication.
When just a handful of pieces can matter, removing individual pieces of trash is not meaningless.
A plastic bag collected from a beach is one bag that cannot become food for a turtle.
A balloon fragment removed from a shoreline cannot enter a seabird.
A length of fishing line retrieved from the water cannot become lodged inside a marine mammal.
But cleanup alone cannot keep pace indefinitely with a continuous flow of new debris.
The authors argue that reducing harm requires several approaches together:
reducing unnecessary plastic production
improving waste collection
improving recycling
and
removing existing pollution from the environment.
There is no single technological fix.
The most effective piece of plastic to remove from the ocean is often the one that never enters it.
Why Certain Products Deserve Special Attention
The study may also help regulators prioritize specific categories of plastic rather than treating all debris as equivalent.
If soft bags consistently create high risks for turtles, policies targeting lightweight plastic bags may have disproportionately valuable wildlife benefits.
If rubber fragments are especially dangerous to seabirds, that category deserves targeted monitoring.
If lost fishing gear produces high mortality risk for marine mammals, then:
gear retrieval,
marking,
tracking,
better disposal,
and alternative fishing technologies
could prevent deaths much more efficiently than generic cleanup programs.
The research therefore does more than demonstrate that plastic is harmful.
It begins quantifying which plastics cause the greatest risk to which animals.
That is useful for conservation policy.
The Numbers Are Disturbing Because They Make the Problem Personal
Millions of tons is difficult to visualize.
So is 11 million metric tons per year.
But everybody knows the size of:
a sugar cube,
a baseball,
a soccer ball.
That is why these comparisons are so powerful.
For an Atlantic puffin:
less than three sugar cubes → roughly 90% modeled mortality probability.
For a loggerhead turtle:
just over two baseballs → roughly 90%.
For a harbor porpoise:
about one soccer ball → roughly 90%.
And for 50% mortality:
less than one sugar cube
less than half a baseball
and
less than one-sixth of a soccer ball, respectively.
The numbers transform plastic pollution from an abstract environmental problem into a biological one.
But Don't Turn the Study Into a Misleading “Lethal Dose” Meme
The research deserves better than that.
It did not establish that:
three sugar cubes always kill every puffin,
two baseballs automatically kill every turtle,
or
one soccer ball of plastic inevitably kills every porpoise.
These are modeled examples based on pooled necropsy data.
Risk varies with:
species,
animal size,
plastic material,
object geometry,
number of objects,
location inside the digestive tract,
and individual health.
Nor did the researchers explicitly “account for feeding behavior” in the simple sense sometimes claimed in viral summaries.
Their quantitative models incorporated variables such as plastic amount, type, animal group, and size-related normalization.
The strongest interpretation is therefore not:
“Scientists found the exact amount of plastic that kills every marine animal.”
It is:
“Scientists have now quantified how rapidly mortality risk rises as different marine animals accumulate different kinds and volumes of macroplastic.”
That is both accurate and alarming.
The Bottom Line
The viral claim is based on real, peer-reviewed research.
Scientists analyzed 10,412 marine-animal necropsies and modeled the relationship between macroplastic in the gastrointestinal tract and plastic-induced mortality.
They found that plastic ingestion was documented in:
35% of necropsied seabirds
47% of sea turtles
and
12% of marine mammals.
For animals of representative sizes, modeled plastic volumes associated with approximately 90% mortality probability were surprisingly small:
less than three sugar cubes for an Atlantic puffin
just over two baseballs for a loggerhead sea turtle
and
about one soccer ball for a harbor porpoise.
The most dangerous materials varied:
rubber and hard plastic for seabirds
hard and soft plastics for sea turtles
soft plastics and fishing debris for marine mammals.
For seabirds, only six tiny pieces of synthetic rubber were associated with a 90% mortality probability in the material-specific analysis.
But the figures are risk estimates, not guaranteed lethal doses.
The study focused on macroplastic at least 5 millimeters in size.
It did not quantify microplastic mortality.
It did not include entanglement deaths.
And its ingestion percentages come from a necropsy dataset, not a random census of all living marine wildlife.
Those caveats do not weaken the central finding.
They make it clearer.
Marine animals do not necessarily need to ingest enormous piles of garbage before plastic becomes dangerous.
Sometimes a volume that looks trivial to a human can become an obstruction occupying a critical part of a much smaller digestive system.
A shopping bag does not need to cover an ocean to kill a turtle.
A handful of rubber does not need to fill a beach to kill a seabird.
A discarded section of fishing gear does not need to weigh hundreds of pounds to kill a marine mammal.
For an individual animal, one encounter can be enough.
And that may be the most disturbing lesson of the study:
The enormous scale of ocean plastic pollution is measured in millions of tons.
But for the animal that swallows it, the difference between survival and death may be measured in something as small as a few sugar cubes.
Frequently Asked Questions
Did scientists really analyze more than 10,000 marine-animal autopsies?
Yes. The researchers analyzed 10,412 necropsies involving seabirds, sea turtles, and marine mammals from global literature and stranding databases.
When was the study published?
It was published online on November 17, 2025, in Proceedings of the National Academy of Sciences.
How much plastic can kill a puffin?
For a seabird approximately the size of an Atlantic puffin, less than three sugar cubes' volume was associated with about a 90% modeled probability of plastic-induced death.
What about a 50% mortality probability?
Less than one sugar cube's worth was associated with approximately 50% mortality for a puffin-sized bird.
How much plastic can kill a sea turtle?
For a loggerhead-sized turtle, slightly more than two baseballs' volume was associated with about a 90% mortality probability.
Less than half a baseball corresponded to roughly 50%.
How much can kill a marine mammal?
For an animal approximately the size of a harbor porpoise, roughly a soccer ball's volume corresponded to a 90% modeled mortality probability.
Less than one-sixth of a soccer ball corresponded to roughly 50%.
Does swallowing exactly that amount guarantee death?
No.
These are statistical risk estimates derived from necropsies. Individual outcomes depend on species, size, health, plastic type, shape, location in the digestive tract, and other factors.
Could less plastic still kill an animal?
Yes.
A single badly positioned object could potentially cause obstruction or perforation. The modeled thresholds do not represent safe limits.
Which plastic was most dangerous for seabirds?
Rubber and hard plastic produced particularly high risks.
Is it true six tiny pieces of rubber can kill a seabird?
The model estimated that six synthetic-rubber pieces, each smaller than a pea, were associated with a 90% mortality probability for seabirds.
Which plastics were especially dangerous for sea turtles?
Hard and soft plastics.
Why are plastic bags dangerous to turtles?
Soft plastic can resemble prey such as jellyfish and, after ingestion, can cause obstruction or other gastrointestinal injury.
Which plastic was especially dangerous to marine mammals?
Soft plastics and fishing debris such as lines, ropes, and nets posed particularly high risks.
How many animals in the study had eaten plastic?
Plastic occurred in 47% of sea turtles, 35% of seabirds, and 12% of marine mammals represented in the dataset.
Does that mean 47% of every sea turtle in the ocean contains plastic?
No.
Those percentages describe animals represented in the necropsy dataset and should not be treated as a random population survey of every living animal.
How many actually died because of plastic?
The researchers attributed plastic-ingestion mortality to approximately 4.4% of sea turtles, 1.6% of seabirds, and 0.7% of marine mammals in the dataset.
How does swallowed plastic kill wildlife?
Documented mechanisms include gastrointestinal obstruction, perforation, and torsion, as well as subsequent starvation and internal damage.
Did the study investigate microplastics?
No. It focused on macroplastic measuring at least 5 millimeters.
Did it include animals killed by becoming tangled in plastic?
No. The primary analysis concerned ingestion. Entanglement represents an additional threat that was outside the mortality thresholds analyzed here.
Is every type of plastic equally dangerous?
No. One of the study's major findings is that mortality risk differs substantially by material type and animal group.
Why does body size matter?
A given plastic volume occupies a much larger proportion of a small bird's digestive system than it does that of a whale. The researchers therefore also modeled plastic volume relative to animal body length.
How many marine species have been documented ingesting plastic?
Nearly 1,300 marine species have documented plastic ingestion.
Can picking up one plastic bag actually help wildlife?
Potentially, yes. An individual item removed before entering the water is one less object available to be swallowed or cause entanglement. At population scale, however, prevention requires reducing leakage of plastic into the environment in the first place.
What is the biggest takeaway?
The study provides quantitative evidence for something scientists had long suspected:
The amount of plastic necessary to create a very high risk of death in marine wildlife can be astonishingly small.
For a puffin-sized seabird, the difference can literally be measured in sugar cubes.
