Grey Seal - Biology, Behavior and Ecology

Dive into the world of the Grey Seal, found across the North Atlantic, and explore their remarkable adaptations for cold water like thick blubber. Learn about their vital role as apex predators in marine ecosystems, the conservation efforts that have helped their populations rebound, and the ongoing challenges they face from pollution and fishing gear.

👉 View photos and videos: https://muuuh.com/mammals/grey-seal/

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Episode Transcript

(00:00):
You're listening to MOO and nature documentaries.
Today on our deep dive, we're setting our sights on the Gray
seal, Heliconius grapus. A really fascinating marine
mammal. Absolutely.
We've got this really comprehensive research document
here, packed with details. Our mission, as always, is to
pull out the most important, themost intriguing insights for you

(00:22):
about these animals. Sounds good.
There's certainly a lot to talk about with grey seals.
OK, let's dive right in then. The research paints this picture
of grease seals being pretty widespread across the North
Atlantic. But it seems it's not just one
big happy family, is it? There's a split.
That's exactly right. Geographically there's a fairly
clear separation. You basically got 2 distinct
populations, Western North Atlantic and Eastern North

(00:44):
Atlantic. And where do we find the Western
group? So in the West, you're looking
at the waters off eastern Canada, the Gulf of St.
Lawrence, NL The Scotian Shelf and then they range S into the
northeastern US, Maine down to Massachusetts, including places
like Cape Cod, Nantucket, Martha's Vineyard.
Right, quite a stretch there in the eastern population.

(01:06):
Across the pond, their main strongholds are around the
British Isles. Yes, Scotland's Outer Hebrides,
Orkney, Shetland, Ireland too. Also the Faroe Islands and then
along mainland Europe coasts, Norway, Iceland and even into
parts of the Baltic Sea. Places like Sweden, Finland, the
Baltic states. Wow.
And these two groups, they don'tmix much.

(01:26):
Well, the sheer distance and theocean currents between them act
as a pretty effective barrier. So yeah, there's actually quite
limited interbreeding between the western and eastern
populations. They're largely separate.
That makes sense. So, OK, when they're not out
swimming these huge distances, where do they actually, you
know, hang out? Where do they haul out?
I imagine they have preferred spots.
Definitely they have preferred habitat types.

(01:47):
Coastal areas are key. Rocky coastlines, sandy beaches,
isolated islands. These offer places to rest, to
molt and, crucially, for females, to give birth.
What makes a good spot? Well, they need enough space,
obviously, but also protection. Protection from predators both
on land and from the sea, and increasingly important, minimal

(02:08):
human disturbance. That's becoming a bigger factor.
Right, peace and quiet. But they don't spend all their
time lounging on the beach, do they?
Not at all. Their habitat extends well into
the water. Subtitle zones, The areas that
stay underwater even at low tide, are really important
foraging grounds. These zones are often teeming
with marine. Life and they can dive pretty
deep for that food. Oh yes, grey seals are

(02:31):
impressive divers, capable of reaching significant depths to
chase down prey. They also make use of estuarine
and inshore waters, those areas where saltwater and freshwater
mix. These can be really rich in food
resources too. So coastal subtitle estuaries
anywhere. Else, Yep, even the open seat.
They're quite capable of long distance travel and foraging in

(02:51):
deeper offshore waters. Sometimes they're following
migrating fish or undertaking their own sort of seasonal
movements. OK.
Seasonal movements, you mentioned that, is it like a
proper migration, like birds flying South?
Hmm, not really a true migrationin that sense.
It's not usually a complete round trip between distinct
breeding and feeding grounds farapart.
It's more about seasonal shifts driven by different needs at

(03:14):
different times of year. Needs like what?
Primarily breeding, molting and finding food.
Those are the big drivers. Can you give us some examples?
Where do they go for breeding? Sure.
So for breeding, which is typically autumn or early winter
depending on the location, they gather at traditional haul out
sites. These might be specific islands
like the Farne Islands or Isle of May in the UK.

(03:35):
Your famous seal spots right? Or they could be remote beaches
or rocky outcrops. Pretty much anywhere across
their North Atlantic range. And interestingly, in the Baltic
they sometimes use ice flows. Ice flows.
Wow. OK, so after breeding.
After breeding, they tend to disperse more widely.
They need to feed, replenish their energy reserves, so

(03:56):
they'll seek out areas where their prey.
Things like sandeels, cod, flatfish, even squid and octopus
are a bunch. Of molting.
Does that make them? Move it does.
Their annual malt, usually in the spring, is another key
event. They need to shed their old fur.
We've seen evidence of UK seals traveling quite far, sometimes
even to Norway or Iceland. Possibly linked to finding good

(04:17):
molding spots or maybe food availability around that.
Time. So it's not one-size-fits-all
for these movements. Exactly, the patterns can vary
quite a bit depending on the seals age Essex and definitely
the local environmental conditions like where the food
is that year. It's a really complex picture of
movement, thinking about their range.
Has it always been like this or have things changed over time?

(04:39):
Oh, it's changed significantly. Historically, Gray seals were
very broadly distributed across the North Atlantic.
But then came periods of intenseexploitation.
Exploitation for what? Mainly for their fur, their oil
and meat. This happened particularly in
the 18th and 19th centuries and it led to a really dramatic
declines in many areas in the Baltic Sea.
They were almost wiped out, nearly extirpated.

(05:03):
The only issue? No.
Alongside that, you had increasing coastal development,
industrial activities, all contributing to habitat loss and
degradation, putting even more pressure on the remaining
populations. So what's the situation now?
Are they still in trouble? Well, the good news is that in
recent decades, many populationshave shown remarkable recovery.

(05:23):
This is largely thanks to legal protections, hunting bans,
marine mammal acts and conservation efforts like
establishing marine protected areas.
Where has the recovery been strongest?
We've seen really significant increases in the UK,
particularly around Scotland. The Baltic populations are also
recovering, though they're stillconsidered quite vulnerable due
to ongoing issues like pollutionand bycatch.

(05:46):
And over in the western Atlantic, eastern Canada and the
US have seen populations bounce back to Sable Island off Nova
Scotia now hosts one of the world's largest grease seal
colonies. That's fantastic news.
Are they popping up in new places too?
Yes, interestingly, as numbers have recovered, they've started
expanding their range again, appearing in areas where they
become rare or absent parts of the North Sea, even down to the

(06:09):
coasts of France and Germany. It really shows their resilience
when given a chance. That's really encouraging, but I
guess it's not all smooth sailing.
Are there still challenges? Absolutely.
Ongoing threats are definitely still a concern.
Accidental captured and fishing gear by catch is a big one.
Pollution remains a problem, both chemical pollutants and
marine debris. And then there's the looming

(06:30):
impact of climate change. And conflicts with humans.
Yes, as seal populations grow and expand, they inevitably
interact more with fisheries. This can lead to perceived
competition for fish stocks and sometimes conflict.
So while the recovery is great, continued monitoring and
proactive conservation are absolutely vital.
OK, let's take a short break there.

(06:51):
When we come back, we'll dive into the physical traits and
adaptations that make these seals so well suited to their
chilly ocean home. Welcome back to our deep dive on
the Grey Seal. We've talked about where they
live. Now let's look at how they live
there, surviving in the cold North Atlantic.
Must take some serious physical kit.
It certainly does. They possess a really impressive

(07:14):
suite of adaptations. First off, just look at their
shape, that streamlined torpedo like body.
Very hydrodynamic. Exactly.
It minimizes drag, making them incredibly efficient swimmers,
essential for hunting fast prey and of course avoiding predators
themselves. It's just perfectly designed for
life in the water. Natures Engineering.
What else keeps them going in those cold seas?

(07:34):
Well, insulation is absolutely critical.
They have a very thick layer of blubber beneath the skin.
Yeah, this provides fantastic thermal protection against the.
Cold, like wearing a built in wet suit.
A very, very thick one. And that blubber isn't just for
warmth. It's also a crucial energy
reserve. Think about the breeding season,
when females especially might fast for weeks.

(07:55):
That blubber keeps them going. Right.
How did they move through the water so effectively?
They used their powerful front flippers for propulsion, really
driving themselves through the water.
And their rear flippers act likerutters, providing steering and
maneuverability. It gives them the agility they
need to catch slippery fish. OK, so warm, streamlined, and

(08:15):
agile. What about finding food
underwater? They can get pretty dark and
murky down there. Their senses are highly adapted.
They have large eyes which are great for gathering light in dim
conditions. They can pick up subtle
movements and contrasts, helpingthem spot prey even when
visibility isn't great. And those whiskers, They look
quite prominent. They are.

(08:37):
Those are called vibrissae, and they're incredibly sensitive.
They function almost like feelers, detecting tiny
vibrations and water movements. This allows them to locate fish
even in total darkness or stirred up water.
They can literally feel their prey nearby.
And they could stay down a long time, too.
Yes, their breath holding ability is significant.
They can often stay submerged for up to 20 minutes while

(08:58):
hunting, a very useful adaptation for pursuing prey
deep underwater. So do they look the same all
their lives or do they change appearance?
No, their appearance definitely changes with age and also
seasonally. Pups are born with that iconic
fluffy white coat. It's called lanugo.
The cute white fluffy ones. That's them.

(09:18):
It's great insulation on land and provides camouflage on snow
or sand, but it's actually not waterproof so they shed it
fairly quickly, usually within two to three weeks, revealing a
more adult like coat underneath.What about after the pup stage
the juveniles? Juveniles develop a shorter,
denser coat that is water repellent.
It's typically Gray or brown with various spot patterns.

(09:40):
This helps them blend in againstrocky seabeds or amongst kelp.
Crucial camouflage. Adults Do males and females look
different? They show clear sexual
dimorphism. Adult males are significantly
larger and tend to be darker often or uniform, dark Gray or
brownish black, sometimes with fewer distinct spots.
Females are generally smaller, lighter in colour, often as

(10:02):
silvery Gray or tan, and usuallyhave more noticeable spotting.
Patterns. And do they change with the
seasons, like getting a winter coat?
Not quite like that, but they dohave an annual molt.
This usually happens after the breeding season, maybe late
spring or early summer. They shed their old worn out fur
and grow a fresh coat. Must look a bit scruffy during
that time. They can look quite patchy or

(10:23):
dull for a while, yeah, but it'sessential for maintaining a
healthy insulating coat. So these appearance changes are
really driven by functional needs, thermal regulation,
camouflage, life stage. Makes sense.
We talked about blubber and fur for warmth.
How else do they cope with the cold or maybe even overheating
sometimes? Beyond the primary insulation,

(10:44):
they have a neat physiological trick called countercurrent heat
exchange, particularly in their flippers.
Countercurrent heat exchange. How does that work?
Basically, warm arterial blood flowing out to the flippers
passes very close to the cold venous blood returning to the
body. Heat gets transferred from the
outgoing warm blood to the incoming cold blood, so less
heat is lost to the environment through the extremities.

(11:06):
It helps keep their core body temperatures stable.
Clever internal heating system. Very clever behaviorally,
they'll haul out onto land or ice to bask in the sun.
If they need to warm up. They can also adjust their
diving patterns. May be staying in deeper water
where the temperature is more stable at the surface is really
cold and metabolically they can actually lower their metabolic

(11:27):
rate during cold snaps or fasting periods like during the
molt to conserve energy. It's a whole suite of strategies
working together. You mentioned the size and
colour differences between malesand females.
Any other giveaways? Apart from the size, males
reaching maybe 2.5 to 3.3 metersand 170 to 310 kilograms
compared to females at 1.6 to 2 meters and 100 to 190 kilograms.

(11:51):
Difference. A big difference and the colour
patterns. Adult males also develop a more
pronounced, robust head with a much broader puzzle, often
called a Roman nose. It becomes more distinct as they
get. Older.
OK so you can usually tell an adult male from a female just by
looking. Are there different types like
subspecies of Gray seals and different areas?
Generally 2 main regional forms are subspecies are recognized.

(12:13):
You have the Eastern Atlantic Grey seal, Helicarriers Gripus
gripus. That's the one found around the
British Isles, Pharaohs, Iceland, Norway and the Baltic.
They tend to be a bit larger, more robustly built, with quite
varied coat patterns. And the other.
The Western Atlantic Gray ideal Heliker's gripe as Atlantica
found off eastern Canada and thenortheastern US.

(12:34):
These are typically a bit smaller and often have a darker
coat with maybe less pronounced spotting.
Are they very different genetically?
Interestingly, genetic studies show relatively low divergences
between them, so while there areobservable differences likely
influenced by local environments, they're still very
closely related. Not quite distinct subspecies in
the way we might think of for some other animals, more like

(12:55):
regional variations on a theme. Fascinating how these little
differences emerge across such vast distances.
OK, let's move into their socialworld.
How do Gray seals actually communicate and interact?
They have a pretty complex communication system.
It involves vocalizations, body language, and physical
interactions, and the context really matters.

(13:16):
What kind of sounds do they make?
Vocalizations are especially keyduring the breeding season.
Males are quite noisy then making loud growls, roars,
sometimes described as moans. This is all about establishing
dominance over territory and attracting females.
Sounds intimidating? What about females and pups?
Females tend to make softer calls, often directed towards

(13:38):
their pups, and the pups themselves have very distinct,
almost plaintive calls which arecrucial for their mothers to
identify them in a crowded, noisy colony.
So breeding colonies must be incredibly loud places.
Oh, absolutely. A real cacophony sometimes.
But communication isn't just vocal.
Body language is huge too. Like what again?

(13:59):
Especially during breeding, males use postures to signal
dominance, raising their heads high, opening their mouths into
threat display towards rivals. Females might use more subtle
body language to show if they'rereceptive to a male or to warn
them. Off and they get physical too.
Definitely you see aggressive fights between males competing
for territories, which can sometimes involve biting and

(14:19):
result in injuries. But you also see gentle
interactions like mothers nuzzling and grooming pups,
which is vital for bonding. It sounds like a very structured
social life, at least during breeding.
Yes. During that period they operate
under a polygynous mating system.
This means dominant males try toestablish and defend territories

(14:40):
on the breeding beach or ice, and they aim to meet with
multiple females that come into their territory.
So intense competition between the males.
Extremely intense. It leads to a pretty clear
hierarchy, with the biggest, strongest, most experienced
males usually securing the best spots and having the most mating
success. What about outside the breeding
season? Are they still social?

(15:02):
Less so, they tend to be more solitary when they're out
foraging. At sea, they might still haul
out in groups for resting or molting, but the social
structure is much less rigid than during breeding.
Are there any particular sounds or signals that stand out?
Well, those male mating calls, the deep growls and roars are
certainly very distinctive and carry a long way underwater.

(15:22):
The mother pup calls are also critical for their survival.
They likely have alarm calls too, to warn others of danger.
And visually, any specific displays?
That head and chest X-rays in males is a classic dominance
posture. The aggressive interactions, the
biting, the flipper slapping, those are clear signals and
sometimes you see them slap in the water surface with their

(15:43):
flippers or splashing. Why do they do that?
The splashing. It could be for various reasons,
maybe attracting attention, signaling aggression, perhaps
even trying to deter a predator or arrival.
And of course, that gentle nuzzling and touching is really
important for reinforcing socialbonds, especially mother put.
A whole repertoire of communication.
You mentioned males defending territories for breeding.

(16:04):
Are they defending food resources then too?
Generally not. The territoriality we see male
Gray seals during breeding is almost entirely about securing
access to females. They fight for prime spots on
the Rookery because that's wherethe females are or will be.
It's not about controlling a feeding patch.
So it's all about mating rights.Pretty much.
The intensity of the competition, the vocal displays,

(16:26):
the posturing, the actual fightsis driven by reproductive
opportunity. The bigger, more dominant males
who win these contests get to pass on their genes outside
breeding when they're foraging their typically covering wide
areas and not defending specificfeeding spots.
There's social structure really seems dictated by the breeding
cycle. Do these behaviors change much

(16:47):
depending on where they live, like Baltic seals versus UK
seals? Yes, you definitely see regional
and habitat based variations. We mentioned breeding sites,
rocky shores and islands, and much of the North Atlantic, but
ice flows in the Baltic. The timing of breeding also
varies quite a bit, likely linked to local climate and food
availability. And foraging, does that differ?

(17:08):
Absolutely. Diet varies regionally based on
what's available. North Sea seals might focus on
sandals and cod, while Baltic seals eat more herring and
sprat. This obviously influences their
foraging behavior, how far they travel, how deep they dive.
Even where they choose to haul out might differ.
Yes, some populations prefer coastal beaches.
Others use offshore sandbanks orremote islands, and their

(17:31):
reaction to humans can vary. In areas with more disturbance,
they might become more nocturnalor abandoned certain sites
altogether. Baltic seals obviously have
specific adaptations for dealingwith ice, and seals in areas
with more predators might be much more vigilant when hauled
out. But they're quite adaptable in
their behavior depending on the local circumstances.

(17:51):
What about just the typical day?What does a grey seal get up to?
A typical day is a mix of foraging, resting, and social
behavior, depending on the season.
Forging takes up a good chunk oftime, their carnivores hunting
fish, squid, crustaceans diving as needed.
Often they seem most active around dawn and dusk.
Crepuscular feeders. And the rest of the time.
Hauling out is crucial. They come ashore or onto ice to

(18:14):
rest, regulate their body temperature, interact socially
and avoid aquatic predators likesharks or orcas.
How often and how long they haulout varies.
A. Lot more during breeding and
molting. Exactly.
They spend significantly more time on land during the breeding
season in autumn, winter, and again during the mold in late
winter. Spring social interactions peak
during breeding, obviously, withall the territorial disputes and

(18:37):
mating activity. Outside of that, they're more
solitary at sea but might rest in groups.
So it's this cycle of underwaterhunting and on land resting
punctuated by these major seasonal events.
A busy life balancing different needs.
OK, let's take another short pause.
Next up, reproduction and the grey seal life cycle.

(18:59):
We're back continuing our deep dive into the world of the
grease seal. Let's talk about how they
reproduce and the stages of their lives.
When exactly is the breeding season?
OK, so Gray seals breed once a year, and it involves hauling
out onto land or ice for both birth and mating, but the timing
isn't uniform across their range.
Right. You mentioned regional
differences earlier. Exactly, and the eastern

(19:19):
Atlantic, places like the UK, Ireland, Scandinavia.
Breeding typically happens between September and December.
The peak in the UK is often around.
October and in Canada and the US.
It's later there, generally fromDecember to February.
On Sable Island, for instance, amajor breeding colony, the peak
is usually in January. For Baltic seals using ice, it's

(19:39):
even later off in February to March.
Why the difference in timing? It's likely an adaptation to
local conditions, things like water temperature, maybe ice
covered duration in the Baltic, and crucially, ensuring pups are
born when food availability is likely to be good for them once
they're weaned and start huntingfor themselves.
Makes sense to time it right? So what are the key steps in a
grey seals? Life from birth onwards.

(20:02):
Well, it starts with birth on land or ice during that regional
breeding window. Us, as we said, are born with
that white Wendigo coat. Great insulation, but not
waterproof. Then comes nursing.
Yes, a really intense but short nursing period.
The mother nurses the pub for about two to three weeks.
Her milk is incredibly high in fat, something like 5060% fat
content. Wow, no wonder they grow fast.

(20:24):
Extremely fast. They can triple their birth
weight in that short time, but then the mother abruptly weans
the pup and leaves often tomate again shortly after.
That seems harsh. What happens to the pup?
The pup stays on land, living off its fat reserves.
During this time, it molds its lanugo code and grows its first
waterproof juvenile fur. Then it has to figure out how to

(20:47):
swim and hunt all on its own. It's a critical transition
period. A steep learning curve.
How long until they can breed themselves?
Females usually reach sexual maturity around 4:00 to six
years old. Males mature a bit later, maybe
6 to 8 years, but because of theintense competition they often
don't successfully hold a territory and breed until
they're even older and larger, maybe 10 years or more.

(21:10):
So a long apprenticeship for themales.
Very much so. Then adulthood involves annual
breeding cycles for females, producing usually a single U
each year, and ongoing competition for males.
We touched on the mating system,polygynous males competing for
territories. How does that actually play out?
It's quite dramatic. Dominant males use those loud,
low frequency calls to advertisetheir presence and quality, both

(21:32):
attracting females and warning off rivals.
These visual displays posturing,making themselves look big and.
Imposing actual fighting. Physical fights are common and
can be quite brutal, involving biting, pushing chest to chest
combat. It's all about establishing and
maintaining control over a primepiece of real estate on the
breeding colony. Do females get any say in this

(21:55):
or do they just mate with whoever controls the territory?
Females likely do exercise some choice.
They might select territories that offer better protection
from harassment or bad weather. Or perhaps they are influenced
by the size, condition or persistence of the male himself.
It's probably a combination of male competition and female
preference. Interesting.
Now a slightly different question.

(22:16):
Have Gray seals ever been known to hybridize to breed with other
seal species? Yes, it does happen, though it
seems to be quite rare. Hybridization has been
documented between Gray seals and harbor seals folk evangelina
in areas where their ranges overlap, particularly in the
North Atlantic. How do they know their hybrids?
Usually through genetic analysis.

(22:36):
Sometimes the hybrids might showphysical traits that are sort of
intermediate between the two species.
It seems to happen most often inplaces where both species haul
out and breed close together. Is it a conservation concern?
At the moment, it doesn't seem to be widespread enough to be
considered a significant threat to the genetic integrity of
either species. Moral biological curiosity for

(22:57):
now. Right, let's talk about
parenting, you said. The mother nurses intensely.
But briefly. What else does maternal care
involve? That intense nursing period is
the core of it. The mother stays with the pup
almost constantly during those 2-3 weeks, providing protection
from predators, bad weather, andeven other aggressive seals.
She's incredibly attentive. Eat during this time.

(23:19):
Remarkably, no. The mother typically fasts
throughout the entire nursing period, relying solely on her
own blubber reserves. It's a huge energy investment
for her. And the father.
The male plays absolutely no role in raising the pup.
His focus is entirely on competing for territories and
mating opportunities during the breeding season.
All the parental care comes fromthe.

(23:41):
Mother a very concentrated burstof maternal effort.
How different are the young seals, the juveniles from the
adults, once they're independent?
Quite different in several ways.Appearance wise, obviously the
code changes from lanugo to the juvenile pelage, which is
different again from the adult patterns and colours, especially
the sexually dimorphic adult codes.
And size. Of course, juveniles are much

(24:02):
smaller and less bulky than adults.
Behaviorally, juveniles are initially very tied to land,
especially around weaning. They have to make that massive
transition from milk to hunting live prey, which is a critical
and dangerous phase. They often appear more playful
and curious than adults, perhapsas part of learning skills.
Are they more vulnerable? Definitely.

(24:22):
They're smaller size, lack of experience, and still developing
immune systems make them much more susceptible to predators,
starvation, disease, and harsh environmental conditions
compared to established adults. Survival through the first year
is a major hurdle. It's a tough start in life.
OK, fascinating stuff on the life cycle.
Let's shift focus slightly to what fuels these animals and

(24:43):
what might hump them. What's on the menu for Grey
Seal? They're primarily carnivores and
quite opportunistic eaters. Their diet varies depending on
what's locally abundant and seasonally available.
But mostly fish. Yes, fish formed the bulk of
their diet. Common prey includes species
like sand eels, cod, haddock, herring, various flatfish like

(25:04):
place or flounder. It really depends on the region.
Anything else besides fish? Oh yes, we're available.
They readily eat cephalopods, things like squid and octopus.
They might also take crustaceanslike crabs or lobsters and
occasionally even seabirds, though that's less common.
Basically, if it's marine and they can catch it, it might be
on the menu. Adaptable eaters.

(25:25):
Then you mentioned regional differences like Baltic versus
North Sea. Exactly.
Studies show Baltic grey seals tend to rely more heavily on
herring and sprat, maybe becauseother stocks like cod are less
abundant there. In the North Sea, sand deals are
often a really crucial part of their diet.
Along with cod and haddock, their diet reflects the local
ecosystem. Makes sense given they eat so

(25:47):
much fish. What role do they play in
controlling those fish populations?
Are they in certain regulators? They certainly play a
significant role as predators byconsuming large quantities of
various fish species and cephalopods.
They undoubtedly help regulate the abundance and distribution
of those prey populations. Does that have knock on effects?
Yes, potentially. For example, by eating lots of

(26:09):
sand eels, they might influence the food available for other
predators that rely on sandals, like certain sea birds or even
larger fish. Their predation pressure can
help maintain biodiversity by preventing any single prey
species from becoming overly dominant.
And like many predators, they might preferentially target
weaker or diseased fish, which could actually contribute to the

(26:30):
overall health of the prey populations.
But the exact impact varies hugely depending on the specific
ecosystem, the number of seals and the status of the fish
stocks. A complex interaction now
turning the tables. Who eats grey seals?
What are their main predators? Despite their size, Gray seals
aren't at the very top the food chain everywhere.
Their main natural predators in the marine environment are large

(26:51):
sharks, particularly great whitesharks where their ranges
overlap, like off the eastern U.S.
Coast, and orcas or killer whales.
Orcas hunt seals. Oh yes, orcas are highly
intelligent predators and are known to hunt various seal
species, including grey seals, sometimes using very
sophisticated coordinated techniques.
What about land predators? Are pups vulnerable?

(27:12):
Pups on breeding colonies can occasionally be vulnerable to
terrestrial predators, maybe large rules or foxes in some
areas, but this is generally a much lesser threat than the
marine predators. And historically, of course,
humans were a major predator. Right, and threats from humans
persist even if not direct hunting.
Yes, accidental entanglement in fishing gear bycatch is

(27:33):
effectively a form of predation pressure caused by humans, and
it's a significant source of mortality.
So even these big, capable animals have things to worry
about. How do they defend themselves?
Their primary defence in the waters, their speed and agility,
simply trying to out swim or outmaneuver a predator, hauling
out in groups can offer safety in numbers, with more eyes

(27:54):
scanning for danger. Does their code help camouflage?
Yes, they're modeled coat can provide decent camouflage
against rocky coastlines or kelpbeds, making them harder to spot
both for predators and potentially for their own prey.
They're also naturally wary and vigilant animals, constantly
scanning their surroundings whenhauled out.
Do they ever fight back? If cornered or threatened,

(28:17):
especially on land, they can be quite aggressive.
They'll use loud vocalizations, barks, growls, bear their teeth
and may even lunge at a threat. This is particularly noticeable
during the breeding season when males are defending territories
but mothers will also fiercely defend their props.
A combination of evasion and potential aggression.
How much does food availability dictate their behavior or where

(28:40):
they live? Food availability is absolutely
fundamental. It's strongly influences their
foraging behavior, how far they travel, how deep they dive, how
much time they spend searching versus resting.
If prey is scarce in one area, they might shift their foraging
efforts elsewhere. Does it drive those seasonal
movements you mentioned? Very much so.
Many of their larger scale movements are likely tied to

(29:00):
tracking seasonal shifts in preyabundance or distribution.
They need to balance the energy demands of breeding and molting
with the need to find enough food.
And it affect their overall range where they are found.
Definitely, their habitat selection is heavily influenced
by prey availability. Areas rich in food will attract
and support larger populations. Conversely, if prey stocks

(29:23):
declined significantly in a region, perhaps due to
overfishing or environmental changes, it could force seals to
move elsewhere or might limit population growth.
We've seen evidence of this in the North Sea, where shifts in
sand eel distribution seem to have influenced Gray seal
foraging patterns and distribution.
So follow the food as a major rule for them.
OK, thinking about the whole ecosystem, what's the Gray seals

(29:45):
overall role in the local food web?
They typically function as high level or apex predators within
their marine ecosystems. Their primary role is exerting
top down control on the populations of the fish and
invertebrates they consume. So keeping those populations in
check? Exactly.
They feed on a range of species,helping to regulate those
populations and influencing the structure of the entire marine

(30:07):
community. While they are predators, they
also serve as prey, albeit less frequently, for the very top
predators like orcas and large sharks.
And of course, human activities like Bycatch impact their place
in the web, too. Are they an indicator of
ecosystem health? Often considered so because they
sit high in the food web and require abundant prey, a healthy

(30:29):
Gray seal population can indicate A relatively healthy
and productive marine environment capable of
supporting them. Changes in their numbers or
health can signal underlying problems in the ecosystem.
A vital piece of the marine puzzle.
We'll take one more quick work and then explore their ecosystem
role further, along with the threats they face and
conservation efforts. Welcome back.

(30:50):
We're exploring the ecological significance of the Grey Seal.
We know they're important predators, but what's their
broader role in the environment?Well beyond predation, which has
those cascading effects we talked about, they contribute to
nutrient cycling. Their waste products, urine and
feces release nutrients like nitrogen back into the water
column. Fertilizing the ocean in a way.
Kind of, yes. Those nutrients can stimulate

(31:13):
the growth of phytoplankton, which forms the very base of the
marine food web. And when seals die, their
carcasses decompose, providing anutrient boost to the sea bed
and food for scavengers. Do they physically alter their
environment much? Their haul out sites can see
some impact. Repeated use by large numbers of
seals can affect vegetation and cause erosion on dunes or

(31:34):
coastal banks. Breeding colonies in particular
become sites of significant nutrient deposition from all the
waste products. And their interactions with
humans have ecological ripples too.
Absolutely. The perceived competition with
fisheries is a major ecological interaction leading to
management decisions in conflicts.
On the other hand, they are a major draw for ecotourism in

(31:55):
many areas, which has its own set of ecological and economic
impacts. So they interact with the
physical environment and other species in many ways.
How do they interact specifically with, say, plants
or microbes? Direct interactions with plants
are minimal beyond the physical impact and haul out sites.
Their most significant interactions are with the
animals they eat and compete with.

(32:16):
They also host their own internal and external microbial
communities. Bacteria in their gut help with
digestion and skin microbes are part of their health, just like
in humans. And as we said, their waste
products fuel phytoplankton, which are microscopic marine
plants. It really is a web of
connections. Are there any examples of Gray
seals having symbiotic relationships where both

(32:38):
partners benefit like cleaner fish?
No, there aren't really any welldocumented examples of direct
mutualism like cleaner fish for grey seals.
Their ecological role is more about their position in the food
web and nutrient cycles. So their influence is broader,
less about specific one-on-one partnerships.
What about the downsides? What common diseases or
parasites affect them? They must get sick sometimes.

(33:00):
They certainly do. Like any wild population,
they're susceptible to various health issues.
Viral diseases can be significant.
Foreseeing distemper virus or PVV has caused major epidemics
with high mortality in the past,particularly in the North Sea.
Influenza viruses can also infect them.
What about parasites? Parasites are quite common.

(33:21):
They can suffer from internal parasites like gastrointestinal
worms, nematodes, cestodes whichaffect digestion and lung worms
which cause respiratory problems.
External parasites like lice canalso occur.
Any bacterial or other? Infections Bacterial infections
like mycoplasma causing respiratory issues or
leptospirosis affecting kidneys and liver can occur.

(33:41):
Fungal infections are less common but possible, especially
in weakened animals. There's also a seal pox virus
that causes skin lesions. Usually not fatal but can be
debilitating. Does the environment play a role
in these diseases? Yes, factors like population
density, nutritional stress, andexposure to pollutants can all
influence a seal susceptibility to disease and the potential for

(34:02):
outbreaks. High density at breeding
colonies, for example, can facilitate disease transmission.
A lot of health challenges. This leads us into the broader
threats they face. What are the major concerns for
Gray seal populations today? It's unfortunately quite a long
list, and many threats stem fromhuman activities.
Habitat disturbance and outrightloss are significant issues.

(34:23):
Coastal development, shipping traffic and recreation can
disrupt crucial breeding and haul out areas.
And pollution. Pollution is a major one.
Chemical pollutants like heavy metals and persistent organic
pollutants, or POP's can accumulate in their blubber and
have serious impacts on their immune systems reproductive
health. Oil spills are devastating if

(34:43):
they occur in your seal colonies.
And then there's marine debris, plastic waste, lost fishing
gear. Entanglement.
Exactly. Entanglement in active fishing
gear, bycatch, or discarded ghost gear is a major cause of
injury and death. They can also ingest plastic,
leading to internal problems. With other food source.
Overfishing of their key prey species can lead to food

(35:04):
shortages, impacting their condition and breeding success.
And overlaid on all of this is climate change.
How does climate change affect them?
In multiple ways, sea level riseand increased storm intensity
can erode or submerge haulout sites.
Changes in ocean temperature andcurrents can shift the
distribution and abundance of their prey.
For Baltic seals relying on ice for breeding, warming

(35:26):
temperatures and reduced ice cover are a direct threat.
And direct conflict with humans still happens.
Yes, particularly conflicts withfisheries where seals are
sometimes seen as competitors and maybe cold legally or
illegally in some areas. And disease outbreaks, as we
mentioned, can sometimes be exacerbated by these other
environmental stressors. The mix and intensity of threats

(35:48):
really vary regionally. It's a complex web of threats.
Can you elaborate a bit more on how pollution and climate change
specifically impact them? With chemical pollutants like
PCB's or heavy metals from industrial runoff, they
accumulate up the food chain. Seals, being near the top, can
build up high concentrations in their blubber.
These toxins are linked to suppressed immune function,

(36:09):
making them more vulnerable to diseases and also reproductive
problems like reduced fertility or pub survival.
And marine debris, the plastic and nuts.
Entanglement is often fatal. They get caught in Nets or
plastic strapping, can't surfaceto breathe, or suffer deep
wounds that get infected. Ingesting plastic can block
their digestive systems or causeinternal injuries.

(36:29):
Oil spills are particularly bad.Oil coats their fur, destroying
its insulation, leading to hypothermia.
If ingested, it's highly toxic. And climate change impacts
beyond habitat loss. Gifts and prey distribution are
a major concern. If the fish they rely on move
northwards or deeper due to warming waters, the seals have

(36:50):
to expend more energy foraging or may struggle to find enough
food, especially nursing mothers.
Warmer waters themselves might increase metabolic stress for
ice dependent populations. The loss of stable sea ice for
pupping is a direct existential threat.
A grim outlook on those fronts. Given all these threats, what's
being done to protect Gray seals?
Are there conservation efforts? Yes, thankfully there are

(37:11):
significant conservation courts in place.
Legal protection is fundamental,like the Marine Mammal
Protection Act in the US or the EU Habitats Directive, which
designates protected. Sites like marine protected
areas. Exactly.
Mpas and special areas of conservation, particularly
around important breeding and haul out sites, help to manage
activities and reduce disturbance in critical areas.

(37:32):
Research and monitoring are vital to tracking population
numbers, assessing health, understanding threats.
What about tackling the threats directly?
Average are being made to reducepollution, control chemical
discharges and manage waste, particularly plastic.
There are ongoing initiatives toreduce bycatch in fisheries,
developing more selective gear or deterrence.

(37:54):
Public awareness campaigns help build support for conservation
and responsible behavior around marine wildlife.
And international cooperation isimportant too, as these animals
cross national boundaries. How successful have these
efforts been, particularly protecting their habitats?
They have definitely had positive impacts in many areas.
Protecting key breeding sites byrestricting access or certain

(38:15):
activities during sensitive periods has demonstrably helped
populations recover. Like we've seen in the UK and
parts of North America, guidelines for wildlife watching
help minimize disturbance. Are the pollution controls
helping? Reducing inputs of certain
pollutants has likely helped, although legacy contaminants can
persist for a long time. Beach cleanups and efforts to

(38:36):
reduce plastic use address the debris issue.
Monitoring programs are crucial for assessing whether these
measures are working and adapting strategies.
But challenges remain. Ohe Absolutely.
Climate change is a huge, overarching challenge that
requires global action beyond specific seal conservation
measures, and resolving conflicts with fisheries remains
complex and often contentious. So while progress has been made,

(39:00):
continued effort and adaptive management are definitely
needed. Let's shift perspective slightly
for our final section. What importance do Gray seals
hold for humans? Maybe in ways we don't
immediately think of. Do they have any say
agricultural significance? Well, not in the direct sense of
farming or livestock, obviously they're wild marine animals.

(39:20):
But indirectly you could argue there are connections.
Healthy marine ecosystems, whichgrey seals are a part of and an
indicator for, supports sustainable fisheries.
Fisheries provide food and alternative protein source to
land based agriculture. Also, biodiversity and thriving
wildlife populations, including seals, support ecotourism, which

(39:41):
brings economic benefits to coastal communities, potentially
diversifying income beyond just agriculture or fishing.
And scientifically. Scientific research on seals
informs marine conservation morebroadly.
Protecting marine habitats for seals benefits overall coastal
health, which can in turn help protect adjacent agricultural
land from things like erosion orsaltwater intrusion.

(40:03):
So the links are indirect but related to overall environmental
health and economic well-being. Interesting links.
What about their role specifically in conservation or
protecting ecosystems? They placed several key roles.
As we've discussed. Their position as apex predators
helps regulate prey populations and maintain ecosystem balance.
They also act as indicators species.

(40:25):
Their health and population trends reflect the condition of
the wider marine environment. Are they good ambassadors for
conservation? Very much so.
They are charismatic animals, often referred to as charismatic
megafauna. This means they can act as
flagship species, helping to raise public awareness and
generate support and funding formarine conservation efforts that

(40:45):
benefit not just seals, but entire ecosystems.
Protecting their habitat inherently protects many other
species, and research on them deepens our understanding of
marine technology, which is vital for effective
conservation. They certainly seem to capture
public imagination. How exactly do they contribute
to scientific research? What can we learn?
From them, a great deal. Actually studying their diet, as

(41:06):
we've seen, tells us about fish stocks and ecosystem dynamics.
Monitoring their populations helps track environmental
changes and the success of conservation actions.
Behavioral studies reveal fascinating insights into social
structures, communication, and meeting strategies in marine
mammals. What about their health?
Health assessments in disease research help us understand how

(41:26):
diseases spread in marine populations and the impacts of
pollutants. Their Physiology is also
remarkable. Studying their diving abilities,
how they manage oxygen and regulate temperature can even
provide insights relevant to human Physiology and medicine.
And genetics. Genetic studies are crucial for
understanding population structure, diversity, migration

(41:47):
patterns, and evolutionary history, all of which informs
conservation, genetics and management strategies and their
responses to climate change. Shifts in range or breeding
timing make them valuable indicators.
A wide range of scientific valueWhat tools do scientists
actually use to study these often elusive animals?
A whole toolkit Tagging is a major one.
Fitting seals with satellite GPSor radio tags allows researchers

(42:11):
to track their movements, divingdeaths, time spent foraging and
habitat use over long periods and vast distances.
How do they count them? Aerial surveys using planes or,
increasingly, drones, are commonfor estimating population size
and mapping distribution, especially at breeding colonies.
Photo identification is also powerful.

(42:32):
Recognizing individual seals by their unique natural fur
patterns allows researchers to track individuals over their
lifetimes, gathering data on survival, reproduction and
social bonds. Can they listen in on them?
Yes, acoustic monitoring using underwater hydrophones can
record their vocalizations, helping to understand
communication and detect their presence even when they can't be

(42:53):
seen. Genetic analysis requires
collecting tissue samples, oftensmall skin biopsies.
Diet and behavior. Diet is often studied by
analyzing scat feces collected at haulout sites, where
sometimes stomach contents from deceased animals.
Direct observation from land or boats, often using cameras and
spotting scopes, is still fundamental for studying

(43:13):
specific behaviors in social interactions.
And sometimes researchers will temporarily capture seals for
health assessments, taking bloodsamples, measuring body
condition, checking for parasites.
A real mix of methods from sitting and watching to high
tech tracking. Given all this research, what
are the big unanswered questions?
Where are the gaps in our knowledge about Gray seals?

(43:34):
Even with all we know, there arestill significant gaps.
We need more detailed understanding of population
dynamics in many areas, including the fine scale,
genetic structure, and connectivity between different
colonies. How exactly are they adapting
their foraging behavior to shifting prey resources?
What are the precise long term impacts of climate change on

(43:56):
puff survival and habitat availability across their entire
range? What human impacts?
Quantifying the true extent of competition with fisheries and
the actual impact of bycatch mortality remains challenging.
The sub lethal effects of chronic exposure to various
pollutants need more investigation.
Understanding the prevalence andimpact of emerging diseases is
also crucial. And there's always more to learn

(44:17):
about their complex social behavior, communication signals,
and mating systems, especially outside the main breeding
season. So plenty more for researchers
to investigate. It's clear Gray seals are
resilient but face many challenges.
We've covered a lot today, from their distribution across the
Atlantic to their complex sociallives and the threats they face.
Considering the grey seals proven adaptability, thriving

(44:39):
from rocky UK coast to Canadian ice flows, what completely
unforeseen challenges might theyencounter in our oceans as
changes accelerate, perhaps beyond historical precedent and
thinking about us, what unexpected roles could long
term, perhaps even citizen science based human observation,
play in helping us detect and understand these future threats
before they become critical? Something to ponder.

(45:00):
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