Marine life articles and reading pathways

Underwater scene. Striped lionfish beneath a rocky overhang.

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Multiple marine regions

Red SeaMediterranean

Biotope · Environment

How do fish from the Red Sea colonise the Mediterranean?

Off Cyprus, a lionfish hangs beneath a rocky ledge. It spreads its striped fins and inches towards a smaller fish sheltering by the rock. The scene might look at home on a Red Sea reef. Here, though, the lionfish is…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeperPublic 5 min · Lic. 10 min Read the article

A ray and several fish over a sandy seabed

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Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

In the company of hunters

Off Malta, cameras have caught blue runners darting after prey in the sand stirred up by feeding rays. On Red Sea reefs, a shake of a grouper’s head can bring a moray out of its shelter. One fish takes advantage of…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 4 min · Lic. 9 min Read the article

Artist’s view of a tropical reef with coral rubble in the foreground.

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Multiple marine regions

Red SeaRaja Ampat

Ecology · Science

WHAT DIVERS DON’T SEE ON A CORAL REEF

Picture a branching coral on a tropical reef. Damselfish shelter between its branches. A wrasse swims through, and a shrimp slips into a crack. A diver might stop to look at the fish and the living polyps, then swim on.…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 6 min · Lic. 13 min Read the article

Artist’s view of fish in the sunlit shallows of a tropical reef.

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Multiple marine regions

Red SeaRaja Ampat

Ecology · Science

HOW DO FISH PROTECT THEMSELVES FROM THE SUN?

A bluestreak cleaner wrasse leaves its station and swims through a shaft of sunlight. Nearby, damselfish hold their territories above the reef. In such clear water, some of the Sun’s ultraviolet radiation travels far…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeperPublic 4 min · Lic. 12 min Read the article

Artist’s view of a reef slope in the Gulf of Aqaba.

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Article region: Red Sea

Red Sea

Ecology · Science

RED SEA: WHY DO SOME CORALS WITHSTAND HIGH TEMPERATURES?

A coral in the Gulf of Aqaba can keep its colour when the water warms well beyond its usual summer temperatures. Nearly a thousand kilometres farther south, a smaller rise above local summer conditions can be enough to…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeperPublic 5 min · Lic. 14 min Read the article

A translucent young fish above a tropical reef at dusk.

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Multiple marine regions

Red SeaRaja Ampat

Way of life · Science

Does the reef have a voice?

At dusk, fish vanish into cracks and coral polyps extend their tentacles. Drop a hydrophone beside the reef and another shift becomes audible. Snaps come thick and fast from the rubble, with low pulses and bursts of…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeperPublic 4 min · Lic. 10 min Read the article

Two neighbouring coral colonies, one golden and the other bleached.

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Multiple marine regions

Red SeaRaja Ampat

Way of life · Science

What happens when a coral bleaches?

Picture two coral colonies a few centimetres apart. One has brown and golden branches covered in tiny polyps. The other is white. Its polyps may still be alive and catching prey, even though they have lost much of the…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 3 min · Lic. 9 min Read the article

A moray with its mouth ajar in a reef crevice.

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Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

Why do morays keep opening their mouths?

At the entrance to a reef crevice, a moray can lie almost entirely out of sight. Its jaws part, the pointed teeth show, and the throat moves. Then the jaws close and the whole sequence begins again. That steady rhythm…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 3 min · Lic. 6 min Read the article

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Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

Do sharks sleep?

Picture a shark lying on the sand at the back of a cave, pectoral fins spread and tail still. Its gill slits open and close in a steady rhythm. Its eyes are open. It could still be asleep. Out in the blue, a shark that…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeperPublic 3 min · Lic. 7 min Read the article

Clownfish among the tentacles of an anemone.

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Multiple marine regions

Red SeaRaja Ampat

Way of life · Behaviour

How do clownfish avoid anemone stings?

A clownfish pauses at the edge of an anemone, brushes a tentacle and backs away. A moment later it is among the tentacles, out of sight. Those same tentacles can immobilise a shrimp, yet the fish can spend the night…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeperPublic 3 min · Lic. 7 min Read the article

A crown-of-thorns sea star on branching coral beside a pale feeding scar.

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Multiple marine regions

Red SeaRaja Ampat

Way of life · Behaviour

How can a sea star devour a reef?

As a crown-of-thorns sea star works its way over a coral colony, its arms grip the branches. The meal takes place out of sight. Beneath the sea star, part of its stomach spreads over the living coral. When the animal…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeper8 min Read the article

Reef-building corals spawn at night. Gamete bundles rise above the reef.

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Multiple marine regions

Red SeaRaja Ampat

Way of life · Behaviour

How do corals reproduce?

A few nights after a full moon on the Great Barrier Reef, pink bundles appear at the mouths of coral polyps. They hang briefly, then rise. Nearby colonies release bundles of their own, and the surface water begins to…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 3 min · Lic. 7 min Read the article

A white sand beach and the reef that supplies some of its grains.

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Multiple marine regions

Red SeaRaja Ampat

Biotope · Environment

Who makes the white sand on tropical islands?

A dazzling white beach, coconut palms leaning over a lagoon and turquoise water clear enough to see the seabed. In the Maldives, the Seychelles or the Pacific atolls, the scene can look timeless. Yet some of the grains…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeperPublic 3 min · Lic. 6 min Read the article

Nassau groupers (Epinephelus striatus) converge above a Caribbean reef.

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Multiple marine regions

Red SeaRaja Ampat

Way of life · Behaviour

The secret gatherings behind marine spawning

A Nassau grouper approaches the edge of a Caribbean reef. Others arrive from different directions, some after travelling tens of kilometres. The fish may stay together for days before a small group breaks away at dusk…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeperPublic 5 min · Lic. 10 min Read the article

A veined octopus (Amphioctopus marginatus) carries a shell across the sand.

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Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

Intelligence beneath the surface: learning, remembering and solving problems

A crab moves behind the glass of a sealed jar, within sight of an octopus but out of reach. On a Red Sea reef, a grouper can break off a chase to seek out a moray. Off Indonesia, another octopus carries coconut shells…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeper11 min Read the article

Two mandarinfish (Synchiropus splendidus) begin to rise above the reef.

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Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

Courtship underwater: displays, rivals and mate choice

A flash of colour can be part of courtship or a warning to a rival. Around a wrasse’s nest, two males may vie for access while another waits for a chance to slip in. In some species, the female inspects several…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 6 min · Lic. 11 min Read the article

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Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Swallow, filter, suck in: surprising ways to feed

A mussel can clamp its shell shut with powerful muscles. A sea star needs only a sliver of space between the valves to begin its meal. A fish chasing a crustacean has a different problem: the prey can dart away before…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 3 min · Lic. 7 min Read the article

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Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

What happens when an animal dies in the sea?

In an experiment in the deep Atlantic, fish arrived at a dead cetacean within about an hour. They were catching the small crustaceans that had gathered to feed. Long after the last scavenger leaves a carcass, some of its…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeperPublic 4 min · Lic. 8 min Read the article

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Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Territorial disputes on the reef

A fish only a few centimetres long can drive off an intruder three times its size. A short chase may be all it takes. Elsewhere on the reef, a dispute can cost a whole group its shelter. What makes a patch of rock, a…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 4 min · Lic. 9 min Read the article

A red scorpionfish on a rocky Mediterranean seabed.

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Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Venoms, poisons and chemical weapons: the invisible battle

A scorpionfish can disappear against the rocks. A brightly coloured nudibranch moves slowly in full view, and an anemone waits with its tentacles spread. The chemistry behind those encounters becomes visible in what…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 2 min · Lic. 4 min Read the article

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Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Do Fish Really Sleep?

A parrotfish spends the night in a transparent cocoon. Sharks lie still on the seabed. In the brain of a tiny zebrafish, waves of activity can spread during sleep. Each offers a different clue to what happens when fish…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 4 min · Lic. 9 min Read the article

A terminal-phase bluehead wrasse on a Caribbean reef.

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Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

When Animals Change Sex

When a dominant bluehead wrasse disappears, a large female can take over his territory. Within days, she may be producing sperm. A clownfish can change in the opposite direction, and a small reef goby can change back…

6–10 yearsUnavailable 11–14 years 15–17 years Adults (18+)

Going deeperPublic 5 min · Lic. 10 min Read the article

A camouflaged frogfish faces a small fish on the reef.

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Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Eat or Be Eaten: Hunting Strategies Underwater

A frogfish can wait on the seabed with only its lure moving. When another fish comes close enough, the mouth opens and the water does the rest. Elsewhere, a sailfish can sweep its bill through a school or a grouper can…

6–10 years 11–14 years 15–17 years Adults (18+)

Getting started10 min Read the article

Fish gathering over a reef in moonlight.

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Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Born in the Sea: The Perils of Early Life

An egg drifts with the current. A transparent larva crosses open water. A young fish searches for shelter. Some marine animals release millions of offspring, while others spend weeks guarding a handful. What makes such…

6–10 years 11–14 years 15–17 years Adults (18+)

Getting startedPublic 8 min · Lic. 15 min Read the article

A parrotfish in shelter and squirrelfish on a reef at dusk.

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Multiple marine regions

Red SeaMediterranean

Ecology · Natural history

When the Sea Comes Alive at Night

At dusk, fish that fed in the open begin to tuck themselves into the reef. Others leave the crevices where they spent the day. Farther offshore, billions of small animals start swimming towards the surface. A night dive…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 4 min · Lic. 8 min Read the article

A grouper approaches an octopus at a rocky crevice.

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Multiple marine regions

Red SeaMediterranean

Anatomy · Natural history

How marine animals regrow lost body parts

A sea star survives a bite but loses an arm. An octopus can lose part of an arm as it pulls free of a predator. Some sea cucumbers respond to a threat by expelling internal organs. Escaping is only the first hurdle. The…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeperPublic 4 min · Lic. 10 min Read the article

A blue glowing wave breaking on a beach at night.

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Multiple marine regions

Red SeaMediterranean

Ecology · Natural history

Who Turns on the Light Underwater?

Picture a wave breaking after dark. Blue sparks run along the foam, fade, then return with the next wave. The light comes from living things, some too small to see individually. Below the reach of sunlight, a glow can…

6–10 years 11–14 years 15–17 years Adults (18+)

Going deeperPublic 5 min · Lic. 8 min Read the article

A striped wrasse approaches the head of a stationary grouper.

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Multiple marine regions

Red SeaMediterranean

Ecology · Natural history

Who Helps Whom in the Sea?

On an Indian Ocean reef, a grouper can come to a stop in front of a fish striped in blue and black and open its jaws. The little fish moves closer. A grouper can swallow prey much bigger than this visitor. Yet a cleaner…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 4 min · Lic. 9 min Read the article

White polyps of red coral (Corallium rubrum) connected along a branch.

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Multiple marine regions

Red SeaMediterranean

Anatomy · Science

The Hidden Life of Polyps: How Does a Colony Work?

A sea fan holds its polyps out in the current. On a branch of red coral, white tentacles form little crowns against the red. Each crown surrounds a mouth that can take in food. The tissue below links those mouths to the…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 2 min · Lic. 5 min Read the article

Comparison of three habitats: tropical reef, Mediterranean coralligenous habitat and temperate Atlantic coast.

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Multiple marine regions

Red SeaRaja Ampat

Ecology · Behaviour

Why are reef fish so colourful?

On a tropical dive, a flash of yellow, blue or orange can catch your eye against brown or beige coral. To another fish, the same colours might identify a potential mate or a territorial rival. With so many species…

6–10 years 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 2 min · Lic. 3 min Read the article

Tropical reef: stony coral colonies and shelters between the reef structures

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Multiple marine regions

Red SeaRaja Ampat

Biotope · Environment

THE SECRETS OF CORAL REEFS

A grazer scrapes a hard surface beside a coral colony. A few centimetres away, a fish disappears into a crack. Both are using a structure that grew as generations of polyps left their skeletons behind. From the Red Sea…

6–10 years 11–14 years 15–17 years Adults (18+)

Getting startedPublic 2 min · Lic. 4 min Read the article

Mediterranean seagrass and rocky seabed with organisms whose functions are connected.

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Multiple marine regions

Red SeaMediterranean

Ecology · Natural history

What marine animals do and why it matters

Some fish feed on seagrass leaves. Others shelter among them. Even leaves that fall to the seabed can feed other organisms. Ecological roles help trace those connections, in a meadow, on a reef or out in open water. The…

6–10 years 11–14 years 15–17 years Adults (18+)

Understanding6 min Read the article

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Multiple marine regions

Red SeaMediterranean

Miscellaneous · Natural history

PHYLA WITHOUT THE FUSS

If you’ve taken a marine biology course for divers, you may remember the table of phyla. It came with unfamiliar names and an evolutionary timeline, and it was easy to forget as soon as you’d learnt it. Start instead…

6–10 yearsUnavailable 11–14 years 15–17 years Adults (18+)

Getting startedPublic 2 min · Lic. 5 min Read the article

AvailableFree access

Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

SCHOOLS OF FISH

A school can turn, tighten or stretch out as it moves. Each fish adjusts to what it sees and senses nearby, and those adjustments keep the group together. How does a change made by one fish become a movement shared by…

6–10 years 11–14 years 15–17 years Adults (18+)

Understanding5 min Read the article

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Multiple marine regions

Red SeaMediterranean

Anatomy · Science

MASTERS OF BUOYANCY

A fish can hang above a Mediterranean reef with barely a stroke of its fins. In many bony fish, a pocket of gas inside the body makes that possible. The swim bladder saves effort at a steady depth, but what happens to…

6–10 yearsUnavailable 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 2 min · Lic. 5 min Read the article

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Multiple marine regions

Red SeaMediterranean

Anatomy · Science

How fish sense the world around them

In murky water, a fish can lose sight of its prey before losing track of it. A disturbance nearby may register along its lateral line, and dissolved molecules can carry information about what passed. Which cue matters…

6–10 yearsUnavailable 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 1 min · Lic. 3 min Read the article

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Multiple marine regions

Red SeaMediterranean

Anatomy · Science

The lateral line, a fish’s sixth sense

A passing animal leaves a trace in the water that a fish can detect before it sees what moved. The lateral line picks up nearby flows and vibrations, adding information to what the fish learns through sight, hearing,…

6–10 yearsUnavailable 11–14 years 15–17 years Adults (18+)

UnderstandingPublic 1 min · Lic. 2 min Read the article

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Multiple marine regions

Red SeaMediterranean

Anatomy · Science

WHAT DO FISH SEE?

Switch on a torch underwater and colours can appear that were hard to make out a moment earlier. A fish looking at the same patch of reef has its own set of limits, set by the light and the structure of its eyes. Vision…

6–10 yearsUnavailable 11–14 years 15–17 years Adults (18+)

Getting startedPublic 1 min · Lic. 3 min Read the article

A naturalist diver and a marine biologist diver

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Multiple marine regions

Red SeaMediterranean

Miscellaneous · Technique

Naturalist diving and marine biology

A dive can begin with the simple pleasure of being underwater. Then a sponge or a fish catches your eye and you start asking questions. What lives here? What is it doing? How does it fit into the habitat? For some…

6–10 yearsUnavailable 11–14 years 15–17 years Adults (18+)

Getting started3 min Read the article

Understand marine biodiversity and underwater environments

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How do fish from the Red Sea colonise the Mediterranean?

In the company of hunters

WHAT DIVERS DON’T SEE ON A CORAL REEF

HOW DO FISH PROTECT THEMSELVES FROM THE SUN?

RED SEA: WHY DO SOME CORALS WITHSTAND HIGH TEMPERATURES?

Does the reef have a voice?

What happens when a coral bleaches?

Why do morays keep opening their mouths?

Do sharks sleep?

How do clownfish avoid anemone stings?

How can a sea star devour a reef?

How do corals reproduce?

Who makes the white sand on tropical islands?

The secret gatherings behind marine spawning

Intelligence beneath the surface: learning, remembering and solving problems

Courtship underwater: displays, rivals and mate choice

Swallow, filter, suck in: surprising ways to feed

What happens when an animal dies in the sea?

Territorial disputes on the reef

Venoms, poisons and chemical weapons: the invisible battle

Do Fish Really Sleep?

When Animals Change Sex

Eat or Be Eaten: Hunting Strategies Underwater

Born in the Sea: The Perils of Early Life

When the Sea Comes Alive at Night

How marine animals regrow lost body parts

Who Turns on the Light Underwater?

Who Helps Whom in the Sea?

The Hidden Life of Polyps: How Does a Colony Work?

Why are reef fish so colourful?

THE SECRETS OF CORAL REEFS

What marine animals do and why it matters

PHYLA WITHOUT THE FUSS

SCHOOLS OF FISH

MASTERS OF BUOYANCY

How fish sense the world around them

The lateral line, a fish’s sixth sense

WHAT DO FISH SEE?

Naturalist diving and marine biology