Original subtitles

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ANNOUNCER: WHEN YOU SEE THIS SYMBOL YOU KNOW YOU'RE

WATCHING TELEVISION THAT'S EDUCATIONAL AND INFORMATIONAL.THE MORE YOU KNOW ON NBC.

DYLAN: I'M DYLAN DREYER.

TODAY WE'RE ON AN ADVENTURE TO THE

WILDERNESS OF ALASKA TO WITNESS ONE OF THE MOST

EXTRAORDINARY JOURNEYS ON EARTH,

AND UNCOVER THE SECRETS OF SALMON.

THROUGH ROUGH OCEAN CURRENTS,

PAST HUNGRY SHARKS, OVER ROARING RAPIDS,

UP STEEP WATERFALLS, TINY MOUNTAIN STREAMS,

PAST DEADLY GRIZZLY BEARS; WE'LL EXPLORE THE

FANTASTIC LIVES OF THESE AMAZING FISH AND WATCH

THEIR RELENTLESS STRUGGLE FOR SURVIVAL.

THE JOURNEY STARTS RIGHT NOW.

♪ MUSIC ♪

DYLAN: SALMON ARE TRULY REMARKABLE CREATURES.

THEY ARE BORN IN FRESHWATER RIVERS AND

STREAMS, TRAVEL ALL THE WAY DOWN TO THE SALTWATER

OCEAN AND THEN AFTER MANY YEARS AT SEA THEY MAKE AN

INCREDIBLE JOURNEY BACK UPSTREAM;

SOMETIMES HUNDREDS OF MILES TO THE VERY SAME

PLACES THEY WERE BORN TO BRING THE NEXT GENERATION

INTO THE WORLD.

SALMON ARE ABSOLUTELY CRITICAL TO THE ALASKAN

ECOSYSTEM.

BUT THE ALASKAN ECOSYSTEM IS FULL OF ENDLESS DANGERS

TO SALMON OVER THE COURSE OF THEIR LONG JOURNEY.

FROM FISHERMEN TO GRIZZLY BEARS AND SOMETIMES EVEN

VOLCANOES.

YOUNG SOCKEYE SALMON FEED AND GROW IN A VAST STRETCH

OF THE PACIFIC OCEAN WHERE WARM WATERS FROM THE

TROPICS MIX WITH COLD ARCTIC CURRENTS.

THEY GATHER IN LARGE SHOALS,

EACH SALMON SEEKING THE SCENT OF ITS NATIVE RIVER.

♪ MUSIC ♪

DYLAN: THESE SILVERY FISH HAVE GROWN FAT AND RIPE ON

PLANKTON BUT NOW THEY STOP FEEDING;

THEIR ONE GOAL, TO SWIM TO THEIR BIRTHPLACE TO LAY

THEIR EGGS, KNOWN AS SPAWNING.

BUT THE OCEAN IS NOT AS CLEAR AS IT SHOULD BE.

THE WATER CARRIES WITH IT A FAINT SCENT OF SULFUR;

THE MOUNTAIN IS ON FIRE.

THE SALMON ARE CONFUSED.

THEY CAN SMELL THE SULFUR DISSOLVED IN THE WATER BUT

THEY ALSO SMELL THE UNIQUE CHEMICAL SIGNATURE OF

THEIR NATIVE RIVER.

THEY FOLLOW THEIR NOSES INTO THE PATH OF A

VOLCANO.

UPSTREAM, A THICK SLUDGE OF BLACK ASH IS HEADING

THEIR WAY.

THE RIVER GATHERS UP POISONS AND CARRIES THEM

TOWARD THE FISH.

THE SALMON BEGIN TO GET THE MESSAGE AS MORE CLOUDS

OF BURNING ASH TUMBLE DOWN THE MOUNTAIN.

THEY HAVE NO CHOICE BUT TO RETRACE THEIR JOURNEY BACK

TO THE OPEN OCEAN.

THESE ARE NOW LOST SALMON WITH NO SENSE OF

DIRECTION.

THE VOLCANIC ASH HAS STIRRED UP THE OCEAN

STIMULATING THE GROWTH OF PLANKTON AND ENCOURAGING

CLOUDS OF STINGING JELLYFISH.

BUT THE HIGHLY SENSITIVE SALMON CAN ACTUALLY SMELL

THESE JELLYFISH AND SO AVOID THEIR DEADLY

TENTACLES.

THIS LOST SALMON HAS SWUM ALL THE WAY TO A

SWEET-SMELLING RIVER.

LIKE ALL OTHER SALMON, THIS FISH WILL NEVER STOP

TO FEED OR SLEEP.

IT IS PROGRAMMED TO FIND FRESH WATER OR DIE TRYING.

AT THE RIVER MOUTH A STAIRCASE AND THE

TANTALIZING SCENT OF FRESH WATER GUSHING TOWARDS

THEM.

BUT FOR THOSE THAT MAKE IT PAST THE GULLS,

THE TRAP SLOWLY CLOSES IN.

[MUSIC - BEAR SOUNDS]

DYLAN: THESE GRIZZLIES NEED TO DOUBLE THEIR BODY

WEIGHT DURING THE SHORT ARCTIC SUMMER TO PREPARE

FOR HIBERNATION.

WITH THE TIDE FALLING BACK,

THE SALMON ARE ESPECIALLY VULNERABLE IN SHALLOW

WATER.

TO REACH THE RIVER THE SALMON HAVE TO GET UP THE

STAIRS AND ON EVERY STEP AN ADULT FEMALE IS READY.

THESE OLDER BEARS FOUGHT FOR THESE POSITIONS.

THEY'VE LEARNED THAT THIS IS THE BEST PLACE TO STAND

AND WAIT.

THE SALMON RUSH AS ONE; THEIR ONLY CHANCE,

SAFETY IN NUMBERS.

ONCE THE SALMON ARE RUNNING THE FEMALES LET

THE CUBS JOIN THE FREE-FOR-ALL.

WITH SO MANY FISH IT'S ALL TOO EASY FOR THE BEARS.

THEY ABANDON THE FLESH, THE GULLS FINISH IT OFF.

IT MAY SEEM A TRAGIC WASTE BUT THE OILY SKIN IS THE

BEST BET FOR BUILDING UP THE BEAR'S FAT RESERVES.

AND WITH SO MANY FISH, THEY CAN AFFORD TO BE

CHOOSY.

FOR THE BEARS IT'S GLUTTONY.

YET BECAUSE THERE ARE SO MANY SALMON THEY KEEP ON

COMING AND SOME MAKE IT PAST THE FIRST HURDLE.

THEY PUSH ON HARD TO CONQUER THE CURRENT,

TO LEAP THE STEPS, TO BEAT THE BEARS.

COMING UP NEXT, THE SALMON FACE A NEW DANGER AS THE

VOLCANOES OF ALASKA RUMBLE.

AND LATER, THE SALMON RETURN TO THEIR MOUNTAIN

LAKES AND STREAMS TO BRING THE NEXT GENERATION INTO

THE WORLD.

DON'T GO AWAY, THE JOURNEY WILL BE RIGHT BACK.

ANNOUNCER: WE'LL BE RIGHT BACK TO THE MORE YOU KNOW ON NBC.

.

ANNOUNCER: WE NOW RETURN TO THE MORE YOU KNOW ON NBC.

♪ MUSIC ♪

DYLAN: WELCOME BACK TO JOURNEY,

I'M DYLAN DREYER.

THE ALASKAN SALMON HAVE MADE IT THROUGH THEIR

FIRST GREAT CHALLENGE, PAST A HOARD OF HUNGRY

GRIZZLY BEARS.

BUT AS THEY CONTINUE UPSTREAM NEW OBSTACLES

AWAIT THEM.

MANY OF THE FISH ARE TRAVELING UP A GREAT RIVER

NAMED ANIAKCHAK, BUT AHEAD OF THEM A VOLCANO HAS

BEGUN TO STIR.

EVERY RIVER CARRIES ITS OWN UNIQUE SCENT DOWN TO

THE OCEAN.

SALMON GATHER TO CATCH THE SCENT AND FOLLOW THE TRAIL

UPSTREAM TO THEIR BIRTHPLACE.

IN ALASKA THE FRESHWATER THAT FEEDS THE RIVERS IS

SNOW MELT FROM NORTH AMERICA'S HIGHEST

MOUNTAIN.

BUT UNDER MANY OF THESE ICE-COVERED PEAKS A

FURNACE BURNS FIERCELY, FOR THESE ARE ALSO NORTH

AMERICA'S MOST ACTIVE VOLCANOES.

SOCKEYE SALMON HAVE INCREDIBLE STAMINA.

IN THEIR LIFETIME THEY CAN TRAVEL OVER

6,000 MILES.

ONCE AGAIN, THE SCENT OF FRESH WATER LURES THE

SALMON CLOSE TO THE SHORE.

THE NATIVE AMERICANS NAMED THIS RIVER ANIAKCHAK,

THE WAY OUT.

AND ITS WIDE RIVERBED SUGGESTS THAT IT HAS SEEN

MORE TURBULENT TIMES.

ITS MEANDERING PATH LEADS TO MANY TRIBUTARIES AND

DEAD-ENDS.

AND NOW THESE LOST SALMON MUST SWIM ON INTO THE

UNKNOWN.

THEIR JOURNEY IS FAR FROM OVER.

UNLIKE OTHER SALMON, SOCKEYES DON'T LAY THEIR

EGGS IN FLOWING STREAMS OR RIVERS,

THEY KEEP ON GOING FOR MILES UNTIL THEY FIND A

CALM BACKWATER, A POOL OR LAKE.

AHEAD OF THEM LIES ANIAKCHAK,

THE VOLCANO AFTER WHICH THE RIVER IS NAMED.

ANIAKCHAK IS ACTUALLY A 7-MILE WIDE BASIN OR

CALDARA, CREATED BY A GIANT VOLCANO WHICH

COLLAPSED IN ON ITSELF.

IN 200 A.D. THE CALDARA

IS FILLED WITH A VAST FROZEN LAKE OVER

300 FEET DEEP.

HIDDEN UNDER THE LAYERS OF ICE ARE THOUSANDS OF TONS

OF WATER, AND SEVERAL MORE VOLCANIC CONES WHICH ERUPT

IN TURN.

THE FORCE OF THE BLAST SHATTERS THE ICE.

THE WIND BLOWS THE POISONOUS FUMES AWAY FROM

THE FISH IN THE RIVER SO THEY DON'T SMELL THE

DANGER.

UNDER CONTINUAL BOMBARDMENT AND SHAKING,

THE CALDARA'S RAMPARTS BEGIN TO CRACK.

WATER FINDS THE WEAK SPOT.

THE TERRIFYING FORCE BREAKS OPEN BARRIERS AND

FORGES NEW CHANNELS DOWN THROUGH THE VALLEY.

IT GRABS EVERY LIVING THING IN ITS PATH.

WITHIN HOURS MOST OF THE LAKE HAS DRAINED AWAY,

BUT DOWNSTREAM THE FLOOD CONTINUES ITS DESTRUCTION.

ANIAKCHAK, THE WAY OUT, HAS ONCE AGAIN RECREATED

THE LANDSCAPE.

THE BULK OF THE FLOOD WATER HAS DISAPPEARED INTO

THE SEA BUT IT HAS LEFT BEHIND A WHOLE NEW FLOOD

PLAIN OF MEANDERS AND BACKWATERS AND DEAD-END

POOLS.

AND INTO SOME OF THESE IT FLUNG THE SALMON.

TIME AND AGAIN OVER THE CENTURIES THE VOLCANOES OF

ALASKA HAVE ERUPTED, TURNING THE CRYSTAL-CLEAR

RIVER WATERS BLACK AND POISONOUS.

SCIENTISTS HAVE ONLY JUST BEGUN TO PIECE TOGETHER

WHAT MIGHT HAVE HAPPENED NEARLY 2,000

YEARS AGO WHEN ONE POPULATION OF SALMON FACED

THE DEATH OF THEIR NATAL RIVER AND WERE FORCED BACK

TO THE OPEN OCEAN ON AN EXTRAORDINARY ADVENTURE

LEAVING BEHIND AN AMAZING LEGACY.

THE URGE TO FIND FRESH WATER IS SO POWERFUL THAT

SLOWLY THE TENACIOUS LOST SALMON FIGHT ON.

BATTERED AND BRUISED, THEY GRADUALLY BEGIN TO

REGROUP.

THEY SWIM ON PAST SKULLS OF THEIR OLD ENEMY,

THE BEAR.

EVEN A GIANT FROM AN EARLIER AGE;

A WOOLY MAMMOTH TUSK.

BUT BECAUSE THESE INDIVIDUAL SALMON ARE ALL

FOLLOWING THE SAME FAINT MINERAL TRAIL,

THE SCENT OF FRESHWATER, AMAZINGLY STILL POTENT

AMID THE CHAOS, GRADUALLY THEY FIND THEIR WAY BACK

TO THE MAIN CHANNEL.

NOW ANOTHER TICKING CLOCK BEGINS TO WORK AGAINST

THEM; THEIR BIOLOGICAL CLOCK.

THEY MUST FIND A SAFE BACKWATER TO SPAWN IN SOON

OR THE WHOLE EPIC JOURNEY WILL HAVE BEEN IN VAIN.

DON'T GO AWAY, THE JOURNEY WILL BE RIGHT BACK.

ANNOUNCER: WE'LL BE RIGHT BACK TO THE MORE YOU KNOW ON NBC.

.

ANNOUNCER: WE NOW RETURN TO THE MORE YOU KNOW ON NBC.

♪ MUSIC ♪

DYLAN: THE REMAINING ALASKAN SALMON HAVE DODGED

HUNGRY BEARS, DEADLY BIRDS,

DESTRUCTIVE VOLCANOES, BUT NOW THEY MUST FACE ANOTHER

CHALLENGE; THEIR BIOLOGICAL CLOCKS.

THEY HAVE LOST A LOT OF TIME MAKING THEIR WAY BACK

TO THEIR HOME STREAMS TO SPAWN THE NEXT GENERATION.

THEIR HEADS BEGIN TO TURN GREEN,

THEIR BODIES RED; A SIGN THAT THE END OF THEIR LIFE

CYCLE IS NEAR.

THIS RED PIGMENT, BRIGHTER IN THE MALES,

HELPS TO PROTECT THE FISH FROM HARMFUL ULTRAVIOLET

RAYS, BUT IT ALSO SIGNALS THE BEGINNING OF THE END

FOR THE ADULT SALMON.

THEY MUST FIND A SAFE BACKWATER TO SPAWN IN SOON

OR THE WHOLE EPIC JOURNEY WILL HAVE BEEN IN VAIN.

BUT THE CALL OF FRESHWATER SEEMS TO BE COMING FROM

THE CENTER OF THE RAVAGED VOLCANO ITSELF.

THE SALMON HAVE ACTUALLY SWUM THROUGH A BREAK IN

THE WALL INTO THE VERY HEART OF THE VOLCANO.

THIS SMALL GREEN LAKE IS APTLY NAMED SURPRISE LAKE.

SURPRISE LAKE COLLECTS RAINWATER FROM THE CALDARA

WALLS.

THE WATER GATHERS UP A COCKTAIL OF VOLCANIC

POISONS AND ENTERS THE LAKE HOT,

ACIDIFIED AND TOXIC WITH MINERALS.

IS THIS THE JOURNEY'S END FOR THE SALMON?

THE ONLY WILDLIFE THAT CAN SURVIVE ARE SPECIALIZED

BACTERIA WHICH WERE PROBABLY AMONG THE VERY

FIRST SPECIES TO COLONIZE EARTH.

AND YET THIS IS WHERE THE SOCKEYES HAVE COME TO SWIM

AND LAY THEIR EGGS.

SURPRISE LAKE HIDES A SECRET.

DESPITE THE POISONOUS COCKTAIL,

IN SOME PARTS THERE IS ENOUGH OXYGEN FOR SALMON

TO BREED, EVEN FOR PLANKTON TO GROW.

THE MIRACLE BEGINS WITH THE CLOUDS WHICH MEET THE

WARM ROCK OF THE CALDARA WALLS.

THE CLOUDS CONDENSE INTO DROPLETS AND SEEP THROUGH

THE ROCK.

IN SOME PARTS THE WATER PICKS UP POISONS,

BUT IN OTHERS THE ANCIENT ROCK FILTERS THE WATER

FROM THE SNOW-WHITE CLOUDS,

MAKING IT EVEN PURER AND SWEETER.

THIS IS THE SOURCE; FRESH, CLEAN,

FULLY OXYGENATED WATER FLOWS THROUGH A CRACK IN

THE WALLS INTO THE TOXIC SURPRISE LAKE.

AT LAST SEVERAL MONTHS AFTER THEY WERE TURNED

BACK FROM THEIR NATAL RIVER THESE LOST SALMON

FOUND A TINY BIT OF PARADISE IN THE BOWELS OF

A VOLCANO; A PLACE WHERE THEY CAN GIVE THEIR YOUNG

A CHANCE.

DON'T GO AWAY, THE JOURNEY WILL BE RIGHT BACK.

ANNOUNCER: WE'LL BE RIGHT BACK TO THE MORE YOU KNOW ON NBC.

.

ANNOUNCER: WE NOW RETURN TO THE MORE YOU KNOW ON NBC.

♪ MUSIC ♪

DYLAN: THE AMAZING SALMON HAVE FINALLY COMPLETED

THEIR EPIC QUEST HOME.

THEIR BODIES ARE SPENT, THEY'VE BEEN GOING AND

GOING FOR THOUSANDS OF MILES.

NOW THEY CAN SPAWN AND SECURE THE NEXT GENERATION

OF THEIR SPECIES AND THE GREAT CYCLE OF THEIR

INCREDIBLE LIVES WILL BEGIN AGAIN.

IN THE SHADOW OF THE VOLCANO THE MALE GUARDS

HIS FEMALE WHILE SHE DIGS A SHALLOW NEST.

THEN SHE SHEDS UP TO 5,000 EGGS WHICH SHE HAS CARRIED

ALL THIS WAY.

THEIR QUEST COMPLETE, THEIR BODIES SPENT,

THE ADULT SALMON START TO DETERIORATE.

THEY'VE KEPT GOING FOR THOUSANDS OF MILES BUT THE

MINUTE THEY'VE SPAWNED THEY BEGIN TO DIE.

BY DYING HERE THEY LEAVE THEIR BODIES AND ALL THE

MINERALS WITHIN TO HELP FEED THE WILDLIFE AND

PLANT LIFE.

NO ONE KNOWS EXACTLY HOW MANY HUNDREDS OF YEARS AGO

THOSE FIRST PIONEERING SALMON FOUND THEIR WAY TO

THE HEART OF THE VOLCANO.

BUT WE KNOW THEY DID BECAUSE EACH YEAR NEW

SALMON FRY HATCH OUT IN SURPRISE LAKE.

THE YOUNG FRY FEED AND GROW FOR 2 YEARS WHILE THE

UNIQUE SMELL OF SURPRISE LAKE IS IMPRINTED ON THEIR

BRAIN.

OVER THE YEARS THE DESCENDANTS OF THOSE

ORIGINAL PIONEERING SALMON BECAME A NEW RACE OF

SOCKEYE SALMON; THE SURPRISE SALMON.

AS THE YOUNG SALMON HEAD DOWNSTREAM RETRACING THE

ANCIENT ROUTE OF THEIR ANCESTORS,

CAN THEY KNOW THE SIZE OF THE GREAT JOURNEY BEFORE

THEM OR HOW FEW OF THEM WILL MAKE IT BACK,

OR THE DANGERS THEY WILL FACE ALONG THE WAY?

PROBABLY NOT.

BUT SOMETHING DEEP WITHIN THEM DRIVES THEM FORWARD;

A WILLPOWER UNLIKE ANYTHING ON EARTH.

I HOPE YOU ENJOYED OUR JOURNEY WITH ALASKAN

SALMON.

UNTIL WE MEET AGAIN, SAFE TRAVELS.

♪ CREDITS ♪