Tip:
Highlight text to annotate it
X
- DEEP INTO THE FOGGY ABYSS
OF THE CENTRAL BERING SEA,
THE PRIBILOF ISLANDS WERE FOUND NOT BY SIGHT BUT BY SOUND.
IN THE 18th CENTURY,
FUR TRADERS TRACKED THE NORTHERN FUR SEAL TO THESE ISLANDS
AND DISCOVERED THAT THE SEALS ARE ONLY THERE
IN SUMMER AND FALL
BECAUSE EVERY YEAR, THEY SWIM THE EQUIVALENT
OF A QUARTER WAY AROUND THE WORLD
IN A NEVER-ENDING SEARCH FOR FOOD.
TODAY, RESEARCHERS FROM THE NATIONAL MARINE MAMMAL LAB
AT NOAA's ALASKA FISHERIES SCIENCE CENTER
TRACK THE MIGRATING FUR SEALS TO UNDERSTAND WHERE THEY FEED
IN WINTER MONTHS
AND WHAT MARINE RESOURCES THEY DEPEND ON FOR SURVIVAL.
IT'S EARLY NOVEMBER, AND THE TEAM AFFIXES
A SATELLITE TRANSMITTER TO AN ADULT FEMALE.
THEY WON'T SEE HER BACK ON THE PRIBILOF ISLANDS
UNTIL NEXT JULY.
AND NOW THAT SHE'S DONE SHEDDING,
THEY HOPE THE TAG WILL STAY ON THROUGHOUT WINTER AND SPRING.
BACK AT THEIR OFFICES IN SEATTLE,
THE RESEARCHERS BEGIN TRACKING TAGGED ANIMALS IMMEDIATELY
VIA SATELLITES.
THIS FEMALE'S JOURNEY TAKES HER SOUTH TO THE ALEUTIAN ISLANDS
IN JUST 3 DAYS,
TRAVELING ABOUT 70 MILES A DAY.
OVER THE NEXT TWO MONTHS,
SHE TRAVELS STRAIGHT ACROSS THE OPEN OCEAN TO CALIFORNIA,
COVERING ABOUT 3,000 MILES.
SHE FEEDS OFF THE COAST OR IN THE OPEN OCEAN FOR MONTHS
AND EVEN SLEEPS FLOATING ON THE SURFACE.
AS SUMMER APPROACHES, SHE HEADS BACK TO THE PRIBILOFS
BUT THIS TIME ALONG THE COAST.
ROUTES VARY FROM INDIVIDUAL TO INDIVIDUAL,
BUT EACH SEAL TRAVELS ON ITS OWN FOR ABOUT 8 MONTHS
AND CAN COVER OVER 6,000 MILES.
BELIEVE IT OR NOT, THIS IS FOURTH OF JULY WEEKEND
ON THE PRIBILOFS.
AT POLOVINA CLIFFS ROOKERY,
THE FEMALE TAGGED IN NOVEMBER IS BACK.
FEMALES ACTUALLY RETURN YEAR AFTER YEAR
TO THE SAME ROCKS WHERE THEY GAVE BIRTH THE SUMMER BEFORE.
IN MANY CASES, THEY WERE BORN IN THE SAME AREA THEMSELVES.
WE KNOW THIS BECAUSE PUPS ARE ALSO TAGGED AND TRACKED.
INCREDIBLY THEY ENDURE THE SAME MIGRATION AS ADULTS
AND START OUT WHEN THEY'RE ONLY 4 MONTHS OLD.
HOWEVER, THE PRIBILOF FUR SEAL POPULATION IS DECLINING.
AND IT SEEMS THAT FEWER AND FEWER YOUNG ANIMALS
ARE RETURNING EACH YEAR.
ENTANGLEMENT IN GARBAGE AND OTHER MARINE DEBRIS,
INCREASED PREDATION AND COMPETITION FOR FOOD,
ALONG WITH CLIMATE CHANGE
ARE SOME OF THE FACTORS THAT MAY BE IMPACTING FUR SEAL SURVIVAL.
THE PRESENT PRIBILOF FUR SEAL DECLINE IS NOT FULLY UNDERSTOOD,
BUT THE KEY MAY LIE IN STUDYING THEIR MIGRATION PATTERNS,
ESPECIALLY THOSE OF PUPS.