The Wandering Seal
NOAA National Marine Mammal Laboratory
Deep into the foggy abyss of the central Bering Sea, the Pribilof Islands were found, not by sight, but by sound.
In the 1800s, fur traders tracked the northern fur seal to these islands. They discovered that the seals are only there in the summer and fall.
Today, researchers from NOAA's National Marine Mammal Lab 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 via satellites.
This female's journey takes her south through 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 4th 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 year before.
In many cases, they were born in the same area themselves. Researchers know this because they have also tagged and tracked pups.
Incredibly, they endure the same migration as adults and start out when they are only 4 months old.
Sadly, 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, may be impacting fur seal survival.
The present Pribilof fur seal decline is not fully understood, but the key may lie in studying them along their wandering migration route.