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Marine Mammals

Marine Mammals

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Download Episode: Ancient Bowhead Whales (MP3 file 3,603 kB)

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Download Episode: Beluga (MP3 file 3,715 kB)

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Download Episode: Beluga research (MP3 file 1,403 kB)

Beluga research

In the silty coastal waters of upper Cook Inlet southwest of Anchorage, a pod of beluga whales is feeding. Beluga whales use sound to find their prey, and to communicate with each other. They hunt in murky coastal waters and swim up silty glacier rivers, and can hunt entirely by echolocation. They are found in Arctic and sub-arctic Alaska waters, including Cook Inlet.

These belugas are year-round residents of Cook Inlet. Cook Inlet belugas were once common in both the upper and lower inlet with a historical population estimate of 1,300. The population dropped to just half that number in the mid-1990s due to unmanaged subsistence harvests. Since the 1990s it's declined further and population in 2017 is estimated to be 340 belugas, which mostly stay in the upper inlet.

In 1999, Congress imposed a moratorium on the subsistence harvest of Cook Inlet belugas, and the population was designated as depleted under the Marine Mammal Protection Act. In 2008 they were listed as endangered under the Endangered Species Act. In 2011, an area of 3,013 square miles of critical habitat was established. In spite of these efforts, Cook Inlet belugas have not recovered and the reasons why are unknown.

Fish and Game is studying these endangered Cook Inlet beluga whales. Understanding the foraging ecology, diet and habitat use of the Cook Inlet beluga may help determine if changes in prey availability were a factor in the population decline, and if it is impeding recovery.

Because they use sound to find prey, communicate, and navigate, loud human-generated noise may interfere with their ability to find and capture prey. Biologists are using hydrophones to detect and identify noise sources, and learn if noise may displace belugas from feeding areas. This acoustic monitoring has already provided insights into the seasonal distribution of belugas in Cook Inlet.

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Download Episode: Belugas - Canaries of the Sea (MP3 file 1,408 kB)

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Download Episode: Belugas Count (MP3 file 1,409 kB)

Belugas Count

On a sunny day in mid-September, 2018, a group of whale watchers is gathered near the Seward Highway south of Anchorage, on the shore of Cook Inlet. These wildlife viewers are organized - they're participating in Belugas Count, an annual effort to document the white whales in the silty waters of Cook Inlet.

Biologists estimate that there are about 330 belugas in the inlet, down from more than 1,000 in the 1970s. The federal government listed Cook Inlet beluga whales as an endangered species in 2008. The state of Alaska and the federal government have a beluga recovery team working to monitor and study the Cook Inlet belugas. Biologists think hunting originally caused the decline. But even though hunting has stopped, the population hasn't recovered, and scientists want to know why - a lack of food, the presence of contaminants, or noise pollution are all factors being considered. For the 2018 Belugas count event, 18 viewing stations were set up across Cook Inlet. About 2,000 people showed up to count belugas. In addition to shore-based volunteer beluga watchers, oil company workers looked for whales from their platforms in Cook Inlet. About 100 beluga whales were spotted by whale watchers in the 2018 Belugas Count event.

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Download Episode: Biggest Brain - Sperm Whales (MP3 file 3,533 kB)

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Download Episode: Bowheads (MP3 file 1,408 kB)

Bowheads

Bowhead whales, like humpback whales, have elaborate and complex songs. Researchers are finding that pods of bowhead whales share songs, and sing a variety of shared songs during migration. Underwater recordings made in the spring of 2011 documented a dozen different songs sung by at least 32 whales swimming off Point Barrow. The recordings also pick up the eerie, ringing vocalizations of bearded seals - the bowhead songs are deeper, in a lower register.

Biologists suspect the songs are sung by males, related to breeding. The songs are recorded by sonobuoys, underwater recording devices that are sunk and rest on the sea floor for about six months. Researchers send the sonobuoys a signal that causes them to surface so they can be recovered. The devices are deployed in a line from the Bering Sea almost 1,500 miles east to the Canadian Beaufort Sea, recording songs as the whales move through their migratory route in the Arctic.

The North Slope Borough, Cornell's Bioacoustics Research Program, and other collaborators have been recording bowhead vocalizations, beluga whales, bearded seals and other animals in the Beaufort Sea for years. The recordings help determine the size of the bowhead population, which is growing at a rate of almost four percent a year. In 2011 the population was estimated at about 17,000 whales, good news for a population that heavily impacted by commercial whaling.

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Download Episode: Chattering Walrus (MP3 file 3,599 kB)

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Download Episode: Deep Diving Sea Lions (MP3 file 2,341 kB)

Deep diving sea lions

A Steller sea lion breaks the surface of the wave-tossed Gulf of Alaska 40 miles south of Kodiak. She takes a few deep breaths and floats at the surface, resting. She just made a dive of 300 meters, more than a thousand feet, and was underwater for ten minutes catching cod on the sea floor.

The pressure at that depth is about 450 pounds per square inch. It's remarkable that a sea lion can withstand such pressure, and transition between that pressure and the surface. Terrestrial animals like us experience a steady pressure of one atmosphere - about 15 pounds per square inch - the weight of the air above us. But water is heavier than air, and every 10 meters of depth adds another atmosphere of pressure. At 300 meters below the surface, that sea lion experienced 30 atmospheres of pressure.

Fish and Game researchers found that sea lions in PWS were making dives deeper than 400-meters, and one female went as deep as 600 meters, over a-third of a mile, where the pressure tops 900 pounds per square inch. Specially designed bathyscapes can reach such depths, but that's about twice as deep as a modern military submarine can go.

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Download Episode: Entangled Sea Lions (MP3 file 3,518 kB)

Entangled sea lions

About 40 sea lions lounged on the rocks at the Benjamin Island haulout north of Juneau, but one was special. A thin, white plastic packing band encircled his neck, cutting into his skin.

Two biologists studied the animal from a skiff 40 yards off the rocks. Lauri Jemison and Jamie King of the Alaska Department of Fish and Game discussed possible ways to free the entangled animal. None seemed very promising.

Jemison is studying sea lion entanglements in Alaska, and working on ways to reduce entanglements and free animals that are wrapped in ropes, netting, plastic packing bands and rubber loops. Sea lions will sometimes chase salmon that fishermen have hooked, catch the salmon and wind up getting hooked into fishing gear. But trash is probably the biggest problem, and the most easily preventable.

QUOTE: "Any kind of loop that goes into the water can be deadly. A small loop can be deadly to seabirds and fish, a larger loop can entangle marine mammals. Synthetic materials are the worst. A simple solution is to cut any kind of loop you might have. Trash on board a boat, or if you're having a picnic on the beach.

Bait boxes have those packing bands around the box, that's a hard plastic material, and if that isn't cut we see animals entangled in that. Other types are black rubber bands, rubber inner tube material that are used to secure crab pots. Loops in rope, fishing line, nets, anything like that can potentially be hazardous.

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Download Episode: Fluke print (MP3 file 1,405 kB)

Fluke Prints

On an overcast July day, four biologists in a skiff are speeding across the waters of Sumner Strait near Wrangell in Southeast Alaska. They're following a group of harbor porpoises to learn more about the distinct populations of these animals in Southeast waters. They're looking at stock structure - a stock is a group of animals that interbreeds and interacts, distinct from other groups of the same species. They're looking at two stocks of harbor porpoises in Southeast, those in the Sumner strait area, and those in Icy Strait and Glacier Bay, about 200 miles northwest.

Genetic tests of tissue reveal the relatedness between individuals - but how do you get a tissue sample from a fast-swimming, skittish marine mammal like a harbor porpoise? These biologists are pioneering a new method called fluke prints. A fluke print is a water sample taken immediately after the porpoise surfaces for a quick breath of air. A two-liter sample of water is scooped from the surface of the ocean right where the porpoise was swimming. The water is filtered immediately and the filter paper is stored - analysis can be done any time in the next few months. The animals shed a tiny amount of skin, but it's enough to provide what's known as environmental DNA. This eDNA can identify the animals to the specific stock, and provides insights into the stock structure - and the gene flow between those different stocks of harbor porpoise in Southeast Alaska and beyond.

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Download Episode: Grey Whales (MP3 file 1,407 kB)

Gray Whales

On a fall afternoon, a pod of grey whales passes a fishing boat off the coast of Alaska. Grey whales are a bit smaller than humpbacks. Like humpbacks, they are filter feeders, but unlike humpbacks, they don't feed in the water column, instead, grey whales are bottom feeders, scooping sediment from the sandy or muddy sea floor and filtering out crustaceans and other food. Alaska's grey whales are part of a population known as the eastern Pacific stock, and these whales are headed south to their winter calving areas in the Gulf of California and Baja.

Grey whales were almost exterminated in the industrial whaling days. Gray whales were heavily hunted in the 1850s after the discovery of the calving lagoons, and again in the early 1900s with the introduction of floating factories. Hunting ended in 1947 when the gray whale was given full protection by the International Whaling Commission. Since that time the eastern north Pacific gray whale population has made a remarkable recovery and now numbers about 20,000, probably close to the carrying capacity.

Alaska's grey whales spend the summer feeding in shallow waters (usually less than 200 feet deep) in the northern Bering and Chukchi Seas. They begin their southward migration in mid-October, a 5,000 to 7,000 mile trip down the west coast that takes about two and a half months, and they arrive in Baja in December and January.

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Download Episode: Harbor Seals Underwater View (MP3 file 1,407 kB)

Harbor seals underwater view

It's high tide at a rocky beach on a sunny summer day near Juneau. Chum salmon are running, and harbor seals are cruising just off the beach. One animal looks really weird, and I raise my binoculars to get a better look. I realize it's a harbor seal swimming upside-down, belly up, head underwater.

Juneau naturalist, author and photographer Bob Armstrong has spent hours watching seals and using an underwater remote camera to take video of harbor seals underwater, documenting a wide range of behavior. He said swimming upside allows them to better scan the water beneath them for fish. Seals also swim upside-down underwater, just over the seafloor, searching for crabs and flounder. They also sleep underwater, maintaining a neutral buoyancy near the bottom, or lightly grasping a rock or log on the seafloor, and a single breath lasts 20 to 25 minutes. They bob to the surface for a quick breath and sink again to continue their nap.

Their eyesight underwater is very good. A harbor seal's eyes glow when struck by light, for the same reason cat or deer eyes shine in the dark in car headlights or a flashlight. They have a reflective layer in the back of the eyeball called the tapetum that directs more light into the retina, enhancing their vision in low light conditions.

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Download Episode: Humpbacks Head South (MP3 file 3,522 kB)

Humpbacks head south

On sunny July day, a group of humpback whales feeds in the waters of Icy Straits in northern Southeast Alaska. But when fall comes to Alaska, most of the humpback whales that summer in Southeast Alaska waters head to Hawaii to breed and to give birth. It's a month-long migration of about 2,500 miles. This year the first whales were sighted off Maui on October 20; in 2008 the first whales arrived in Hawaiian waters on Oct. 12. They return to Alaska in the spring and summer to feed. Most, but not all the whales leave - each year, a few whales remain in Southeast Alaska waters for the winter.

When commercial whaling was banned in the mid-1960s, only about 1,000 humpbacks were left in the north Pacific. But the population has grown tremendously over the past 40 years. Today, there are about 18,500 humpback whales estimated in the North Pacific, belonging to three distinct stocks. The humpback whales that spend summers in Southeast Alaska are a distinct population known as the central north Pacific stock. The stocks are defined by their use of specific summer feeding areas, winter breeding areas, and the particular migration routes and patterns they take between these areas. There are about 4,000 whales estimated in the Central North Pacific Stock, and the population is growing about five percent each year.

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Download Episode: Killer Whales and Gray Whales (MP3 file 1,406 kB)

Killer whales

A gentle surf is rolling up a beach near Pashayjack Bay on Kodiak Island. It's June 25, 2018, and there's something unusual rocking in the surf, like a grey log. It's a dead grey whale, a calf. The calf's tongue is missing, indicating that it was likely killed and eaten by killer whales. Two months later, on August 2, in the same area of Kodiak Island, the body of another grey whale washed up on the beach, this one missing its head and jaws, likely another victim of killer whale predation.

Some killer whales feed on fish. Others eat marine mammals, and in Alaska, that's usually seals, sea lions, dolphins and porpoises. But killer whales are known to attack and eat other whales, including the giant blue whale. Australian researchers have documented killer whales in the South Pacific attacking migrating humpback whales, targeting the calves.

Killer whales are known to target grey whales as they migrate up the California coastline in the spring, from their calving grounds in Mexico to their summer feeding areas in Alaska waters. In April of 2017, researchers counted 33 killer whales in Monterey Bay on the central California coast, and the predators intercepted the passing grey whales and killed a number of grey whale calves. The killer whales were back in April 2018, repeating their ambush on the migrating grey whales.

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Download Episode: Mother Whales! (MP3 file 1,769 kB)

Glacier Bay whales: Whale mothers and calves.

Humpback whales can be recognized and identified by distinguishing marks. Identifying specific animals enables biologists to chart their migrations and movements, their preferences for specific feeding areas, and their reproductive histories and activities. Many of the whales that spend summers in the Glacier Bay-Icy Strait area in Southeast Alaska have been identified and assigned individual numbers, and some have been tracked for almost 40 years.

The number of whales that visits the Glacier Bay area varies from summer to summer, ranging from a low of 40 different whales to as many as 160. Between 1974 and 2008, 575 different individuals were identified. In that same 34-year period, 217 calves were born and documented, and many have returned multiple years. A female humpback whale is sexually mature at five years old, and can live 40 to 50 years. There are seven known grandmothers in the group, and there have been several cases where both grandmother and daughter returned to the Bay with calves in the same year.

A mature female humpback whale is either pregnant or lactating almost all the time - most have a calf every other year and nurse it for a year before having another calf. But five Glacier Bay whales have given birth every year for successive years. One of these whales, Number 581, calved three years in a row, twice. She is the most prolific of the Glacier Bay females and had 12 calves between 1984 and 2007.

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Download Episode: Old Whale (MP3 file 1,403 kB)

Old Whale

A group of whale watchers is delighted to see a pod of humpback whales surface in Lynn Canal. Humpback whales can be identified as individual animals based on the marks and patterns on the whales' tail flukes. A large photo database exists, and researchers are able to document the movements and life histories of whales.

In Mid-July 2015, a humpback whale that was first identified in 1972 in Lynn Canal was resighted near Petersburg in Frederick sound. The 44-year span between the two sightings in Southeast Alaska marks the longest re-sighting span of a humpback whale in the world.

Pioneering whale researcher Chuck Jurasz of Juneau first documented the whale in 1972. The whale was subsequently re-sighted by researchers with the University of Hawaii in 1990 and in 2006, first escorting a mother and calf and later defending its position near a lone female from other competing males, indicating that this is a male humpback.

The second longest re-sighting is a male humpback first documented as a calf in 1974, and frequently re-sighted over a 42-year span, often in Glacier Bay. Although these more-than-40-year-re-sightings are among the longest in the world, humpbacks are known to live much longer. Most appear to live into their 60s, and the oldest known humpback whale was 96 years old.

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Download Episode: Pup Count (MP3 file 3,524 kB)

Pup count

2009 was a good year for Steller sea lion pups. Between June 24 and July 15, 2009, Steller sea lion biologists conducted an aerial photographic survey of all the rookeries and major haulouts throughout most of the sea lions' range in Alaska. The goal was to count Steller sea lion pups.

Steller sea lions in Alaska are separated into two stocks. The dividing line is Cape Suckling, near Cordova. Sea lions in Southeast Alaska and in the eastern Gulf of Alaska are part of the eastern stock. Sea lions in Prince William Sound and points west out along the Aleutians are in the western stock.

The number of Steller sea lion has declined significantly in recent decades, especially the western stock, which is listed as threatened under the Endangered Species Act. But pup numbers are up in some areas. Pup production by Alaska's western stock increased from 9,950 in 2005 to 11,120 in 2009, but there was considerable variability. Numbers improved in Gulf of Alaska and in the eastern Aleutians, but continue to decline in the central and western Aleutian Islands.

The number of pups in the eastern stock was 7,462, which exceeded any previous counts going back to the 1960s. That indicates pup production has increased almost 4 percent per year at Southeast Alaska's five major rookeries since the late 1970s.

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Download Episode: Right Whales (MP3 file 3,533 kB)

Right Whales

In late August 2021, marine biologists off the west coast of Kodiak Island saw a pair of remarkable whale spouts in the choppy blue waters of the Gulf of Alaska. The distinctive V-shaped spouts proved to be a pair of right whales, one of the rarest and most endangered whales in the world. A few days later, they spotted a different pair of right whales. There are only about 30 right whales in Alaska waters – a population known as the eastern North Pacific stock. The Western North Pacific stock is found off the coast of Russia and numbers two or three hundred whales.

Right whales are so named because they were the “right” whale to hunt. They're slow-moving and they float after being killed. At least 26,000 were killed in the north Pacific in the time of commercial whaling.

These marine biologists were surveying large whale species in the Kodiak area because right whales have been seen here before. The area is important habitat for this relic population of North Pacific right whales, and part of the region is designated as critical habitat under the Endangered Species Act.

Right whales can be identified as individuals based on distinctive marks and scars. Two of the four whales spotted are known - one was seen nearby in 2006 and the was seen earlier in 2021 off the coast of British Columbia. The other two are completely new individuals never before identified by researchers. For SW..

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Round Island Walrus

Hundreds of walrus are hauled out on a rocky beach on a wave beaten island at the northern edge of Bristol Bay. Some bask contentedly in the sun, others lumber around, their white tusks gleaming as they jockey for more comfortable positions. This is Round Island, part of the Walrus Islands sanctuary, and a half-dozen visitors watch the walrus from a grassy cliff above. Even more are watching at home on their computers. In the summer of 2015, cameras were set up to provide live, real-time streaming of Round Island walrus.

Round Island is one of the only land-based walrus haulouts in the southern Bering Sea. When spring comes to the Bering Sea, females and young walrus follow the retreating icepack north, resting on the sea ice and feeding at the fringes. But thousands of males stay behind at Round Island to forage. The walrus bellow like sea lions, but they also make unusual vocalizations underwater called belling or chiming that can be heard on the surface.

Wildlife watchers aren't the only visitors - close to half a million seabirds nest on the cliffs of Round Island, and cormorant, murre, and kittiwake colonies cover the crags and cliff faces. Parakeet auklets and puffins fly over the choppy waters, where Steller sea lions, grey whales and humpback whales swim. Red foxes feed on seabird eggs and the voles and shrews that scurry through the island's lush summertime grass. But it's walrus, with their unusual belling and gonging calls that are the highlight for most visitors to round Island.

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Download Episode: Savvy Seals, Killer Whales (MP3 file 3,521 kB)

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Download Episode: Sea Lion Mystery (MP3 file 3,787 kB)

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Download Episode: Sea Lions on Camera (MP3 file 1,407 kB)

Sea Lions on Camera

South Marble Island is a rocky outcrop in Glacier Bay, and in summer it's home to thousands of nesting sea birds. Cormorants, puffins, and gulls nest on thin ledges. Closer to the water, hundreds of Steller sea lions lay on the rocks, jostling for prime spots. South Marble Island is a major sea lion haulout, but that wasn't always the case. Sea lions began using the island in the 1980s, and over past decades, numbers there have increased more than 16 percent each year - a phenomenal rate of growth.

Sea lion numbers have seriously declined in the Aleutians and Western Alaska, even as populations have grown in Southeast waters. Biologists want to know if sea lions are dying off, or abandoning old haulouts and moving to new locations, and to better understand survival rates in different populations. A number of sea lions have been marked and can be identified. Biologists document sightings and resightings of the animals, and now they have a new tool. In the summer of 2016, Fish and Game researchers installed camouflaged time-lapse cameras at six haulouts, including South Marble Island. Digital cameras, batteries, and solar panels have improved tremendously - and gotten less expensive - which means deploying a year-round automated observation post like this is a good tool for documenting sea lions and marked sea lions. The camera system should allow for a year or more of uninterrupted observations.

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Download Episode: Sea Otters (MP3 file 1,407 kB)

Sea Otters

On a spring day in Glacier Bay in Southeast Alaska, a raft of sea otters is floating near Bartlett Cove. The water is cold, but these otters aren't feeling it. Most marine mammals in Alaska retain their body heat with a thick layer of blubber. Sea otters are different. They don't have a lot of body fat and instead depend on thick, well-groomed fur. Otters have phenomenally thick fur. We humans have about 2,000 hairs per square inch on our heads. Dogs have as much as 60,000 hairs per square inch, and the luxurious coat of a cat can be five times that dense. A sea otter can have up to a million hairs per square inch - the densest fur coat of any animal in the world. Long, waterproof guard hairs protect dense underfur.

Hair that thick requires constant grooming. Otters groom themselves to dry their underfur and to distribute oil from their skin into the fur, making it waterproof. Air trapped in the fur keeps the otter's skin dry. The sea otter is essentially encased in a thick bubble of air, which insulates four times better than a similar layer of blubber.

Sea otters groom a bit like cats - licking themselves and rubbing their fur with their paws. But they do this while floating in the water, somersaulting and rolling to reach every part. They spend a lot of time grooming - their lives depend on it. They also spend a lot of time eating - A high metabolism is coupled with that thick fur to keep sea otters warm in frigid Alaska waters.

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Download Episode: Sea Otters and Kelp (MP3 file 2,453 kB)

Sea otters and kelp

In a glacial fjord in Southeast Alaska, a group of sea otters has gathered at a big kelp. Some have draped kelp blades across their bodies so they won't drift away as they doze in the spring sunshine. Otters are good for kelp, in a roundabout way, and this kelp bed is far larger than it was 20 years ago. Here's why:

Sea otters are relatively new here, although they were a part of this ecosystem for thousands of years after the glaciers that carved these fjords retreated. They were harvested in small numbers for their fur by Native Alaskans, but in the 1800s, Russian and British fur traders wiped them out. Sea otters eats eat sea urchins, and in the absence of sea otters, sea urchins thrived. And sea urchins eat kelp.

In the early 1970s, a few hundred sea otters from a surviving Aleutian Island population were re-introduced to Southeast Alaska. With abundant prey the otters thrived and they've grown to number in the tens of thousands. Feeding heavily on sea urchins -- kelp beds have noticeably expanded.

Fishermen harvest close to 80,000 blades of macrocystis kelp each spring in Southeast Alaska for the herring roe on kelp fishery and they've noted the increase.

"The kelp beds are just huge now because of the sea otters, there's no shortage of kelp," one fisherman told me.

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Download Episode: Seal Pupping (MP3 file 3,525 kB)

Seal pupping

Hundreds of harbor seals rest on ice bergs in an ice-filled bay in Southeast Alaska. This is Johns Hopkins Inlet in Glacier Bay. Johns Hopkins glacier is actively calving into the water, and the icebergs are extremely important habitat for pupping and nursing harbor seals in Alaska. Harbor seals in Glacier Bay mate during July and August and have their pups in May and June. Pups are about 25 pounds when they are born, and grow quickly on fat-rich milk, doubling their birth weight in the three to six weeks before they are weaned.

Johns Hopkins Inlet is the site of one of Alaska's largest breeding colonies of harbor seals. In 1992, more than 4,000 harbor seals were counted in the Inlet. But that's changed, and today there are far fewer seals here than there used to be.

In August 1992, 6,370 seals were counted in a survey of Glacier Bay, and most of the seals were in the ice-filled waters of Johns Hopkins Inlet. In 2001, just 2,650 seals were counted in Glacier Bay, and there were 60% fewer seals were in Johns Hopkins. Rates of decline in harbor seal numbers in Glacier Bay are comparable to those observed in the Gulf of Alaska, where an area-wide decline in harbor seals, Steller sea lions and fish-eating seabirds has been documented.

Causes of decline could be increased mortality, reduced birth rates, or emigration from Glacier Bay to other areas. Increased predation by sleeper sharks and Steller sea lions, and shifts in diet are hypothesized causes of the declines, and researchers are testing or plan to test these hypothesis in the near future. In addition to monitoring the distribution and abundance of seals in the Bay, researchers are also studying seal diet, genetics, and behavior, including responses to vessel traffic.

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Seals of summer

On a cool, overcast summer day, a cruise ship slowly glides through a deep glacial fjord. Vertical cliffs rise more than a thousand feet on either side and icebergs drift on the current. As the ship approaches the face of the tidewater glacier and stops, icebergs fill the water. Hundreds of the icebergs are topped with dark shapes, and a closer look with binoculars reveals harbor seals. Hundreds of harbor seals are hauled out on these icebergs - for good reasons. These are mother seals with pups, and this fjord is a nursery. The icebergs offer protection from predators, like killer whales, and offer good resting places regardless of the tides.

The presence of large ships and small boats can frighten these mothers and pups, causing them to flee into the water. Even kayaks disturb seals when people approach too close. This interferes with nursing, makes newborns and mothers more prone to become separated, and stresses the animals at a vulnerable time.

To avoid this - this cruise ship has stopped about 1,200 yards - three-quarters of a mile - from the concentration of seals near the face of the glacier. Even the smaller boats are keeping their distance. They move slowly, with virtually no wake, the public address system is off and everyone is quiet. The bay is peaceful. The seals may be aware of the boats, but they aren't jumping in the water or otherwise acting stressed.

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Download Episode: Songs of the Sea - Bearded Seals (MP3 file 1,440 kB)

Bearded seals

During the spring, you can hear some strange sounds in the Arctic. One of the strangest is the mating song of the beard seal. These calls are produced underwater, and may be heard both above and below the surface.

Male bearded seals vocalize during the spring breeding season using four types of calls: trills, ascents, sweeps, and moans. Each male has a unique call and males return to a specific breeding territory each year for mating. Scars on the males indicate that fighting may be involved in defending territories as well. Eskimo hunters follow the sound of singing bearded seals to hunt them.

Bearded seals are one of four northern seal species that rely on ice for feeding, resting, and pupping; these four species are collectively called "ice seals." Bearded seals are the most important seal for coastal Alaska villages because they provide large quantities of meat, oil, and skins for boats and for warm boots, called mukluks. Bearded seals are also an important food for polar bears.

The bearded seal is the largest seal in Alaska's waters. Bearded seals can be nearly 8 feet long from the nose to the tip of the tail. They weigh up to 800 pounds in late winter and spring when they are heaviest. They have conspicuous whiskers, hence the name bearded seal.

Bearded seals mainly feed on the bottom and eat crab, shrimp, clams, and snails, and bottom fish like sculpins and flatfish.

Females can have one pup every year, but may pup less often depending upon food availability. Bearded seals are usually solitary and tend to be very wary. They rest close to a hole or crack in the ice so that a quick escape is possible.

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Download Episode: Stranded Killer Whale (MP3 file 2,350 kB)

A 20-foot-long killer whale lies stranded on a rocky outcrop off Prince of Wales island in Southeast Alaska in late July of 2021. It's low tide, and although the whale is alive, its skin is drying in the warm sun. Passing boaters radioed federal biologists, who gave them permission to wet it down with buckets of water while the tide came in. At high tide it was able to free itself and swam off.

Killer whales have scars, and uniquely shaped dorsal fins and white patches, and can be identified as individuals. B iologist have a photo-identification catalog of West Coast transient killer whales like this one. About 300 are documented and biologists were able to identify the stranded 13-year old juvenile, known as T146D, from past photos of it and its mother, T146.

Transient killer whales eat marine mammals, and stalk harbor seals in shallow coastal waters. This whale was likely hunting seals and inadvertently ventured too close to shore. Odds are good it will be okay. Over the past 20 years, five killer whales from this population have been stranded like this and documented by biologists. All of them survived and were re-sighted in following years.

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Download Episode: Thriving Whales (MP3 file 3,645 kB)

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Download Episode: Walrus (MP3 file 3,520 kB)

Walrus

On a summer day, hundreds of walrus swim in the waters near Round Island, part of the walrus island complex in the Bering Sea west of Dillingham. Most walrus move north to the Arctic waters of the Chukchi Sea in the summer, but a number of males stay at the Walrus Islands in northern Bristol Bay. Their unusual belling and gonging calls can be heard as they forage in the waters around the island. Walrus feed on clams that they excavate from the sea floor - they use their sensitive, bushy whiskers to locate the mollusks and they literally suck them up out of the sea bottom mud. The walrus's distinctive tusks are not used for foraging or feeding.

Walrus move seasonally following the retreat and advance of ice - most of the population moves north in the spring and migrates south in the fall. The animals rest on the edge of the sea ice between bouts of foraging. Recent reductions in the extent, thickness, and duration of the summer sea ice may have profound effects on walrus distribution, movement patterns, and feeding opportunities, as less ice is available for a resting platform.

Biologists are working to learn more about walrus, their numbers, and these seasonal movements. A 1990 census of the Pacific walrus population indicated about 200,000 animals. Russian and American biologists recently conducted new, updated survey in the Chukchi and Bering seas. Russian biologists deployed about 40 satellite tracking tags on walrus in 2007, and this year, U.S. researchers tagged 70 walruses in Alaska to gain insights into walruses foraging areas, sea ice habitats and movements.

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Download Episode: Walrus Islands (MP3 file 1,559 kB)

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Download Episode: Whale Barnacles (MP3 file 1,408 kB)

Whale Barnacles

On a summer day in Southeast Alaska, a pod of humpback whales breaks the surface to the delight of a boatload of whale watchers. A crust of barnacles covers the whales' chins, and the edges of their big pectoral fins. These whales have hitch-hikers on board, a species of barnacle that only lives on humpback whales.

Whale barnacles are different than shoreline barnacles and are unique to the species of whale they piggyback on. One species lives only on humpbacks, and another only lives on gray whales. They colonize the skin of these filter-feeding whales in huge numbers - a humpback whale can host almost 1,000 pounds of barnacles. That's a lot of baggage, but relative to the humpback's 80,000-pound body, it's about as much extra weight as clothing on a person.

Barnacles begin their lives as free swimming planktonic larvae that settle onto a substrate and develop into the sturdy, immobile barnacles were familiar with. But how does a planktonic barnacle larvae hook up with a swimming whale? During the breeding season, when the whales mill around together in warm, shallow waters, the planktonic larvae picks up a chemical signal when the whale is close by. It swims over and hangs on. Once onboard, the larvae crawls to the head or fins, where the flow of water is consistent. Once they've settled on a location, the barnacle morphs into the immobile adult form.

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Download Episode: Whale Killers (MP3 file 3,594 kB)

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Download Episode: Whale Spout (MP3 file 3,582 kB)

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Download Episode: White-Sided Dolphins (MP3 file 1,407 kB)

Pacific white-sided dolphins

On a summer day a sport fisherman trolling for salmon in Stephens Passage near Juneau is visited by an unusual animal for northern Southeast Alaska - a Pacific white-sided dolphin. The six-foot-long dolphin is right beneath his bow, jumping out of the water and spinning, playing in the wake created by the bow of the boat.

Pacific white-sided dolphins are fairly common in the Gulf of Alaska and are most often seen by boaters in southern southeast off Ketchikan or around Dixon Entrance. They prefer deeper water than the Dall's porpoises and harbor porpoises more commonly seen in the inside passage. They are fast swimmers, common bowriders, and very playful and acrobatic. Pacific white-sided dolphins travel in close-knit pods, and have been observed caring for sick or injured individuals. They form groups of several hundred animals, and use cooperative foraging techniques to catch schooling fish and squid. Like this one, they can be very sociable with people and other marine mammals. They are often seen in the company of Dall's porpoises and other dolphin species. They can be found as far north as the Aleutians but rarely venture into the Bering Sea.

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