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Thursday,  April 25 , 2024

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News / Northwest

Ghost shrimp, humpbacks, tiny plankton: See Puget Sound surge with springtime life

By Lynda V. Mapes, The Seattle Times
Published: April 25, 2021, 12:37pm

POSSESSION SOUND, Everett — Now is the sweet season, with its lengthening days and warm radiance of spring on Puget Sound.

The return of the light is rousing the natural world from dormancy. Puget Sound is on the rebound, not only in the turn of the season, but in a resurgence of life.

Today there are more humpbacks and gray whales, more harbor porpoises and seals, more sea lions and more orcas in these waters than a generation ago. These surging populations are the result of decades of protection. An exception are southern resident killer whales, an endangered species. They, and the Chinook salmon the southern residents primarily eat, are struggling for survival against an array of threats.

But there is another story underway here, too, of a marine mammal comeback in Washington from the urban waters of Puget Sound, to the seascapes of the San Juan Islands. The ordinary places we think we know onshore are an altogether different matter seen — and heard — from the water, where the creatures with whom we share this place are cavorting in a spring catenation of life.

In an uncertain world, made even more precarious by a warming climate, it’s also important to celebrate what’s getting better, and understand that changes we make can allow nature to heal and recover.

Ardi Kveven was at the helm of the research vessel Phocoena just offshore of Everett on a recent spring morning. She had the vessel built with funding from the National Science Foundation for the Ocean Research College Academy (ORCA) she directs at Everett Community College. The program instructs kids in the science, wonder and history of Puget Sound through a curriculum centered on getting students out on the water.

Instructors use an interdisciplinary approach, with all hands literally on deck, as professors of English, history and science all explore what Puget Sound can teach. And who knew there was so much to see and explore, all within sight of Interstate 5, whizzing by in the distance?

Here was a menagerie in an ecosystem that actually starts in the forests miles away, in the Snohomish River.

“Marbled murrelet!” called out Kveven, pointing to a chunky pair of birds bobbing in the blue not far off the bow of the boat. These birds nest in the forests of the Cascades and fly all the way to the estuary of the Snohomish River, where they feed on sand lance, herring, and other fish they take back to their forests nest.

The Snohomish also carries the nutrients and silty sediment in a freshwater plume all the way out to these nearshore waters of Puget Sound around Whidbey and Camano islands. Ghost shrimp feast on the detritus, as they burrow in the soft silt — and become a meal for one of the largest animals in the Sound: gray whales.

Snuffling in the mud, a small population of gray whales, nicknamed the Sounders, has taught itself to split off from the northbound migration of grays each spring for a side trip to this estuary, for a ghost shrimp snack that plumps them up before they return to the rest of the population to finish their trip.

Laurie Weitkamp, a research fisheries biologist at the National Oceanic and Atmospheric Administration’s Newport Research Station, was lead author on a 1992 paper reporting that the grays were eating an estimated 12.5 tons of shrimp in a four-month season, sucked up from more than 3,000 pits. So rich was the food source that a 60,000-pound whale could get all the food it needed for the day in as little as an hour.

Weitkamp discovered the feeding strategy in 1990, when she was doing her final day of field work with her adviser for her master’s degree research and discovered huge pits right along shore that were not supposed to be there. Then suddenly came a gray whale “so close if I wanted to get wet, I could have touched it,” Weitkamp said. “We were going, ‘What? What is this?’

“It was just putting two and two together, here is this really cool opportunity, let’s do everything we can think of to understand what it is.”

The discovery was front page news and propelled a body of research still going strong — as are the whales.

Off in the distance, Kveven pointed out Little Patch, one of the Sounders that has been a regular in Possession Sound every spring since the ’90s. Named for the white patches on his gray body, the long, slow slide of the whale’s back was a glim in the sun as he made leisurely dives, arcing across the water.

It was all connected, Kveven pointed out, from the forest, to the nutrient-rich freshwater plume from the Snohomish feeding sediment to the mud flats. The whales even help sustain seabirds that follow their travels, snagging tidbits churned up by the whales as they work the mud, tireless rototillers of the intertidal zone. In this way, the revival of the gray whales is also helping to rebuild populations of sea birds, including diving ducks and surf scoters.

Being a mud eater does have its side effects, as everyone on the boat quickly discovered when a breeze coming from Little Patch’s direction brought a sewer gas stench, something between sauerkraut and sulfur. “Well, they are mud eaters, and that is coming out of both ends,” Kveven said.

Protections enabled gray whales, once hunted nearly to extinction, to recover so robustly they were taken off the endangered species list in 1994.

Today the northeast Pacific population of grays has burgeoned above 20,000 whales. A recent “unusual mortality event” has taken a toll — but not dented their recovery.

Kveven hurled a long white net overboard for a plankton tow, to sample the constituents of the bloom. The net that went in white came back up brown, but what looked like inconsequential slime was just what she was looking for.

The spring plankton bloom went off just a few weeks ago, in a ka-boom of nutrition.

The spring sunshine set a single drop of Puget Sound water, seen under a microscope, sizzling with shimmering life: a spangled scatter of gold diatoms, microscopic algae called phytoplankton that feeds everything else in the great pastures of the sea.

“This is what everything else depends on,” she explained. The chain-forming diatom thalassiosira by the billions is what created the color, a result of the brown chloroplasts in each tiny algae cell. When sandpipers run along the shores of Washington beaches in the spring, racing to suck up the brown foam pushed up the beach by the tide, it is this rich sea fare they are slurping.

Zooplankton, tiny animals in the water drop so minute most could only be seen with a microscope, were sculling, swimming, twitching and spinning too. There were crab larvae, tiny crustaceans called copepods, bright pink krill, even baby barnacles.

Plankton and herring also are spring fare for seabirds of Puget Sound. A rhinoceros auklet in spring prom dating plumage hurled past the Phocoena, and a loon, in boxy black and white grandeur, floated serenely, as a bald eagle — another comeback species — looked on from atop a buoy. Perhaps on the lookout for herring. This crucial forage fish — so-called because so many species eat it — had its biggest spawn event in decades in 2020, according to the Puget Sound Partnership.

The herring spawn is a seasonal rite, a serial explosion of life that starts in California in November and rolls up to the coasts of Oregon, Washington and B.C. through April, feeding everything from humpback whales to sea ducks that eat herring eggs off eelgrass like corn off a cob.

To be sure, herring still need to rebuild their numbers, as do salmon and seabirds and many other creatures. To help, major restoration projects are underway throughout the Puget Sound region, including at the Snohomish River Delta.

Puget Sound urban waters also are much cleaner today than they were in the middle of the 20th century. Levels of long-banned persistent pollutants, such as the pesticide DDT, reached their peaks in the 1960s and have been in steady decline in recent decades. Landmark environmental legislation of the ’60s and ’70s, including the Clean Water Act, Endangered Species Act and Marine Mammal Protection Act, are working.

Aboard the Phocoena, the water was so still, the spring cloudscape shone in billowing purple and white reflections on the water. It was so quiet, the great huffing exhalations of Little Patch could be heard in the distance, and the whale’s blow shone silver in the sun.

These are the sounds returning to the Salish Sea with the rebound of marine mammals, noted Joe Gaydos, science director of the SeaDoc Society, a science research and conservation nonprofit. A few weeks later, he piloted the Molly B, the SeaDoc Society’s research vessel, through the San Juan Islands.

Hunted nearly to extinction by commercial whalers, humpback sightings were rare even through the late 2000s in the Salish Sea — the transboundary waters between the U.S. and Canada, including all of Puget Sound. But long term studies by the Cascadia Research Collective of Olympia have documented a steady recovery, with a population increase of about 7 to 8% per year through about 2010, and stabilizing thereafter.

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That suggests humpbacks may have recovered from pre-whaling numbers. Humpbacks are now common in the Salish Sea — and even a focus of whale-watch operations on both sides of the border. Unthinkable just decades ago.

“I never thought I would see humpbacks come back, but now I’ve been seeing them every week for the last five years,” Gaydos said. Humpbacks are filter feeders, unique among baleen whales in their ability to exploit a wide range of prey, from krill, to crab, squid, herring, sand lance and sardines. Humpbacks will even cooperate to concentrate schools of fish with a net of blown bubbles, for easy capture.

At Whale Rock off the south end of San Juan Island, Steller’s sea lions pig-piled in great fleshy heaps on the rocks, lazing and sunning and roaring. These more than 1,000 pound mammals would stay here a bit longer before migrating to rookeries.

Gaydos motored past an uninhabited island, where the water was so clear, bands of broken white shell left at low tide glimmered through a pellucid lens of green as the tide crept back up the beach. Fawn lilies nodded dainty heads in the long, lush spring green up. The soft gray curve of a secret cove beckoned, overhung with the brick-red arms of madronas.

Gaydos raised his binoculars, scanning the water offshore of Anacortes not far from the ferry dock, when there it came: Quick as a blink, a tiny dark fin. Harbor porpoise.

Round as a barrel and about as long as the spread of an adult human’s arms, harbor porpoises also are called whistle pigs, for their plump, chuffing ways. In the distance a mother and baby moved in perfect echelon formation, the baby drafting the mother’s slipstream.

Common as recently as the 1940s, whistle pigs all but disappeared. Perhaps because of bycatch in gillnets and pollution, but scientists don’t know for sure.

What is certain is they are back in droves, according to the Cascadia Research Collective, which estimates there are some 11,000 chuffing around Puget Sound today in a population growing by some 10% a year in the inner marine waters of Washington state. So many that the return of the whistle pig can’t be explained by reproduction alone; they must also be migrating in from all over.

Generalists in their diet, whistle pigs thrive on blackbelly eelpouts, an abundant fish that thrives in Puget Sound, along with any other shiny little fish: herring, sand lance and all the rest.

The marine mammal surge is good pickings for transient, or Bigg’s killer whales, which specialize in slaying everything from harbor seals to sea lions and even gray whale calves. Transients are surging, with record sightings in the Salish Sea in 2017. The population has grown steadily over the last 40 years, doubling since 1990 to a 2018 total of over 500 Bigg’s in the Salish Sea. One reason is all those luscious harbor seals, a favorite prey.

Transients nailed more than 1,000 seals in 2017 alone — serious population control, noted biologist Monika Shields, lead author on a paper about the Bigg’s boom published in PeerJ.

Bigg’s with nicknames like Chainsaw are a delight for whale watch tourists following the oil slicks of their kills.

The rebound of marine mammals in Washington is not without its consequences. Recovering populations of northern resident killer whales, sea lions and harbor seals on the West Coast have dramatically increased consumption of Chinook salmon in the past 40 years — a challenge for managers charged with protecting burgeoning marine mammals and declining salmon alike. Endangered southern resident orcas also have more competition for already scarce Chinook.

Jason Colby, chairman of the history department at the University of Victoria and a professor of history, is the author of “Orca: How We Came to Know and Love the Ocean’s Greatest Predator.” He knows well the story of the decline of the southern residents, and said their recovery deserves intense focus.

But, he reminds, it is not the only story.

“What has been really interesting and heartening to watch for me is that species that I hardly ever saw in Puget Sound in the 1980s as a boy — we did not see pinnipeds very much, we didn’t see humpbacks, we didn’t see gray whales, we didn’t see sea lions — now, they are common,” Colby said. That’s a fact to remember, Colby said, beyond the doom and gloom.

Furthermore, this success isn’t random. It’s the result of changes in government policy and investments that people supported — even demanded.

“Nature can heal if we give it time and space. This is a really important message for people to hear,” Colby said.

“It shows we can cohabit this space with wildlife and enable it to thrive. It shows we are not beyond redemption.”

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