Spring on Puget Sound is about gardens bursting with tulips and daffodils, white sails set against glistening blue seas, and massive, shimmering schools of silvery herring.

Schools of what?

In an ecosystem where whales and other charismatic megafauna get most of the attention, herring are neither charismatic nor mega.  At four to eight inches, they are easily ignored and usually are — except in the early spring, when millions upon millions of herring converge on the shallows around Port Townsend, Discovery Bay, Hood Canal and throughout the sound.

Beachwalkers may not see the fish themselves, but they’ve marveled at the chaotic swarms of seabirds massed at the surface, and at seals, sea lions and even an occasional humpback whale diving and cavorting as they gorge themselves on one of their favorite meals.

All that activity is about Pacific herring, crucial to Puget Sound ecology.  And state biologists believe they have had a very good year.

Herring show up along Puget Sound shorelines for one reason – sex.  They spawn in the spring and, while not exactly intimate, their reproductive strategy is hugely effective. Schools of fish form over the winter in deeper water until March or April, when they collectively decide it’s time.  The females move into the shallows, depositing tiny eggs on blades of eelgrass or kelp or any surface that looks right.  A single herring may deposit 10,000 eggs or more.  Meanwhile, the males spread their milt, clouding the waters so that the spawning activity becomes evident from the beach. 

Drawing courtesy Washington Department of Fish and Wildlife.

The numbers are so staggering that biologists don’t even try to count the fish.  They estimate herring spawning by the metric ton (2200 pounds) – and usually by hundreds or thousands of tons.  A good spawning year of 10,000 tons translates to at least 250 million fish.

State biologists who track these things projected that more than 100 tons of herring would spawn along the east shoreline of Discovery Bay this spring. And that’s nothing compared to Quilcene Bay, where they projected a spawning run in the thousands of tons – many millions of fish. “Quilcene has been crazy the last few years,” says Adam Lindquist, a forage fish biologist for the state Department of Fish and Wildlife.

 Similar runs were projected for Port Gamble, Port Orchard, Port Madison and other Puget Sound bays.

Why are herring thriving?   Nobody knows for sure, Lindquist says.  There are too many variables, one of them being spawning habitat. Herring will deposit their eggs on a variety of shallow water surfaces, but they especially like eelgrass.  And there is ample eelgrass habitat around Puget Sound, he says.  

Predators are another major factor.  Salmon prey heavily on herring, but so do halibut, seals, gulls, diving birds, and virtually every creature larger than herring.

Whatever the reason, healthy herring runs may help explain why Puget Sound ecosystems appear to be improving, as reported recently by Lynda Mapes in the Seattle Times. The primary mission of all those forage fish is to be eaten by something else.  As go herring, so go all the wildlife that depend on them for food.

Herring runs have fluctuated wildly.  In the 70s and early 80s, Puget Sound herring estimates exceeded 20,000 tons – half a billion fish.  By the late 90s, those estimates dropped below 10,000.

Why? Commercial fishing may have been a factor.  For most of the last century, herring were netted mostly for bait, or ground up and processed into fertilizer. In the 1970s, however, commercial fishermen learned that herring roe are a prized Japanese delicacy – especially if it can be harvested on kelp leaves, or in the fish just before they spawn.   These resulted in lucrative fisheries through the 1980s and 1990s.  But those fisheries declined as stocks diminished. 

Now spawning runs appear to be recovering, Lindquist reports.  Discovery Bay and Quilcene Bay estimates are good, and the runs across Puget Sound have exceeded 10,000 tons – promising news for the salmon that feed on them, for the orcas and other megafauna that feed on salmon, and for the rest of us who yearn for a healthier Puget Sound.

Top photo by Axel Kuhlmann, CC0 Public Domain

3 COMMENTS

  1. We call it “Happy Hour” for the gulls and other seabirds. It is always noticeable this season. I am happy to be more informed about the reason behind “Happy Hour” Ross! Keep on educating us buddy!!!

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