Coast Tip: Pacific Herring

Something fishy is going on in our nearest coastal bay. Areas of turquoise water have been seen in its shallows, with a beige froth rimming water edges like a dirty tub. But do not fear, for this fishy phenomenon is truly fishy in nature, or naturally fishy: Pacific herring (Clupea pallasii) are spawning in Yaquina Bay. 

Every year, generally between February and May, these slender, silver fish—similar to anchovies—enter shallow bays across the North Pacific Ocean. Numbering up to the tens of thousands, they congregate to mate and lay their eggs. Herring eggs are pale yellow, only a millimeter wide. Females lay up to 50,000 eggs at a time, attaching them to aquatic vegetation and algae such as eelgrass (Zostera marina) or rockweed (Fucus gardneri), respectively. The turquoise color and beige froth seen are due to the presence of herring sperm, called milt, in the water column. 

The presence of so many herring and their eggs in a confined location during a narrow time period attracts a whole swath of marine predators to the area. Herons, gulls, cormorants, harbor seals, sea lions—and even the occasional humpback and orca whale—feast on adult herring prior to their spawning. Post-spawn, scoters, harlequin ducks, and buffleheads gorge on the eggs. At its peak, this is a spectacle worthy of narration by the likes of David Attenborough.

As long as they survive the gauntlet of predators, herring that spawn return to the ocean, where they live in schools to depths of thousands of feet, and are trickier for the average land-hominid to view. The spawning can last from as little as 2-3 weeks, to several months. This variability should provide motivation for you, dear reader, to take a little coastal excursion sooner rather than later. 

Try visiting South Jetty State Park at the mouth of the Yaquina River. Plentiful pullouts provide opportunities to observe this marvel from a relatively perched position. Another option is the nearby Estuary Trail around Hatfield Marine Science Center, which may allow closer viewing by foot. And a drive down scenic Bay Road between Newport and Toledo is always highly suggested. 

Go forth, find the froth, and rejoice in experiencing a seasonal wonder on both local and global scales. 

 

By Ari Blatt