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Central Coast steelhead are tough, but still need our conservation help

San Luis Obispo County’s Coon Creek provides important steelhead trout habitat.
San Luis Obispo County’s Coon Creek provides important steelhead trout habitat. Special to The Tribune

I spent a good part of my childhood in the late 1960s in and around Mark West Creek, north of Santa Rosa.

Most of the neighborhood kids built dams, pathways and tree forts 40 or 50 feet above the ground along that creek. We caught crawdads, bullfrogs and bluegill fish. In summer, the minty smell of sting nettles drifted through the air and western pond turtles would absorb the sun’s heat on top of logs that were partially submerged during the late morning hours.

With the arrival of winter, heavy rains often flooded and cleaned that waterway; when it flowed fast and hard, steelhead trout migrated against its powerful current to lay eggs. These fish were metallic in color with smooth, glasslike heads. Their sheer size in such a small creek made them nearly mythical in our young eyes. In fact, they can live up to 11 years, reach 45 inches in length and weigh 55 pounds.

Throughout coastal California, these sea-going rainbow trout have a fascinating life cycle. Like Pacific salmon, these anadromous (meaning “running upward”) fish are born in freshwater, spend a part of their adult life in the Pacific Ocean where most of their growth occurs and then return to the freshwater streams, creeks and rivers whence they were born to spawn.

Unlike Pacific salmon, they don’t inevitably die after spawning, and they can journey back to the ocean and return to spawn more than once. On the other hand, rainbow trout remain in freshwater their entire lives.

However, if one of these trout was to spend time in the brackish waters of an estuary, like Morro Bay, they become steelhead as their body chemistry adjusts their osmoregulation to cope with the higher salinity levels, which allows them to survive in the ocean. Even more intriguing, steelhead can convert to resident trout when drought blocks their access to the ocean or resident rainbow trout can become steelhead if floods and high-energy ocean waves open their pathway to the sea.

Once in the sea, they turn more silvery in color. Otherwise, a steelhead’s life in the Pacific is mostly a mystery. And their future in California coastal waters is uncertain.

“We are working diligently to protect and improve water quality in our creek system to ensure healthy fish populations persist,” San Luis Obispo city biologist Freddy Otte told me.

As recently as the 1930s and ’40s, many of the creeks of San Luis Obispo and northern Santa Barbara counties had large populations of steelhead trout. These fish kept a lot of people from going hungry during the Great Depression.

Since then, habitat destruction, barriers to navigation (like man-made structures and nonnative plant species that suck up large amounts of water and clog streams), sedimentation that covers gravel beds where steelhead lay their eggs, invasive fish species and the recent drought — steelhead need a vigorous flow of cold, clear water to swim upstream — have combined to drastically reduce their numbers.

Today, the south central California coast steelhead population, which encompasses San Luis Obispo County, is listed as a threatened species, while the Southern California coast steelhead, which covers Santa Barbara County and extends southward to Mexico, is listed as endangered.

Along the Central Coast, steelhead must survive in streams that see huge fluctuations in flow between winter and summer. But these fish are tough, and many conservation groups — like Morro Bay National Estuary Program, Land Conservancy of San Luis Obispo, Central Coast Salmon Enhancement, California Conservation Corps and many others — are working to increase their population.

In 2004, the city of San Luis Obispo implemented a mitigation project within Coon Creek that involved the removal of a culvert that was blocking passage of steelhead upstream.

Hikers cross the Coon Creek bridge near Montaña de Oro State Park to access the Point Buchon Trail, which was constructed as part of this project.

“Hikers should take the opportunity to look into the step pools on either side of the bridge to get a glimpse of steelhead utilizing the habitat created by this project,” said Kelly Kephart, PG&E’s terrestrial biologist.

“Our partnership with PG&E allowed the opening of 7 miles of pristine spawning and rearing habitat to support these iconic fish,” Otte added.

The Point Buchon trailhead is accessed through the south end of the park and is open from 8 a.m. to 5 p.m. Thursday through Monday. To learn more about the trail, visit www.pge.com/trails. Large rainfall amounts this winter have caused Coon Creek to breach the sand buildup at Coon Creek Beach; this allows steelhead in the creek to head out to the ocean for the first time in many years.

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PG&E note: Nearly 70 percent of the electricity PG&E delivered to its customers in 2016 came from greenhouse gas-free resources.

John Lindsey’s column is special to The Tribune. He is PG&E’s Diablo Canyon marine meteorologist and a media relations representative. Email him at pgeweather@pge.com or follow him on Twitter: @PGE_John.

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