The drought dried up Santa Rosa Creek, but this winter’s rains have opened its flowing waters to the sea. The creek broke through Dec. 16 and flowed at higher-than-normal levels for more than two months. A sandbar has now enclosed it, creating a lagoon.
“Days of rain brought water into the main stem of Santa Rosa Creek and all the tributaries,” said Stephanie Wald, watershed projects manager for Central Coast Salmon Enhancement, a regional nonprofit dedicated to our watersheds and fisheries. “With that quantity and speed, boom, the creeks broke open. The fish are waiting there.”
Steelhead are anadromous fish, hatched in freshwater but spending part of their lives in the ocean. They migrate back from the ocean to freshwater to spawn upstream in the creeks’ gravel beds. Santa Rosa and San Simeon creeks are prime habitat for steelhead. Fish hatched there will migrate into the ocean, where they grow and mature and eventually return to complete their life cycle. Unlike their salmon cousins, adult steelhead will make as many as four round-trip migrations in their lifetimes.
Beckoned by chemicals in the water, steelhead start gathering in December near the mouths of the creeks. As-yet-unknown signals tell them it’s time.
After water starts flowing, they wait until it slows down enough for them to enter the creek.
“They have the ability to sense when it is the right velocity, what they evolved to deal with,” Wald said. “By then, the water has also become more clear. The sediment has settled out.”
During the past few drought years, they have waited in vain. Creek levels were too low for them to swim upstream. Steelhead that stay in fresh water become rainbow trout. No current population estimates exist, but anecdotal reports from people along the creek suggest numbers are very low.
Central Coast Salmon Enhancement will soon send teams out to peer into San Luis Obispo and Arroyo Grande creeks, looking for steelhead spawning nests, called redds. Females use their tails to scrape out shallow areas in the gravel, where they’ll deposit their eggs.
“We count the redds and watch them over time,” Wald said. “If they are viable, anywhere from a few hundred to thousands of fish will be born. After growing for a year or two, they will go out into the ocean to mature.”
After Santa Rosa Creek is running clearer, Greenspace executive director Connie Gannon, operations manager Rick Hawley and Upper Salinas-Las Tablas Resource Conservation District executive director Devin Best will scout instream areas in Cambria for redds. Future projects may allow for more detailed monitoring of the steelhead life cycle.
Steelhead are iconic fish, the subject of myth and lore, but very real. Longtime local residents tell tales of catching fish nearly 30 inches long from Santa Rosa Creek. They are listed as threatened on federal lists and as a species of special concern by the California Department of Fish and Wildlife.
“Understanding how important adequate stream flow is to this fascinating species and other native plants and animals of our creeks can help Cambrians appreciate what’s at stake in thoughtfully managing ground and surface waters,” Gannon said. “The goal is water for people and for wildlife.”
Christine Heinrichs of Cambria is an author, certified California Naturalist and FES docent.