Photo by from nmfs.noaa.gov
Southern California steelhead trout
They are among the last of their kind in San Diego County — a small batch of Southern California steelhead trout, trapped in a fish bowl: the San Luis Rey River.
Once, they were easy to spot in spawning season (January through March) as they returned from sea to streams as far south as the border. But the road home is vanishing.
Two new grants from the California Department of Fish and Wildlife will help restore salmonid habitat in the San Luis Rey River, a key watershed for the endangered species. Statewide, 67 projects will receive funding to address drought, forest loss, and coastal salmon and steelhead habitat restoration.
“Steelhead historically migrated between the ocean and fresh water but are now locked into their headwaters due to dam-building, habitat degradation, and low water flow,” says biologist Sandra Jacobson, South Coast Steelhead Coalition Coordinator for CalTrout.
A unique adaptation helps the native fish hang on. Steelhead begin life as rainbow trout. Some, like their salmon cousins, then migrate to the ocean, returning one to three years later to spawn. If blocked from seafaring by obstacles such as dams, they can remain in freshwater, as rainbow trout (same species, different lifestyle).
“Amazingly, there are still resilient populations of rainbow trout in remote headwaters in this region,” Jacobson says. While landlocked, they retain the potential to become anadromous — to move between ocean and upriver freshwater spawning areas.
“During winter storms, when the rivers have high flow, they can use that short time window — if there aren’t barriers — to migrate more than 50 miles down to the ocean or back up to the mountain headwaters in a matter of days.”
El Niño has helped, bringing more cool water and clearing sediment from spawning gravels. In January, high flow in San Mateo Creek blew out the sand berm in the estuary, which Jabobson says is a signal to ocean steelhead of an open path home to spawning sites. But in the longer run, the drought has been a scourge.
Surface flows decreased greatly in a stream considered one of the best trout habitats in Southern California. Two tributaries of the San Luis Rey are vital for steelhead recovery in Southern California, Jacobson says. One holds trout of coastal steelhead descent and is the southernmost known native population in the U.S. Another key stream contains wild rainbow trout of hatchery lineage that may mingle with native rainbows in the lower reaches. Both groups help improve the diversity and fitness of fragmented native populations, she says.
Fishing isn’t allowed in anadromous waters, which are basically sections of rivers downstream of natural or manmade barriers like dams. In 1997, the U.S. National Marine Fisheries Service listed southern steelhead as endangered but left out its southernmost range, where it was considered extinct. When the fish was found on the border of Orange and San Diego counties in 2002, the Center for Biological Diversity, CalTrout, and other groups filed a lawsuit to broaden the listing. Now, the federal recovery plan includes Los Angeles, Orange, and San Diego counties.
The local grants, focused on community water conservation and habitat restoration, support that work. At the steelhead coalition’s quarterly meeting on February 24, Heidi Brow, an environmental scientist with Pala Band of Mission Indians, discussed work about to begin on groundwater recharge and habitat in the upper San Luis Rey. Led by San Luis Rey Watershed Council, it entails a pilot project to boost agricultural irrigation efficiency and residential graywater use.
The tools for water savings on farms and in households include weather-station and soil-moisture sensors and “laundry-to-landscape” and rain barrels. The goal is to keep water available to residents, businesses, and trout in Pauma Creek and the broader San Luis Rey basin. Since their listing, a struggle over water rights has sometimes clouded efforts to protect them. Advocates argue that if native fish are being harmed by pollutants or low supplies, those same factors will affect human uses, from recreation to drinking water.
“The fixes we are working on to save the fish will also help save our rivers,” Jacobson says.