When a July fire ravaged 3,900 acres in Angeles National Forest, the beleaguered wild trout in the West Fork of the San Gabriel River faced a new menace.
The fire destroyed vegetation that prevented soil erosion. Officials fear that soil runoffs and sedimentation will cover the gravel where the fish spawn, fill holes where the fish gather and kill insects on which the fish feed.
In an effort to protect the spawning grounds, the U.S. Forest Service this week will begin reseeding 403 acres of the burned area to replace the lost grass.
"We know we can't save them all, but we can reduce the damage," said Max Copenhagen, a water-quality specialist for the Forest Service.
Slowing the Flow
Additional steps will be taken to help the trout. Later this year, rocks will be dumped into the creek bed of Big Mermaids Canyon to slow the water flow of the tributary into the West Fork to decrease erosion and sediment build-up. And next spring, gabions, wire baskets filled with rocks, will be placed in the West Fork to help filter mud and debris.
The rehabilitation effort will cost $28,000, with half of the money going for the reseeding project, Copenhagen said.
The fire was the latest threat to the trout in the picturesque mountain stream, one of the few areas left in Southern California where the fish breed and one of the 30 most heavily fished streams in the state.
While testing valves in Cogswell Dam last March, the Los Angeles County Department of Public Works released a wall of water that crushed thousands of trout eggs, washed away gravel beds used by the fish as spawning grounds and killed or dispersed insects needed by the fish for survival.
"It was right at the time that the fish had put down their eggs, so it just wiped away the spawn for the whole year," said Henry Palmer, president of the Pasadena Casting Club.
The group was active in restoring the West Fork after the Los Angeles County Flood Control District (now a Department of Public Works subdivision) released water carrying tons of silt into the West Fork during 1981 repairs to Cogswell Dam, north of Azusa. About 200,000 cubic yards of silt from a reservoir behind the dam destroyed the seven-mile-long habitat for an estimated 24,000 trout, killing or displacing thousands of fish, according to Department of Fish and Game officials.
As many as 18,000 people fish the stream each year and another 32,000 visit the creek for other activities, such as photography and bird-watching, according to Jim Edmonson of California Trout, a group that works to protect trout resources in the state.
Edmonson said the stream has been recognized as a premier trout fishery since before the Civil War.
"It's a clean environment, there's no litter and the fish you catch there are basically all born in the creek," said Edmonson.
Although the state Department of Fish and Game stocks part of the creek, some fishermen say it is the fight in the native trout that makes the West Fork a popular fishing site.
"The stock fish has no fight to it," said Bob Moore, a member of the Pasadena Casting Club who has fished in the West Fork for more than 10 years. "A fairly large native fish will fight like heck."
Officials believe that the fire, which burned along the West Fork and the nearby Bear Canyon Trail, started when unidentified visitors dumped hot barbecue coals along California 39, the main road into the forest.
Planting by Helicopter
The Forest Service hopes to combat the latest danger to the trout by spreading 2,500 pounds of fescue seed, a grass native to the wilderness, and 300 pounds of clover seed from a helicopter onto terraces along Bear Creek and Big Mermaids Canyon, tributaries to the West Fork.
Because the area is hilly and the soil layer is thin, only 10% of the burned area will be seeded, Copenhagen said.
If nature were left alone, the vegetation would grow back within three to five years, he added.
But officials do not think they can wait that long. As much as 90% of the soil erosion could occur during the first year after the fire, Copenhagen said.
Recent rains make planting favorable now because of the damp soil, he said. Copenhagen said he expects the seed take root this winter.
No matter what steps are taken, the impact of the fire on the trout depends on rainfall patterns, said Charles Marshall, a biologist for the Department of Fish and Game. Heavy rains will increase erosion on the burned slopes and sediment will enter the stream, he said.
"There's a potential for strong damage, but it's all guesswork right now because we have to wait and see what the rainfall pattern is," Marshall said, adding that he is not sure what impact recent rains will have on the stream.
Fishermen like Will Trefry, a member of the Pasadena Casting Club, worry about the future of the West Fork.
"There are so many things that the river has to contend with," Trefry said. "It's one of the best wild trout streams in Southern California and represents a valuable resource that, if it's lost, would be a tragedy."