Outdoors : The Crowley Caper : Recent Fish Deaths at Eastern Sierra Lake Take On Plot of Mystery Novel
The decline of Crowley Lake remains a mystery, and the plot thickened when Curtis Milliron counted 1,331 dead fish along the shore recently.
The Los Angeles Department of Water and Power’s Eastern Sierra reservoir was once a premier trophy trout fishery. But it has come to be known as “the black hole of fishery management”--a complex puzzle even to experts such as Milliron, a California Department of Fish and Game fishery biologist from Bishop.
The recent fish deaths were as mysterious as an Agatha Christie plot.
What killed the fish? Where have all the big fish gone in recent years?
On a dark (and stormy?) night this week, Milliron planned to probe the depths of Crowley, without even a moon to light his way in his pursuit of the intrigue.
Whodunnit?
Ask any number of folks around Long Valley and you will get many theories. Some think the prolific Sacramento perch are eating the trouts’ forage. Others think the white pelicans are eating the trout. Still others point to the lack of normal precipitation for four consecutive years.
“The problem is, we’re in a drought,” said Fred Rowe, who operates fly fishing tours out of nearby Mammoth Lakes. “It’s the lowest I’ve seen it in 10 years.”
Dave Griffith, who manages the lake’s concessions for the Los Angeles City Recreation and Parks Department, said: “I’m not a biologist, but back in ’85 and ’86 the water level was up real high and those were our best years.”
Milliron, assisted by volunteer sportsmen’s groups, heads the search for solutions. With trout season opening in the Eastern Sierra Saturday, he is electroshocking at night from a boat to stun fish and bring them to the surface for “a preseason view of what the fish are like right now,” he said.
This one-time fish kill, according to Milliron’s limited count, took 1,225 perch, 57 rainbows and 25 browns. Afterward, he set gillnets to collect 111 fish for clues.
Griffith said: “The perch are the most durable fish. That would really worry me if those guys are dying (regularly).”
One thing of which Milliron seems certain: The Crowley fish are safe to eat. Two trout found dead last December were analyzed at the DFG laboratory in Rancho Cordova and found to have levels of mercury and arsenic much lower than the Food and Drug Administration guidelines.
“I don’t think there’s a cause for alarm here,” Milliron said. “ I’ll eat ‘em.”
But if poison isn’t the killer, what is? Installation last weekend of a fish trap where the Upper Owens River feeds into Crowley and ongoing fin-clipping programs with hatchery fish may offer a clue.
“The purpose of the fin-clip program is to monitor the performance of the various strains of trout that are stocked into Crowley, as well as getting an estimate of the numbers of wild fish that are produced in the tributaries,” Milliron said.
Last year several dozen volunteers from Cal Trout and the Pasadena Casting Club spent a few weekends clipping certain nonessential fins of 75,000 trout, about 20% of the plant destined for Crowley, so their history could be documented when they are caught, show up in the fish trap--or, like a few weeks ago, wash up on shore.
Last Saturday 30 volunteers from the Izaak Walton League of America, organized by the Westwood Village chapter, helped four DFG workers install the fish trap, which brought quick results.
“We went out Sunday morning and checked the trap,” Milliron said. “We had one rainbow trout almost three pounds in very good shape, going upstream. We got one spawned-out female the same size going downstream.”
Not much, but a start. Milliron will learn more when the browns and Coleman-strain rainbows swim upstream to migrate in the fall.
Meanwhile, the lake is about eight vertical feet below normal, Griffith said, and the catch has dropped proportionately.
“Last year opening day (and) opening week were not up to the year before, which was slow,” Griffith said. “It picked up, though. Bigger fish were caught in July (by) the locals and people that stick around. (The DFG) found that while the catch was down, the (average) size was 13 ounces, which is a pretty good size fish.”
Last year the DFG stocked the lake with three strains of rainbow trout--250,000 Colemans, 80,000 Kamloops and 50,000 Hot Creeks. This year they planned to try 150,000 Colemans, 75,000 Kamloops and 150,000 Eagle Lake trout--the latter being a particularly hardy strain from the alkaline northern California lake.
“The rainbow trout don’t seem to live past the age of 3 or 4,” Milliron said. “There are couple of things that may explain this. The growth rate at Crowley is very fast, and if fish grow fast they don’t tend to live as long.
“We’ve also wondered if there is some accumulation of parasites or toxicity in the fish that may shorten their life span.”
Milliron leans toward the latter theory. Crowley had no ice cover until December last year and the water may have been stirred from top to bottom by strong winds. That does not happen in the summer, when the warmer water stays on top.
“If that bottom substrate gets stirred up, you liberate oxygen-depleting organic decomposed material, and the fish suffocate,” Milliron said. “In December (when) the lake temperature is nearly uniform from top to bottom, you don’t have that protective stratifying layer, and when the wind does kick up the potential is to mix the lake from top to bottom.
“I don’t think that’s what happened here, though.”
There was another problem last fall when the water level dropped below the normal channel of the Owens River. The inflow then spread into a delta.
“We were concerned about a blockage of fish migration into the Upper Owens River,” Milliron said.
Later they suspected that “the hydraulic action of the water moving over dirt digs through layers of sediment that have been there for years and liberates that material into the lake,” Milliron said.
“During the time that the delta was being formed . . . there were certain levels of tested minerals that were increased--and it was coming from Crowley, because the upstream and downstream levels were not the same.”
Bob Wilson, a DWP engineer based in Bishop, said: “I’m not aware of that, (but) I wouldn’t find it unusual.”
Finally, there is the Mono Lake factor. Last year a court ordered the DWP to maintain a minimum level in that lake, which is too alkaline to support fish, instead of diverting Rush Creek into the L.A. aqueduct.
Rush Creek is a good trout stream--the biggest fish on opening day in ’88 was caught there--and Mono activists won their case by using a regulation from the state Fish and Game Code that prohibits potentially harmful diversions from fisheries.
But by holding water in Mono, upstream from Crowley, “There’s no import from the Mono Basin into the upper end of the Owens River, so there’s less inflow coming into Crowley,” Wilson said.
There may be irony here.
“The Fish and Game code was used to protect a live fishing stream (Rush Creek),” Wilson said. “It results in the water going into a dead (no fish) lake.”
At the expense of a prime fishery--Crowley.
Jim Edmondson, regional director for Cal Trout, said: “You can’t strangle one ecosystem to save another. We aren’t in the Mono Lake business. We’re in the trout business.”
Milliron said: “I don’t think we can really say we’ve hurt the Crowley fishery.”
He said the DWP has been concerned and cooperative in preserving fisheries all along the Eastern Sierra.
For years, opening day was special at Crowley. Anglers jammed the lake in hundreds of boats before dawn, awaiting the signal to cast their lines. It’s not like that now.
“We expect fewer people,” Griffith said. “We can tell by the pre-inspection (boat) applications. We’re just hoping that the people that are there will suddenly catch fish.”
Milliron said: “There are large brown trout in Crowley. I’ve been on Crowley electroshocking at night and I’ve caught fish up to 20 pounds. That’s quite a bit larger than what we typically see in the catch.”
Griffith: “The size is good, but we’re really concerned about the die-off and what would cause that, and the fact that fish are not being caught. If 380,000 are in there, where do they go?”
Obviously, it’s still a mystery.