By Art Merrill

Atomic warfare has an unexpected connection to secluded fly-fishing on a mountain meadow stream. If you travel to New Mexico's newest trout fishing opportunity at Valles Caldera National Preserve, you'll probably stay overnight at nearby Los Alamos, home of World War II atom bomb labs and modern-day warfare. In contrast to the original violent purpose of Los Alamos' defense industry, Valles Caldera guards its peaceful serenity as jealously as the military guards protect weapons secrets.

"Preserving solitude is our overriding concern - that's where we draw the line," said Valles Caldera NP spokeswoman Julie Grey. "Our biggest hangup has been the fishing reservations."

The United States government built Los Alamos in 1943 to provide physicists a secret location in which to develop an atomic bomb. In the 1960s, except for the Los Alamos National Laboratories complex, the government turned Los Alamos over to private hands.

Valles Caldera, a working cattle ranch just west of Los Alamos, went from private hands to public lands in 2000 when the government purchased the 89,000-acre ranch for $101 million. Last year the preserve opened about half of its 20 miles of streams to strictly controlled fishing from July to October. The problem, as Grey mentioned, is that anglers clamoring to be among the first to fish the Caldera overloaded the system.

"We received 900 requests for reservations to fish on opening day," she said. Unfortunately, the Caldera can only host 22 anglers per day.

I fished the Caldera with a friend in September, about six weeks after it opened to angling. I spoke with anglers there, and with others at a Santa Fe fly shop, that had fished the Caldera. As you'll see, your chances of hooking into a decent brown trout there depends not upon your choice of fly but upon a throw of the dice.

Ryan Tracy learns that the reward of a stealthy approach at the Valles Caldera is non-stop action with hungry browns. Photo by Art Merrill

Preserve officials divided nearly 10 miles of San Antonio Creek into 11 fishing beats, then limited each section so that only two anglers fish a beat each day. Fishing starts at about 8 a.m. when a shuttle van leaves the parking/staging area in a 40-minute drive to drop anglers off along the creek. The shuttle van returns in the afternoon to pick up anglers for the ride back to the parking area. (Every party gets temporary loan of a handheld radio in case they want to leave early.)

My fishing partner, Ryan Tracy, and I were assigned Beat 1, the highest point in the stream open to fishing. Here the stream is very narrow and shallow. Riffles and runs are only inches deep, with the best pools boasting only a foot of water. In many places it is easy to cross the stream in one jump. The bottom varies from silt to gravel, and the banks are undercut with overhanging grass.

Wading is not allowed anywhere in the preserve, which is protection again the damage 22 anglers per day could cause to the stream bottom. The stream is so tiny and the fish so spooky that wading is out of the question anyway.

GO TERRESTRIAL While mayflies hatch virtually each summer day on San Antonio Creek in Valles Caldera and browns rise to spinners that hit the water, hatches are rarely worth celebrating here because the trout feed continuously on terrestrials.   I experimented with various terrestrial patterns and was rewarded with a strike on just about every other cast.   "The trout are so opportunistic that if it doesn't look scary, they'll eat it," said Karen Denison at High Desert Angler in Santa Fe (505-988-7688). She was right. As long as my presence went undetected, the trout literally hit everything "leggy" I threw at them, including grasshoppers, beetles, Elk Hair Caddis patterns, and even Stimulators and blue damselflies in sizes 14 to 20. -- Art Merrill

I started with a 4X leader and tippet to cast a No. 16 yellow 'hopper. It was a good decision, and I ended up using it much of the morning. In later conversations, other anglers said they started with 6X tippets, but changed to heavier 4X after snapping off the 6Xs in the grass and losing flies.

At first I cast for trout holding close to the undercut banks with the predictable result (for me) of occasionally snagging grass. Walking over to disentangle the fly spooked the trout, of course, forcing me to move on. I soon found that casting to the center of the narrow stream was just as effective at producing a fish. It was exciting, even though it became routine, to drop the 'hopper in the middle of the stream and watch the wakes of two browns from opposite banks race for the fly.

The key in fishing Valles Caldera is stealth. Browns, as you know, are very skittish. Once they see you, all you can do is move on to the next spot. Because open meadow surrounds the San Antonio on the Valles Caldera, you'll be knee-crawling through elk droppings to sneak up on these fish. I noted one gentleman in the staging area had thoughtfully brought kneepads. He's a veteran.

The alternative is to make longer casts from farther away. But you'll have to drop your fly into an opening that's often no more than a foot wide and surrounded by two-foot tall grass, and sometimes with a wind to complicate matters. It will certainly test your casting skill.

I used my 3-weight rod this day, but a seven-foot or longer 1-weight would have done just as well. The 1-weight I built to use on tight Arizona canyon streams is only 6 feet, 6 inches long, making my 3-weight the better choice for this meadow environment. I think a 5-weight would be overkill for the short distances and small fish.

You won't use your drag on Valles Caldera trout, so a reel is just a place to store line.

The San Antonio widens and deepens only slightly as it flows down through the other beats, and I got mixed reviews from anglers fishing below Beat 1. Those fishing Beat 2 were very disappointed; they had caught few fish, which were, apparently, as small as the browns on Beat 1. Beats 3 and 4 reported the best fishing. A lone angler on Beat 4 said he hooked about 50 fish and landed seven that measured over 13 inches. Two men fishing Beat 3 said they caught 60 to 70 trout between them, most of them 10 to 12 inches in length. No one reported catching anything other than brown trout.

Unfortunately I didn't get an opportunity to talk with the anglers who fished beats five through nine this day. However, I have read or heard other reports of 10- to 15-inch browns on Beats 9 through 11. It appears the larger fish are definitely in the lower beats.