The doomsday prophets saw an early end to the quality big-water fishing that Lake Anna's 13,000 acres brought us seven years ago. Acid leaching from an open mine on Contrary Creek was supposed to taint it; thermal pollution from the nuclear power plant was supposed to warm it into ranges unfit for life. And if this didn't finish it off, pressure from anglers was supposed to create gamefish so lure-wary that they'd be impossible to catch. Traffic lights would be needed to direct the zooming boats.

But it's the predictions that have fizzled, not the high-class sport fishing. "Lake Anna is doing very well. Just like we'd expect a good new reservoir to fish," says Virginia fishery biologist Charlie Sledd. None of the threats has slowed things down yet.

In 1976, the Harrisonburg bureau of the State Water Control Board went to work on Contrary Creek, planting grass and trying to reclaim the area hit by leaching; the creek's acid level has been cut significantly. "Biological activity remains low in that small part of the lake," says Sledd, "but I don't see any major ill effects for Anna as a whole. This is a very small area and only a minor amount of acid is coming out."

The nuclear plant's warming effect has had no adverse effects, either. Only one of the plant's planned four units is working now, but VEPCO and the Virginia Game Commission are both monitoring temperatures continually. In the 3,000 sectioned-off acres that serve as cooling ponds for the plant water, the temperature increased last year by only about 1* to 2* c. above the reading in the main lake's 9,600 acres.

"i always tend to look at things optimistically," says bilogist Sledd, "but I think we may end up getting positive results from the thermal discharges. The slightly warmer water could result in a longer growing season and an ealier spawn." Already one of the top spots in the lake for both largemouths and stripers is the outlet where water from the last cooling pond empties into the main lake. A second unit at the plant is scheduled to go into operation this year, perhaps as early as next month.

And the intense fishing pressure simply hasn't materialized: Game Commission surveys show that Anna has gotten about the same amount of pressure in its early years as Smith Mountain Lake did. And Smith Mountain is miles from nowhere, not, like Anna, two hours from The Nation's Capital. This year, thanks to the gas crunch, Anna is just about deserted on weekdays.

If the lake's fishing has slacked off a bit in recent years, the reasons are far less spectacular than nuclear power and acid drainage, says Bill Mathias, a bass and striper guide who has probed the lake since Hurricane Agnes filled it in 1972.

"all man-made lakes seem to follow a pattern of offering super fishing for the first couple years. At Anna there was hardly a place you could throw your lure and not catch fish during those early years. But like most lakes, the fishing gets tougher after the newly flooded vegetation begins to disappear. You have to search for your fish now."

But while largemouths are no longer caught in huge numbers, Mathias says the average size has grown steadily. This spring the lake's first verified 10-pounder was caught, and Sledd predicts a steady increase in the number of citation-size bass over eight pounds. Slightly smaller bass are unusually plentiful. "Over the last two years we've caught just an exceptional number of three-to seven-pounders," says Mathias.

Verni Bossi co-owner of the Chesapeake Bay Seafood Houses, will verify that. Bossi had done quite a bit of saltwater fishing before last year, but little largemouth fishing.

"he was a quick learner," said the guide. He was also a prime candidate for the bass bug. Within a year he had purchased a $7,000 Pro-V Challenger bass boat and was pounding the lake with his own assortment of lunker sticks and plastic worms.

And catching bass.

Last week, while Anna's bass were in an "up" feeding cycle, Bossi fished a single hole in mid-lake and caught three bass: six pounds six ounces, six pounds 13 ounces and seven pounds nine ounces.

Getting these bigger base on Anna in August in strictly an offshore-structure proposition. No one is more adept on this semi-scientific fishing method than Mathias, nor more dedicated. Throughout the winter, when most of us are huddled around a warm fire, Mathias is out gathering discarded Christmas trees, assembling cinder blocks and planting private brushpiles on islands, humps and ridges that crop up near the river channel in 40 to 50 feet of water.

With the aid of two depth-recorders -- a graph model and a flasher -- Mathias then locates these structures in the heat of summer and has his party inch slinky plastic worms over them. It's a potent technique, and if you're interested in a trip you can reach him at 703/895-5533. For those who wish to try the lake on their own, Mathias recommends searching out similar submerged islands and points running far out into the main lake. Depth-finders are a prerequisite, and buoys are helpful to mark the structure beforle probing it with plastic worms and grubs.

Equating Anna strictly with largemouth is a mistake, however. The lake holds a diversity of gamefish, many of them underfished.

Big stripers are getting more and more plentiful in Anna, according to Charlie Sledd. Each year except 1974, 150,000 to 200,000 fingerlings have been stocked. This year 335,000 went in. Two of the stockings are now over the 20-inch limit -- the '73 and '75 classes. An 18-pounder from the '73 class has already been taken. Mathias probably takes as many stripers as anyone, and his best luck has come finding fish with a depth-finder in open water near the dam, then jigging Hopkins spoons over them.

Walleyes are perhaps the biggest surprise in Anna. The state stocked 56,000 on an experimental basis in 1975 and they've "done tremendously well," says Sledd. "We think they might have spawned." The original fish stocked are waxing fat on a steady diet of yellow perch. Five- and six-pounders have been netted, and more than one base fisherman has been surprised to reel in one of these toothy, tasty walleyes.

Crappie catches from Anna have become legendary, with fishermen anchoring beneath the Route 208 bridge and hauling in a hundred or more of the speckled perch in an afternoon's fishing. Both minnows and small marabou jigs take the crappie right through August's heat if you drop them right alongside the pilings to six to 12 feet.

And not all are tiny, either, as they were for the first few years at Anna. More and more fish in the two-thirds to one-pound range are sinking anglers' corks. April 3 a three-pound, four-ounce crappie was taken.

Perhaps the most neglected of all of Anna's fish is the bluegill. Fish around brush in medium-depth water in the coves with earthworms or crickets, a bobber, split shot and No. 8 hook. A heavy stringer of tasty panfish shouldn't be long in coming.

Far from being over the hill, Lake Anna is thriving, its gamefish surprisingly active in spite of the heat. CAPTION: Picture, ONE OF LAKE ANNA'S WALLEYES, 56,000 WERE STOCKED, AND A SIX-POUNDER HAS BEEN RECORDED. By Gerald Almy