The No. 1 telephone question around here is: "I have promised my son (daughter) a fishing trip, including camping out overnight. Where do I go?

My No. 1 answer this time of year is the South Fork of the Shenandoah River around Luray, Va., preferably with a canoe or jon boat for carrying the gear. The scenery is uplifting as autumn evolves, the river is low and managable, the temperatures are finally bearable and on the right day the fishing can be nonstop.

Little bass, mostly, but by the millions.

Red Sturgis and Ben Roberts, both retired Air Force colonels, invited me to join them overnight at their Shenandoah cabin last week. Sturgis worried that the river might be too low and clear for good fishing and when we crossed the bridge at Luray he peered over the guardrail and muttered bad things.

But even on what should have been a bad day, the Shenandoah proved mind-boggling in its fecundity.

Before the car was unpacked, Roberts and I had put on old tennis shoes and werre wading over the rock ledges and through great beds of green stargrass that chokes the river in hot, dry years.

Roberts began casting a small spinner next to the shoreline and invited me to fish the same pocket, but it was small for two people. I waded out, the river being shallow enough to cross on foot anywhere.

About midstream the stargrass parted in a channel. Downstream 50 feet, I could see where this channel split in a Y. I watched the water at the Y and before long it dimpled with the rise of a bass and there was a splash as the bass took some dinner.

I cast my spinner exactly where the rise had been, turned the reel handle one time and set the hook on a bass, which leaped clear of the water twice on its way to captivity. It was a small fish, perhaps 10 inches. I set it free.

I cast eight more times into the same small pocket and hooked eight straight bass, losing only one, which spit the hook. All were shy of the legal size, 12 inches.

We had started fishing about 5 p.m. By 7, with daylight fading into the green of Massanutten Mountain, I had captured about 50 bass and two dozen bluegills. Only two bass werer legal size. I switched to a fly rod and a black marabou streamer and caught several more bass before dark.

This is an unsurprising day on the Shenandoah. The fishing will slow when cooler weather arrives, but late summer/early fall is high season.

The prevalence of small, hungry bass willing to take lures, flies or bait makes the South Fork an unbeatable attraction for youngsters, and I find it thoroughly satisfying sport for a day or two for even a wizened river rat.

Longtime Shenandoah anglers remember days when keeper bass weren't as hard to come by. Joe Sottosanti, who runs Shenandoah River Outfitters just a mile downstream from Sturgis' place, said that years ago large bass were much more common. He said he's caught smallmouth up to seven pounds out of the river.

His feelings about the decline in large bass is borne out by a pair of studies the Virginia Fish Commission did. In 1936 they sent out a good fisherman for a day. He caught 51 bass, 88 percent of which were 10 inches or better. A similar survey in 1978 produced 136 fish, but only 36 percent were 10 inches or better.

In an effort to improve the average size of South Fork bass, the fish commission is considering special standards for this stretch of the river, which would permit anglers to keep bass that are less than 11 inches or more than 13. The proposed regulation would protect fish 11-13 inches.

"We're trying to think along the lines of a garden," said John Kauffman, fish biologist supervisor for the state. "You thin out some of the vegetables so the remaining ones will do better. The existing regulations protect the small bass at the expense of the larger ones."

The commission will vote on the proposal this fall. Meantime, great fishing and exploring awaits the traveler, even if he does have to turn back most of the bass he catches.

One of the advantages of the South Fork below Luray is that Shenandoah Outfitters has marked off good camping spots along the way and mapped out the 25-mile stretch so that there are no surprises. A stop at Sotto santi's shop is worthwile for advice, which his people dispense whether you rent canoes and equipment from them or not.

They have broken down the river into sections, with whitewater recommendations for experienced paddlers and other stretches that are placid and flat for less adventurous novices. Also, they can predict water-level fluctuations to help you avoid sudden change while on the river.

If you happen to bump into one of the younger Sottosantis, you'll hear wild tales of the giant fish that do remain in the river. Lately Joe's offspring have taken up drifting downstream in swimsuits, wearing snorkels and masks, and they claim that five-pound smallmouths and giant catfish and carp still are plentiful in the deep holes. Evidently these fish are just too smart for the fishermen.