Anglers, like hunters, need to know their prey. Since he was 9, Jacques D'Epremesnal, a 61-year-old fisherman, has found succor standing quietly by lake or stream, intently recording fishkind. "I learned a lot by standing still."

Dr. David Gruber is a more complex aficionado, he of laboratories, computers and electronic gewgaws. Armed with a Defense Department contract, Gruber studies the effects of pollution on fish at an ammunition factory in Radford, Virginia.

Day after day, he measures their reaction to such irritants as TNT, missile propellants, lead and nitroglycerin. Out of all this, the good doctor has determined that, when exposed to irritants, fish hold their breath and even cough. He tells us that fish feel stress and emit a tiny electrical field, somewhere near 75 microvolts.

Now a little psychoanalytical work on these slippery creatures, and we should know the whole story.

WSSC -- "Autumn Angling Yields Smallmouth Bass" said the release from the Washington Suburban Sanitary Commission: "Jim Storey of Wheaton didn't let the beginning of autumn signal the end of the fishing season." Certainly not. In the Triadelphia Reservoir, Storey caught a 4-pound, 7-ounce smallmouth, the third largest bronzeback of the year. Throughout the year, the WSSC impoundments may have offered the best fishing in the area. For details, call Alice Galligan at 699-4172 between 9 and 5. The WSSC fishing season ends Dec. 15; devotees note that single-season permits will be available for hunting, fishing and mooring Jan. 1; permits will no longer be available by mail. Inflatable watercraft won't be allowed on water supply lakes.

CHESAPEAKE -- Bluefish chumming is still productive at Smith Point. Bill Bonds says chummers are boating 50 or more fish each trip. Most, he notes, are in the one- to five-pound range -- perfect for eating. As most captains note, if the blues are plentiful, chances are good that schools of sea trout cruise beneath. If last year is any guide, Jack Randolph's records show sea trout picked up for a few weeks in mid-October in the Bay. Otherwise, the Bay conditions are a repeat of last week's: Blues in the mouth of the Potomac. Use cut bait, spoons or hose. Fish for flounder around the shallows near the Point Lookout Hotel and in Cornfield Harbor. Any white bait, especially three-inch strips of squid should work. The Patuxent is windblown but productive. Fish near shore on the incoming and outgoing tides. Trolling with rubber hoses is popular. In the Severn River, the weakfish are still willing to strike bucktails trimmed with soft crab. In the mouth of the Rappahannock, trout are busy in the Waterview area. Norfolk anglers are catching large tautog by the score near the bridge tunnel.

POTOMAC -- "A few catfish, a few crappie, some bass. Nothing spectacular," notes Ray Fletcher. "If you take some night crawlers or cut bait out there, you're bound to catch at least a catfish. We get a lot of fathers and sons out at this time of year. It's nice just to come and sit," said Fletcher. Colorful foliage is an added attraction.

SHENANDOAH RIVER -- Normally, right now is a great time to fish the riffles and pools for smallmouth throughout the valley. Unfortunately, the lack of rainfall has dried up many fine fishing holes. The fishing will probably be poor until next spring. Goose Creek fans say it's just as bad there.

SMITH MOUNTAIN LAKE -- Striped-bass guide Dale Wilson ended the drought at Smith Mountain with a 19-pound striper. A few more landlocked rockfish have hit various jigs. But the fishing is terrible compared to last year. Cold weather may help the muskie and walleye fishing.

RAPPAHANNOCK RIVER -- Largemouth bass fishing is excellent in tidal creeks. A few stripers are lurking near the new dam near Fredericksburg. Again, the water level is low.

OCCOQUAN -- In the river, catfishing near Fountain head landing is terrific. In the creek, bass fishing is reported to be picking up.