Sometimes the best fishing is right under your nose.

Within 100 miles of Washington the blues are tearing up Chesapeake Bay; sea trout fishing is just short of fantastic in the Lower Bay; some of the regional bass hotspots are ready to melt, and the Pennsylvania trout streams are producing the best hatch of sulphur mayflies in twenty years.

Those stories in brief in a minute, but first, within the borders of the District are schools of rockfish - one of the best piscatorial delicacies that ever graced a table, a bottle of wine and good company. That's right. Rockfish in the Potomac. The very same creature fishermen drive miles for.

Nice pan-size rock, one to three pounds, have been hitting bloodworms around Fletcher's Landing. Catches have been sporadic, but have ranged as high as 46 fish to a boat within the past week. The schools move frequently, so the trick is always one of finding the fish. The best advice I can give is to ask at Fletcher's. That subtle technique led me to half a dozen rock last weekend. Early this week experts like Billy Collins of Falls Church were taking as many as 30 rock in the three-poind class, plus one six-pounder.

According to John Murto at Fletcher's, two months of good fishing for rock is probably just begining. "At first you get the smaller fish and lots of them when you locate a school," says Murto. "Then by late June the smaller fish thin out and you get fewer but bigger fish, up to 10 pounds." The best fishing is usually on the incoming tide, which stirs up the food supply and starts the fish feeding.

For fishermen who choose to travel, there is plenty to choose from. Probably the best choice is sea trout in the southern part of Chesapeake Bay. The trout started hitting last week and pulled out all stops this week, apparently beginning their annual two-week orgy of feeding. Previous years indicate that fishing will remain good for up to six weeks, but most experts on the Lower bay, of which I am not one, say that these first weeks should be a bonanza with catches by the cooler-full being common.

Bass are starting to come off their beds and should soon begin their post-spawning feeding binge. Most females don't feed heavily during spawning, and strike only to protect their nests. After spawning the males protect the nests, and the bigger females leave to commence their version of compensatory gluttony. Some lakes are ahead of others. The best choice this week seems to be Lake Manassas. Fish the shallows with broken back rapalas, plastic worms, large shiners and spring lizards.

Finally, trout fishermen in southern Pennsylvania are finding excellent dusk hatches of sulphurs on the Yellow Breeches near Boiling Springs, Falling Spring Run near Chambersburg and on the Letort Spring Run near Carlisle.