Floyd Gross is fond of fish. He eats it two or three times a week. But he thinks about it nearly all the time. Gross is a charter boat captain, one of 30 licensed guides here who take sport fisherfolk onto the Chespeake in search of adventure and a manageable tussle at the end of long line.

Last week the Maryland Seafood Marketing Authority invited a number of food editors to meet Bay fish intheir native habitat. The editors, whose interest in fish normally begins at the stove and ends at the stomach, responded gamely, climbing aboard Captain Gross' Ruby Ann and two other boats under cloudy skies. In turn, the fish responded by virtually jumping into the boats once the fishing grounds had been reached.

They were bluefish, "fighters" said Bob Prier, who is executive director of the Chesapeake Bay Seafood Industries Association. "They have been the main source of entertainment and excitement as rockfish declined," he said.

The decline of rockfish - there has been a shortage in the Bay for several years nor - was supposed to be reversed this year if the fish followed traditional migration cycles. So far they haven't. But according to Captain Gross, "Business is fairly good.

"Fishing has changed a lot since I got here in 1944," he said. "Then it was hard-heads (croakers). They stopped about 1960 (as is the nature of Nature, they have reappeared recetly, further down the Bay near Crisfield), so we moved to spots, perch and rock. The last four or five years have been big for blue."

Gross and his fellow captains don't keep secrets from one another. "We're competitors," he said, "but we keep in contact by radio and troll close. We're all friends." There are about 250 licensed sport fishing captains on the Maryland side of the Bay. To them Virginia is another world. For those who tie up at Chesapeake Beach - a thriving resort area in days of legal slot machines and segregation; something a backwater today - the season runs from mid-April through Thanksgiving. The mid-Bay is a prime area, they claim, and they charge six people $85 for half-a-day's fishing or $145 for six to 10 hours. Poles, if provided, are $3.

Floyd Gross shouted with glee as the first fish struck on the Bay and said, "I've been fishing all these years and I still get excited." The kepone scare hurt business some last year, but the charter boat captains and seafood marketing officials hope that is past. After all, the boat tied to the dock here is named "Optimist."

Yet catching fish and cooking them are two different exercises. Once the blues were on shore, scaled were cleaned, the Seafood Marketing Authority's home economists demonstrated a number of preparations that passed several taste tests. They advised people who catch more fish than they will eat immediately to freeze some, preferably in water in half-gallon milk cartons or plastic bags. With blue, they suggested removing the skin and dark, oily flesh before freezing. Fish are placed in a salt brine before smoking to make them firm.

"People tend to overcook fish," said Marilyn [WORD ILLEGIBLE] of the Marketing Authority. "They should think of cooking fish as you cook eggs.Once a piece of fish [WORD ILLEGIBLE] it can only become tough and dry with further cooking."

As even greater problem is that many people tend to avoid fresh fish altogether. Gerald Donovan, who [WORD ILLEGIBLE] the Rod 'n' Reel Restaurant, verified what a survey of other seafood restuarant owners has shown: The most popular items are frozen shellfish, usually imported. People come to the water's edge in search of atmosphere, then in overwhelming number choose to eat shrimp or lobster tails and seem to prefer deep frying to any other form of cooking.

The true flavor of fish shows best when the meat is not hidden under seasoned breading or batter.But people don't order poached fish very often. They even by-pass pan-fried or broiled fish. "There's one hell of a difference between a piece of fresh fish and frozen, but people dont' seem to realize it," said one old-time restaurant man. "Furthermore they are geared to easy eating. They don't want bones and they don't want to look at a head or tail on the fish."

These comtemporary problems - the need for greater appreciation of fresh fish, even on the Chesapeake, and the desirability of more varied and skillful preparation in homes and restaurants - are framed in the following passage:

"Up to the present time fish has been insufficiently understood and its value almost unknown. Its cheapness when compared with meat offered a pretext for its nutritive properties being instinctively scorned. It has happened that the present crisis of the high cost of living has created new problems for solution, and it is thanks to these that the products of the sea have begun to take, during the last few years, the place they deserve . . .

"It only remains to popularize the methods of preparing it for the table, and fish at last will have its due."

This didn't come from literature provided by the Seafood Marketing Authority, although the information and several of the recipes that follow did. If was part of the introduction to a French volume known as "Madame Prunier's Fish Cookery" and was written in 1929. Some things haven't changed so very much in the past half century after all.

Here is advice for charcoal-grilling fish from the Maryland Seafood Marketing Authority, plus recipes for a marinade, a basting sauce and several ways to prepare bluefish.

To charcoal-grill fish: Make a fire in a charcoal grill with 30 to 36 briquets, spreading coals out after about 30 minutes when white ash appears on them. Place fish in a well-olied, hinged hand grill, baste and place it, skin-side down, about 4 inches from the coals. Cook fillets or steaks 1/2-inch thick about 15 mintes, turning twice; fillets 3/4-to 1-inch thick 15 to 20 minutes, turning twice; fillets 1/2-inch thick 20 to 25 minutes, turning twice. Soft shelled crabs should harpoked about 15 minutes, turned and, as with all fished during grilling, basted. If fire flames up, remove fished until it dies down.

SPICY MARINADE (Makes about 3/4 cup) 1/4 cup butter or margarine 1/2 cup dry white wine 1/2 teaspoon prepared mustard 1/2 teaspoon salt 1/4 teaspoon lemon and pepper seasoning (or 1/4 teaspoon pepper and 1 teaspoon lemon juice) 1/4 teaspoon seafood seasoning 1/4 teaspoon dried tarragon, crushed 1/4 teaspoon dried rosemary, curshed Melt butter. Add remaining ingreditents, stir and took over low heat to warm the mixture and blend the flavors.

EASY BASTING SAUCE (Makes about 3/4 cup) 3/2 cup bottled French-style dressing 1 tablespoon instant minced onion 1 tablespoon soy sauce 1 clove garlic, minced or crushed 1/2 teaspoon pepper Mix ingredients together several hours before mixing. Leave covered at rom temperature.

BARBECUE BASTING SAUCE (Makes about 1 cup) 3/4 cup bottled barbecue sauce 3 tablespoons salad oil 3 tablespoons lemon juice 1 teaspoon worcestershire sauce Mix ingredients and let stand several hours at in temperature. Stir before using. SMOKED BLUEFISH, OYSTERMEN'S INN (Appetizer for 36, Entree for 6) 6 blue fish fillets 1/2 cup salt 1 cup salt 1 cup bottled barbecue sauce 1 cup apple cider vinegar 1/2 teaspoon prepared mustard 2 teaspoon hot pepper sauce 1 1/2 teaspoons butter or margarine 1 tablespoon lemon juice 1/4 green pepper, cut in strips 2 ribs celery, cut in pieces 2 teaspoons Worcestershire sauce 1/4 cup lemon-lime soda Hickory chips, soaked in water and dried 1/4 teaspoon black pepper 1/4 teaspoon cayenne pepper

Mix salt with 2 quarts water and pour over fillets in a pan or pot. Refrigerate overnight or during the day. Combine remaining ingredients except black and cayenne pepper in saucepan, bring to a boil and simmer for 30 minutes. Strain and set aside or refrigerate until needed.

To cook, prepare coals in a charcoal cooker with a cover.When coals are covered with ash, add soaked and dried hickory chips. Cover cooker and close vents until smoke accumulates. Remove bluefish from brine and pat dry. Sprinkle fillets with black and cayenne peppers and place in a well-oiled, hinged grill. Baste. Place on cooker grill about 4 inches from coals, skin-side doen, and put an oven thermometer on grill. Cook for about 1 hour at 200 degrees, turning fish twice and basting every 10 to 15 minutes. Fish will feel firm to the finger and develop a film when it is cooked.

Note: At about 250 degrees, the fish will cook in 30 minutes; at 150 degrees allow 1 1/2 hours, but replenish chips and coals as needed. The fish may be smoked without the basting sauce. Simply brush it with salad oil during cooking. Use other fish, including croaker, shad and herring. Once smoked, the fish may be kept wrapped and refrigerated for about a week.

BAKED BLUEFISH (6 to 8 servings) 1 whole bluefish, about 6 pounds, gutted and scaled, preferably with head left on 6 to 8 slices onion 1 carrot, sliced 2 bay leaves 1/4 teaspoon dried thyme 2 or 3 sprigs parsley Salt and freshly ground pepper Salad oil

Wash fish, removing any loose scales. Place onion, carrot and herbs in cavity, sprinkle with salt and pepper. Oil a baking dish, place fish in it and cover fish lightly with oil, salt and pepper. Cover dish with foil and place in pre-heated 375-degree oven. Bake 30 to 40 minutes. Cut from bone and serve. Pass melted butter to which chopped parsley and, if you wish, a few drops of hot pepper sauce have been added.

BLUEFISH BENCHLEY (6 servings) 2 large bluefish fillets (about 2 1/2 pounds) Juice of 1 large lime 2 teaspoons dehydrated, minced onion Freshly ground pepper 1/4 pound (1 stick) melted butter or margarine 2 ounces gin Salt

Half an hour before cooking, lay fillets skin side down in a 9-by-13-inch heatproof dish. Pour lime juice over fish, sprinkle on 1 teaspoon minced onion and pepper and cover with about 3/4 of the melted butter.

Heat broiler. Place fish 3 inches from the flame and cook until top begins to brown. Bring gin to a boil in a Saucepan with remaining butter. Pour over fish and urturn to broiler. Liquid will ignite. Baste once flame has died, sprinkle on remaining onion and cook until fish is firm, 5 to 10 minutes more. Season with salt just before serving.