Canada geese are arriving in predicted fall hordes. The first big waves came pouring the fields and ponds of Maryland's Eastern Shore last weekend and the migration has been booming ever since.

Down on scenic Asquith Island, hard by the unfortunately dubbed town of Crapo, Md., Don Madole and his nine partners have been preparing their blinds and the old schoolhouse that serves as their hunting lodge.

Madole and friends are ready for the Oct. 20 start of goose season, doubly so because this year they won't be burdened with Blackjack, the untrainable Labrador that cost them a few shots too many.

Madole needed a retriever because much of his shooting was over water. Blackjack he didn't need.

The big Lab was a fine friend, to hear Madole tell it, but he couldn't pass muster in the field. "We'd train and train but he couldn't get it right."

The final straw came opening day. Madole and the others had been in the blinds since 3 a.m., waiting for the first glint of rosy dawn. Sure enough with the sun came the first flights, and one phalanx of big Canadas headed straight for the hunters' hideaway.

"The birds are coming in," said Madole. "They're pitching in perfectly to the decoys. They're just about in range when out pops Blackjack, up on his hind legs and barking away . . ."

That misstep cost Blackjack his role in Madole's fall flight of fancy. "He's barked at his last goose," the hunter said.

Even with the big Lab's antics, Madole, like most Eastern Shore goose hunters, has had little to complain about hunting in recent years.

Goose populations have been so thick that Maryland Natural Resources officials are getting worried.

"We had a November count last year of 540,000 birds in Maryland alone," said state waterfowl chief Vernon Stotts. "That's our index, and it's a very, very low estimate. There could well have been twice that number."

Maryland hunters harvested something like 240,000 Canadas last year. That's about 80,000 more than they took the year before, a figure that owes much to the lengthening of the 1977-78 season by 20 days.

This year the same 90-day season applies and Stotts and his colleagues are hoping for another record harvest.

"We really would like to have fewer birds," said Stotts, "or at least to spread them out more. We need to reduce the danger of disease and cut down depredation on early spring green crops."

Despite the big hunter harvest last year, Stotts is expecting another bumper crop of Eastern Shore Canadas. "Our outlook is just about exactly what it was last year, he said, "good to excellent for Canada geese.

"All excellent breeding population remained after last year's season," he said. "Satellite photos of the arctic Canada breeding grounds showed substantial melting in May and June. That's good for breeding. We expect that our population of geese, which nests there, had average to excellent reproduction.

"If we have just average production, with our magnificent goose population, that means a very large fall flight."

A large fall flight means more superb hunting.

Few of us are as lucky as Madole, found and bought into a perfect patch of land.

For less-fortunate types, goose hunting generally involves hiring out with a guide. There are worse ways to go.

A day with a guide generally costs from a minimum of about $40 a maximum of $80, depending on the number of shooters, the quality of the facilities and the services offered.

An average guided goose hunt goes like this: you'll meet the guide before dawn and follow him to his fields, walking through corn stubblefields to a pit blind or field blind. You settle in.

Just about at dawn you hear the honks or rising geese. Usually the birds roost in rafts on the water, then get up with the sun to fly into the fields and feed.

You see the first flights far in the distance, silhouetted against the pink of dawn. Before long, if you're in the right spot, they'll be winging overhead in great vees. You hunker down while the guide toots his call, beckoning the birds to his field and the stand of decoys he's set up outside the blind.

Presumably, along the way a flight or two will answer the call, wheel and begin to circle your blind. When the birds pitch their wings for a landing, get ready to shoot.

The shooting is the least difficult part, once the birds are pitching in. Even first-timers have good success because a pitching bird is usually no more than 30 or 35 yards from the blind. Pass shooting is harder, and is usually resorted to only late in the day when all else has failed.

The worst thing that can happen is a perfect day, cloudy and cold, when the birds fly in en masse at daybreak. You're likely to have your limit of three by 8 o'clock, and then what do you do?

The accompanying list of Maryland guides was compiled by the state. It isn't a complete list - only guides who asked to be are named. Not all the guides are goose guides, but almost all with Eastern Shore addresses are.

If you schedule a date, try for a time when the moon is small. When the moon is full, geese will feed at night and head for open water during the day. That makes for bad hunting.

A group of charter boat skippers in the Cape Charles, Va., area is working to conserve black drum fish, which have shown a remarkable surge in the bay in recent years.

The King's Creek Charter Boat Association, composed of 19 skippers, recently voted to impose its own 12-fish-per-boat limit on black drum to be kept. the group also plans to encourage fishing parties to release as many captured drum as possible.

Ben Walls, who heads the association, said, "We don't want to wait until we see a falling-off of the species in the bay," before conservation steps are taken.

The Prince George's Chapter of Ducks Unlimited will hold its annual chapter night banquet Oct. 9 at the Sheraton Lanham Motor Inn. Tickets are $35 a person and include a one-year DU membership.