To most Mainers, autumn means apples, squash and pumpkins. But it’s also prime time for local oysters.

“As temperatures decrease, oysters know that they’re headed into winter, and to generate some energy reserves they store it in the form of glycogen,” explains Dana Morse, a Maine Sea Grant scientist who works with oysters and other shellfish. “That is part of what explains the plumpness of the oysters” in the fall.

And many people think a plump oyster is a better-tasting oyster.

“There’s definitely a noticeable taste difference, but the preference is entirely up to the individual,” Morse said. “I happen to think that oysters are indeed best in the fall when they’re sweet, and they’re fat and they’re full.”

As the number of oyster farms has grown by leaps and bounds in southern and midcoast Maine, so has the number of ways to enjoy them. Here are seven (mostly new and mostly Maine) ways to enjoy fall oysters:

OYSTERS ON THE HALF PRICE

So you say you don’t care about having a three-course dinner or small plates of fancy food? You just want oysters, and you want them now – as many as you can slide down your gullet.

Island Creek Oysters, the new oyster retail shop and casual, quick-service restaurant on Washington Avenue in Portland, is the place for you. The Duxbury, Massachusetts-based company, which has four other oyster bars in Massachusetts and New Hampshire, has direct connections with about 100 oyster farms, so it’s able to keep prices low. All oysters at Island Creek cost just $1.50 each, whether they are Eider Cove oysters from the New Meadows River or Petit Belons from Plymouth, Massachusetts. (Prices at many Portland restaurants – outside of daily specials and happy hours – hover around $3 per oyster.)

“It’s all about the product,” says Chris Sherman, who is overseeing the Portland shop and working with Maine oyster farmers to distribute their oysters out of state. “It’s really tailored to people who are big oyster fans, and also maybe to people who just want to try them out and don’t want to sit down for a big, long dinner to do so.”

Sherman said Island Creek, which opened Aug. 31, will be hosting a lot of educational events this fall focusing on oysters and the people who raise them. The goal? To get you to eat more oysters, of course. Island Creek is on a larger quest, Sherman says, to “get back to a period of time when there were oyster bars on every corner in New York City, and they were really an active and everyday part of American cuisine.”

ISLAND CREEK OYSTER CO.

123 Washington Ave., Portland

HOURS: Noon to 8 p.m. Sunday, Wednesday and Thursday; noon to 9 p.m. Friday and Saturday

INFO: (207) 699-4466

BEER AND BIVALVES

Oysters and Guinness go together like peas and carrots but are a much better reason to throw a party.

Years ago, the company that owns the Ri Ra Irish Pubs threw oyster festivals at a few of its locations around the country. They were “massive events,” according to Spencer Brantley, general manager of the Portland pub at 72 Commercial St.

“We did one in Raleigh, North Carolina, and we shut the streets down,” he said, “and almost 15,000 people attended.”

At the beginning of this year, brainstorming about the kind of events they’d like to have, the staff at the Portland Ri Ra’s decided to bring back the oyster festival. Now that Maine has become known for its stunning oysters grown in local waters, it seemed an obvious choice.

The plan is to start small. Portland’s inaugural Guinness Oyster Festival, to be held from noon to 5 p.m. on Oct. 8, will be contained within the pub’s walls, but, Brantley hopes, will expand in the coming years.

Brantley is still choosing oyster vendors, but he promises a variety of oysters from different parts of Maine. An oyster shucking and eating contest will feature teams of chefs from local restaurants. One chef shucks the oyster, the other swallows it, and the team that downs the most oysters within a certain time frame wins. The teams aren’t confirmed yet, but we hear that chefs from Eventide Oyster Co. (wouldn’t they be considered ringers?) and Rhum are considering entering the competition.

A Dublin-trained Guinness “ambassador” will be on hand to teach party-goers how to pour a proper pint to enjoy with their oysters.

“Guinness is traditionally done in a two-part pour,” Brantley explained. “So you pour it about three-quarters of the way up, and then you let it sit for about 90 seconds or so, then you top it off to make what they call the perfect pint. It’s one of those bartending traditions that has stood up and lasted for hundreds of years.”

Every attendee will receive a free Guinness glass (as long as they last), and a machine on site can engrave your name on it, or anything else you want.

How about: “I (heart) oysters?”

INAUGURAL GUINNESS OYSTER FESTIVAL

Ri Ra Irish Pub & Restaurant

72 Commercial St., Portland

HOURS: Noon to 5 p.m. Oct. 8

INFO: (207) 761-4446; rira.com/portland

A THREE (AND A HALF) HOUR TOUR

If you grew up on 1960s television sitcoms, you might not be inclined to go out in a small boat with a half-dozen tourists for a three (and a half) hour tour.

But the new aquaculture tour being offered by Maine Foodie Tours has a happier ending and includes lobster rolls and oysters that go straight from Casco Bay into your mouth.

The cozy tour – it’s limited to six people – requires an adventuresome spirit and deep pockets. The scheduling seems random but that’s because it is only offered on days when the tides are favorable for touring the Chebeague Island Oyster Company, the oyster farm that supplies Scales, Fore Street and Street and Co. in Portland. It costs $200 per person – even for children 5 and older, but Pamela Laskey, owner of Maine Foodie Tours, says the price may come down as the tour expands.

“It’s on a wooden lobster boat that’s been beautifully restored,” Laskey said. “We like to keep to a nice small number so there’s plenty of room on board. It’s also an exclusive opportunity.”

As you step on board the boat, which is owned by Casco Bay Custom Charters, you’ll be handed a lobster roll from the High Roller Lobster Co. The treats continue with smoked mussels, smoked fish, oysters and peekytoe crab. There may be a little sightseeing along the way – the boat motors out to Portland Head Light if the weather and timing permits – but since Maine Foodie Tours’ customers are interested in food culture, this is mostly an educational tour about aquaculture in Casco Bay, with a focus on oysters.

“The guide on the boat is quite familiar with the aquaculture going on, so we’re able to talk about Bangs Island, sea kelp farming, and the other oyster harvesters in area,” Laskey said.

When the boat arrives at Chebeague, it motors up to a float at the company’s oyster beds, where one of the owners starts shucking and serving oysters while he lectures about oyster ecology.

“The talk is an easy half-hour if not longer, Laskey said, “and there’s usually lots of questions.”

Reservations for this tour can, occasionally, be made online, but it’s probably best to call. Don’t forget to bring along a nice bottle of white wine.

MAINE FOODIE TOURS

INFO: (207) 233-7485; mainefoodietours.com

BIGGER IS BETTER

Brendan Parsons spent the past two years peddling oysters from Portland’s first oyster food cart. Now he has expanded his business to Newcastle, hoping to educate his customers as well as feed them. (If you can’t get up to Newcastle, don’t worry, his two oyster carts are still working Portland’s streets.)

River Bottom Raw Bar opened in August, inside a retrofitted gas station. A shellfish distribution center called Damariscotta River Distribution is also on site, along with a tasting room and retail shop where oysters are for sale. He carries eight varieties of oysters, most from the Damariscotta River, but he expects that number to grow in the coming months.

As soon as customers walk in the door, they are greeted by large photos of local oyster farmers hanging from the walls with short biographies. The menus include descriptions of the oysters and the farms they were grown on, and on the back a map of the Damariscotta River shows the location of each oyster farm. Then there’s the wait staff, hand-picked by Parsons for their knowledge about oysters and oyster farming.

“Everybody who works here has worked on an oyster farm, whether it’s volunteering for a day or working in a hatchery or diving for a company,” Parsons said. “Not only are they knowledgeable but they’re passionate about it, too. I’ve gone to a lot of raw bars, and the wait staff, they’re great wait staff. They’re attentive and everything, but they don’t know the nuances about the oysters.”

Parsons charges $2.50-$3 per oyster, or $14-$17 for a half-dozen. The best deal is the “Taste of the River” – a dozen oysters from three different parts of the river. The server explains where they come from, how they’re grown, and answers questions.

One interesting thing Parsons is doing is serving jumbo oysters, both raw and baked. These are oysters that have somehow avoided harvest at around age 2 or 3, the age they usually reach their legal size, and may be as much as 10 years old. Parsons says they have more body than younger oysters and taste a little more buttery. They can be “bigger than your hand,” but they do shrink during baking.

Parsons uses them to make Oysters Rockefeller and a Korean barbecue-inspired oyster dish. Four baked oysters – just under a pound of oyster meat – sell for $15.

Of course, you can always try slurping a jumbo down raw, a feat that Parsons says is always amusing to watch.

RIVER BOTTOM RAW BAR

68 Main St., Newcastle

HOURS: Noon to 8 p.m. Sunday and Monday; 3 p.m. to midnight Friday; noon to 10 p.m. Saturday; closed Tuesday, Wednesday and Thursday

INFO: (207) 682-0129

AN OYSTER SAFARI

The Maine Oyster Trail, a map that shows oyster lovers the location of oyster farms in Maine, has been in the works since 2011. An online version finally went public this summer, and a print version is expected to be published by the end of the month.

The map includes more than 50 of the state’s 80 oyster farms, noting that the oysters are named after where they were grown because local conditions help determine their size, taste and shape. In 2016, these Maine oyster growers harvested 2 million pounds of oysters valued at more than $5 million.

In addition to oyster farms, the map lists restaurants that sell Maine oysters and places that offer oyster tours, whether by boat or kayak.

“If someone comes to Maine and wants to go on oyster safari, and buy lots of different oysters from different places, this is a tool to help them have some kind of oyster experience, whether it’s a farm tour or going to eat at a restaurant, or buying an oyster,” said Dana Morse, a scientist with Maine Sea Grant who has been involved in developing the map.

The map also includes information on the history of Maine oyster culture, what the industry is like today, and tips on handling oysters. (Store them in the fridge, covered with a damp towel, and eat them within 14 days.)

To see the online version of the map, go to oystertrailmaine.org. The paper version is expected to be ready in time for the Pemaquid Oyster Festival Sept. 24, and it will also eventually be stocked at participating oyster farms, restaurants, retailers, and distributed through the Maine Office of Tourism.

MAINE OYSTER TRAIL

INFO: oystertrailmaine.org

THE GRANDDADDY

Long before Maine oysters started grabbing national attention, the Pemaquid Oyster Co. in Damariscotta celebrated them locally with a big party. It’s the only thing on our list that’s not new, but as the granddaddy of oyster bashes it cannot be ignored.

This is the 17th year of the Pemaquid Oyster Festival, famous for its oyster stew and other good eats, including, of course, lots of raw oysters. It’s always held on the last Sunday in September, which is Sept. 24 this year.

“The oyster festival is the original event that celebrated Maine oysters and was originally really focused on Damariscotta oysters – and still is, really,” says Sebastian Belle, executive director of the Maine Aquaculture Association. “They serve a sampling from a number of farms on the river, but most come from the Pemaquid Oyster farm because they really founded the festival.”

Last year, festival goers gulped down 15,000 oysters, and that number is expected to go up this year.

The festival has music, boat tours of oyster farms, and exhibits from environmental groups. It’s also the home of the Maine Champion Oyster Shucking Contest. The winner is qualified to participate in the national contest in Maryland.

The Pemaquid festival benefits the Ed Myers Marine Conservation Fund, which awards grants to local environmental groups.

PEMAQUID OYSTER FESTIVAL

Schooner Landing Restaurant and Marina

HOURS: Noon to 8 p.m. Set. 24

BOSTON BOUND?

Check out the brand new Eventide Fenway, sister restaurant to Eventide Oyster Co. in Portland. The Boston location, near the city’s famed baseball stadium, will be opening in another couple of weeks, according to co-owner Arlin Smith.

Eventide Fenway will offer counter service only. It will be interesting, this time next year, to compare statistics between the two restaurants: The Portland Eventide sold 15,000 oysters a week this summer, and had as much as four-hour wait times for a seat. In Boston, how long will the line to order stretch out the door?

EVENTIDE FENWAY

1321 Boylston St., Boston

HOURS: 11 a.m. to 10 p.m. daily