Farm fields will soon go fallow, but Vineyard shellfish beds are about to see their peak season begin. October brings the opening of the bay scallop season, and also now the reopening of Sengekontacket Pond for all shellfishing.

The pond, which spans Edgartown and Oak Bluffs, has been subject to mandatory state closures for shellfishing in the summer months for the past four years. Sengekontacket reopens tomorrow.

Family bay scalloping also opens in Edgartown, Oak Bluffs and Chilmark tomorrow, and many Islanders are no doubt readying their waders, dip nets and peep sights. The commercial season opens later in the month; each town sets its own rules for shellfishing, including scalloping, which is allowed generally from October or November until March.

Few places remain along the Eastern seaboard that support a bay scallop fishery; the Vineyard is one, Nantucket is another and Chatham on Cape Cod is another.

“It is part of the winter economy,” said Edgartown shellfish constable Paul Bagnall.

Shellfish constables in down-Island towns are cautiously optimistic that this will be a good year for bay scallops.

Tisbury opens its scallop season later in the month at Lake Tashmoo and in Lagoon Pond (which also spans the town of Oak Bluffs). Aquinnah usually opens its season later in November; shellfish managers in that town prefer to wait a little longer and reap the rewards of fat scallops that have had a few extra weeks of growth. Scallops grow to maturity in 18 months to two years. And more than quahaugs and oysters, they are sensitive to subtle changes in environment, including the loss of eegrass beds in saltwater ponds where the scallops settle after completing a swimming stage.

In his report to the town selectmen this week, Mr. Bagnall wrote: “The outlook is good for this year, with a crop of bay scallops available in Cape Pogue and Sengekontacket.” Last year saw good scalloping in Edgartown, which has many productive ponds and in its heyday led the state for bay scallop landings. Mr. Bagnall said there is reason to believe that this year will follow with another good harvest.

Family scallopers are the first test of the crop. “We will watch the first weekend and see how they [the family scallopers] do,” said Edgartown deputy shellfish constable Warren Gaines. “From there we will know more about our efforts last summer.”

In the summer of 2010, shellfish constables found Cape Pogue Pond peppered with bay scallops. But much of the seed died due to severe storms. The Edgartown shellfish department has now begun a program using volunteers to help move seed scallops from shallow water at Cape Pogue to Sengekontacket Pond.

Rick Karney, director of the Martha’s Vineyard Shellfish Group, said conditions were excellent this summer for producing seed scallops in nearly all the Island coastal ponds that open to the sea. That should portend good news for next year.

At a meeting of the Cape and Islands Harbor Masters Association at the Black Dog Tavern on Monday night, a number of area harbor masters said it had been a good year for seed scallops from Chatham to Westport.

Oak Bluffs shellfish constable David Grunden was only cautiously optimistic about this year for scalloping in his town. “Sengekontacket is not going to be fantastic. It will be about as good as last year,” Mr. Grunden said. “We don’t have the eelgrass we need to support a bay scallop population. If we can restore the eelgrass in the pond, we will have better bay scallops.” He continued: “Lagoon Pond will be better than last year, on our side.” Mr. Grunden said there were about 15 commercial fishermen working the Oak Bluffs side of the Lagoon last fall and winter.

In Sengekontacket there also is concern about the threat to the scallops from a growing starfish population. Starfish are the bay scallop’s worst predator.

Tisbury shellfish constable Danielle Ewart said Lagoon Pond looks good from her side. “I think it will be a decent season,” she said. Last year there were about 20 shellfishermen working the Tisbury side of the pond. “We may have more, maybe some new shellfishermen,” Ms. Ewart said.

She said extra effort will go into enforcement of the town shellfish regulations this season.

The bay scallop season, by town, follows:

Chilmark. Recreational season opens tomorrow. Fishermen are limited to half a bushel per week. A decision on the commercial season will be made on Tuesday by the selectmen, according to Tim Carroll, executive secretary to the board.

Edgartown: Recreational season opens tomorrow with a limit of one ten-gallon wash basket including shells per week. There will be no dragging in Cape Pogue until Friday, Oct. 21. There is no dragging in Sengekontacket all season. The commercial season opens on Monday, Oct. 24, with a limit of three ten-gallon wash baskets per day including shells.

Oak Bluffs: The recreational season opens tomorrow in Sengekontacket Pond. Fishermen are limited to one bushel per week. Sengekontacket Pond opens for commercial shellfishermen on Oct. 10. All waters outside of Oak Bluffs open on Oct. 15 for recreational scalloping; Oct. 17 is the date for commercial. Lagoon Pond opens for recreational scalloping on Saturday, Oct. 29; commercial scalloping begins in that pond on Monday, Oct. 31. Recreational fishermen have a limit of one bushel per week. Commercial shellfishermen have a limit of three struck bushels per day.

Tisbury: Recreational bay scalloping, outside of Tisbury pond waters, begins on Saturday, Oct. 15. Lake Tashmoo, which has not opened in awhile for scalloping, opens on that date. The commercial season for Lake Tashmoo and the outside waters around the town opens on Monday, Oct. 17. Lake Tashmoo is restricted to dip netting for all scallopers; no dragging is allowed. Lagoon Pond opens for family scallopers on Saturday, Oct. 29; commercial scalloping begins on Monday, Oct. 31, the same as in Oak Bluffs. Tisbury recreational fishermen are limited to one struck bushel per week. Commercial shellfishermen are limited to three struck bushels per day. Two commercial fishermen are allowed on one boat per day.

Family scalloping in Aquinnah is well over a month away. Shellfish constable Brian (Chip) Vanderhoop said that while he has seen a lot of seed on the Aquinnah side of Menemsha Pond, he is not sure about the status of the adult population. Opening dates and catch limits will be determined later in the fall.