State Raises Threshold For Rainfall Closures in Plum Island Sound

Local shellfishers could now have up to 72 more harvesting days a year thanks to improved water quality in Plum Island Sound.

State officials announced Thursday that the improvements have allowed them to raise the threshold for rainfall closures in the Sound (known as N4.0) from 0.5 inches to 1 inch, effective immediately. 

Closures after significant rainfall will also be shortened from eight to five days, officials said.

“Because the water in Plum Island Sound is cleaner and the science says it’s safe, we can give more than 200 commercial shellfishers up to 72 more days a year to harvest,” Governor Maura Healey said. “That means more certainty for their businesses, more local seafood on our tables and more support for a North Shore industry that has been part of these communities for generations.”

The Division of Marine Fisheries (DMF), which oversees fisheries across the state, said it imposes temporary rainfall closures for public health reasons.

During heavy rain, stormwater can carry pollution from buildings, roads and parking lots into waterways. As filterfeeders, shellfish can quickly accumulate and concentrate the contaminants, potentially making them unsafe to eat.

Plum Island Sound has been subject to rainfall-based closures since the 1980s, according to DMF. Historically, the area has been closed to harvesting for an average of roughly 130 days a year due to rainfall. 

The updated regulations are expected to cut rainfall-related shut downs by more than half, officials said. 

Closures will remain the same, however, in certain tributaries (N 4.1, N 4.6, N 4.16, and N 4.7). 

“Rainfall closures are a major challenge for those in the shellfish sector because they are unpredictable and can cause significant and extended loss of harvest opportunity, resulting in substantial loss of income,” Sen. Bruce Tarr said. 

Public health must always come first, Tarr said, but since the data shows closures can safely be reduced, he said he is grateful to DMF for making the change possible.

The expanded shellfishing access grants harvesters a reprieve after several blows to the local industry, including the permanent closure of the Ipswich River, the months-long closure at Middle Ground, and the Merrimack River sewage spill earlier this year.

“Our region’s clammers and oyster farmers work hard to produce shellfish of the highest quality despite operating in an increasingly challenging regulatory landscape,” Rep. Kristin Kassner said. 

Rainfall closures have imposed “significant constraints” on the industry, she added, thanking DMF and the Healey Administration for conducting the testing needed to show that local shellfish are not adversely affected by small rainfall events. 

“This enables the Commonwealth to expand shellfish harvesting opportunities to preserve an industry that has been integral to the economic and cultural identity of our communities for generations,” Kassner said.