2026 Long Island Sound Pathogen Monitoring Network Expansion

Now entering its fourth year, the Long Island Sound Pathogen Monitoring Network (PMN) has officially begun sampling for the 2026 season. This year brings further expansion to the network, including two new groups and additional stations in both states in the Long Island Sound watershed. Cornell Cooperative Extension is monitoring three waterbodies in New York and the Town of Darien, Connecticut is monitoring three waterbodies in Connecticut. With the addition of these two groups, there are now eleven groups participating in this network, gathering crucial fecal indicator bacteria data to fill pathogen data gaps in the Long Island Sound Watershed. This network aims to create a coordinated, geographically strategic, scalable monitoring network for fecal indicator bacteria in the Long Island Sound in order to inform sound-wide management and restoration actions and has expanded each year since it began in 2023.

Cornell Cooperative Extension’s (CCE) monitoring focuses on sites that have been impaired by high pathogen levels and are not currently being monitored. Three of their sites are located at the mouths of tributaries that flow into the Huntington Harbor, Centerport Harbor, and Northport Harbor. In addition, these three sites are part of CCE’s Unified Water Study nutrient monitoring stations. The pairing of pathogen data with nutrient data at this site can help identify problem areas and track down pollutant pathways to these impaired waters. The other CCE monitoring locations, located in Mattituck Inlet and Goldsmith’s Inlet, have been identified by NYSDEC as priority sampling locations due to high coliform counts with no existing pollution source identified. These sites also have limited data and are not currently being monitored for pathogens. CCE’s monitoring locations expand the monitoring network further west on the New York side into Suffolk County. Their focus on unassessed tributaries and inlets makes them a valuable addition to the network.

The Town of Darien, Connecticut has begun sampling at twelve sites that directly align with their current Unified Water Study sampling sites. By collecting additional pathogen data that pairs with existing data at these sites, they may be able to more closely identify problem areas. Their sampling includes four sites in Darien Harbor, four sites in Cove Harbor, and four sites in the Zieglers/Scott/Fish Island area. The scope of these sampling locations covers the major embayments surrounding the Town of Darien. Collecting pathogen data in these three areas allows the town to monitor for harmful bacteria from point sources or stormwater runoff coming from the town’s major rivers and shoreside residential areas. This will contribute to improving water quality in both the waters surrounding Darien and in the larger Long Island Sound.

In addition to these two new groups, four existing groups have begun sampling at new waterbodies. Salonga Wetlands Advocates Network (SWAN) added a group of sites at the Narrows, a waterbody at the confluence of Conscience Bay and Port Jefferson Harbor. This area has seen significant increases in fecal coliform levels with no known pollution source and SWAN’s data can help assess pathogen increases to better inform local officials and environmental agencies. Alliance for the Mystic River Watershed (AMRW) added two sites to their 2026 sampling. One of these sites will serve as an upstream baseline for another site on Whitford Brook to inform potential contamination from cattle at the downstream site. The other site was added to test Haley’s Brook, a year-round significant stream that flows through multiple developed areas into the Mystic River. These additional sites will help to collect pathogen data from tributaries entering the Mystic River and larger Long Island Sound watershed. Harbor Watch at Earthplace added sites in Fivemile River Harbor, a popular location for waterfront activities and recreation, with the goal of identifying and addressing pollution sources in order to improve the waterbody for its current uses. Finally, Connecticut National Estuary Research and Reserve (CTNERR) began sampling in the Poquonnock River in Groton, Connecticut. The Connecticut Department of Energy and Environmental Protection identified this river as a priority due to bacterial contamination affecting shellfish harvesting in these waters. Continued bacterial monitoring at this site is crucial to guide actions that reduce bacterial pollution in the Poquonnock River.

The addition of these waterbodies across Connecticut and New York within the Long Island Sound watershed provides crucial data regarding widespread sources of fecal indicator bacteria in the Sound. Data collected in this network can be used to inform management decisions for local and state officials and environmental agencies, as well as help identify and reduce major bacterial pollution sources. The Pathogen Monitoring Network’s efforts work towards a cleaner future for the entirety of the Long Island Sound.