Massive Fish, Turtle Die-Offs Point to Water Quality Crisis on Long Island

Beach season isn’t off to a great start for parts of Long Island. Last weekend, thousands of dead bunker fish washed up on the shores of Long Island’s Peconic Bay, just two weeks after hundreds of dead diamondback turtles were found nearby.

Experts, including the New York State Department of Environmental Conservation, say the culprit in both mass die-offs is a recent red tide—large algal blooms fueled by an excessive supply of nitrogen.

The turtles are believed to have eaten shellfish contaminated by an algae-produced neurotoxin; the fish appear to have suffocated because algal blooms severely reduce oxygen in the water.

Now, community members and environmental groups are renewing their call for a comprehensive, state-level plan to address the region’s water quality issues, once and for all.

As Far As The Eye Can See

Most of the fish kills have been found on public and private beaches in towns surrounding Flanders Bay, but have been reported as far east as Cutchogue and Southold.

Dead bunker fish mark the high tide line. Photo credit: Peter Blasl via RiverheadLocal.

Residents in Riverhead described the high tide line last weekend as “marked by piles of dead fish, stretching out as far as the eye can see.”

“This may be the biggest fish kill I’ve ever seen and I’ve been working for more than 20 years,” Christopher Gobler, a biologist at Stony Brook University’s School of Marine and Atmospheric Sciences, told the Riverhead News Review.

Gobler said levels of the algae Prorocentrum—responsible for the red tide—are some of the highest researchers have seen in the region.

During the day, these algae produce oxygen through photosynthesis, but at night, photosynthesis stops. Algae then use up oxygen right along with other organisms. The lowest dissolved oxygen is often found early in the morning, before photosynthesis begins.

When schools of bunker swim into this “dead zone,” they suffocate and die.

Dissolved oxygen levels have dropped to zero for extended periods of time in this area, noted Gobler.

Bunker fish kills in this area are not uncommon this time of year. Bluefish, a predator fish, will chase schools of bunker up the Peconic River, where they become trapped. The volume of fish combined with low tidal flushing in these areas drives oxygen levels down and the fish die.

However, Gobler said the current die-off is the largest he’s ever seen—and likely the largest in decades.

A Dangerous Neurotoxin

A dead diamondback turtle and dead bunker washed up on the beach at Simmons Point in South Jamesport, May 29. Photo credit: Peter Blasl via RiverheadLocal

Another type of algae also present in the Peconic, Alexandrium, produces saxitoxin, a “dangerous neurotoxin” that can damage or impair nerve tissue. Shellfish filter the toxic algae cells from the water. When other creatures—like turtles—consume the oysters, they can become paralyzed by the toxin and drown.

Gobler said saxitoxin is normally detected in the region’s waters, but he has never seen levels this high and never seen it cause such a wildlife die-off.

Nick Mancuso, a state wildlife technician, collects bodies of dead turtles from Iron Point in Flanders. Photo credit: Peter Blasl via RiverheadLocal.

“We’re seeing bodies washing up in perfect condition. This has never happened before. It’s an alarming thing,” Karen Testa, executive director of Turtle Rescue of the Hamptons, told the AP.

Testa also said the poisoned turtles may have been just coming out of hibernation when they ate the toxic shellfish.

“What that does is it paralyzes them and they would just drown. It’s a horrible death, “she said. “They get their first meal and its poison. It’s horrible.”

Experts say this die-off could have serious and long-term consequences to Long Island’s turtle population. “We’ve seen very few instances like this before,” said Dr. Russell Burke, the chairman of the biology department at Hofstra University, told CBS New York. “It can take decades to recover.”

Shortly before the turtles were found, the DEC issued an emergency ban on shellfish harvesting in Meetinghouse Creek, Terry Creek, both tributaries of Flanders Bay, and James Creek, a tributary of Great Peconic Bay due to the presence of marine biotoxins.

Saxitoxin can also cause paralytic shellfish poisoning in humans, which typically results in numbness and tightening in the face and a loss of coordination. In most cases, patients make a full recovery in a few days, but rare cases have resulted in death.

The Longer We Wait, the Worse it Will Get

Traditional septic systems don’t treat for nitrogen. Instead, nitrogen seeps into groundwater and eventually works its way into coves and harbors, where it can become pollution.

Most of Long Island’s water quality issues—including algae blooms—are a direct result of excess nitrogen. Nitrogen enters waterways from septic/cesspool systems, and waste water treatment plants, as well as run-off from yards and agricultural lands.

As the nutrient leeches into the sandy soil and ultimately the surrounding waters, it acts as an incredible source of plant food, triggering massive algal blooms in the Great South Bay, the Peconic Bay, Moriches Bay, and many other bays, ponds, harbors, and fresh water lakes. These blooms reduce oxygen levels, kill eelgrass and other wildlife, and produce harmful toxins.

“Such occurrences will become the norm if we don’t reduce 30-50 percent of the nitrogen going into the Peconic Estuary,” Kevin McDonald of The Nature Conservancy on Long Island, said in a statement. “While some strides have been made to reduce nitrogen in our waters, the longer we wait to fix our water quality problems, the worse it will get, the longer it will take and the more expensive it will be.”

Cat drinking from faucet. Photo credit: Dave Dugdale / Creative Commons

Nitrogen pollution is also a threat to drinking water. All of Long Island’s drinking water, whether from public or private wells, comes from three underground aquifers: the Upper Glacial, the Magothy, and the Lloyd.

Nitrogen levels in these aquifers are increasing; groundwater with concentrations above 10mg/liter is toxic to humans.

New York State’s 2015-16 budget includes $5 million for a plan to combat nitrogen pollution on Long Island. According to The Nature Conservancy, the funding will be used to “develop an Island-wide plan to identify a thoughtful path forward and make sure that state, county and local water resource planning efforts are coordinated and actively addressing immediate coastal resilience and water quality challenges.”

State Bolsters Efforts to Address Nitrogen Poisoning of Long Island’s Waterways

Excess nitrogen is poisoning Long Island’s coastal vegetation, making the region more susceptible to the impacts of flooding and storms. A Suffolk county executive described the problem as “the most critical issue our community has faced in a generation,” and all levels of government are now working on a multi-pronged solution.

Nitrogen is a “natural part” of aquatic ecosystems, and it is also the “most abundant element in the air we breathe,” says the U.S. Environmental Protection Agency.

But excess nitrogen in air and water causes “nutrient pollution,” which the EPA describes as “one of America’s most widespread, costly and challenging environmental problems.

One visible sign of nitrogen’s local impact are the algae “blooms” seen with more frequency off the Long Island coast.

Yesterday, state regulators, some Long Island elected officials, and environmental and economic groups met to examine the impact of excess nitrogen in the first of three public meetings. The discussion-in Nassau County’s Legislative Chambers- focused in part on how to reduce high nitrogen levels in the back-bay area north of Long Beach Island.

Long Island’s Wastewater Challenge

The objective of the three meetings, said state Department of Environmental Conservation commissioner Joseph Martens in a press release, is “to build a plan that will address longstanding wastewater issues in Nassau and Suffolk counties.”

[pullquote]68 percent of the total nitrogen entering Long Island’s Great South Bay comes from wastewater, “including wastewater from septic systems and sewage effluent discharges.”[/pullquote]

The state says that 68 percent of the total nitrogen entering Long Island’s Great South Bay, for example, comes from wastewater, “including wastewater from septic systems and sewage effluent discharges.”

Because nitrogen is not a pathogen and does not pose a threat to human health, local treatment facilities were not typically designed to remove nitrogen as they processed wastewater. The nitrogen-heavy wastewater is then released into local waterways after treatment.

Another challenge is that some sections of Long Island rely heavily on individual septic systems, which also do not remove nitrogen. Approximately 70 percent of homes and businesses in Suffolk County, for example, are not served by sewers.

A More Vulnerable Coastline

Photo credit: National Park Service / Diane Abell
Photo credit: National Park Service / Diane Abell

Of particular concern to state and local officials is the impact of excess nitrogen on Long Island’s marshes, which are a “critical line of defense against severe storms and flooding.”

According to the state, “coastal marshes and their vegetation provide a natural infrastructure that calms storm surges and damaging waves along Long Island’s south shore bays.” Nitrogen pollution is “a threat to these marshes, causing the grasses to grow taller, but produce fewer and less dense roots, which destabilizes the marsh grasses”.

A white paper released by the DEC last week cites specific examples of significant marsh loss over the past several decades on Long Island, including marshes in the Great South Bay.

From 1974-2001, “there was an 18-36 percent loss in tidal wetlands in the Great South Bay as a result of factors including excess nitrogen entering the watershed,” the state found.

Reducing Nitrogen Levels Across the Region

A number of strategies are being examined to help reduce nitrogen levels. In Suffolk County, the state is considering financing options for septic system replacements and retrofits that it would offer in partnership with the county.

The state DEC and Suffolk County are also rolling out a $6 million plan for testing and implementation of nitrogen treatment pilot projects at individual homes and small subdivisions that are not easily reachable by sewer lines.

[pullquote]Protecting the Bay is critical as it is a “regionally important fish, wildlife and plant habitat complex.”[/pullquote]

Upgrading wastewater treatment plants is another solution.

New York City’s Department of Environmental Protection announced last week that it had completed a $230 million upgrade to a local wastewater treatment plant that “will reduce the amount of nitrogen discharged from the plant into the Upper East River and Long Island Sound by more than 3,500 pounds per day, or nearly 1.3 million pounds each year.”

The city says that the upgrade to the Tallman Island Wastewater Treatment Plant will allow it to convert the organic nitrogen present in wastewater into “inert nitrogen gas that can then be released harmlessly into the atmosphere before the treated water is released into the surrounding waterways.”

Loss of protective marshland and excess nitrogen levels are an issue for New York City too. The state says that Jamaica Bay has seen “dramatic losses in intertidal marshes.” Protecting the Bay is critical as it is a “regionally important fish, wildlife and plant habitat complex.”

In response, New York City has invested $460 million in nitrogen reduction upgrades at the Jamaica Bay and 26th Ward Treatment Plants, which discharge into Jamaica Bay.

The city says it has invested more than $1.5 billion to reduce nitrogen discharges from its wastewater treatment plants over the last decade.

How Can Long Islanders Participate in Clean Water Planning?

Crafting a strategy to reduce nitrogen levels is part of a broader review by the Cuomo administration of Long Island’s clean water infrastructure needs. Long Island’s sole source aquifer serves as the water supply for 2.5 million residents.

The Governor’s office states that they are committed to providing “additional protections for Long Island’s groundwater resources,” along with increasing resiliency against future storms, and improving water quality.

A second meeting on “coastal resiliency and clean water infrastructure” will be held on May 19 at SUNY Stony Brook and will feature presentations from researchers. The third meeting will be held May 28 in Suffolk County. The public will have the opportunity to make oral comments during the evening portion of the May 28 meeting.

The public can submit written comments at all three meetings or by emailing

A final meeting in June will feature recommendations to Governor Cuomo on how to address wastewater and septic problems “to make Long Island more resilient.”