Historic Low in Long Island Sound's Toxic Dead Zones Marks New Era for Wildlife Recovery
The Long Island Sound, a vital waterway shared by New York and Connecticut, has reached its lowest levels of toxic "dead zones" in nearly four decades. The decline, according to the Connecticut Department of Energy and Environmental Protection's 2025 Long Island Sound Water Quality Monitoring Program report, could signal a surge in marine life, including dolphins and whales.
The reduced dead zones cover just 18 square miles of the sprawling 1,300-square-mile sound, a significant decrease from the approximately 430 miles it measured back in 1987. The decrease is attributed to unregulated sewage and stormwater runoff, which has been slowly addressed through advocacy efforts and state guidelines requiring wastewater treatment plants to reduce nitrogen concentrations.
The results are remarkable, with Peter Linderoth, director of healthy waters and lands for Save the Sound, calling it a "remarkable success story" and one that he hopes will continue. The massive fish die-offs, lobsters crawling out of the water trying to breathe, and animals suffocating due to low oxygen levels have largely subsided.
The drop in dead zones has already had a profound impact, including the emergence of nearly 70 dolphins spotted in the sound this summer. Tricia Leicht, who witnessed the pod, recalled that it was "amazing" and described the experience as a life-changing moment for everyone on board.
However, Linderoth cautioned that while the trend is encouraging, there are still challenges ahead. The western portion of the open sound continues to harbor clusters of dead zones, including some areas with zero levels of oxygen. Additionally, the study does not account for smaller waterways, such as the polluted Harlem River.
Environmentalists urge individuals to limit nutrient runoff in wastewater, reducing fertilizer use, clearing up after pets, and keeping storm drains clear to mitigate hypoxia. As global warming ramps up, there is a risk that the progress could be reversed.
The Long Island Sound, a vital waterway shared by New York and Connecticut, has reached its lowest levels of toxic "dead zones" in nearly four decades. The decline, according to the Connecticut Department of Energy and Environmental Protection's 2025 Long Island Sound Water Quality Monitoring Program report, could signal a surge in marine life, including dolphins and whales.
The reduced dead zones cover just 18 square miles of the sprawling 1,300-square-mile sound, a significant decrease from the approximately 430 miles it measured back in 1987. The decrease is attributed to unregulated sewage and stormwater runoff, which has been slowly addressed through advocacy efforts and state guidelines requiring wastewater treatment plants to reduce nitrogen concentrations.
The results are remarkable, with Peter Linderoth, director of healthy waters and lands for Save the Sound, calling it a "remarkable success story" and one that he hopes will continue. The massive fish die-offs, lobsters crawling out of the water trying to breathe, and animals suffocating due to low oxygen levels have largely subsided.
The drop in dead zones has already had a profound impact, including the emergence of nearly 70 dolphins spotted in the sound this summer. Tricia Leicht, who witnessed the pod, recalled that it was "amazing" and described the experience as a life-changing moment for everyone on board.
However, Linderoth cautioned that while the trend is encouraging, there are still challenges ahead. The western portion of the open sound continues to harbor clusters of dead zones, including some areas with zero levels of oxygen. Additionally, the study does not account for smaller waterways, such as the polluted Harlem River.
Environmentalists urge individuals to limit nutrient runoff in wastewater, reducing fertilizer use, clearing up after pets, and keeping storm drains clear to mitigate hypoxia. As global warming ramps up, there is a risk that the progress could be reversed.
I was on a beach somewhere and there were these tiny mermaids playing with seashells and it was so peaceful 
then I woke up and my cat was trying to "help" me type on my laptop by pawing at the keys lol anyway back to Long Island Sound... 70 dolphins spotted this summer is wild 
I wonder if they'll start appearing in local aquariums soon
now we just gotta keep up da good work & make sure those wastewater treatment plants r doin thier part 2 reduce nitrogen concentrations 
also i'm low-key worried bout global warming tho, it's like, r we prepared 4 what's comin' ?? 
still, this is a great start & i'm all 4 da environmental efforts 
. But, at the same time, I'm not sure if we can just relax yet... there are still some areas with zero oxygen levels and smaller waterways like Harlem River that need attention 
.
I'm glad they finally did something about those toxic dead zones in Long Island Sound, but 70 dolphins isn't exactly breaking news 
. What's really going on here is that people are only reporting dolphin sightings now because of Instagram 
, not because it's some groundbreaking scientific discovery. And what about the Harlem River? They're still just as polluted as ever... it's like they forgot about it or something 
. I mean, I'm all for progress and all, but let's not get too hyped here until we see real, sustainable change 
!! 18 sq miles less toxic dead zones in Long Island Sound is like a major plot twist from The Day After Tomorrow (2004) movie, where the polar ice caps started melting and the consequences were devastating 
. We gotta stay vigilant & keep working towards a cleaner environment for all marine life 
! It's like we're flipping a switch and turning up the volume on marine life 
. There's still some heavy lifting to do (literally) on the western end of that sound. And don't even get me started on those smaller waterways... The Harlem River? Yeah, let's keep an eye on that one 
.
! I mean, who doesn't love dolphins popping up in their local sound? But seriously, 18 sq mi down from 430 sq mi is still a pretty big deal. It's like, we were on the brink of total disaster back in '87 and now...now it's not so bad 
. I'm all for reducing sewage and stormwater runoff - it's common sense, right? 
But let's be real, there's still a lot of work to be done. Those zero-oxygen zones are no joke 
. Can we please keep the momentum going without turning it into just another fad? 
We've got to keep up the good work, reduce our nutrient runoff, and make sure everyone's doing their part to protect this incredible ecosystem 
i dont really know how they deal with all the sewage and stuff in the water though 
, lets keep up the good work saving the sound !
but, let's be real, there's still work to be done, especially with those western open sound clusters of dead zones still lingering. and don't even get me started on the Harlem River... gotta keep spreading awareness about limiting nutrient runoff and keeping our waters clean, you know? 
! It's crazy to think that the huge progress made in reducing pollution has led to a surge in marine life, including dolphins and whales 
.
. We still have some areas with zero oxygen levels, and the Harlem River is still a major concern 
. It's super important that we continue to take care of our waterways and limit nutrient runoff in wastewater, reducing fertilizer use, clearing up after pets, and keeping storm drains clear 
, but we can't let our guard down. We need to keep pushing forward with advocacy efforts and state guidelines to ensure that our waterways stay healthy and thriving 
we gotta keep workin on those sewage & stormwater runoff issues 'cause that's still the main culprit behind all this toxic stuff. and what about the Harlem River, though? 
. gotta keep makin moves to protect that sound, especially with global warming causin all sorts of trouble 
