- The Delaware River was once the caviar capital of the world, boasting perhaps millions of sturgeon
- Now, perhaps only 125 to 250 adult Atlantic sturgeon are breeding in the Delaware River
- Sturgeon are hit by cargo ships, and hurt by river dredging. A new effort aims to help change that
Just how different is a Delaware River fish?
The answer might matter to more than just the fish.
A new petition by environmental group the Delaware Riverkeeper Network may set off a pitched battle between two giants of the Delaware: On the one side, there are the massive container ships worth billions in commerce to ports in Philadelphia and Wilmington.
On the other is the largest freshwater fish on the East Coast, a prehistoric leviathan on the brink of extinction.
The Atlantic sturgeon is a survivor from the time of the dinosaurs, a scale-armored tank of a fish that can live for 60 years, hoover crabs whole and swell to 800 pounds — the size of a full-grown grizzly.
Not too long ago, the Delaware River was its densest home. The river teemed with sturgeon, a burly-meated lifeline for Lenape tribes that was praised by William Penn for its bounty. The sturgeon ran so thick the brave could conk them with a skillet, and jumped with such force and regularity the meek might need to dodge them while riding a ferry.
This abundance made the Delaware River into the caviar center of the world in the late 19th century, transforming fishermen into black-gold millionaires in the boomtown of Caviar, New Jersey.
Now Caviar is gone without a trace, sunk into Greenwich’s Bayside Tract. And the endangered sturgeon fights to exist.
From an estimated population of 360,000 Atlantic sturgeon in 1890 near the the tail end of the caviar boom, new research shows that fewer than 250 breeding adults likely remain in the Delaware River — victims to overfishing, pollution and a new apex predator in the form of giant cargo ships.
“They’ve survived since the time of the dinosaurs,” said Delaware Riverkeeper Maya K. van Rossum. “Will they survive the time of people?
Other rivers, from the Hudson in New York to the James and the Nantichoke on the Chesapeake Bay, have shown signs of a resurgence in Atlantic sturgeon since fishing was halted in 1997 and the species was listed as endangered fifteen years later.
But there’s no evidence yet that’s happening in the Delaware, according to the National Oceanic and Atmospheric Administration — a situation advocates attribute in part to pollution and a narrow maritime corridor that causes fish to get run over by cargo ships.
The river, van Rossum says, is “on the precipice of losing our genetically unique population forever.”
Why does it matter whether a Delaware sturgeon belongs to New York?
The fate of the Delaware River sturgeon might hinge on just how unique the federal government believes those sturgeon are.
This federal determination could also affect river dredging and port renovation projects projected to be worth billions of dollars in increased ship commerce at ports in Wilmington and Philadelphia.
Last month, van Rossum petitioned the U.S. Secretary of Commerce and NOAA to treat Atlantic sturgeon in the Delaware River as a genetically distinct endangered population in dire need of protection, one of the last three such river populations to survive in the Northeast.
Delaware River Atlantic sturgeon are considered part of what’s called the New York Bight, a larger population that includes the much more robust sturgeon population in the Hudson River, whose population is believed to be on the rise.
When federal agencies assess the environmental impact of a dredging or construction project in the Delaware River, they’re looking at the impact on this much larger population.
Because the Delaware population is estimated to be anywhere from half to a quarter as big, this practice masks the actual impact of commercial projects on the foundering Delaware River population, van Rossum said, allowing the National Marine Fishery Service to continue to approve big projects.
Theoretically, argued van Rossum, the Delaware population could go extinct — but the overall New York Bight population could still be considered healthy if the much larger Hudson River population continued to grow.
“The current conflation of the Delaware River and Hudson River populations into a single DPS undermines the potential continued existence of the Delaware River’s population, precludes its recovery, and likely accelerates its downward spiral into extinction,” van Rossum wrote in the July 19 application.
Is a Delaware River Sturgeon distinct, or just different?
The petition’s argument hinges, in part, on the notion that Delaware River sturgeon are genetically distinct from Hudson River sturgeon.
Each river’s population of Atlantic sturgeon has its own genetic signature, said David Kazyak, a research fish biologist with the U.S. Geological Survey.
In 2021, Kazyak’s research team used a relatively novel genetic approach to estimate the number of adult sturgeon. The team estimated that just 125 to 250 adults were breeding in the Delaware, fewer than previously thought.
Sturgeon, like salmon, are imbued with both wanderlust and a homing instinct. Tagged Atlantic sturgeon born in the Delaware River have been found in the ocean from Canada to the Outer Banks of North Carolina, and may take anywhere from 15 to 30 years to reach breeding age.
Over thousands or likely millions of years, each new generation has returned to spawn in the river where it was born. There’s remarkably little crossover between Delaware and Hudson River sturgeon, Kazyak said — even less than you’d find in Southern rivers whose mouths might be closer together.
“It’s essentially a group of fish that is behaving as a population,” Kazyak said. “They’re born in the river. They grow up, they come back, and they spawn within their same population. … When they’re gone, they’re gone.”
Kazyak will not weigh in on whether this difference makes the Delaware River sturgeon “distinct,” however — a word that carries regulatory weight.
“’Distinct’ in this context is a policy choice,” Kazyak said. “Genetic differences are something that we can go out and measure.”
‘Death by a thousand cuts’: Why Delaware River sturgeon are dying
Delaware State University fisheries professor Dewayne Fox is less circumspect, saying that the Hudson and Delaware River populations face distinct threats.
“As a scientist, I see little reason to put them together,” Fox said.
The Delaware River populations faces obstacles that amount to “death by a thousand cuts,” Fox said, including a head-on match with enormous container ships in a Delaware channel that’s narrower and shallower than the Hudson.
Currently, it’s a losing battle for the fish.
Sturgeon are “rolling the dice” anytime they travel near large container ships, Fox said. The tight quarters of the Delaware River leave little room for error.
Around 400 sturgeon in the Delaware River lost this game of chicken in 2018 and 2019, according to Fox’s recent research.
But though the shallowness of the Delaware is part of the problem, deepening the river carries its own hazards.
For more than a decade, the Army Corps of Engineers has been at work on a main channel project to deepen 100 miles of the Delaware River from 40 to 45 feet, including maintenance dredging at the Tacony-Palmyra bridge due to begin this month.
The river deepening is an essential component of a proposed Edgemoor container terminal project at the Port of Wilmington, and a planned $3.5 billion expansion at the Port of Philadelphia.
Proponents say these projects are necessary to compete with other ports around the region and country, and to accommodate the ever-inflating size of massive container ships. The Army Corp of Engineers limits the use of explosives to the winter months when sturgeon don’t migrate upstream.
Dredging increases the volume of the water, the speed of the currents and saltiness of the water. All of these are disadvantageous to the sturgeon, Fox said, as is muddying the river bottom where sturgeon lay eggs and find food.
The economic goals of the project likely also mean more and larger ships. Even the massive dredge itself runs a risk of killing sturgeon.
Add it all up, said Fox, and “pretty soon, you got a whole lot of dead sturgeon.”
The Delaware Riverkeeper petition is “unprecedented”
Changing the classification of Delaware River sturgeon could change the math on how the National Marine Fisheries Service calculates the environmental impact of these large river projects, van Rossum hopes.
If the petition is successful, it may make new projects harder to approve or reduce the allowable “take”: the expected number of sturgeon killed by dredging or other manmade activity.
The success of the Riverkeeper’s petition is far from assured. Fellow advocates say there’s no precedent for this petition to NOAA.
But van Rossum succeeded last year with another federal petition sturgeon advocates called unprecedented, leapfrogging officials at the Delaware River Basin Commission that van Rossum alleged were dragging their heels.
In December, she convinced the Environmental Protection Agency to step in to develop tighter regulations governing the amount of dissolved oxygen in the Delaware River: a measure of how much life the river can sustain.
“The fact that they stepped up in the way they did was really a very loud repudiation (of) DRBC’s failure to take timely and meaningful action,” van Rossum said.
In a statement responding to the EPA’s determination, the DRBC called the petition “unnecessary,” but accepted the federal agency’s stance. In response to inquiries last week, the agency said they will “continue to work cooperatively on improving water quality in the Delaware River Estuary.”
In 2014, the Delaware Riverkeeper successfully litigated to obtain a settlement forcing the fisheries service to designate critical spawning habitat on the Delaware River.
Experts at NOAA, the parent agency of the fisheries service, say the data on Delaware River sturgeon abundance is thin.
While there’s no evidence that Delaware River sturgeon are recovering, wrote NOAA’s Atlantic sturgeon coordinator Lynn Lankshear, there’s also not enough data to say for certain that the population is declining.
The long life cycle of northern Atlantic sturgeon, which can wait more than a decade to breed, can make year-to-year trends difficult to assess.
In a 2018 assessment, the fisheries service concluded that the continued dredging of the Delaware “may adversely affect, but is not likely to jeopardize the continued existence” of the Atlantic sturgeon and other threatened species.
In the face of this uncertainty, van Rossum argues the government shouldn’t take any chances: Any moment, any year, could be the tipping point beyond which the Delaware River loses its Atlantic sturgeon forever.
“In terms of being saved, your guess is as good as mine and that’s part of the problem,” she said. “We could have a couple of years. We could not. Every year has an impact.”
Matthew Korfhage is a Philadelphia-based reporter for USA TODAY Network. Contact him at mkorfhage@gannett.com or follow him on Twitter/X @matthewkorfhage. Contact Konner Metz at kmetz@gannett.com and follow him on Twitter/X @konner_metz.
