Rebuilding sturgeon numbers in the Delaware River

Once the Delaware River held millions of Atlantic sturgeon; today there are but a few hundred.

Prompted by action taken by the Delaware Riverkeeper Network, federal fisheries managers have proposed thousands of river miles as critical habitat for Atlantic sturgeon from Maine to Virginia – areas that are vitally important for migration, spawning and juvenile growth for the endangered fish – to jumpstart the species' recovery.

Included are 340 miles of aquatic habitat in the Delaware River from Trenton south to Liston Range near Smyrna, where the Delaware River becomes Delaware Bay. This stretch is among the most industrialized areas of the river and includes nuclear power plants, factories, oil refineries, piers and wastewater treatment facilities.

In addition, a stretch of the nearby Susquehanna River around Conowingo Dam has been designated critical. Federal officials may ultimately add additional habitat in Marshyhope Creek, a tributary of the Nanticoke River, because Maryland environmental officials discovered adult sturgeon in spawning condition. A project to map the bottom and determine where there is spawning habitat on the Marshyhope is underway.

In all, the proposal designates critical habitat in 16 rivers. Atlantic sturgeon were listed as an endangered species in 2012.

“Sturgeon need this habitat to recover, and these designations give us an important additional conservation tool," said Eileen Sobeck, the National Oceanic and Atmospheric Administration's assistant administrator for fisheries. "Fully recovering Atlantic sturgeon in the future will take partnerships with state and federal agencies, the scientific community and the public, but designating critical habitat is another step in the right direction.”

Sturgeon in the Delaware estuary are vulnerable to ship strikes, dredging operations and industrial cooling water intakes.

Adult Atlantic sturgeon have also been found in the Delaware stretch of the Nanticoke River. The Nanticoke is considered one of the most pristine tributaries of Chesapeake Bay. The Nanticoke is not included in the critical habitat proposal.

The critical habitat designation was prompted by a court settlement between the Delaware Riverkeeper Network, the Natural Resources Defense Council and the National Marine Fisheries Service in 2014. The conservation groups pressed the federal agency to designate critical habitats as required by the federal Endangered Species Act.

“NMFS has made a strong proposal for the protection of this ecologically, historically and once-economically important species,” said Maya van Rossum, the Delaware Riverkeeper and leader of the regional nonprofit organization, the Delaware Riverkeeper Network.  “It is now up to the public to participate firmly and strongly in the public comment process to ensure NMFS's proposed rule is strengthened and that efforts to weaken it do not succeed.

"Once this designation is finalized, our work must continue to ensure that these protections are enforced and that the Atlantic sturgeon receives the highest level of protection possible under the law. Although we have already seen protections for the Atlantic sturgeon undermined and diluted by past decisions, like the deepening of the Delaware River, we will work even harder to ensure accountability and protect our local ecosystems.”

Van Rossum said that the Delaware River population of Atlantic sturgeon may number as few as 300 fish.

Critical habitat are areas that are "essential for the Atlantic sturgeon’s recovery," said Nick Patton, attorney for the Delaware Riverkeeper Network.

Among the areas in the Delaware are the distinctive bottom habitats where sturgeon are believed to spawn. These include hard bottom where there are cobbles, coarse sand, hard clay or bedrock. In addition, there are the places where water shifts from salt to fresh.

While no one is certain exactly where Atlantic sturgeon spawn in the Delaware, scientists know they need well-oxygenated areas with flowing water and water temperatures that range from about 54 to 78 degrees for spawning.

Within minutes of fertilization, Atlantic sturgeon eggs get sticky and they adhere to the hard bottom. Researchers believe that when water temperatures are in the 68-degree range, the eggs hatch within 60 hours of fertilization. The young fish feed on a yolk sack and then on invertebrates. They spend much of their young lives in the Delaware estuary.

In recent years, state environmental officials have caught young-of-the-year Atlantic sturgeon during survey work in the Delaware, and there have been adult fish caught in the Delaware portion of the Nanticoke River as well, said Stewart Michels, a state fisheries program manager.

Two years ago, state sturgeon biologist Ian Park caught hundreds of young sturgeon in sampling work in the Delaware River, Michels said. And on Thursday, state fisheries biologists caught a juvenile Atlantic sturgeon during a trawl survey. All of these fish are returned to the water alive and are tagged if they are large enough, Michels said.

Sturgeon haven't had it easy in the Delaware. Before the Federal Clean Water Act, pollution and low oxygen levels in the Delaware River probably limited spawning, Michels said. Before that, the species was overfished for caviar.

These days state officials are working with researchers at Delaware State University and the University of Delaware to find ways to reduce threats such as ship strikes, Michels said.

"Ship strikes are a major source of mortality," he said. But with the proposed habitat designations, state officials may be able to develop tools to help minimize them, he said. Among the possibilities are slowing ship traffic when sturgeon are moving in the river or time-of-year restrictions for dredging and construction projects, he said.

The proposed critical habitat areas also may have an impact on the proposed Rehoboth Beach ocean outfall. The pipeline is proposed to discharge the city's treated wastewater into the ocean at the north end of the city.

"We'll probably look to NOAA to take the lead" on the outfall issue, Michels said. As for now, state officials are trying to better understand what the potential impacts could be, from the outfall itself to construction of the pipeline, he said.

Sturgeon are anadromous fish, meaning they spawn in freshwater rivers that flow to coastal estuaries. They spend much of their adult lives in the salt waters of the ocean. Ocean habitats are not included in the critical habitat proposal.

The fish are especially vulnerable because they are slow moving, bottom feeders that reach sexual maturity later in life – anywhere between 5 and 34 years. Females produce thousands of eggs, but they may not spawn every year. They can live as long as 60 years, but most are believed to not survive that long in the wild. The fish return to their natal river to spawn. Some scientists believe the fish may follow cues as they move along the coast, signals that tell them how to navigate to their birth river.

Native Americans fished for sturgeon, but early European settlers considered them a nuisance because they tangled and tore the nets set to bag more desirable shad.

But then, European immigrants developed the salt solutions that were needed to process the eggs into caviar, and an industry was born.

The fishery emerged in 1870, and the Delaware River and Bay supported the largest sturgeon fishery in the United States between 1890 and 1899.

At its peak in 1888, the Atlantic sturgeon harvest was more than 7 million pounds, with Delaware Bay landings accounting for 6 million pounds of the fish.

By 1901 the fishery crashed. Landings in New Jersey and Delaware dropped to 6 percent of the peak levels. It has never recovered.

The critical habitat designation won't create preserves or refuges. If adopted, federal officials work to avoid or limit impacts on habitat. This proposal includes no restrictions on recreational or commercial fishing.

“The proposed critical habitat identifies areas that provide important spawning and rearing grounds, plus migratory corridors for the Atlantic sturgeon,” Sobeck said.

Reach Molly Murray at (302) 463-3334 or mmurray@delawareonline.com. Follow her on Twitter @MollyMurraytnj.

How to comment 

The Delaware River is covered under the New York Bight section of the plan.

Electronic submissions: Submit all electronic public comments via the Federal eRulemaking Portal. Go to www.regulations.gov/#!docketDetail;D=NOAA-NMFS-2015-0107. Click the “Comment Now!” icon, complete the required fields and enter or attach your comments.

Mail: Kimberly B. Damon-Randall, assistant regional administrator, Protected Resources Division, NMFS, Greater Atlantic Regional Office, 55 Great Republic Drive, Gloucester, MA 01930

Public hearing: The July 21, 2016, public hearings will be held at the NMFS, Greater Atlantic Region Fisheries Office, 55 Great Republic Drive, Gloucester, Massachusetts.