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Sturgeon exodus a mystery
Delaware River and Bay once supported the largest fishery in the U.S.

Sussex Bureau reporter
06/30/2004-Delaware Online

Each time Jed Brown goes fishing, he looks for breaks in the water, listens for the splash and then waits.

There is nothing more to do once he sets the net, a fabric of line and knots with openings perfectly spaced to snag the gills of really big fish.

For a scientist such as Brown, it is the best way to reach through the murk of the Delaware River to the shadowy world of the Atlantic sturgeon.

The Atlantic sturgeon is a bottom dweller that was once plentiful enough to support a thriving Delaware River caviar industry.

But many things about it remain a mystery.

The biggest part of that mystery is whether the fish can survive and once again thrive here.

Brown, the Delaware River fisheries coordinator with the U.S. Fish & Wildlife Service, was on the river in May and June with state biologists trying to determine whether there are enough sturgeon to reproduce.

Atlantic sturgeon differ genetically based upon the river where they spawn. Scientists want to know what the future holds for the fish that spawn in the Delaware.

They are concerned that scarcity of the sturgeon is one more sign that the Delaware River still suffers from the legacy of overfishing and industrial and municipal pollution.

Another part of the mystery is what role these big fish play in the food chain or what would happen to the ecology of the river if they no longer spawn here.

Even with improvements in the Delaware's quality and a 1998 ban imposed on fishing sturgeon, it could be a long time before it is clear how the fish are doing.

"At least 40 years," said David H. Secor, a fisheries ecologist and associate professor at the Center for Environmental Sciences at the University of Maryland. "A generation and a half."

No protection

The trouble with Atlantic sturgeon, Brown said, is that they don't have a constituency.

It is not a fish Saturday afternoon anglers go after. It is illegal for commercial fishermen to land them. Dead or alive, they must be thrown back.

The Atlantic sturgeon, though rare, is not protected as an endangered species.

Without a recreational fishing base, there is no money for research from the taxes recreational anglers pay on fishing tackle.

Without endangered species protection, federal research dollars also are limited.

"They kind of fall between the cracks," Brown said.

Scientists say that sturgeon in the wild are beleaguered everywhere. Much of the caviar today comes from farm-grown sturgeon.

Yet scientists believe the Atlantic sturgeon is making a comeback in the Hudson River in New York. How they are doing in Chesapeake and Delaware waters remains a mystery.

One reason Secor believes a recovery will take decades is because female sturgeon are late to reach sexual maturity. When they reach that point depends on the temperature of the water. The colder the water, the longer it takes to reach maturity. For example, in the Delaware, the estimate is 14 years of age. In the Hudson, it is 20.

A single female can produce well over a million eggs in a spawn, but she doesn't spawn every year, Secor said.

In the Delaware River, they spawn north of the Chesapeake & Delaware Canal in places where the eggs laid by the females can adhere to hard and rocky bottoms. They spawn - most scientists believe - between Wilmington and Philadelphia.

The spawning area mirrored a dead zone where pollution from sewage treatment plants caused oxygen levels to drop.

Secor said that of fish species, sturgeon "are the most sensitive" to low oxygen levels.

Low oxygen levels are no longer a significant problem in the river. Normally, Secor said, that should be a good sign for sturgeon. But before there is a comeback, the fish will need several good spawning years.

Gone for a century

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

Brown said it probably went bust because female sturgeon don't spawn every year. Once the breeding fish were depleted, other factors such as river pollution may have kept the population low.

Craig Shirey, the state fisheries biologist, said the younger fish probably spend several years in the Delaware growing and then join the ocean stock. Delaware fisheries biologists have been monitoring and tagging young sturgeon in the river.

Shirey said they started looking at juvenile sturgeon populations in the river in the early 1990s after a Port Penn fisherman reported catching some young sturgeon in his nets.

In 1994, Shirey and his team caught 500 Atlantic sturgeon

during a monitoring project. The fish were immature but surprising plentiful. Shirey looked at it as a good sign.

But by 1998, they caught no more than 20 fish.

"For some reason, the number of young fish was sharply declining, and that was after the management plan was in place," Shirey said.

Recently, off Augustine Beach, Shirey and biologists Greg Murphy and Cathy Martin set a series of nets. Martin and Murphy fed out 1,200 feet of net.

Then, they waited for slack tide, when the water in the river slows and the net was easier to pull.

When they finished pulling in the net, they had caught five sturgeon. The team then moved quickly to science mode - taking each fish, one by one, and working through the tagging and samples.

Shirey handed a fish to Murphy, who laid it in a measuring tray. Then, using a scalpel, they sliced a small incision between two of the bony scutes. Then, with a quick jab, they insert the state tag.

A second tag, a computer chip, was attached by the tail. Then a tiny sliver of fin was sliced off and preserved in a solution for genetic sampling. This could be the key to determining where the fish are from.

Then, the fish were weighed and returned to the river.

They were all juveniles. If it turns out these fish were born here - genetically linked to the Delaware - that would be a good sign.

The first set of answers will take months to come. The bigger question of survival will take years of study to answer.


1,596 Posts
Night Strikes

nice post. my cousin does work for the state of maryland. one project he worked on for awhile was the replacement of delaware bay/river sturgeon into the chesapeake region. they took several mature and very big sturgeon as brood stock. they got a lot of samples from what he was telling me. we see up river many short nose sturgeon making a comeback. as a teen in the late 80's, we would inadvertently snag them while shad fishing. Now is see roughly 100 a year while striper fishing in and around trenton. the short nose are roughly 3 feet long but i have seen many in the 5-8 foot range. Quite a site to see in a jon boat.

i hope they come back. it would be a great fishery for my kids. i once asked larry dahlberg how to land one. he said for atlantics, get tuna gear and pull straight up. sturgeon actually swim on angles making it tought fight. he said to get vertical to the fish and pull straight up. once his head is turned the fight is in our hands. he then went on about boat size. make sure its big enough he said.

I will never forget the look on his face when i said atlantic sturgeon. he said 'Boy are you from the delaware bay region?' Shocked, i never asked why he thought that. i wonder if he was ever here fishing for them.

chris gatley
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