Sturgeon study on tidal James offers evidence of fall spawn
Female caught below Richmond on Sept. 6 was ready to release eggs.
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Matthew Balazik has been getting e-mails from fish the last couple of months. Lots of them.
Every couple of days, one or more Atlantic sturgeon sends a message to his in box.
“I’m here now,” the message basically says. Receivers in the James River relay the coordinates and time of contact.
The fish are identified by the number associated with a tag attached to their bodies. Fish tracking with telemetry is one tool that Balazik and other researchers use to better understand Atlantic sturgeon in the Chesapeake Bay.
“A tagged female has just come by,” Balazik explained. “She’s on her way up here (Richmond). And I need to get out there.”
“Out there” is on the James River, where Balazik has spent most of his waking hours from August through October trying to intercept sturgeon as they congregate to spawn.
Atlantic sturgeon, Acipenser oxyrinchu, are anadromous fish. They begin life in freshwater and spend a year or so in the brackish water of estuaries before swimming to Atlantic coastal waters. They return to their natal rivers to spawn.
Scientists know little about the larval and juvenile life stages of the sturgeon, which has changed little from the time of the dinosaurs.
Balazik has been working at Virginia Commonwealth University’s Rice Center since 2007 to document James River sturgeon spawning in the autumn. Previously, it was thought that sturgeon spawned only in spring. (See “Spawning female Atlantic sturgeon found in James River,” June 2011.)
Now a post-doctoral fellow at the Rice Center, Balazik continues to amass evidence of the fall spawning run. This year, Balazik and his team have caught – and released – more than 160 sturgeons since early August when he started setting gill nets to catch them.
He usually fishes in a section of the Lower James 15–20 miles below Richmond, where water from the Bay meets freshwater from the upland watershed. Sturgeon are known to spawn in water that is just barely fresh.
The serpentine windings of this stretch of the river created “necks,” where the river almost doubles back on itself. During and after the Civil War, shipping channels were cut down to hard substrate to shorten the distance to the Port of Richmond upstream. These channels provide hard bottom and good current, both optimum conditions for sturgeon spawn.
Balazik works from VCU’s 27-foot, flat-bottomed research skiff specially fitted out for setting and hauling back a series of gill nets that average 280 feet long. He sets four or five at a time and lets them “soak” for about an hour. More soak time might catch more fish, but it would also increase the stress on any sturgeon caught in the net.
The sturgeon that are caught are hauled aboard, disentangled from the net, and placed upside down in a “live well” of fresh, circulating water.
Using an electronic reader, Balazik checks to see whether the fish has previously been tagged. Most Atlantic sturgeon researchers on the East Coast use the same tags and share fish identification numbers.
The fish are tagged, if needed, and measured. Balazik also takes tissue samples for DNA and other analyses.
Sometimes it’s a “water haul,” but on other days, one net might yield six or seven fish. On Sept. 19, Balazik caught 23 fish in 50 minutes.
Coworkers congratulated him, but Balazik didn’t much feel like celebrating. “Well, if you care about fish, you wouldn’t call it that,” he said. “For me, it was pure hell. With that many coming in at one time on a small boat, it’s hard to take care of them, and it’s hard to get the data you need.”
Luckily, Balazik was working with the U.S. Fish and Wildlife Service on nearby Presquile Island, where he maintains a large tank for holding sturgeon, and there were plenty of extra hands to help out.
It’s hard to say whether the fish or Balazik were more stressed. “But they weren’t in life-threatening danger. I am very careful with these fish. The last thing I want to do is to kill a fish or endanger them in any way.”
Tributaries of the Chesapeake, including the James, were once abundant with sturgeon, but overfishing and loss of habitat resulted in populations plummeting in the early 1900s. Virginia has maintained a ban on the catch and sale of sturgeon since 1974.
In 2012, the National Marine Fisheries Service listed four separate populations of Atlantic sturgeon, including the Chesapeake Bay population, as “endangered” (and a fifth as “threatened”) under the Endangered Species Act.
Since then, Balazik and his partners at the Virginia Institute of Marine Science and the U.S. Fish and Wildlife Service have been operating under a special permit from the NMFS that allows a specific number of fish to be brought on board, tagged, measured and sampled each year.
Balazik and his crew anchor 10– to 14-inch stretch mesh nets to the bottom with lead weights. Plastic floats hold the nets 12–14 feet upright from the bottom. The nets are set at depths ranging 20–50 feet along the edge of the channel to snare the sturgeon.
The size of mesh determines the likelihood of catching larger fish. “The 14-inch mesh will catch a few of the bigger ones, but the really large females are likely to bust right through,” Balazik said.
So he can catch a good number of male fish, which are generally smaller than females and become sexually mature at a younger age — or he can use a larger mesh that is more likely to catch females, but may let many of the mature males swim right through.
By Oct. 21, Balazik had caught 162 sturgeon, all males.
Except for one, very important fish.
On Sept. 6, Balazik’s nets caught a large female that was unmistakably gravid (full of eggs) and ready to spawn.
Balazik and several managers from the USF&WS examined the fish at the holding tank at Presquile Island before returning her to the James.
“That was a really big day,” Balazik said. “She was the first confirmed, pre-spawn female found in the tidal James since research commenced here in the late 1990s.”
She was named “Annie Ruth” by a supporter to whom Balazik had given naming rights. “This gentleman had been supporting our work for years, long before the results started to come in,” Balazik said. “It seemed only right.”
Albert Spells, the U.S. Fish and Wildlife Service’s Virginia Fisheries coordinator, was on Presquile that day. Later, he said, “What Matt’s work has demonstrated is that the area near the confluence of the Appomattox and the James is important habitat for spawning fish. Year after year at the same time it appears that they go up the river to spawn.”
Like other fish, it’s all about having the right habitat at the right time.
Sturgeon eggs, once fertilized, have an adhesive coating that helps them attach to hard surfaces on the river bottom. In the larval stage, sturgeons find refuge in cracks between smaller rocks.
To give the fish more spawning habitat, the James River Association in July installed a spawning reef on this section of the river. In partnership with the USF&WS, The Nature Conservancy, VCU, the National Oceanic and Atmospheric Administration, and the Luck Stone Corp., the association installed 200 feet of stone and cobble adjacent to the ship channel just below the Varina Bridge on Interstate 95.
A yellow cylindrical buoy equipped with navigation lights and a radio receiver and transmitter marks the reef. Two other reefs were also installed, one in 2010 and the other in 2011. Together, they offer additional opportunities for spawning sturgeon not directly in the channel.
“Sturgeon come to these sections of the river because of the rocky bottom,” Balazik said. “There’s also enough tidal and river flow to scour much of the sediment clean, and that’s important.”
But it’s not without risk.
“Those deepwater boat propellers just chew up sturgeon and spit them out,” Balazik said. In 2011, he identified 11 separate incidents of “ship strike” interactions between vessels and fish, many of which were fatal to the fish.
Even so, Balazik continues to inspect the “egg mats” he has placed on these spawning reefs with the hope of recovering fertilized eggs. In sturgeon research, this is like finding the Holy Grail — living proof that sturgeon have spawned here.
The river association has been working on sturgeon restoration in other ways. “We’ve been working to help coordinate the multiple partners who work on sturgeon restoration,” said Bill Street, its executive director.
The association also offers “sturgeon tours” to get people out on the water to see the fish breaching, a common sight during spawning months.
“We really use the sturgeon as a representation of the river and how it is doing,” Street said. While sturgeon reefs provide additional habitat, “we are also addressing the pollution that comes into the river, specifically sediment pollution.”
But Street also provided a sobering perspective, comparing Balazik’s 23-fish day to the time when sturgeon were abundant in the river. Capt. John Smith, he said, recorded in his journals that it was common for the English settlers to catch 50–70 fish in one haul in the early 1600s.
Reflecting on Balazik’s research, Street said, “I think the most astounding thing is just the number of sturgeon that have been tagged and released into the James. Few of them are previously tagged sturgeon.”
Spells said that analyzing Balazik’s fishing data using a common fisheries metric would likely show that over the last few years, the number of fish found in the upper James is increasing or, at worst, is stable. “Matt’s work has the potential to shed a lot of light on sturgeon activity in the James.”
There has been a bit of a feeding frenzy in the local press this fall to follow Balazik and the fish. A Facebook site (facebook.com/JamesRiverSturgeon) also gets a lot of action and makes his research accessible to school programs and the general public.
“People get so excited and fascinated with sturgeon,” Street said. “It’s a great way to connect people with the river and help them care about it.”
When the fall spawning run is over, Balazik will continue to get e-mails from his fish on their way back down the river. He might even get some from Annie Ruth on her way to the Atlantic where she will stay until it is time to return to the James to spawn again.
See the Bay Journal blog, “Sturgeon Sex on the James” (www.bayjournal.com/blog/post/sturgeon_excursion) for more details about Atlantic sturgeons’ spawning behavior.
- Category: Fisheries
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