Hudson murder mystery: Who's killing sturgeon?

The trail of death reads like the grim jottings of a homicide detective.

"Floating belly up, looks like side is sliced open," one entry reads.

"Head missing and pectoral area gone," reads another.

"Beacon, among the sailboat moorings," reads a July 1 entry.

Culled from eyewitness accounts kept by the state, the entries chart a surge in reported deaths of the endangered Atlantic sturgeon in the Hudson River over the past three years.

They form Exhibit A in the environmental group Riverkeeper's efforts to make the case that the spike in deaths points to a likely assailant — the propellers of boats ferrying workers to and from the $4 billion Tappan Zee Bridge construction project.

"I understand they have a big job," Riverkeeper boat Capt. John Lipscomb said during a patrol of the waters north of the bridge last month. "It's awesome. If they say we can't slow down the crews because time is money I understand that. But you can't tell me those propellers are a long way from the bottom. Fish are dying."

Some 76 sturgeon were found dead between 2012, when construction started on the river, and 2014, state records show. This year, another 40 have been found, Lipscomb says. Between 2009 and 2011, six were reported dead, state records show.

So far, the jury is still out as state and federal officials remain unconvinced of Riverkeeper's claims.

After Riverkeeper petitioned the National Marine Fisheries Service to probe the sturgeon deaths this summer, federal officials suggested that, while many of the fish had injuries indicating "they were likely struck by vessels and/or propellers," it could be that the bump in reports is due to new-found interest in a pre-historic fish declared endangered in 2012.

"While we agree that the number of reports has increased over the last few years, it also seems that the level of interest and effort to report these sightings has increased," wrote Kimberly B. Damon-Randall, the service's assistant regional administrator for Protected Resources.

"Since no records have been kept on the amount of survey effort that has taken place in the past and since so many of the reports are the result of opportunistic sightings by the public, it is impossible to determine if there has been a true increase, or if we are merely seeing the results of increased interest and effort to document these mortalities," she added. "However, we share your concern regarding the effects of vessel operations in the river on short nose and Atlantic sturgeon."

It wasn't the answer Lipscomb was hoping for.

"It's really a lame response," he said.

Sherlock Holmes on the river

Lipscomb, 62, grew up in Tarrytown and sailed these waters as a boy. As an adult, he schooled his daughter in the mysteries of the "mighty Hudson" while working as a rigger and yard master in a nearby boatyard.

From April through December for the past 15 years, he's patrolled the Hudson from New York Harbor to the federal dam in Troy. In his search for the sturgeon's killers, he has become something of a waterborne Sherlock Holmes, scouring the Hudson for clues.

One morning last month, Lipscomb, a weathered baseball cap perched on his head, angled the bow of his 36-foot patrol boat, the R. Ian Fletcher, toward the Rockland County side of the river where he spied a boat churning through shallow water on its way to the waters beneath the Tappan Zee Bridge.

"He's coming down off Petersen," Lipscomb said in a reference Petersen's Boat Yard in Upper Nyack. "He's going like hell."

The sturgeon, with its bony plates, or scutes, adorning its back, can grow as long as 14 feet and weigh as much as 800 pounds. Over time, its ranks have been thinned by the over-harvesting of female sturgeon whose eggs turn up on the tables of high-end restaurants in the form of caviar.

More recently, the destruction of the sturgeon's habitat, coupled with being accidentally caught in fish nets and vessel strikes, have posed the biggest challenge to its future. Current estimates of the sturgeon population in the Hudson are hard to come by, but a 2007 study, based on 1995 figures, pinned the adult spawning population at 870.

Sturgeon, which can live to the age of 60, spawn in the Hudson before swimming out to sea.

Boats going too fast

Lipscomb believes the work boats' propellers are travelling too fast in the river's shallowest depths, striking the fish as they scour the river's bottom for food, in some cases leaving huge gashes or severed fins.

"These creatures eat stuff that lives in the mud," Lipscomb said. "It's like an all-you-can eat buffet. The deep water is not where the food is. They're bottom grazers."

He would like to see the boats equipped with cages over propellers, or jet propulsion. And he would like to see the boats slow down in shallow water to less than 6 knots per hour.

State officials say they've taken steps to insure the sturgeon remains a viable presence in the river. During pile driving, bridge contractors used "bubble curtains" to limit noise and vibration that might disturb the sturgeon and employed other techniques to warn the fish to scatter.

"The New NY Bridge project is working with the appropriate state and federal oversight agencies to look into the claims recently made by Riverkeeper," said Brian Conybeare, a spokesman for the project. "Since construction began, the project team has taken unprecedented measures to protect endangered sturgeon and other aquatic life in the Hudson River, including the use of bubble curtains during pile driving to reduce underwater noise, extensive sturgeon monitoring, tracking and habitat studies."

In report after report, project officials have concluded that, while a vessel strike may have been the cause of a sturgeon death, there's no way of determining if a Tappan Zee boat crew is to blame.

"While vessel activity is the likely cause of mortality for this fish," they write in the June necropsy of a dead Atlantic sturgeon found by bridge contractors with cuts to its tail on Pier 21 on the west side of the river. "It is not possible to determine if the vessel that struck this sturgeon was a project vessel or one of the many non-project vessels that traverse this part of Hudson River."

State officials note that, while more than 16,000 boats travel in and around the Tappan Zee bridge, there are just 36 boats with propellers assigned to the bridge project.

Officials with the state Department of Environmental Conservation say they have not found a link between bridge construction and sturgeon deaths.

"DEC evaluates each reported sturgeon death in the Hudson River and, despite an increase in reported deaths, has not concluded that the deaths of any of these sturgeon could be reasonably attributed to bridge construction activities," said spokesman Kevin Frazier.

He said the recent reports are "likely due" to the sturgeon's inclusion on the species list in 2012.

"Atlantic sturgeon in the Hudson River are slowly beginning to increase their population size and a larger population will likely result in more mortality," he added. "Increased boat traffic could also result in a greater frequency of direct collisions with sturgeon. DEC remains committed to ensuring that all reasonable steps are taken to minimize impacts to sturgeon."

Dead fish don't talk

Complicating Lipscomb's task is that many of the dead fish have been discovered far from the work zone, some as far as the 79th Street Boat Basin in Manhattan. In a tidal estuary like the Hudson, fish can float for miles.

"If a deer is clipped by a car, it doesn't stand there," Lipscomb says. "It runs off in the woods and dies two days later. We have never seen this mortality before."