Call them fish GPS.
Builders of the new Tappan Zee bridge will start installing underwater acoustic monitors this week to keep the Hudson River's endangered sturgeon population in check as preliminary work on the massive project gets under way.
The bridge contractors, Tappan Zee Constructors, are required to monitor the movement and migration of Atlantic and short-nosed sturgeon under the terms of a permit from the New York State Department of Environmental Conservation. Data collected from the fish monitors will be reported to the state DEC and the National Marine Fisheries Service, according to state officials.
The sturgeon monitoring system is one of numerous requirements of the March issued DEC permit, including oyster bed restoration, water quality monitoring, wetlands restoration and other environmental remediation to offset the project's impact.
The cylinder-shaped monitors, which will be anchored to the river bottom every five kilometers from the George Washington Bridge to Stony Point, will pick up transmissions from about 120 sturgeon tagged with sonic transmitters, officials said.
It was unclear Sunday how much the aquatic monitors cost or how long installation would take. A call to Tappan Zee Constructors was not immediately returned.
"The Thruway Authority and Tappan Zee Constructors are committed to minimizing the environmental effects of construction," said Brian Conybeare, special adviser to Gov. Andrew M. Cuomo on the new Tappan Zee Bridge project.
He said those actions include "monitoring endangered sturgeon movement, the use of sound attenuation systems to safeguard fish from acoustic effects of pile driving, seasonal limits on dredging to avoid peak fish migration and spawning and requiring an independent Environmental Compliance Monitor to observe the work."
Local environmental groups Riverkeeper and Scenic Hudson made a deal with Cuomo in March to drop objections to the $3.9 billion project if the state agreed to spend $11.5 million to restore wildlife habitat and monitor species along the river.
Underwater barriers also will be installed to protect fish from noise and silt. No more than four of the endangered fish, two from each species, are allowed to perish during the project, according to state environmental approvals. No more than 86 total can be injured as a result of bridge construction. There are no specific penalties for exceeding the number of injured of killed fish in the DEC permit, according to the state.
Up until the early mid-1900s, Atlantic sturgeon were a plentiful and important Hudson Valley food source earning the nickname "Albany beef" and prized for its caviar. But overfishing and riverfront factory pollution decimated the species. In 1998, Atlantic sturgeon fishing was banned along the entire East Coast.
The female adult population of the prehistoric fish in the Hudson has sunk from highs of about 6,800 in the late 1800s to barely 270 females and 600 males today, according to National Oceanic and Atmospheric Administration.
A federal study released last year concluded that the new Tappan Zee bridge construction is likely to "adversely affect" but will not "jeopardize" the continued survival of the Hudson River's two endangered species -- the Atlantic sturgeon, which was declared endangered in February 2012, and the short-nosed sturgeon, which has been endangered since 1967.
The region is home to the country's largest population of short-nosed sturgeon.