Efforts towards the recovery of Chesapeake Bay Atlantic sturgeon recently got a boost when NOAA Fisheries awarded a three-year, $1.75 million species recovery grant to the Maryland Department of Natural Resources and the Virginia Department of Game and Inland Fisheries.
In 1997, biologists were surprised to find juvenile Atlantic sturgeon in the Chesapeake Bay. Although still rare, the population of sturgeon that spawn in the Chesapeake Bay has grown. Despite progress, the Chesapeake Bay sturgeon population was added to the endangered species list in 2012.
Atlantic sturgeon spend most of their time at sea, travelling up and down the shelf break where they plow the bottom with their snouts, eating worms and crustaceans. Like salmon, they return to their natal streams to spawn.
Unlike most salmon, however, which spawn once and die, sturgeon make the spawning run repeatedly. They can live up to 60 years and can grow up to 14 feet (4.3 meters) and 800 pounds (370 kg).
A major part of the new research will involve tagging and tracking sturgeon in the watershed. The acoustic tag, about the size of a Sharpie marker, is inserted into the belly of the fish through a small incision.
The tag emits a coded sound roughly once a minute, a signal that’s recorded whenever the fish passes within range of a receiver. Each tag has a unique acoustic signature, allowing scientists to track individual fish.
Scientists have tagged sturgeon all along the Eastern seaboard, but the Chesapeake is uniquely difficult because it’s a meta-estuary—an estuary comprised of many smaller estuaries—and it’s the largest one in the nation.
“In the Hudson it’s a piece of cake,” said Dave Secor. “A few receivers bank to bank and you’ve got the river covered at that point.” The mouth of the Chesapeake, on the other hand, is 20 miles wide.
But the tagging project got a big boost from the Navy, which recently installed an array of 58 receivers, most attached to Coast Guard buoys, throughout the mouth of the Chesapeake Bay.
The Naval Base at Norfolk, Virginia is the largest in the nation, and it’s one of several naval installations in the lower Chesapeake Bay. As a federal agency, the Navy is required to minimize interactions with endangered species.
“We want to know where and when sturgeon are utilizing the Bay,” said Carter Watterson, a Navy biologist. “Once we know that, we can work to minimize any impact we have on the species.”
The Navy will benefit from the tags that Maryland and Virginia researchers deploy because they increase the value of the receiver array. And the state researchers will benefit every time Watterson sends them tracking data on their fish.
The buoys the receivers are attached to also record environmental data, allowing scientists to correlate sturgeon activity with ocean conditions. This will be key to understanding how those conditions affect the fish, and in particular how sensitive the fish are to the low oxygen levels that plague the Bay every summer.
For more information, visit http://www.fisheries.noaa.gov/stories/2013/11/11_20_2013sturgeon_we_forgot_all_about_you.html
source: NOAA Fisheries