News and Events
Since its origin, more than 40,000 years ago, fishing has taken a variety of forms — from spearing to hook-and-line fishing. In the 1960s, scientists began using a method called “electrofishing” to study aquatic populations.
For the first time, people can distinguish one bat species from another by smell alone. Scientists from the USDA Forest Service and Arkansas State University found that a new, portable electronic nose (e-nose) device is capable of distinguishing between bat species by their smells.
Native freshwater mussels grew more slowly when invasive Asian clams (Corbicula fluminea) were abundant. The study was led by Wendell Haag, a USDA Forest Service research fisheries biologist. It was published in the journal Freshwater Biology. Mussels live out of sight – buried in the river bottom, eating algae and other small particles of organic material. Mussels are filter feeders and key members of aquatic ecosystems.
The highly anticipated second volume of Freshwater Fishes of North America was just published by Johns Hopkins University Press. This volume was edited by USDA Forest Service fisheries research scientist Mel Warren and four other editors. Warren also contributed to seven of the book’s 35 chapters.
Increasingly, recovery plans for imperiled fish species include raising them in captivity and releasing them in the wild. Crystal Ruble of Conservation Fisheries, Inc, with SRS researchers Ken Sterling and Melvin Warren published a protocol for captive propagation of the Yazoo Darter (Etheostoma raneyi). The researchers also summarize its early life-history.
USDA Forest Service scientists are measuring surface water quality in the Big Sunflower River watershed of the Mississippi Delta to better understand eutrophication of the Gulf of Mexico. Extensive crop production contributes nutrients and suspended solids and leads to concerns about low dissolved oxygen and pathogens. Ying Ouyang, Ted Leininger, and colleagues monitored water quality for several years at three study sites in the watershed.
Electronic noses are sensitive to a vast suite of volatile organic compounds that every living organism emits. A new USDA Forest Service study shows that e-noses can detect emerald ash borer (Agrilus planipennis) larvae lurking under the bark – an early, noninvasive detection method.
In Alabama, crayfishes are being separated and genetically changed, which increases the risk of local extinction. This work is not done by a mad scientist, but by dams with their reservoirs and unnatural pools of water. A novel study published in the journal Freshwater Biology by USDA Forest Service scientists Zanethia Barnett and Susan Adams, along with colleagues from the University of Mississippi, covers this phenomenon.
The Lower Mississippi River Alluvial Valley is a floodplain that spans seven states. It is suffering from groundwater depletion – a long-term water level decline due to human use. Irrigation and overuse of water resources have led to a seven meter drop in groundwater levels from 1987 to 2014. Water from precipitation and other sources naturally makes its way into groundwater – in a process known as groundwater recharge. Groundwater recharge is known to vary between agricultural and forest land.
In 2011, a group of researchers traveled to southern Alabama and Mississippi in search of the Rusty Gravedigger crayfish (Lacunicambarus miltus). They wanted to refine the species’ range and hoped to find a new population west of Mobile Bay. Instead, they found a potentially undescribed species of crayfish. Years later, a team led by Mael Glon, a Ph.D. candidate at Ohio State University, and USDA Forest Service scientist Susie Adams returned to Mobile Bay in January 2020.
Zanethia Barnett’s alma mater, North Carolina Agricultural and Technical State University, College of Agriculture and Environmental Sciences, has featured her on their website!
Just by existing and eating, mussels improve water quality. They are filter feeders, which means they eat small pieces of organic matter that float past them. But mussels are dying, often in streams that otherwise seem healthy. Many streams that formerly supported diverse mussel communities now are essentially defaunated. These events are enigmatic because other animals in the streams seem unaffected.
Kneeling in a wet prairie, arm extended to the armpit in a muddy hole, most biologists would quickly arrive at the thought, “There’s got to be a better way.” So it’s not surprising that, when it comes to sampling for burrowing crayfishes, researchers have devised some creative solutions.