The largest landed fish, the insatiable northern snake head, will run away from water that is too acidic, salty, or high in carbon dioxide ̵
Snake heads eat native species of fish, frogs and crabs, destroying the food web in some habitats. They can survive on land for up to 20 hours if conditions are humid.
In a new study published on October 21 in the peer-reviewed journal Integrative Biology Wake Forest researcher Noah Bressman reports for the first time the aquatic conditions that could drive snake heads on land.
Earlier this month, Georgia wildlife officials advised fishermen to kill species of fish after one was caught in Lake Gwyneth and the Pennsylvania Fish and Boat Commission confirmed a 28-inch northbound. a snake head was caught on the Monongahela River in Pittsburgh.
Bressman also watches the fish move in a way that no other amphibian fish does: It makes almost simultaneous rowing movements with its breast fins as it bends its axial fin back and forth. These combined movements could help the snake's head travel on uneven surfaces like grass.
"Snake heads are moving faster and incorrectly than ever thought," says Bressman, Ph.D. candidate and corresponding author of Emmersion and the ground movement of the northern snake head on multiple substrates. "The fish we studied were moving super-fast on rough surfaces like grass, and we think they are using their pectoral fins to push these three-dimensional surfaces."
Native to Asia, the northern snake head was first found in the United States in 2002 on a pond in Maryland. Since then, fish have been found in the Potomac, Florida, New York, Philadelphia, Massachusetts, California and North Carolina rivers.
Bressman studies populations of snakeheads in Maryland, where fish are considered a threat to Chesapeake Bay Falls, the Maryland Department of Natural Resources collects snakeheads through electric fishing in tributaries of the Potomac River and adjacent drainage ditches. The fish, which ranged in size from about 1 inch to 27 inches, were subjected to poor water conditions, including high salinity, high acidity, stagnation, clumping, high temperatures, pollution and low light.
Fish withstood all conditions but high salinity and acidity and stagnant water with too much carbon dioxide
Although it is not clear how often snakeheads leave water voluntarily and pass through land to invade other waterways, Bressman said these findings could inform how natural resource agencies plan to contain fish
"When snake heads were found on land, it caused a lot of fear because not much is known about them," he said. "Of course, they can move fairly quickly on land and have sharp teeth. But you can easily outnumber them and they won't harm you, your children or your pets.
" But you better find out how is amphibians they can help us better manage their populations. "
Bressman's current research focuses on the invasive walking catfish in Florida.
N R Bressman et al, Emersion and terrestrial movement of the northern snake head (Channa argus) on multiple substrates, Integrative Organic Biology (2019). Doi: 10.1093 / iob / obz026
Wake Forest University
Bad water conditions cause invasive snake heads on land (2019, October 23)
retrieved 23 October 2019
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