Asian Carp Spread Through Spillways

It is the opening of the Morganza and Bonnet Carre spillways that LSU experts fear may have distributed the Asian carp, which was first introduced privately into the US in the 1970's, but has since escaped and reproduced in the wild.

A highly invasive species, concern is mainly over their affects in Lake Pontchartrain- on its aquatic vegetation and fish species which the carp are likely to dominate if they are to enter via the Bonnet Carre spillway.

Allen Rutherford, director of the LSU AgCenter School of Renewable Resources and a fisheries expert said, “Lake Pontchartrain has a mixture of different salinities. The southern part of the lake is typically more saline while the north shore has fresher water.”

“The Asian carp, comprising both the “silver” and “bighead” species, is a freshwater fish and does not survive well in higher salinity waters.”

“Everything below the Rigolets Pass is saltwater, and that restricts Asian carp from spreading into more saline water south of that point,” Mr Rutherford said.

“The north shore of the lake has more freshwater because Lake Maurepas and the Tangipahoa and Tchefuncte rivers flow into it. For that reason, higher numbers of Asian carp could invade the north shore portion of Lake Pontchartrain and freshwater rivers and lakes feeding into it.”

“In the past fish kills have occurred in Lake Pontchartrain after opening the Bonnet Carre Spillway. That’s because increased amounts of incoming nutrients create algal blooms that rob oxygen from the water. So that likely will kill Asian carp as well.”

However, Mr Rutherford went on to state that Asian carp are filter feeders that feed on algae and aquatic invertebrates, meaning they may not be killed off but instead left as the dominant species.

Mr Rutherford concluded by saying the only true way of dealing with the Asian carp is by encouraging consumers to eat more of them.