Study shows invasive blue catfish can tolerate high salinities

NOVEMBER 6, 2019

by David Malmquist, Virginia Institute of Marine Science

A new study by researchers at the Virginia Institute of Marine Science warns that blue catfish—an invasive species in several Chesapeake Bay tributaries—tolerate salinities higher than most freshwater fishes, and thus may be able to expand their range downstream into mainstem Chesapeake waters, and from there into new Bay tributaries and even Delaware Bay.

Conducting the study, reported in the November 5th issue of PLOS ONE, were Ph.D. student Vaskar Nepal of William & Mary's School of Marine Science at VIMS and VIMS fisheries professor Mary Fabrizio.

Nepal and Fabrizio undertook the study to better constrain the salinity tolerance of blue catfish in their non-native Chesapeake Bay habitat. The value used in the 2014 report that currently guides management of invasive Bay catfishes was based on a study of blue catfish from their native range: the fresh waters of the Mississippi River basin. Evidence suggests that populations of "blue cats" and other fishes may become more salt tolerant when exposed to brackish estuarine waters.

"We wanted to see how long blue catfish can survive at a given salinity to help us better understand the extent to which they can colonize areas other than those where they were originally stocked," says Nepal.

Continued