flathead catfish is at the top of many “least wanted” invasive
species lists because of its ferocious feeding habits, large size, and
ability to swim long distances in a short time. Under ideal conditions,
flatheads can grow to more than 55 kg (124 pounds is the record).
This flathead catfish is an example of a species native to the Mississippi
and Ohio River watersheds, has caused problems when people released them
into new locations.
Flathead catfish are found in large rivers, streams and lakes; they prefer
deep, sluggish pools, with logs and submerged debris cover. Males set
up housekeeping in nest cavities dug into the bank where females then
lay their eggs. Young flatheads live in rocky or sandy runs in the river
and in the riffles.
As the name suggests, flatheads are most easily recognized by their flat
broad flat head and lower jaw which projects beyond the upper jaw. The
flathead catfish also has a distinctive tail fin outline that is square
or slightly notched. While the coloration can vary, most adults have an
olive cast to their back and sides with dark-brown to yellow-brown mottling.
Their belly is yellowish-white, and their eyes are relatively small.
The earliest record of flatheads in the Delaware River Watershed was a
1991 sighting at Blue Marsh Reservoir. Since then, populations have been
found in Springton Reservoir, below Blackrock Dam as well as in the main
stem of the Delaware River near Robling, New Jersey; reproducing populations
of flathead catfish have been documented in the Schuylkill River basin,
and several hundred flathead catfish have been captured in the Fairmont
Dam fishway on the Schuylkill River.
2010 Distribution Map of Flathead Catfish
The flathead catfish is a highly desired game fish; however its release
into new watersheds has created problems for other fish species. There
are several impacts such as:
Flatheads compete with native fish populations for food and habitat.
Flatheads introduced in Georgia and North Carolina rivers have eliminated
native catfish populations and were found to prey heavily on crayfish,
crabs, and shad.
health risks. Flathead meat tends to accumulate toxins such as PCBs.
For this reason, The Commonwealth of Pennsylvania advises eating no
more than one meal a month of flatheads caught in the lower Schuylkill.
impacts. Flathead catfish may have an economic impact on the blue
crab industry as well as shad, sturgeon, and striped bass.
PREVENTION AND CONTROL
Anglers are urged not to release flathead catfish caught in the Delaware
or Susquehanna river watersheds.
To read more, view the Pennsylvania Sea Grant Flathead catfish fact sheet.
MORE INFOMRAITON ON FLATHEAD CATFISH