Aug 16

Species Profile: Blue Catfish

Today’s post was contributed by Dr. Christopher Patrick, an ecologist at the Smithsonian Environmental Research Center.

These fish fight hard, and the small ones (5-20 lbs) taste great!  For this reason they were introduced into lakes, reservoirs, and river around the United States during the 20th century and have become a controversial invasive presence. 

The blue catfish Ictalurus furcatus is one of North America’s largest catfish.  Native to the Mississippi River drainage, these long-lived, fast growing top predators will consume anything in their path and can reach astonishing sizes in excess of 140 lbs.

Blue catfish at the Tennessee Aquarium. Photo courtesy of Wikimedia Commons.

In 1974, blue catfish were introduced into the James River in Virginia, a tributary of the Chesapeake Bay.  Authorities believed that the catfish would remain contained by high salinity levels down river, and would not be able to spread throughout the many rivers and tributaries that make up the largest estuary in the United States.  Today, the blue catfish can be found in increasing numbers in the Potomac River, another tributary of the Chesapeake, and there is fear that it is only a matter of time before these fish spread to the remaining uninvaded rivers in the Chesapeake Bay ecosystem.  While Blue Catfish cannot tolerate salinity levels in the lower reaches of the main channel, fish may get the opportunity to swim into the channel during major inundation events that reduce salinity levels, such as massive flows recorded on the Susquehanna River following Hurricane Irene in 2011.

Blue catfish have become very popular with local recreational and commercial anglers, while this is a good thing in an invasivore kind of way, Maryland DNR also the fear that misguided anglers could be moving fish to help speed their invasion.  Control efforts in Maryland have been largely unsuccessful so far, but new regulations may begin to have an effect on catfish numbers.

The next time you are in the Chesapeake Bay region, do your part by ordering some local blue catfish, and help eat these voracious invaders out of the Bay!


2 pings

  1. Casey

    That’s now blue cat, that’s a channel cat.

    1. Matthew

      That’s possible, since this is not a picture we took ourselves and the two species are often confused. We’d be interested to hear what makes you think it’s a channel cat though. It doesn’t have the spotted pattern typical of channel cats (although this pattern is known to fade as fish age), and the most distinctive way we are aware of to tell the fish apart is the anal fin (straight margin with >30 rays in blue catfish vs curved margin with <30 rays in channel catfish), which is pretty tough to distinguish in this picture…

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