The giant blue catfish, a Mississippi River native introduced to the Bay in the 1970s, thrills anglers but worries fishery managers.
by Karl Blankenship
When a 102-pound blue catfish was caught on the James River south of Richmond in May 2009, it took two men to land the behemoth. It was the largest blue catfish ever landed in a Bay tributary. But it's a record that may not stand for long. Blue catfish populations are booming around the Chesapeake. Overall numbers and average sizes of the predators continue to increase in the James and other Bay tributaries.
The lower James in particular has become nationally recognized for its production of trophy-size blue catfish. "People are coming from all around the country to fish for blue catfish in the James River," says Bob Greenlee, a biologist with the Virginia Department of Game and Inland Fisheries.
Not a single blue catfish was present in the Bay watershed just four decades ago. Today, by contrast, scientists estimate that in some Bay locations the species accounts for 75 percent of fish biomass. In the Rappahannock River, using "electro-fishing" (zapping the water and then collecting the stunned fish that float to the surface), Greenlee and his crew have scooped out more than 6,000 catfish per hour. "It is just unbelievable," Greenlee says. "You have to scratch your head and wonder [what] the ramifications are for other resources." Some scientists and fishery managers worry that the large blue catfish population may add to the woes facing threatened native fish such as American shad and river herring.
It was the state fisheries department itself that introduced the blue catfish to the James River, stocking some 300,000 of them in 1974. Native to the Mississippi River basin, it is the largest catfish species in the United States. It can live 20 years, weigh more than 100 pounds and grow longer than 5 feet. Stocking non-native fish is nothing out of the ordinary for the Bay watershed, which now has many species that wouldn't have been found here a century or two ago--largemouth bass, smallmouth bass, channel catfish, flathead catfish, common carp, bluegill and brown trout, to name just a few of the freshwater newcomers. Without introductions, "freshwater sportfishing wouldn't be much of a sport or viable industry," says Don Cosden, director of inland fisheries for the Maryland Department of Natural Resources.
But the rapidly expanding blue catfish population bears special attention, the scientists say, because it's not just a new species for the Chesapeake; it's an "apex" predator, like a polar bear or tiger, that sits at the top of the food web. And, unlike the rockfish, which hunts the tidal fresh rivers only in the spring; the blue catfish is there year-round, putting far more pressure on smaller resident fish and migratory species such as American shad, river herring, hickory shad and other species. Scientists also worry that blue catfish outcompete native white catfish, as well as the non-native channel cat, which was introduced more than a century ago. And in Virginia's Mattaponi River, Greenlee says, it appears likely that large numbers of blue catfish have also significantly reduced the freshwater mussel populations.
But the main concerns are focused on American shad and river herring. Tens of millions of dollars have been spent to bolster populations of American shad, which once supported the Bay's largest commercial fishery. Now, some worry, much of the spring spawning run may simply end up in the bellies of blue catfish. Proving that is difficult. Blue catfish have rapid digestive systems, so only fish consumed within the past several hours will be found in their gut. The Atlantic States Marine Fisheries Commission and a sustainable fisheries team from the Chesapeake Bay Program hope to make management recommendations this summer.
It has already been suggested by some conservationists that recreational fishermen should be killing all the blue catfish they catch, but Greenlee says that is not likely to make a dent in the population--and it runs counter to the ethics of most trophy fishermen. And the commercial catch, he says, already meets market demand at about 2 million pounds--a catch level that has failed to curb population growth.
And he expects that any action that threatens to reduce the number of trophy catches will meet resistance among recreational anglers. American and hickory shad have been prized for years, but only weigh a few pounds. Anglers seeking large trophy fish, like blue catfish, represent an increasingly popular part of the recreational fishery. As they say on the Catfish Nation website, which organizes catfish trophy tournaments: "Why fish for bait when you can catch a beast?"
Karl Blankenship is editor of the Bay Journal and the Bay Journal News Service, from which this article is adapted.