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When a 102-pound, 4-ounce 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, the Potomac and likely in several Maryland tributaries.
The lower James in particular has become nationally recognized for its production of trophy-size blue catfish, which support a multimillion dollar recreational fishery. "People are coming from all around the country to fish for blue catfish in the James River," said Bob Greenlee, a fisheries 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, scientists say they account for 75 percent of all fish biomass in some places. While electro-fishing in the Rappahannock River, Greenlee and his four-man survey crew have scooped as many as 6,600 fish per hour out of the river using their 16-inch dip nets.
"It is just unbelievable," Greenlee said. "You have to scratch your head and wonder exactly what is going on out there and 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 native fish such as American shad and river herring, whose populations are near all-time lows.
Blue catfish are the largest catfish species in the United States. They can live 20 years, weigh more than 100 pounds and grow to more than 5 feet. They are native to the Mississippi River basin. Virginia Department of Game and Inland Fisheries managers introduced them to the James River in 1974 when they stocked around 300,000 small catfish.
That was not unusual. Like kids turning goldfish loose in a local pond, fisheries managers have been moving fish to new areas for more than a century. "The history of freshwater fisheries management is like Johnny Appleseed with fish," Greenlee said.
Largemouth bass, smallmouth bass, channel catfish, flathead catfish, common carp, bluegill and brown trout are only some of the common nonnative species that dominate freshwater fisheries in the Bay watershed. Without introductions, "freshwater sportfishing wouldn't be much of a sport or viable industry," said Don Cosden, director of inland fisheries for the Maryland Department of Natural Resources.
The blue catfish expansion, though, has been rapid. They are now established in all of Virginia's tidal tributaries, and have colonized and are rapidly expanding in the Potomac. In Maryland, they have also been found in the Patuxent and Nanticoke rivers, as well as in the Upper Bay, including the mouth of the Susquehanna. Biologists have had reports of blue catfish in the Choptank River, and they may be in the Bay proper.
The blue catfish, according to Garman, is not just a new species for the Chesapeake - it's an "apex" predator that rules at the top of food webs - like polar bears or Bengal tigers - and controls abundance of species at lower layers of the web.
For the Bay's tidal fresh rivers, Garman added, a big resident predator is a whole new thing. While some large predators such as striped bass visited those areas during spring spawning runs, tidal fresh rivers historically were not inhabited by large numbers of year-round predators. Instead, those areas were dominated by smaller resident fish and migratory species such as American shad, river herring, hickory shad and other species that would pass through on spawning runs or use those areas to release eggs.
The blue catfish changed that. Now, Garman and others worry that other species are becoming a moving smorgasbord. "The blue catfish is an opportunistic predator," Garman said. "It will eat whatever swims in front of it" as long as it fits in its mouth.
Scientists believe that blue catfish outcompete native white catfish, whose numbers have declined as blue catfish increase. Some believe that the channel catfish, a nonnative introduced more than a century ago, may also be declining because of blue catfish competition. In the Mattaponi River, Greenlee said it appears likely that large numbers of blue catfish have dramatically reduced the freshwater mussel populations.
But the main concerns are focused on American shad and river herring. Tens of millions of dollars have been poured into stocking programs and fish passage construction to bolster populations of American shad, which once supported the largest commercial fishery in the Bay. 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 may be found inside. And because numbers of river herring and American shad are relatively low compared to populations of nonmigratory gizzard shad and other species, the odds of finding them in a fish gut are low.
The Atlantic States Marine Fisheries Commission is considering a resolution supporting efforts to control blue catfish populations in the Bay watershed, and the Bay Program's Sustainable Fisheries Goal Implementation Team, which includes state and federal fishery managers, scientists and others, hopes to make recommendations for blue catfish management this summer.
But what to do is not so clear.
Some have suggested that anglers who catch large blue catfish should kill them. But, Greenlee said, that runs counter to the ethics of trophy fishermen. "If you come into a tournament and you have a dead catfish, you are basically ostracized for life." Besides, he added, "a few recreational anglers out there killing blue catfish might make you feel good. But is it going to impact the population? I don't think so."
There is no obvious way to control such a large population. Greenlee said the commercial catch of blue catfish saturates market demand at about 2 million pounds - a catch level that has failed to curtail population growth. And any action or regulation perceived as harmful to blue catfish could stir conflict among angler groups.
American and hickory shad have been prized by many recreational anglers 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 the website of Catfish Nation, which organizes catfish trophy tournaments, put it: "Why fish for bait when you can catch a beast?"
Most fishery managers agree that raising awareness of potential impacts might at least help deter fishermen from intentionally moving blue catfish into new tributaries. "There is good reason to believe that these fish that showed up in the Nanticoke and the Patuxent didn't swim there," Cosden noted.
Cosden and other manager acknowledge that blue catfish populations are here to stay. While they may not be native to the Bay, they are ideally adapted to the nutrient-enriched estuary as it exists today, Greenlee said. Those nutrients have helped fuel growth of huge numbers of gizzard shad and other prey fish in tidal fresh areas of rivers that support larger predator populations.
"We have wholesale changes that have gone on out there," Greenlee said. "Blue catfish are not a cause. They are a symptom. “
This article credits Bay Journal News Service
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