By Julia Robins, Staff Writer
When the blue catfish was introduced to Virginia in the 1970s, recreational fishermen were eager to catch the new trophy fish that grew to over 40 pounds. No one expected that decades later the blue catfish would expand to nearly every major tributary in the Chesapeake Bay watershed. In fact, the blue catfish has now spread so far and become so numerous that it is considered an invasive species.
“It’s startling, actually, to see how many of these fish are out there,” says Thomas Murray, Virginia Institute of Marine Science extension staff affiliated with Virginia Sea Grant. Murray manages the Virginia Fishery Resource Grant Fund, which awards grants to members of the seafood industry for projects related to improving seafood production and processing in the state.
In 2014, Virginia waterman George Earl Trice IV received funding to document the effectiveness of electrofishing blue catfish for commercial harvest. Though it may sound outlandish to mix electricity and water, electrofishing uses an electric current to stun fish so they can be caught. Commonly used by scientists to sample fish populations, electrofishing doesn’t kill the fish; instead, it stuns them and causes them to surface, where they can be collected with nets.
The process begins by dipping two electrodes into the water, one positive and one negative. The electrodes emit a current that attracts the fish, which are then stunned. Those fish that are not captured will recover and swim away after about two minutes.
During the summer of 2014, Trice, accompanied by observers from VIMS and VCU, went electrofishing 47 times in the James River. He reported success in catching blue catfish and also noted that he did not observe any accidental stunning of other fish or any detriment to local plants and wildlife. He added in his final report that electrofishing was “very easy compared to other methods of catfish harvest, i.e. gill nets and hoop nets.”
Trice also reported, however, that he could only net five percent of the stunned catfish before the rest recovered and swam off. For a consistently profitable fishery using electrofishing, work is still needed to find more efficient harvesting devices to collect the catfish and to determine how often an area can be fished; some argue that fish can build a resistance to the current used in electrofishing over time.
Murray says he’s also heard some concerns about electrofishing; for example, he says some commercial fishermen are worried about what will happen to their target fish and about losing income on the blue catfish they sell as bycatch. Recreational fishermen are concerned that electrofishing could remove the large catfish that make trophy fishing so appealing. Other observers, he says, are simply skeptical of the idea of electrofishing in general.
“We’ve even heard some comments that ‘it’s not fair, it’s not fishing,’” says Murray.
Yet others see electrofishing as a way to curb blue catfish’s effect on native species in Chesapeake Bay. According to NOAA’s Chesapeake Bay Office, blue catfish live long, grow quickly, and have expansive appetites for native species, like menhaden and blue crab, which play an important role in the Chesapeake Bay ecosystem and economy.
Trice’s study focused on the effectiveness and profitability of electrofishing, but other findings may help inform some of these questions and concerns.
Right now, “we’re just learning,” says Murray.
