Article featured in the November / December 2024 Virginia Wildlife Magazine

“From River to Table”

Wendy Hyde and northern snakehead

Electrofishing boat

Shocking on Mt. Landing Creek

Chris Dahlem (left) and Wendy Hyde (right)

Electrode and net on bow of boat, Piscataway Creek

Measuring northern snakehead

Scott Herrmann and northern snakehead

Population sampling is a tool used by Virginia Department of Wildlife Resources (DWR) fisheries biologists to assess the variety, health, and age of fish species found across Virginia. Included in that diversity is the northern snakehead, an invasive species first discovered in Virginia waters in 2004. I joined Scott Herrmann, DWR district fisheries biologist, for a summer survey trip and an opportunity to learn about snakeheads. The tidal Rappahannock River and the various tributaries within Region 1 are his focus, and similar samplings are conducted annually state-wide. 

 Scott skillfully operates the 20’ modified Clark boat and specialized equipment, with DWR fisheries staff members typically assisting with the fish collections. Catherine Lim, a biologist specializing in age and growth analysis of fish species, assisted with this sampling.

 We launched from the Hoskins Creek dock in Tappahannock to collect samples by high-frequency electrofishing. The method uses a generator-powered electrofishing unit that allows the operator to deliver just enough electric current into the water to momentarily stun fish. Salt content affects how electricity travels through water, so the amount of amperage relayed to the water is adjusted by changing the voltage settings. Several dry months of late summer into mid-fall allowed for the salinity wedge to push higher into the middle reaches of the Rappahannock River. Higher salinity levels make the conduction poor and decreases the ability of the electric field to properly stun fish. The fresher the water the better, with 3.5 parts per thousand (ppt) salinity typically the high end, cut-off level.  

 The initial salinity at Hoskins was 7 ppt. As we moved farther inland along the Rappahannock River and into Piscataway Creek, Scott made occasional stops to check the salinity.
Three miles inland, we found a suitable level and completed final set-up by connecting spider-like electrode heads to poles attached to the boat’s hull, then extending them in front of the boat. We filled the 165-gallon holding tank with creek water, two spotters with long handled nets took positions behind the waist-high rail on the elevated bow platform, and the generator, timer, and action started. Scott eased the boat along the vegetation-dense creek edges while the netters watched the water for a white belly or water swirl indicating a fish was nearby. They are stunned so briefly that if the fish are not caught on the first try, they’re gone. Catches were quickly transferred into the holding tank and once the 20-minute timer stopped, the species, length, and weight were documented. As we moved to new locations, the tank water was drained and re-filled to ensure the fish were in as similar an environment as possible, reducing stress during the collection and documentation process.  

 In addition to catching seven northern snakeheads, we also found bowfin, largemouth bass, brown bullhead, bluegill, American eel, yellow perch, and white catfish. The survey allowed for an opportunity to collect a representative sample of fish species for the Virginia Department of Environmental Quality (DEQ) Fish Tissue Contaminant testing program. DEQ selected numerous locations from Fredericksburg down to the mouth of the Rappahannock River in 2023 to allow for wide scoping analysis of the fishery and any possible detection of contaminants. Fish that aren’t kept for analysis are returned to the water. As part of the tidal Rappahannock River largemouth bass tagging study, all collected bass were tagged with a specific numbered Floy tag. Each deployed tag can provide analysis of growth rates and potential large-scale movements upon recapture or through angler catch and reporting. The tag color, number, and catch location were recorded before their release. Several snakeheads were sent for data, three were killed, and the remaining were released live. 

 Snakeheads are strong, adaptable fish that are fun to catch, but they aren’t a part of Virginia’s native species, and transporting live northern snakehead fish is illegal. DWR’s fishing regulations state: Anglers are required to report snakeheads kept but are not required to kill them if caught and immediately released.  Snakeheads must be dead if in possession (contained in live well, cooler, etc.)  However, the Department asks that all snakeheads be killed if possible. If an angler wishes to keep a legally caught northern snakehead, the fish must be killed to be in possession, and the angler must call the hotline or other DWR contact and report the angler’s last name, date of catch, location of catch, and size.

 Determining the impact of invasives on ecosystems takes countless hours of research and years of monitoring by wildlife agencies. State and Federal regulations are developed to control unwanted spread and help maintain natural balance and diversity. Monitoring also depends on support from the public by reporting catches and sightings. As responsible outdoors enthusiasts, hunters, and anglers, we play an important role in the effort. 

 I went home with three prehistoric-looking snakeheads to cook. These fish epitomize the saying, “don’t judge a book by its cover.”