The Blue Catfish Population Explosion

by

Environment

Mitigating the Threat of This Invasive Species in the Chesapeake Bay 

When the Virginia Department of Wildlife Resources (DWR) introduced blue catfish into three tributaries of the Chesapeake Bay (the James, Rappahannock, and York Rivers) in the 1970s and 1980s to create a recreational trophy fishery, the resource managers couldn’t have foreseen the impact that the fish would have on the Bay ecosystem. A popular recreational catch, blue catfish can grow large in size—providing a fun, challenging experience for anglers. Since coastal striped bass populations were declining throughout the Atlantic Ocean, the fishery was intended to offer new opportunities for recreational anglers.

The freshwater catfish, which are native to the Mississippi, Missouri, and Ohio River basins, were expected to remain in the tributaries in which they were stocked. However, since blue catfish can tolerate higher salinities than the resource managers originally thought, they were able to thrive in the brackish waters of the Bay. As a result, blue catfish expanded their range at an alarming rate. Today, they are found in nearly every tributary of the Bay. 

“It seems that blue catfish may use periods when salinities decrease, like during years of high rainfall, to disperse and invade new habitats,” says Branson Williams, invasive fishes program manager for the Maryland Department of Natural Resources (DNR). “This may have been the case during 2018 and 2019 when we began hearing about more reports of blue catfish in the upper Bay. While they can tolerate higher salinities than initially thought, they typically don’t spend time in higher salinity waters, such as 17 ppt (parts per thousand), for very long because they can’t handle it.”

The unintended consequences of the resource managers’ decision to stock blue catfish in the Virginia tributaries shines a light on the risks of introducing an invasive species into the Bay. Since their initial introduction, blue catfish have greatly expanded their range and become so populous that they now pose a serious threat to the Bay ecosystem. According to the DNR, commercial harvesters removed 4.2 million pounds of blue catfish from the Potomac and Maryland waters in 2023—a more than 500 percent increase from 10 years earlier. In addition, they comprise as much as 75 percent of the total fish biomass in some portions of the James and Rappahannock Rivers.  

Concerned about the spread of blue catfish, a diverse group of stakeholders, including state agencies, environmental organizations, educational institutions, commercial fisheries, watermen, seafood processors, and several other partners, are working together to help mitigate the impact of blue catfish. The management strategy is focused on science, research, policy, increased commercial harvest, and public awareness among consumers and recreational anglers. 

Blue Catfish Occurrences

According to the DNR, blue catfish were first reported in Maryland in the Potomac River in 1987. They became abundant in the Potomac in the 1990s and continued to expand their range in the 2000s. By the 2010s, the blue catfish population was identified as a bay-wide issue that required action. In response to the threat to the Bay ecosystem, resource managers adopted an Invasive Catfish Policy in 2012. The Chesapeake Bay Program’s Invasive Catfish Workgroup was later formed in 2014.

“The Workgroup brings together members on a bay-wide scale to manage blue catfish and minimize their spread and ecological impact,” says Bruce Vogt, manager of ecosystem science and synthesis, National Oceanic and Atmospheric Administration (NOAA) Chesapeake Bay Office, and chair of the Workgroup. “We’re a diverse group of partners committed to change—both on the ground and through the exchange of information. When we first formed the Workgroup, the blue catfish problem was new. We had to explore management strategies and create a roadmap to guide progress. Bringing together a group of talented people has greatly helped us accelerate our efforts and raise public awareness.” 

Silvery-blue with a white belly, blue catfish have a flat dorsal fin, a deeply forked tail, and four pairs of black whisker-like barbels around their mouths. Their smooth skin lacks scales. Although adults are typically less than two feet long, they can grow up to five feet long and weigh more than 100 pounds. According to state records, the largest blue catfish caught in Maryland weighed 84 pounds.

Although blue catfish are omnivores, their diet consists mainly of native fish species, including menhaden, American shad, striped bass, American eel, and white perch, as well as blue crabs, plants, and insects. Not only are these species ecologically and economically beneficial, but many of them, such as the iconic blue crab, are also symbols of Bay history and culture.

“It’s difficult to quantify how many native species blue catfish are eating,” Williams says. “Diet studies are useful and have identified 30 to 40 different prey items in their stomach contents. This may have an impact on native fishes that are ecologically and recreationally significant, especially where blue catfish are well established.” 

Opportunistic and generalist predators, blue catfish have a ravenous appetite and can outcompete other fish species for food and habitat. With the exception of osprey and bald eagles, they have few natural predators. According to NOAA Fisheries, blue catfish spawn once a year from late May to June—mostly in lower-salinity streams and smaller tributaries. Females produce 4,000 to 8,000 eggs per kilogram of body weight, which means that a 10-pound fish could produce more than 20,000 eggs.

A Relatively New Fishery

Since the vast population makes eradication of blue catfish impossible, the management strategy focuses on developing and expanding commercial fisheries in an effort to remove as many of them as possible from the Bay. According to NOAA Fisheries, commercial fisheries for blue catfish were limited during the early 2000s due to low market demand and lack of consumer awareness. So, the development of a commercial fishery management plan is relatively new. But thanks to increased public awareness, the commercial fishery for blue catfish is growing. 

“A broad and diverse group of stakeholders, including environmental organizations, state agencies, seafood processors, watermen, and even the state’s Food System Resiliency Council, are working together to help facilitate as much harvest of blue catfish as possible,” says Allison Colden, Ph.D., Maryland executive director, Chesapeake Bay Foundation (CBF). “The DNR also recently expanded the types of commercial fishing gear that could be used to target blue catfish, including bowfishing and catfish trotlines. 

“On the federal side, blue catfish are in a unique regulatory position since catfish are the only fish inspected by the USDA rather than the FDA. This makes the inspection process expensive and cumbersome for processors. While mostly a federal issue, efforts have been made in the Maryland General Assembly to help make processing blue catfish less burdensome.” 

To further facilitate commercial harvest, the Workforce identified a need for population studies. Since blue catfish are highly productive and able to disperse throughout the Bay tributaries, monitoring programs to track their abundance through time (year to year) and population projection models to estimate future population size and distribution are critical. 

“We are pleased that the DNR is working with the U.S. Geological Survey (USGS) Eastern Ecological Science Center on a program to monitor the blue catfish population in Maryland’s portion of the Bay and to create population projection models,” Vogt says. “These models can estimate how the population will respond to different levels of commercial harvest—allowing us to develop harvest targets and determine how much biomass to remove.” 

The overabundance of blue catfish in the Bay has not only reshaped the commercial fishing industry—leading to the development of a fishery for blue catfish—but it has also affected Maryland watermen. Due to the immense population, some watermen have moved away from other fisheries, such as crabbing, to focus on blue catfish. By pivoting to the harvest of blue catfish, watermen throughout Maryland are doing their part in the effort to remove as many of them as possible from the Bay.

“The blue catfish population has affected the way that independent watermen operate their businesses,” says Robert T. Brown, Sr., president of the Maryland Watermen’s Association. “They are bringing in good blue catfish harvests, but they may have had to change where they work or how they work. The fishery is new and affects Maryland watermen’s livelihoods, so they have had to adapt to meet the challenges to their way of life.”

Raising Public Awareness

During the past few years, the Maryland Department of Agriculture (MDA) has launched several marketing campaigns to educate consumers about the benefits of incorporating blue catfish into their diets. Since adult blue catfish aren’t bottom feeders, they don’t taste “muddy” like some catfish species. A white, flaky fish with a taste that has been compared to striped bass, blue catfish are a good source of protein and Omega-3 fatty acids. A 4-ounce serving contains only 90 calories and 1.5 grams of fat. 

“We have really ramped up our efforts to promote blue catfish,” says Matthew Scales, seafood marketing director for the MDA. “By attending events, partnering with restaurants and chefs to provide cooking demonstrations—and free samples—and sponsoring giveaways, we’re increasing consumers’ interest in blue catfish, and the response has been great. We’re definitely noticing more demand among consumers who are excited to learn where they can buy blue catfish—whether in their local grocery stores or at restaurants. Not only are the fish delicious and nutritious, but eating them is also a great way for the public to help reduce the population and protect the Bay.”

Launched in 2004, Maryland’s Best, a website operated by the MDA’s marketing department, connects Maryland farmers and watermen with consumers. The website provides a wealth of information about blue catfish, which are marketed as “wild-caught Chesapeake blue catfish.” Not only does this appeal to consumers who prefer to “buy local,” but it also differentiates the fish from other species of catfish and emphasizes that they are harvested in the Bay. Consumers can search for retailers, restaurants, recipes, and more. For information, visit marylandsbest.maryland.gov.

In addition to engaging the public, several organizations are helping educate recreational anglers about the harm posed by blue catfish to the environment. Maryland offers several tournaments that not only encourage recreational anglers to help reduce the number of blue catfish in the Bay but also enjoy a fun day on the water.

Coastal Conservation Association Maryland (CCA Maryland) launched the Great Chesapeake Invasives Count in 2020 to help fishery managers collect data about where invasive fish, including blue catfish, are being caught and to support science-based management strategies. The event, which offers year-round opportunities for participants, is a fun way for anglers to support a great cause while competing for prizes.

“The Great Chesapeake Invasives Count allows recreational anglers to engage in the conversation about invasive species and their impact on the ecosystem,” says David Sikorski, executive director of CCA Maryland. “The event brings people together and offers a sense of community. It’s also a great way to help make a difference and have a lot of fun.” To learn more, visit ccamd.org/the-great-chesapeake-invasives-count. 

The Rod & Reef Slam fishing tournament, co-hosted annually by CBF, CCA Maryland, and the Chesapeake Oyster Alliance (COA) is another popular event for recreational anglers. The tournament offers an invasive species division that awards prizes for the largest blue catfish or other invasive species caught. 

In Maryland, since blue catfish are invasive, they cannot be overfished. However, catch and release is discouraged. Anglers should remove and kill any blue catfish they catch.

Although the blue catfish population may seem overwhelming, the partners engaged in the critical effort to reduce their numbers are optimistic about the future. They plan to continue to focus on growing commercial fisheries and minimizing harm to the Bay’s native species. 

“We’ll never remove every blue catfish from the Chesapeake Bay,” Colden says. “However, by creating a lucrative blue catfish fishery, we could get their population to a sustainable level. The more demand there is for the species, whether it’s restaurants, grocery stores, or recreational fishing, the more we can mitigate their harm to our native Bay ecosystem.”

Special thanks to Kim Couranz, communications specialist, NOAA Chesapeake Bay Office, and Valerie Keefer, Maryland communications & media relations manager, CBF

Blackened Blue Catfish & Grits

Note: All the recipes can be adjusted to the portion needed or even be altered to taste preference!

Ingredients

Serves 4

Catfish

  • 1 Lb. Catfish cut into 3 in. strips
  • 1/4 Cup Blackening/Cajun Seasoning 
  • Or seasoning of your choice
  • 2 Ea. Garlic Cloves Minced.
  • (Can substitute 2 tsp. Garlic Powder)
  • 3 Tbsp Olive Oil/Vegetable Oil
  • Black Pepper & Table Salt To taste

Grits Sauce

  • 1/4 Lb. Bacon Chopped small (optional)
  • 3 Sprigs Thyme (Substitute 1 Tbsp. Dried Thyme)
  • 1 Qt. Canned Tomatoes Chopped
  • 1 Yellow Onion Large diced
  • 1 Bell Pepper Large diced
  • 1 Tsp. red pepper flakes/ chili powder
  • Blackening/Cajun Seasoning to taste
  • 2 Cups Stock of Choice/Water
  • 4 Ea. Garlic Minced (Substitute 4 Tsp. garlic powder)

Grits

  • 2 Cups Grits
  • 4 Cups Stock of Your Choice or Water
  • 5 Large White Onions Minced
  • 4 Tbsp butter, unsalted
  • Salt and Black Pepper to taste

Instructions

Catfish: Combine in a mixing bowl and let marinate for at least 1 hour. Cook in a cast iron skillet to blacken until just cooked through. Grits Sauce: Saute peppers, onions, garlic, bacon/oil, and spices until browned. Add stock, tomatoes, and thyme. Simmer until slightly thickened. Season to taste Grits: Saute onions until aromatic. Pour in the stock and bring to a boil. Add the grits and stir well. Bring back to a boil and then reduce to a simmer. Cook until the grits are tender. Stir in butter and season to taste. Assembly: Serve grits in a bowl, top with the blackened blue catfish, and sauce.