New Predatory and Prey Relations with the Northern Snakehead

One of the biggest unknowns scientists had when the Northern Snakehead species was found in the Potomac River, in 2004, was how will this fish’s population be kept in check with no natural predators?

So much has been done to study this species’ behaviors. As you know, my specific research area, in Howard County in the state of Maryland, is studying this non native fish for the last three years in the Little Patuxent and Middle Patuxent rivers. As anglers, we know that big fish eat little fish. Snakehead fry are a great new food source to lots of other fish, especially bass. Over the last 18 months alone new predators of the Northern Snakehead fish have been photographically verified, which is a big deal to us scientists! The newly confirmed avian foes of the snakehead fish in the Maryland and Pennsylvania area are the Green Heron and the Great Egret. Check out these amazing photos by wildlife photographer Debra Bangasser taken at John Heinz National Wildlife Refuge in Philadelphia, PA.

Did you know the Great Egret inhabits swamps, lakes, ponds, areas near the rivers, streams and islands?

Did you know the Green Heron creates fishing lures with bread crusts, insects, earthworms, twigs, feathers and other objects, dropping them on the surface of the water to entice small fish?

Some other important birds of prey that I am observing in my research area are the Osprey, Kingfisher and hawks. Though it has not been photographically proven, after speaking with an ornithologist at University of Maryland, he said the Northern Snakehead fish could definitely become a potential food source for these native birds in the area. One of the things I look for in my observations is how long and often are these species being spotted in the research area? Is it longer than usual because of a more consistent available food source? Are more numbers of these birds being spotted in the research area than previous years?

Birds are often associated with habitats modified by small mammal ecosystem engineers. One of the most intriguing finds this year came from a picture an angler out at Patuxent Wildlife Refuge, just below my research area, in Anne Arundel County sent in. Check out this picture of the North American River Otter!

Did you know that the North American River Otter as an adult can weigh up to 18 lbs. and grow to 2.2 ft?

Small mammal predators may serve to reduce invertebrate species that are themselves predators of phytophagous insects. Small mammals serve as a food supply for a large number of predators and can exert significant influence on predator population cycles. These pictures clearly show that Snakeheads need to be more aware of predators than the previous decade of research has shown us. It also infers that the Northern Snakehead fish is finding a niche in our ecosystem in the USA and that nature is balancing their prolific breeding with some natural predators in small and large river systems. Next thing to look at is closed water systems impacts!