Northern Snakehead - Biology

Biology

Distinguishing features of the northern snakehead include a long dorsal fin with 49-50 rays,(Hogan, 2012) anal fin with 31-32 rays, small anteriorly-depressed head, eye above the middle part of the upper jaw, large mouth extending well beyond the eye, villiform teeth in bands, large canine on the lower jaw and palatines, length up to 40 inches (1.0 m), with one report of 60 inches (1.5m), and weight up to 15 pounds (7 kg). Coloration is a golden tan to pale brown, with dark blotches on the sides and saddle-like blotches across the back. Blotches toward the front tend to separate between top and bottom sections, while rear blotches are more likely to be contiguous. Coloration is nearly the same between juveniles and adults, which is unusual among snakeheads. Coloration is similar to Channa maculata, but can be distinguished by two bar-like marks on the caudal peduncle (where the tail attaches): in Channa maculata, the rear bar is usually complete, with pale bar-like areas before and after, while in Channa argus, the rear bar is irregular and blotched, with no pale areas around it.

The Northern snakehead is a freshwater species and cannot tolerate salinity in excess of ten parts per thousand (Courtenay and Williams 2004). The northern snakehead is an obligate air breather; it utilizes a suprabranchial organ and a bifurcate ventral aorta that permits aquatic and aerial respiration (Ishimatsu and Itazaw 1981, Graham 1997). This unusual respiratory system allows it to live outside of water for several days, where concern is that it might wriggle its way to other bodies of water or be transported by humans. Note that only young of this species (not adults) may be able to move overland for short distances using wriggling motions (Courtenay and Williams 2004). The preferred habitats of this species are stagnant water with mud substrate and aquatic vegetation, or slow muddy streams; it is primarily piscivorous but is known to eat crustaceans, other invertebrates, and amphibians (Okada 1960). They build spawning nests in aquatic vegetation and females discharge eggs over the nest, which are externally fertilized by males (Okada 1960).

Two subspecies are distinguished – Channa argus argus originating from China and Korea and Channa argus warpachowskii originating from eastern Russia.