The Bowfin (Amia calva) is an ancient freshwater fish species, the last living member of an order dating back over 150 million years, making it a “living fossil.” These hardy predators are found across the eastern United States and parts of southern Canada. The question of whether the Bowfin is invasive in Michigan often stems from confusion with other, non-native fish. This article clarifies the Bowfin’s true status and details its characteristics within Michigan’s aquatic environment.
The Native Status of Bowfin in Michigan
The Bowfin is a native species to Michigan and the Great Lakes region. It has been a natural component of the state’s aquatic life for millennia, long before modern human development. The term “invasive species” is specifically reserved for non-native organisms that cause, or are likely to cause, economic or environmental harm. Since the Bowfin naturally evolved in and is original to these waters, it cannot be classified as invasive.
Its historical range includes slow-moving, vegetated sloughs, lowland lakes, and backwaters found throughout the region. The presence of Bowfin is entirely natural and is not a sign of environmental degradation. Misidentification and a general misunderstanding of its role have historically led to the species being erroneously categorized as a “trash fish” by some anglers.
Identification and Common Misunderstandings
The confusion about the Bowfin’s status is largely due to its physical similarity to the highly publicized invasive Northern Snakehead (Channa argus), which is native to China. While both species are long, cylindrical, and predatory, the Bowfin possesses several distinct anatomical features that confirm its identity.
The most immediate identifier is the very long, continuous dorsal fin that runs over half the length of the Bowfin’s back. Another key characteristic is the presence of a bony plate, called a gular plate, located underneath the jaw between the lower halves of the gill covers. This plate is unique to the Bowfin family and is absent in the Northern Snakehead.
Furthermore, many Bowfin, particularly males, have a prominent black spot, or ocellus, circled in yellow or orange, at the base of their tail fin. The Northern Snakehead lacks this specific eyespot.
The Bowfin’s pelvic fins are positioned farther back on its body, roughly at mid-body, while the Northern Snakehead’s pelvic fins are located much closer to its head. The Bowfin has a short anal fin, whereas the Northern Snakehead’s anal fin is long, running nearly the entire length of the dorsal fin. The Northern Snakehead also has enlarged, snake-like scales covering its head, which the Bowfin does not. Learning these specific details is important for anglers and citizens to correctly distinguish the native species from actual invasive threats.
Bowfin’s Role in Michigan’s Aquatic Ecosystem
The Bowfin is a predator that plays an important role in maintaining the balance of its native habitats. Its diet consists mainly of crayfish, smaller forage fish like minnows, and amphibians, though it will also consume sunfish. By preying on abundant species, the Bowfin contributes to the regulation of local fish populations, which helps prevent overpopulation and stunting.
The species is known for its hardiness and ability to tolerate challenging environmental conditions. This resilience is partly due to its physiology as a facultative air-breather. The Bowfin can breathe air directly from the surface using a modified swim bladder, allowing it to survive in shallow, stagnant waters where oxygen levels are too low for most other fish.
This adaptation enables the Bowfin to persist in backwater areas and vegetated shallows where many other predators cannot, filling an important ecological niche. Its continued presence in Michigan’s waters is a sign of a healthy, functioning ecosystem.