Bowfin (Amia calva)

Bowfin

Described as a living fossil, the bowfin is the only existing member of the Amiidae family, a group of fish that originated in the Cretaceous period more than 100 million years ago. Of little commercial value because of their poor-tasting flesh, bowfin are excellent fighters and are caught by anglers wherever they are abundant, although mostly unintentionally.

When not abundant, they are a rare catch, and many anglers are unfamiliar with them. Although they are sometimes considered pests or nuisances by anglers seeking other quarry, bowfin are helpful in constraining otherwise large, stunted populations of smaller fish.

Identification

An ancient fish in design and described by some as looking more like a serpent than a fish, the bowfin has a rounded tail and a considerable amount of cartilage in its skeletal system. Underneath its head is a large, bony gular plate, with several other bony plates protecting the skull.


Distinctive qualities include a large flattened head with tubelike nostrils and long, sharp teeth, as well as a long, spineless dorsal fin that extends almost the entire length of the body. Another interesting feature of the bowfin’s anatomy is a modified, lunglike air bladder, in addition to gills; as in the gar, which possesses a similar organ, the bowfin is able to breathe surface air and, consequently, live in water too polluted or stagnant for most fish.

Its long, thick, cylindrical body is covered with large olive-colored scales, although it occasionally has a brownish or gray cast that fades to white or cream underneath. The male has a dark spot on the upper tail with a yellowish orange rim around it, and the female has a less conspicuous spot without a rim.

Size/Age

The bowfin can grow to up to 43 inches in length but averages 2 feet. The world-record bowfin weighed 21 pounds, 8 ounces, although the average weight is in the 2- to 5-pound range. The male is smaller than the female, and they survive up to 12 years in the wild and 30 years in captivity.

Life history/Behavior

When bowfin are 3 to 5 years old, they reach sexual maturity. They spawn between early April and June, when water temperatures are between 60° and 66°F. Males move into the weedy shallows after dark, before the females, and build bowl-shaped nests of plant material among tree roots or under fallen logs. A single male may try to mate with more than one female, and sometimes several pairs of bowfin will use the same nest.

The male is left to protect the eggs, which hatch in 8 to 10 days. The newly hatched bowfin use adhesive organs on their snouts to attach themselves to the bottom of the nest as they grow to about 1⁄2 inch long.

Once they reach this length, the fry school and follow the male, which guards them for several weeks against potential predators. Adult coloration appears when they are about 1.5 inches long, and the young begin to protect themselves at this stage. They stop schooling entirely when they reach 4 inches in length.

Bowfin swim slowly along the bottom, although they can move very quickly if disturbed or when in pursuit of prey.

Food and feeding habits

Bowfin can be extremely ravenous and eat a large variety of food, including crayfish, shrimp, adult insects and larvae, small fish, frogs, and large amounts of vegetation. Scent is as important as sight in obtaining food, and bowfin have the habit of gulping water to capture their prey. Although bowfin are always ready to feed, they are most active in the evening.

Other Names

dogfish, freshwater dogfish, blackfish, mudfish, western mudfish, mud pike, cabbage pike, shoepike, griddle, grindle, spottail grindle, grinnel, lawyer, scaled ling, speckled cat, cypress trout, cypress bass, cottonfish, John A. Grindle; French: choupiquel, poisson de marais.

Distribution

Bowfin occur only in North America, from the St. Lawrence River and Lake Champlain drainage of Quebec and Vermont west across southern Ontario to the Mississippi drainage, from Minnesota south to Texas and Florida.

Habitat

Bowfin are generally a big-water fish and inhabit warm and swampy lakes with vegetation, as well as weedy rivers and streams. With a significant tolerance for high temperatures and a modified air bladder, the bowfin is able to live in stagnant areas by taking in surface air.
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