What do they look like?

Pirate perch are grayish with black speckles and have a narrow, vertical, dark bar at the base of the tail fin and under the eye. Pirate perch have a single dorsal fin and ctenoid scales (scales with ridged edges) on the head and body. The tail fin is slightly notched, not deeply forked. The gill cover has a sharp spine. Dorsal and anal fins each have 2 or 3 weak spines at front. The mouth is moderately large with a slightly projecting lower jaw. The lateral line (an additional sensory organ used to feel small vibrations) is underdeveloped in pirate perch from the Midwest, but specimens closer to the Atlantic coast show a much better developed lateral line. Also pirate perch are sexually dimorphic with females being larger and more full-bodied than males. Pirate perch are unusual in that their urogenital opening (opening for excretion and reproduction) is positioned far forward on their body and is actually located under the throat. This feature is not present in juveniles because the anus shifts forward with maturity.

Where in the world do they live?

Pirate perch are found only in North America. They are believed to have occupied the Mississippi Valley before the ancestors of most modern-day fishes had migrated into the region. Today pirate perch are found throughout the lowlands and surrounding areas of the southeastern Ozarks, in lakes and pools east of the Mississippi River and as far south as eastern Texas.

What kind of habitat do they need?

Pirate perch are found in clear warm water with low currents, for example bottomland lakes, overflow ponds and the quiet pools and backwaters of low-gradient streams. Within these areas pirate perch tend to congregate where there is dense vegetation, woody debris, root masses and undercut banks.

How do they grow?

Larval pirate perch look very similar to adults except in the placement of the anus. As stated above the anus shifts forward as pirate perch mature.

How do they reproduce?

There have been different ideas proposed about how pirate perch spawn. It is now believed that pirate perch spawn in underwater root masses and use their forward facing urogenital pores to deposit eggs and release sperm into the floating canopy. Recent research (from about 2004) strongly implies that the eggs are deposited and/or fertilized during multiple spawning events.

Male pirate perch guard nests from other males wishing to fertilize the eggs. These behaviors are aggressive and probably relate to pressures and competition for fertilization success in group spawning.

Spawning generally occurs in May in floating root masses. Female clutch size is about 100-400, depending on body size. In a single root mass up to 2000 total offspring were found to be present in a single nest. Female pirate perch thrust their heads and release their eggs into the root masses and males gather there to fertilize them.

The extent of parental involvement in the rearing of pirate perch is debated. Some sources suggest that parents guard the nest until the larvae are a little less than a centimeter long. However more recent papers suggest that there is no evidence of extended parental care.

How long do they live?

Maximum longevity in the wild is 4 years.

How do they behave?

Pirate perch are solitary fish. They are carnivorous and feed mostly at night. Indeed pirate perch got their name from C.C. Abbott who observed that these fish eat all other suitably sized fish when confined in an aquarium. Pirate perch appear to have a life history strategy similar to those of sunfishes, moving into the more open water areas immediately after hatching and remaining there for several weeks before returning to the areas near the shore.

How do they communicate with each other?

In addition to the lateral line sensory system present in most fishes an extensive array of sensory pores on the head of pirate perches may enable these nocturnal fishes to navigate in the dark. There is little known about communication in this species.

What do they eat?

This carnivorous fish eats primarily immature aquatic insects, small crustaceans and sometimes small fish.

What eats them and how do they avoid being eaten?

In the root masses that the pirate perch use for spawning adult and juvenile salamanders, as well as eastern dobsonfly larvae (Corydalus cornutus), have been found. It is unclear whether these animals are predators of the eggs or not. Adult pirate perch may be eaten by larger fish, piscivorous birds, otters or mink.

What roles do they have in the ecosystem?

Pirate perch are solitary and secretive, hiding during the daylight hours in thick growths of aquatic plants or accumulations of organic debris. They are mainly active at night. Pirate perch impact the populations of their small, invertebrate prey.

Do they cause problems?

There are no known negative impacts of pirate perch on humans.

How do they interact with us?

Pirate perch are not widely used as food or recognized as game fish.

Are they endangered?

Pirate perch are not generally common because they occupy relatively uncommon habitats. Within those habitats however they are abundant. In one study in Arkansas pirate perch were the most common species found in their sampling. In Ohio pirate perch are considered endangered. Development has significantly impacted the habitats of pirate perch because the bottomland lakes and ponds they occupy have been extensively destroyed by dredging, ditch construction, draining and filling.

Contributors

Meghan Miner (author), University of Michigan: October, 2005. Kevin Wehrly (editor, instructor), University of Michigan: October, 2005.

Tanya Dewey (editor), Animal Diversity Web, University of Michigan Museum of Zoology. Courtney Egan (editor).

References

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Clay, W. 1962. A Field Manual of Kentucky Fishes. Frankfort, KY: Kentucky Department of Fish and Wildlife Resources.

Eddy, S. 1969. How to know the Freshwater Fishes: Second Edition. Dubuque, IA: Wm. C. Brown Company Publishers.

Fletcher, D., E. Dakin, B. Porter, J. Avise. 2004. Spawning Behavior and Genetic Parentage in the Pirate Perch (Aphredoderus sayanus), a Fish with an Enigmatic Reproductive Morphology.. Copeia, 1: 1-10.

Fontenot, Q., D. Rutherford. 1999. Observations on the Reproductive Ecology of Pirate Perch Aphredoderus sayanus. Journal of Freshwater Ecology, Vol. 14 no. 4: 545-550.

Forbes, S., R. Richardson. 1920. Fishes of Illinois. Springfield, IL: Illinois State Journal Co., State Printers.

Hogue, J. 1976. Preliminary Guide to the Identification of Larval Fishes in the Tennessee River. Tennessee: Tennessee Valley Authority Division of Forestry, Fisheries, and Wildlife Development.

Katula, R. 1992. The Spawning Mode of the Pirate Perch. Trop. Fish Hobby, 40: 156-159.

Killgore, K., J. Baker. 1996. Patterns of larval fish abundance in a bottomland hardwood wetland. Wetlands, Vol. 16, no. 3: 288-295.

Monzyk, F., W. Kelso, D. Rutherford. 1997. Characteristics of Woody Cover Used by Brown Madtoms and Pirate Perch in Coastal Plain Streams. Transactions of the American Fisheries Society, 126: 665-675.

Ohio Division of Wildlife, 2000. "Ohio Biological Survey" (On-line). Biodiversity in Ohio. Accessed December 07, 2005 at http://www.ohiobiologicalsurvey.org/biodiv-v6n2.html.

Pflieger, W. 1975. The Fishes of Missouri.. Missouri: Missouri Department of Conservation.

Tiemann, J. 2004. Observations of the pirate perch, Aphredoderus sayanus (Gilliams), with comments on sexual dimorphism, reproduction, and unique defecation behavior.. Journal of Freshwater Ecology, 19(1): 115-121.

Trautman, M. 1957. The Fishes of Ohio. Baltimore, MD: Ohio State University Press.