Aphredoderus sayanus

Geographic Range

Aphredoderus sayanus is found only in North America and is believed to have occupied the Mississippi Valley before the ancestors of most modern-day fishes had migrated into the region (Pflieger, 1975). 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.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Pirate perch are found in clear warm water with low currents; these include bottomland lakes, overflow ponds and the quiet pools and backwaters of low-gradient streams (Pflieger, 1975). Within these areas pirate perch tend to congregate where there is dense vegetation, woody debris, root masses and undercut banks (Monzyk et al., 1997).

• Habitat Regions
• temperate temperate
• freshwater freshwater

• Aquatic Biomes
• lakes and ponds
• rivers and streams

Physical Description

Pirate perch are unusual in that their urogenital opening is positioned far anteriorally under the throat (Fletcher, et. Al. 2004). This feature is not present in juveniles, as the anus migrates with maturity. 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 (Pflieger, 1975). Pirate perch have a single dorsal fin and ctenoid scales 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 (Pflieger, 1975). The mouth is moderately large with a slightly projecting lower jaw (Clay, 1962). The lateral line is incomplete or underdeveloped in pirate perch from the Midwest, but specimens closer to the Atlantic coast show a much better developed lateral line (Eddy, 1969). Pirate perch are sexually dimorphic with females being larger and more full-bodied than males (Tiemann, 2004).

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger
• sexes shaped differently

Development

Larval pirate perch look very similar to adults, except in the placement of the anus. Prolarvae and early postlarvae have 12-15 preanal and 13-196 postanal myomeres (Hogue, 1976). Once these fish reach 13 mm, the number of preanal myomeres will decrese as the anus begins migration toward the gular region (Hogue, 1976).

Reproduction

It was first suggested that the migration of the anus in A. sayanus was to facilitate gill brooding of its eggs, as is found in northern cavefishes ( Amblyopsis spelaea ) with similar morphological features. However it was noted that the space within the branchial cavity of A. sayanus is insufficient to hold an entire clutch of eggs (Katula, 1992). Pirate perch actually spawn in underwater root masses and use their forward facing urogenital pores to deposit eggs and release sperm into the floating canopy (Fletcher et al., 2004). Fletcher (2004) observed that, within an assemblage, pirate perch were often of distinct developmental stages, strongly implying that the eggs had been 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 selection pressures imposed by intense competition for fertilization success in group spawning (Fletcher et al., 2004).

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Spawning generally occurs in May in floating root masses parallel to water flow. 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 congregate there to fertilize them (Fletcher et al., 2004).

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• sexual sexual
• fertilization fertilization
  • external external
• broadcast (group) spawning
• oviparous oviparous

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 (Forbes and Richardson, 1920). However, more recent papers suggest that there is no evidence of extended parental care (Fletcher et al., 2004).

• Parental Investment
• no parental involvement
• pre-fertilization
  • provisioning
  • protecting
    • female

Lifespan/Longevity

Maximum longevity in the wild is 4 years (Pflieger, 1975).

Behavior

Pirate perch are solitary fish (Fletcher et al., 2004). They are carnivorous, feeding mostly at night (Clay, 1962). 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 (Forbes and Richardson, 1920). Pirate perch appear to have a life history strategy similar to those of sunfishes, moving into the limnetic zone immediately after hatching and remaining there for several weeks before returning to the littoral zone (Fontenot and Rutherford, 1999).

• Key Behaviors
• natatorial natatorial
• nocturnal nocturnal
• motile motile
• solitary solitary

Communication and Perception

In addition to the lateral line sensory system present in most fishes, an extensive array of sensory pores on the head of A. sayanus may enable these nocturnal fishes to navigate in the dark (Fletcher et al., 2004). There is little known about communication in this species.

• Perception Channels
• tactile tactile
• vibrations vibrations
• chemical chemical

Food Habits

This carnivorous fish eats primarily immature aquatic insects, small crustaceans and sometimes small fish (Pflieger, 1975).

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods

• Animal Foods
• fish
• insects
• aquatic crustaceans

Predation

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 (Fletcher, et al 2004). Adult pirate perch may be eaten by larger fish, piscivorous birds, otters or mink.

Ecosystem Roles

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 (Pflieger, 1975). Pirate perch impact the populations of their small, invertebrate prey.

Economic Importance for Humans: Positive

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

Economic Importance for Humans: Negative

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

Conservation Status

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, representing 21% of 8,113 fish taken (Killgore and Baker, 1996). 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 siltation (Trautman, 1957).

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Tanya Dewey (editor), Animal Diversity Web, Courtney Egan (editor).

Meghan Miner (author), University of Michigan-Ann Arbor, Kevin Wehrly (editor, instructor), University of Michigan-Ann Arbor.

References

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.

2006. "Merriam Webster Online" (On-line). Accessed September 12, 2006 at http://m-w.com/dictionary/urogenital .