The pirate perch (''Aphredoderus sayanus'') is a freshwater fish that commonly inhabits coastal waters along the east coast of the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
and the backwater areas of the
Mississippi Valley
The Mississippi River is the List of longest rivers of the United States (by main stem), second-longest river and chief river of the second-largest Drainage system (geomorphology), drainage system in North America, second only to the Hudson B ...
.
This species is often found towards the bottom of clear, warm water habitats with low currents. These fish are normally solitary, carnivorous, and
nocturnal
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite.
Nocturnal creatures generally have highly developed sens ...
. The pirate perch is known to consume live
mosquito
Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...
larva,
amphipods
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far descri ...
,
glass shrimp
''Palaemon'' is a genus of caridean shrimp of the family Palaemonidae. The conventional circumscription of the genus ''Palaemon'' is probably paraphyletic. Molecular data suggest that ''Palaemonetes'', as well as the genera ''Exopalaemon'' and '' ...
, meal worms, small fish,
dragonfly
A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threate ...
and
stonefly
Plecoptera is an order of insects, commonly known as stoneflies. Some 3,500 species are described worldwide, with new species still being discovered. Stoneflies are found worldwide, except Antarctica. Stoneflies are believed to be one of the mo ...
larvae, and earthworms.
The pirate perch is related to the
trout-perch
''Percopsis omiscomaycus'', also known as the trout-perch, the grounder or the sand minnow, is one of two species in the family Percopsidae. Its name comes from the Greek root words ''perc'', meaning perch and ''opsi'' meaning appearance. The sp ...
es, but only loosely; it is the
only species in its family, Aphredoderidae. The specific name ''sayanus'' is a tribute to naturalist
Thomas Say
Thomas Say (June 27, 1787 – October 10, 1834) was an American entomologist, conchologist, and Herpetology, herpetologist. His studies of insects and shells, numerous contributions to scientific journals, and scientific expeditions to Florida, Ge ...
.
[ Charles C. Abbott gave the fish its common name after observing it eating only other fishes.]
Description
This small fish is up to in total length
Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.
Overall length
* Standard length (SL) is the length of a fish ...
. It is dark brown, sometimes with a darker band near the base of the tail. A unique feature of this fish is the forward placement of its cloaca
In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, a ...
, under the head, anterior to the pelvic fin
Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods.
Structure and function Structure
In actinopterygians, the pelvic fin consists of two en ...
s.
Pirate perch may be the only known animal to exhibit a chemical camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...
, or crypsis
In ecology, crypsis is the ability of an animal or a plant to avoid observation or detection by other animals. It may be a predation strategy or an antipredator adaptation. Methods include camouflage, nocturnality, subterranean lifestyle and ...
that is generalized and effective among a wide number of potential prey species.
Distribution
The pirate perch is a freshwater species found in temperate climates where the water temperature generally ranges from .[ They are found most commonly in central and eastern North America. The pirate perch occurs in rivers of the Atlantic and Gulf slopes, the Mississippi Valley, and scattered parts of the eastern ]Great Lakes
The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
Basin. Pirate perch had once occurred in Pennsylvania
Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...
, but has since been extirpated due to the effects of urbanization, according to the Nature Conservancy
The Nature Conservancy (TNC) is a global environmental organization headquartered in Arlington, Virginia. it works via affiliates or branches in 79 countries and territories, as well as across every state in the US.
Founded in 1951, The Natu ...
. Its geographic range is very limited in the United States, and the creation of dams and the increasing effects of urbanization are restricting the overall habitat size for the fish, which could eventually lead to this species becoming extirpated in some areas.
Ecology
These fish can be found in densely vegetated areas, places with woody debris, and underneath banks in root masses. Debris in deep water with undercut banks and slow inside flows are used more by this species. The area where the perch reside is dependent on their size, with medium to large perch occupying places that were more structurally complex than small ones. They are known to congregate in these areas to avoid predation from piscivorous birds, otters, or mink. The pirate perch has nocturnal feeding habits; their diet consists of live mosquito larva, amphipods, glass shrimp, meal worms, small fish, dragonfly and stonefly larvae, and earthworms.[
]
Life history
Breeding occurs from October to December in Florida and in Louisiana as early as February.[ Most breeding occurs around early April until May, depending on latitude.] When breeding, pirate perch use underwater root masses as the microhabitat for their larvae. Females have been observed thrusting their heads into sheltered canals of underwater root masses and releasing eggs. The male perch then come to these sites, enter the canal head-first, and proceed to fertilize the eggs in the same manner they were laid. Females can lay between 100 and 400 eggs, which is dependent on the body size. They are able to reproduce after one year, and can live up to four years in the wild.
This species' method of breeding was misunderstood for quite some time due to difficulties in making ''in situ'' observations.[ At first, the ]urogenital
The genitourinary system, or urogenital system, are the organs of the reproductive system and the urinary system. These are grouped together because of their proximity to each other, their common embryological origin and the use of common pathwa ...
positioning of the pirate perch was speculated to serve to promote egg transfer to the fish's gill
A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...
(branchial) chamber for gill-brooding. However, the pirate perch was found to not brood bronchially; instead, they lay their eggs within underwater root masses which are then fertilized by the males. Nevertheless, a unique spawning behavior has been observed, which has been referred to as transbranchioral ("through the gill chamber"). When the eggs are laid, they are transferred directly from the urogenital to the gill chamber and then spat out through the mouth into the substrate. Among fish, gill-brooding is only known from ''Amblyopsis
''Amblyopsis'' is a genus of small (up to long) fish in the family Amblyopsidae that are endemic to the central and eastern United States. Like other cavefish, they lack pigmentation and are blind. The most recently described species was in 2014 ...
'' cavefish.
Current management
According to the Iowa Department of Natural Resources
The Iowa Department of Natural Resources (Iowa DNR or IA DNR) is a department/agency of the U.S. state of Iowa formed in 1986, charged with maintaining state parks and forests, protecting the environment of Iowa, and managing energy, fish, wild ...
, some major threats that could affect their habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
s could be siltation
Siltation, is water pollution caused by particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the increased accumulation (temporary or ...
due to poor upland treatment. Since these fish reside in habitats with slight water current, a change upstream such as water channels, dams, or drainages could alter the flow of water in that system, which could change the rate at which water flows downstream. Water pollution as a result from agricultural runoff and discharge from urban areas can create environments unsuitable for these species. Ohio has expressed some interest in conserving the species due to the perch having such a small area it can inhabit in the northwestern part of the state. Besides Ohio, little concern has been shown about this species overall.
References
{{Taxonbar, from=Q1457936
Aphredoderidae
Freshwater fish of the Southeastern United States
Fish described in 1824