| Pirate perch | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Percopsiformes |
| Family: | Aphredoderidae |
| Genus: | Aphredoderus Lesueur in Cuvier & Valenciennes, 1833 |
| Species: | A. sayanus |
| Binomial name | |
| Aphredoderus sayanus (Gilliams, 1824) |
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The pirate perch, Aphredoderus sayanus, is a freshwater fish of the Percopsiformes order. This small fish is native to the eastern half of North America. It is dark brown, sometimes with a darker band near the base tail. A unique feature of this fish is the forward placement of its cloaca, under the head, anterior to the pelvic fins.[1] This placement allows the females to place their eggs more precisely into root masses.
Its preferred habitat are backwaters of warm water and little current. The fish was named by Charles C. Abbott on account of the fact that he observed it eating only other fishes.
The pirate perch is related to the trout-perches, but only loosely; it is, for example, the only species in its family: Aphredoderidae. The specific name sayanus is a tribute to naturalist Thomas Say.
The Pirate perch, Aphredoderus sayanus, is a freshwater fish that commonly inhabits coastal waters along the east coast of the United States and the backwater areas of the Mississippi Valley. [2] This species is often found towards the bottom of clear warm water habitats with low currents. These fish are normally solitary, with a carnivorous appetite and are mainly nocturnal. The pirate perch is known to consume food items have included live mosquito larva, amphipods, glass shrimp, meal worms, small fish, dragon fly and stone fly larva and earthworms.[3] This species method of breeding was misunderstood for quite some time due to difficulties in making in situ observations. [2] At first it was speculated that the urogenital positioning of the pirate perch serves to promote egg transfer to the fish's branchial chamber for gill-brooding.[4] However, it was determined that the pirate perch do not bronchial breed, instead lay their eggs within underwater root masses which are then fertilized by the male perch [4]. It has been studied and they release their adhesive eggs into these underwater root masses instead of branchial brooding.[5] While the pirate perch is not an endangered species, they are uncommon due to the habitats they occupy and the time of the day they are active. Urban development does affect this species with dredging and draining of backwater areas for urbanization purposes. While the species is far from imperilment, the habitats of the perch need to be monitored because acts such as the draining of backwater areas can directly result in the loss of a great number of pirate perch species.
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Aphredoderus sayanus is one of the few species of fish in North America that is endemic to this region. They are a freshwater species that prefer temperate climates with a temperature ranging from 5°C – 26̊C. 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 Basin [6]. Pirate perch had once occurred in Pennsylvania but has since been extirpated due to the effects of urbanization, according to the Nature Conservancy. The geographic range of the pirate perch is very limited in America and the creation of dams and the increasing effects of urbanization are restricting the overall habitat size for the pirate perch which could eventually lead to this species becoming extirpated in some areas of America.
These fish are known to live in places with clear warm water with low currents, which include bottomland lakes, overflow ponds and the quiet pools and backwaters of low-gradient streams.[7] These fish can be found where there are densely vegetated areas, as well as places with woody debris, and underneath banks in root masses. Research has shown that 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 size perch occupying places that were more structurally complex than small pirate perch. They are known to congregate in these areas to avoid predation from such predators as piscivorous birds, otters or mink.[4] It has been reported that the pirate perch has nocturnal feeding habits. Their diet has been documented to consist of live mosquito larva, amphipods, glass shrimp, meal worms, small fish, dragon fly and stone fly larva and earthworms.[3]
Many studies have been conducted to analyze the reproductive strategies of the pirate perch. It has been debated on what time of the year the pirate perch breeds with studies showing instances of breeding from October-December in Florida[8] and even instances of breeding in Louisiana as early as February [5]. It is generally assumed that most breeding occurs around early April until May [4]. 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 lain [4]. Females can lay anywhere between 100-400 eggs which is dependent on the body size. They are able to reproduce after one year, and can live up to 4 years in the wild [7].
It is known that the pirate perch inhabit backwater areas, with an absence of fast currents and an abundance of plant life. With the pirate perch using underwater root masses to breed, it can be assumed that most breed near the edges of rivers or lakes. With this in mind, it is easy to see how urbanization and development could cause problems for these fish. According to the Iowa Department of Natural Resources, some major threats that could affect these habitats could be the effects that siltation may have due to poor upland treatment. A big problem that could affect these fish would be the overall loss of their weedy habitat in which they live in during the day. The loss of this habitat would expose them to the pressures of the environment from which they hide. 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. Impacts from humans can also be felt in their habitats. Water pollution as a result from agricultural runoff and discharge from urban areas can create environments unsuitable for these species. There is very little being done for these fish at the current time. Ohio has expressed some interest in conserving the species due to the perch having such a small area in which it can inhabit in the north-western part of the state. Besides Ohio, there is little concern about these species overall.
In order to keep the populations of Pirate perch secure, there needs to be an effort to conserve this species native habitat. Based on the threats observed, management of this species can be geared to those threats. The Department of Natural Resources in Iowa advises that to stop siltation downstream, there needs to be an effort to properly maintain upland areas to keep the sediment from reaching downstream to where it can affect rivers and streams. Also, there needs to be a general promotion of weedy habitats where pirate perch are known to occur. This will enable the species to continue to have shelter and a place to breed. Furthermore, there needs to be a buffer system in place to filter out the negative effects that agricultural runoff and discharge will have on the habitat. When observing the effects that these changes can have on the population, it would be good to examine them around mid summer to early fall. This will give the researcher a good estimate of population densities since breeding season will be over and larvae will have had time to grow to juveniles. This species would be difficult to sample due to their nocturnal nature and since their habitat consists of dense vegetation. Methods such as electroshock may prove useful in examining these species since it would be difficult to collect them in nets. It would be ideal to measure populations on the edges of streams or rivers where root masses are known to occur. Samples should be taken every three months in the same areas to see if changes in population occur as a result of management efforts. If this method does not work, the management plan should be revised to best fit the pirate perch’s needs.