Perch

Perch
Yellow perch (Perca flavescens)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Perciformes Family: Percidae Genus: Perca Linnaeus, 1758
Species
P. flavescens (Yellow perch) P. fluviatilis (European perch) P. schrenkii (Balkhash perch)

In zoology, perch is the common name for freshwater ray-finned fish comprising the genus Perca of the family Percidae and order Perciformes, characterized by two dorsal fins, compressed body, prominent anal spines, and pelvic fins thoracic and with one spine and five soft rays. While these are the "true perches," the term also is used collectively for all members of the family Percidae, a group of over 200 species that also includes such taxa as the pikeperches (Sander sp., including the walleye, Sander vitreus) and the North American darters (four genera). The order Perciformes, which means "perch-like," also is often known as the perch order. This article will be on the genus Perca, which has three extant species.

Some other fish in other families also utilize the common name of perch, such as the white perch (Morone americana) in the Moronidae family and the ocean perch (Sebastes marinus) in the Sebastidae family.

Perch (Perca sp.) provide important ecological, culinary, commercial, and recreational values. Ecologically, they are important in food chains, consuming zooplankton and later benthic microinvertebrates when small and fish prey when larger, and being preyed upon by many fish species (walleyes, northern pike, lake trout, etc.) as well as various birds (gulls, diving ducks, etc.). In a culinary sense, perch are popular in restaurants. Indeed, yellow perch (Perca flavescens) is considered to be one of the finest flavored panfish, and perhaps for this reason the name perch is commonly used in restaurants for unrelated species of fish. In terms of recreation, perch are a very popular fish for sport fishing.

The popularity of perch as food has lead to a substantial commercial fishery. Likewise, the popularity of perch for fishing has lead to the commercial raising of perch for stocking in ponds and to the development of economic benefit through attracting tourists and fishermen.

Overview and description

Perciformes, the order to which perch belong, is the most diverse order of ray-finned fish (Actinopterygii). Indeed, about 40 percent of all species of bony fish are in Perciformes. The name Perciformes comes from the Greek perke, meaning "perch," and the Latin forma, meaning "shape."

Percidae is one of the larger families in Perciformes, with 201 known species placed within ten genera. Member of Percidae are characterized by two dorsal fins, which are separate or narrowly joined (except for Zingel, in which they are broadly joined), and the pelvic fins, which are thoracic, have one spine and five soft rays. There are five to eight branchiostegal rays, the branchiostegal membrane is not joined to the isthmus. The largest member of the family is the walleye (Sander vitreus), which reaches up to 90 centimeters (35 inches) (Nelson 2006).

Nelson (2006) places the ten genera of Percidae into three subfamilies: Percinae, Luciopercinae, and Etheostomatinae. The genus Perca, or true perches, is part of the subfamily Percinae, along with the genera Gymnocephalus and Percarina. This subfamily is characterized by having prominent and usually well-developed anal spines, a well-developed swim bladder, a strongly serrate preopercle, and usually seven or eight branchiostegal rays (Nelson 2006).

The Perca genus has three species: Perca fluviatilis (Eurasian), P. flavescens (north America), and P. schrenki (primarily Balkhash and Alakul' lakes area of Asia). All are freshwater and found in the Northern Hemisphere (as characteristic for the family), but P. fluviatilis has been introduced into several Southern Hemisphere countries, including Australia. The Eurasian P. fluviatilis and the North American P. flavescens are nearly identical (Nelson 2006).

The type species for this genus is the European perch.

Overall, perch have a compressed body with "rough" or ctenoid scales. On the anterior side of the head are the maxilla and lower mandible for the mouth, a pair of nostrils, and two lidless eyes. On the posterior sides are the opercula, which are used to protect the gills. Also there is the lateral line system that is sensitive to vibrations in the water. They have a pair of pectoral and pelvic fins. On the anterior end of the fish, there are two dorsal fins. The first one is spiny and the second is soft. There is also an anal fin, which is also considered spiny, and a caudal fin. Also there is a cloacal opening right behind the anal fin. All perciform (Perciformeds) fish share the perch's general morphology.

Species

Most authorities recognize three species of perch:

• The European perch (Perca fluviatilis) is usually dark green, with red pelvic, anal, and caudal fins. They have five to nine dark vertical bars on their sides. Found in Europe and Asia, the European perch has been successfully introduced in South Africa, New Zealand, and Australia (Nelson 2006). It also is known as redfin perch or English perch. The perch can live for up to 22 years. The maximum recorded length is 60 centimeters (24 inches) and reach a maximum weight of around 10.4 kilograms (23 pounds) in Australasia, but are smaller in Europe.

• The Balkhash perch (Perca schrenkii) is found in Kazakhstan (in Lake Balkhash and Lake Alakol), Uzbekistan, and China. It is very similar to the European perch, and grows to a comparable size.

• The yellow perch (Perca flavescens) is found in the United States and Canada, mainly in lakes and sometimes the impoundments of larger rivers (Creque 2000). Yellow perch look similar to the European perch but are paler and more yellowish, with less red in the fins. The adult P. flavescens are usually a golden yellow, while the young are more whitish (Creque 2000). They have six to eight dark vertical bars on their sides. Yellow perch size can vary greatly between bodies of water, but adults are usually between four to ten inches (10-25.5 centimeters) in length and weigh about 5.29 ounces (150 grams) on average. The perch can live for up to 11 years, and older perch are often much larger than average; the maximum recorded length is 21.0 inches (53.3 centimeters) and the largest recorded weight is 4.2 pounds (1.91 kilograms). They are a schooling fish.

Because of their similar appearance and ability to cross-breed, the yellow perch and European perch have sometimes been classified as the same species, with the yellow perch as a subspecies of the European perch. In such taxonomies, the yellow perch's trinomial name would be Perca fluviatilis flavescens. However, it is unclear whether or not hybrids are viable, and most classifications treat the two fish as separate species.

Perch as a food fish

Perch are a popular panfish and are considered to be very good eating; the commercial catch for them has always been in high demand. Yellow perch are one of the finest flavored of all panfish. This has also led to considerable misuse of the term "perch" in the restaurant business in the United States, such as "ocean perch" (the rose fish, Sebastes marinus, or Sebastes norvegicus) and "rock perch" (a small bass, Ambloplites rupestris, Ambloplites ariommus, or Ambloplites constellatus). Many restaurants will strive to correctly advertise the offering as "yellow lake perch," or the slightly more ambiguous "lake perch." "White perch" (Morone americana), though good eating, is a completely different species of panfish common in New England, and not a member of the family Percidae, but of Moronidae.

Angling

Perch can be caught with a variety of methods, but the two best methods are perhaps float fishing and lure fishing. Spinners work exceptionally well. When float fishing, the angler will want to have a disgorger at all times; Perch are notorious for swallowing the hook, and will need aid of a disgorger or forceps for unhooking. In many parts of the world, they are also a favorite species among ice fishermen. They will take a variety of baits, including minnows, worms, maggots, bread and softshell crayfish.

While perch can grow to several pounds, the most common fish to be caught are around one pound (0.45 kilograms) or less, and anything over two pounds (0.91 kilograms) is considered a good catch.

References

ISBN links support NWE through referral fees

• Craig, J.F. 1987. The Biology of Perch and Related Fish. London: Croom Helm. ISBN 0709934629.
• Creque, S. 2000. Perca flavescens Animal Diversity Web. Retrieved December 06, 2008.
• Ellis, J. 1993. The Sunfishes: A Fly Fishing Journey of Discovery. Bennington, VT: Abenaki Publishers. ISBN 0936644176.
• Luna, S.M., and A.K. Ortañez. 2008. Perca flavescens (yellow perch) FishBase. (R. Froese and D. Pauly, editors). Retrieved December 6, 2008.
• Nature Serve. 2008. Perca flavescens - (Mitchill, 1814) Nature Serve. Retrieved December 6, 2008.
• Nelson, J.S. 2006. Fishes of the World, 4th edition. Hoboken, NJ: John Wiley & Sons. ISBN 0471250317.
• Rice, F.P. 1964. America's Favorite Fishing: A Complete Guide to Angling for Panfish. New York: Harper Row.
• ———. 1984. Panfishing. New York: Stackpole Books. ISBN 0943822254.