Common bluegill
| Common bluegill | ||||||||||||
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Common bluegill |
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| Scientific name | ||||||||||||
| Lepomis gibbosus | ||||||||||||
| ( Linnaeus , 1758) |
The Common sunfish or pumpkinseed perch ( Lepomis gibbosus : lepomis haplology for lepopomis of . Gr : LEPOs "Scale" Poma "cover"; lat. : Gibbosus "humped") is a colorful representative of the sunfish .
distribution and habitat
The original distribution area extends in North America between North Dakota to New Jersey and from Hudson Bay to South Carolina . In the meantime, the common bluegill has spread to the west coast of the United States , mainly through restocking .
As a neozoon , the freshwater fish is naturalized in large parts of Europe, with the exception of Northern Europe. It was first introduced in France in 1877 as a sport fish and for stocking garden ponds. This sun bass was found in Germany as early as 1880 . The distribution is not widespread, however, in Germany occurrences of the common sunfish are to be found mainly in the southwest and in the immediate vicinity of metropolitan areas. Occasionally, new populations are created through illegal stocking. Accidental spreading with other fish species has also been reported.
The preferred habitat are stagnant and slowly flowing waters with clear water and dense vegetation to protect against predators. In summer, the common sunfish live closer to the ground, in a water depth of one to two meters. In winter, however, it also retreats to deeper stretches of water.
features
The common bluegill has a stocky, tall body that is compressed at the sides. Overall, the appearance looks robust. In the wild it reaches a size of 15 to almost 30 centimeters, when kept in an aquarium it remains much smaller. The gap in the mouth is small and does not reach the eyes. Young fish up to a size of four to eight centimeters have a gray-green basic color with five to eight transverse bands that shimmer like mother-of-pearl. In the adult animals a brownish basic color predominates, while the transverse bars shimmer green-blue. Red, yellow-red, blue and emerald-colored swabs are scattered all over the body. The belly and throat are a strong orange, the fins green to yellow. Red lines and dots cover the green, shiny gill covers . The black gill cover flap (the so-called "ear") ends in a crescent-shaped orange border. This edge is the reason for the English name Pumpkinseed and the German common name pumpkin seed perch.
The fin formula is:
- Dorsal X / 10-12
- Anal II / 10-11
- Pectoral 12
The only external characteristic for differentiating the sexes is the less intense coloration of the females.
Differences in growth and size
The growth speed of the larvae and young specimens of the common bluegill is almost identical in North America and Europe. In contrast, there are significant differences in adult animals. In North America these grow much faster and become larger than their European counterparts. Differences in size can also be determined depending on the latitude . North American animals reach a smaller size in the northern ranges than in the southern, in Europe the ratio is reversed.
Way of life
The common sunfish feed on a wide range of small animals: insects and their larvae, snails , crabs and leeches , and small fish are also captured. The food spectrum is supplemented by small amounts of plant-based food. The foraging takes place throughout the day, but the afternoon hours are the time of the most intense hunt.
Like all members of its family, the common sunfish also practices intensive brood care. At spawning time, the male looks for shallow water with a sandy or gravel-covered bottom. With the caudal fin it fans a shallow pit about 30 centimeters in diameter and five to seven centimeters deep, larger objects are removed with the mouth. The milkman defends this spawning pit and its immediate surroundings extremely aggressively. Both male conspecifics and alien fish are attacked. While the nest is being built, the female waits for completion in deeper water. It then approaches the nest and the male apparently tries to chase it away again. After several repetitions, the male allows access to the spawning pit and after a few mock pairings the actual spawning act takes place. The eggs released are clear and colorless, sticky and about one millimeter in diameter. Females can spawn in multiple nests and usually different females spawn in one nest. The father animal alone takes care of and guarding the clutch. It fins the eggs and the hatched larvae with fresh water until they have consumed their yolk sac. At a water temperature of 28 degrees Celsius, hatching occurs within three days, at lower temperatures the brood lasts longer. Larvae that leave the nest early are brought back by the father in his mouth. After ten to eleven days of life, the larvae are able to feed themselves.
During one spawning season a male can raise several broods, an adult female produces 4,000 to 7,000 eggs during this time.
Sexual maturity is reached after about two years, the maximum age in nature is about six to eight years. Specimens kept in captivity are said to be able to live up to twelve years.
Role in the ecosystem
In its native habitat, the common bluegill is an important prey for a number of larger predatory fish and fish-eating birds. Since he meets the predation pressure with a high reproduction rate , populations without corresponding predators tend to mass reproduction and stunted growth. The common sunfish exerts considerable feeding pressure on young and small fish. However, a displacement of native species in the newly populated areas has not yet been proven.
When meeting other Lepomis species, crosses can very easily occur, these hybrids are not fertile .
Economical meaning
As a tasty fish that stays small, the common sunfish is largely uninteresting for fishing. Because of its blaze of color, however, it is sold in the trade as an aquarium fish and stock for garden ponds.
literature
- Günther Sterba : Freshwater fish in the world. Weltbild, Augsburg 1998, ISBN 3-89350-991-7 .
- Horst Müller: Fish of Europe. Neumann, Leipzig 1983, ISBN 3-7402-0044-8 .
- Rüdiger Riel, Hans A. Baensch : Aquariums Atlas: Volume 1, Mergus, Melle 2002, ISBN 3-88244-065-1 .
- Andreas Arnold: Naturalized fish species. Ziemsen, Wittenberg Lutherstadt 1990, ISBN 3-7403-0236-4 .
- Olaf Geiter, Susanne Homma, Ragnar Kinzelbach: Inventory and evaluation of neozoa in Germany. (PDF; 3.3 MB) In: Texts. 25/02, 2002, ISSN 0722-186X .
Web links
- Sunfish on Fishbase.org (English)
- Lepomis gibbosus on the Animal Diversity Web (English)
- Species description at the University of Wisconsin Sea Grant Institute (English)
- Peter Dehus: Alien fish species and their importance for our waters (PDF, 41 kB)
- Lepomis gibbosus inthe IUCN Red List of Threatened Species 2013.2. Posted by: NatureServe, 2012. Retrieved February 10, 2014.
Individual evidence
- ↑ a b Gordon Copp, Michael Fox, Mirosław Przybylski, Francisco Godinho, Anna Vila-Gispert: Life-time growth patterns of pumpkinseed Lepomis gibbosus introduced to Europe, relative to native North American populations. ( Memento of the original from August 24, 2005 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: Folia Zoologica. No. 53, 2004, ISSN 0139-7893 , pp. 237-254
- ↑ a b Günter Sterba: Freshwater fish of the world. 1998, p. 661
