Long-jawed whitefish
| Long-jawed whitefish | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Coregonus alpenae | ||||||||||||
| ( Koelz , 1924) |
The Longjaw Cisco ( Coregonus alpenae ) is an extinct Tiefwassermaräne , usually at depths of 100 meters or more in lakes Huron , Michigan and Erie occurred. Its scientific name is derived from the place Alpena in Michigan.
description
It reached an average length of 28 cm. The largest long-jawed whitefish was 54.6 cm long, weighed 1.8 kg and was caught in Manistique, Lake Michigan in 1932. The body was elongated and compressed on the sides, but sturdy. The heavy head was short and broad. The broad mouth was a little rounded. The eyes were poorly developed. The heavy lower jaw protruded from the upper jaw. The jaws were usually pigmentless and extended beyond the anterior edge of the eyes. The long-jawed whitefish was generally silvery in color with a pink or purple tinge. The back was bluish or greenish, the flanks silver and the underside white. The pigmentation on the jaws and fins was very light.
Since the scheme of whitefish is quite complicated, many scientists believe that the Longjaw Cisco was not a separate species but a different population physically long individuals of short pine whitefish ( Coregonus zenithicus ).
Food and way of life
The spawning season was in late autumn. Their main diet consisted of zooplankton such as the relic crab ( Mysis relicta ).
die out
The causes of their extinction were overfishing and pollution of the Great Lakes as well as parasitism by the invasive sea lamprey . The peak of commercial fishing was during the 1930s when a third of all vendace caught were made of this species. She was sold as a kipper . In the 1950s it was already extinct in Lake Erie . In 1961 she was seriously decimated in Lake Michigan . In 1967 this species was no longer recorded in commercial fishing and in 1975 the last specimen was seen in George Bay in Lake Huron in Ontario .
literature
- David Stephen Lee et al .: Atlas of North American Freshwater Fishes . North Carolina State Museum of Natural History, Raleigh 1980, ISBN 0-917134-03-6 .
Web links
- Long-jawed whitefish on Fishbase.org (English)
- Coregonus alpenae in the Red List of Threatened Species of the IUCN 2008. Posted by: World Conservation Monitoring Center, 1996. Accessed on 24 February, 2009.