Blue eyeglass

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Blue eyeglass
Blue Eyeglass (NOAA)

Blue Eyeglass ( NOAA )

Systematics
Order : Perch-like (Perciformes)
Subordination : Percoidei
Family : Real perch (Percidae)
Genre : Sander
Type : Glass eye perch
Subspecies : Blue eyeglass
Scientific name
Sander vitreus glaucus
( Hubbs , 1926)

The blue eye perch ( Sander vitreus glaucus , syn: Stizostedion vitreum glaucum ) is an extinct subspecies of the glass eye perch ( Sander vitreus ).

description

When it was first described scientifically by Carl Leavitt Hubbs in 1926, it still had the species status and was given the name Stizostedion glaucum . In 1936, however, it was reclassified as a subspecies Stizostedion vitreum glaucum .

With a length of 21 to 41 centimeters and a weight of 225 to 680 grams , the blue eye perch was significantly smaller than the nominate form , which can reach lengths of over 75 centimeters and a weight of over seven kilograms. Its back was colored steel or slate blue, the sides were silvery ice blue and the underside silvery white. In addition, it had bigger eyes than the glass eye bass and the fins were blue and white.

distribution and habitat

The original distribution of the blue eye perch extended from Lake Erie over the Niagara River to Lake Ontario .

The blue eyeglasses usually inhabited deep, cool, and somewhat murky waters with a hard bottom. In autumn and winter the fish could also be found in the shallower water. It is not known where the spawning grounds were; it could probably have been river stone or coarse gravel areas.

Way of life

Little is known about his way of life. While the glass eye perch lay their eggs in April, the spawning time of the blue eye perch was in May. The males were sexually mature at two to three years of age, the females at three to four years.

die out

The cause of its extinction was apparently a combination of phosphate over-fertilization of the waters, overfishing and competition with introduced fish species such as the Arctic smelt ( Osmerus mordax ).

In the 19th century, the blue eyeglass was a common fish in the Great Lakes region , but stocks began to fluctuate from 1915. From the first record of commercial fishing in 1885 through 1962, nearly 500,000 tons of these fish were caught. Between 1915 and 1959, 27% of the total catch quotas for Lake Erie were blue eyeglasses. In some years these catch quotas even exceeded 50%. In addition, 225 tons of phosphates per year were discharged into Lake Erie in the 1950s . This led to over-fertilization and thus to a further serious disturbance of the natural balance in the spawning grounds. In addition, the Arctic smelt, introduced by sports anglers, decimated the brood of the blue eyeglass. It was not until 1959 that it was noticed that the stocks of the blue eyeglass had collapsed to such an extent that fishing was hardly worthwhile. This fish was last detected in 1965. In 1967 the blue eye perch was placed under nature protection and officially declared extinct in September 1983.

annotation

  1. ↑ The naming as Stizostedion led to a scientific misunderstanding. It comes from Rafinesque-Schmaltz and means "small spiked bone", στἰζον ὁστέδιον - what is meant is the preoperculare . The ichthyologist Louis Agassiz claimed, however, that Rafinesque did not transliterate the Greek word correctly - he probably meant stizostethidion , "little prickly breast". Agassiz, however, used the word fugue differently for this interpretation : (Stizo | ste (thi) dion, instead of Stiz | ostedion).

literature

  • Richard Dana Ono, James D. Williams, Anne Wagner: Vanishing Fishes of North America . Stonewall Press Inc., Washington DC 1983, ISBN 0-913276-43-X .

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