Blue walleye explained

The blue walleye (Sander vitreus var. glaucus), also called the blue pike, was a unique color morph (formerly considered a subspecies) of walleye which was endemic to the Great Lakes of North America. Morphometric studies led biologists to classify the blue walleye as a separate species in 1926, although it was later downgraded to a subspecies. Listed as an endangered species by the United States in 1967, it was declared extinct in 1983.

Genetic analyses conducted in the 21st century show that the blue walleye was not genetically different from the yellow walleye (Sander vitreus), rendering the taxon invalid.

Species controversy

The blue walleye was long considered to be different from the yellow walleye.^[1] Based on morphological study, Carl Leavitt Hubbs declared the blue walleye to be a separate species in 1926.^[2] The species was later downgraded to a subspecies.^[3]

The blue walleye was a commercially valuable fish in the Great Lakes. Populations appeared to collapse quickly in the 1950s. Between 1950 and 1957, catches in the U.S. and Canada fluctuated between 2000000lb and 26000000lb a year. In 1959, however, just 79000lb were caught, and in 1964 only 200lb.^[4] The United States declared blue walleye an endangered species in 1967,^{[5] [6]} and extinct in 1983.^{[7] [6]}

A 2014 genetic study of 1,181 preserved "historic" walleye (70 to 90 years old), blue walleye/blue pike, and modern walleye found no evidence for concluding that blue walleye/blue pike were genetically distinct from other walleye.^[8] This rendered the taxon invalid.^[9]

Occasionally, grey-blue or steel-blue walleye are caught in Lake Erie, Lake Ontario, and the Ohio River drainage.^[10] Dark blue yellow perch are also sometimes caught in the same areas.^[11]

A turquoise-colored walleye exists in some waters of the Canadian Shield.^[12] A mucosal pigment, named "sandercyanin", was hypothesized to be the source of the color,^[13] but this has not been confirmed.^[14] This fish was also thought to be a separate subspecies of walleye, but genetic testing showed there is no difference between the turquoise walleye and yellow walleye.

Description

Sander vitreus "glaucus" also known as the "blue pike" is endemic to Lakes Erie and Ontario and co-occurred with Sander vitreus vitreus. It is compared to the walleye in many aspects however, the "blue pike" inhabits the deeper and cooler areas of Lake Erie but was also seen in shallow and warmer areas alongside the walleye. In comparison to the walleye the "blue pike" has a steel blue color, larger eyes placed bit higher than the walleyes eye placement, and the eye distance is smaller as well. ^[15]

Further reading

• Hubbs, Carl L. (1926). A Check-List of the Fishes of the Great Lakes and Tributary Waters, with Nomenclatorial Notes and Analytical Keys. University of Michigan Museum of Zoology Special Publications No. 15. Ann Arbor: University of Michigan. 77 pp. + Plates I-IV. (Stizostedion glaucum, new species, pp. 58–59 + Plate IV, figure 2).
• Trautman, Milton B. (1981). The Fishes of Ohio. Columbus, Ohio: Ohio State University Press. 782 pp. . (Stizostedion vitreum glaucum, new combination).

Notes and References

1. Book: Bolsenga. S.J.. Herdendorf. Charles E.. Lake Erie and Lake St. Clair Handbook. Detroit. Wayne State University Press. 1993. 9780814324707. 323.
2. Book: Wallus. Robert. Scott. Edwin M.. Genus: Sander (Rafinesque). Reproductive Biology and Early Life History of Fishes in the Ohio River Drainage. Vol. 4: Percidae - Perch, Pikeperch and Darters. Simon. Thomas P.. Wallus. Robert. Boca Raton, Fla.. CRC Press. 2004. 084931920X. 570.
3. Bennett. David Henry. Probable Walleye (Stizostedion Vitreum) Habitation in the Snake River and Tributaries of Idaho: Research Technical Completion Report. Boise, Idaho. Idaho Water Resources Research Institute, University of Idaho. 1979. 5525598. 4.
4. Book: Trautman, Milton B.. The Fishes of Ohio. Columbus, Ohio. Ohio State University Press. 1981. 9780814202135. 613.
5. Book: Wilcove, David Samuel. The Condor's Shadow: The Loss and Recovery of Wildlife in America. New York. Anchor Books. 2000. 9780385498814. 129.
6. Web site: Blue pike (Stizostedion vitreum glaucum). Environmental Conservation Online System. U.S. Fish & Wildlife Service. 30 April 2023.
7. Book: Weidensaul, Scott. The Ghost With Trembling Wings: Science, Wishful Thinking, and the Search for Lost Species. New York. North Point Press. 2002. 9780374246648. 72.
8. Haponski. Amanda E.. Stepien. Carol A.. Carol Stepien. A population genetic window into the past and future of the walleye Sander vitreus: relation to historic walleye and the extinct 'blue pike' S. v. 'glaucus'. BMC Evolutionary Biology. 2014. 14. 133. 10.1186/1471-2148-14-133. 4229939. 24941945. 133 . free .
9. Book: Stepien. Carol A.. Haponski. Amanda E.. Taxonomy, Distribution, and Evolution of the Percidae. Biology and Culture of Percid Fishes: Principles and Practices. Kestemont. P.. Dabrowski. Konrad. Summerfelt. Robert C.. New York. Springer. 2015. 9789401772266. 21.
10. Book: Trautman, Milton B.. The Fishes of Ohio. Columbus, Ohio. Ohio State University Press. 1981. 9780814202135. 611, 613. none.

    Book: Scott. William B.. Crossman. Edwin J.. Freshwater Fishes of Canada. Bulletin 184. Ottawa. Fisheries Research Board of Canada. 1973. 256035728. April 27, 2018. 768. none. ; News: Fish thought extinct caught in Tennessee. United Press International. February 9, 2012. September 30, 2018. none. ; News: Blue pike extinct, but did they ever really exist?. The Coloradoan. March 19, 2014. September 30, 2018. none. ; News: Bowman. Dale. Blue pike, silver pike, walleye: Tracking fishing mystery and words. Chicago Sun-Times. July 11, 2016. September 30, 2018.

11. Book: Trautman, Milton B.. The Fishes of Ohio. Columbus, Ohio. Ohio State University Press. 1981. 9780814202135. 612. none.

    Book: Scott. William B.. Crossman. Edwin J.. Freshwater Fishes of Canada. Bulletin 184. Ottawa. Fisheries Research Board of Canada. 1973. 256035728. April 27, 2018. 755–756.

12. Paradis. Yves. Magnan. Pierre. Phenotypic variation of walleye, Sander vitreus, in Canadian Shield lakes: New insights on percid polymorphism. Environmental Biology of Fishes. 2005. 73. 4. 357–366. 10.1007/s10641-005-2261-1. 22471516. April 27, 2018.
13. Yu. Chi-Li. Ferraro. Daniel. Ramaswamy. S.. Schmitz. Mark H.. Schaefer. Wayne F.. Gibson. David T.. Purification and properties of sandercyanin, a blue protein secreted in the mucus of blue forms of walleye, Sander vitreus. Environmental Biology of Fishes. 2008. 82. 1. 51–58. 10.1007/s10641-007-9252-3. 20912874.
14. Schaefer. Wayne F.. Schmitz. Mark H.. Blazer. Vicki S.. Ehlinger. Timothy J.. Bergese. John A.. Localization and seasonal variation of blue pigment (sandercyanin) in walleye (Sander vitreus). Canadian Journal of Fisheries and Aquatic Sciences. 2015. 72. 2. 281–289. 10.1007/s10641-005-2261-1. 22471516. April 27, 2018.
15. Hamponski. Amanda. Stepien. Carol. 2014. A population genetic window into the past and future of the walleye Sander vitreus: relation to historic walleye and the extinct "blue pike" S-v. "glaucus". BMC Evolutionary Biology. 17 June 2014. 14. 1–21. 10.1186/1471-2148-14-133. 24941945. 4229939. free.