Fishes of Wisconsin: Louis Agassiz & the Mississippi Silvery Minnow

Last year we launched an overly ambitious project here on the blog – post each week about one of the 183 species on the epic “FIshes of Wisconsin” poster. That proved easier said than done, but we’re back and ready to tackle more of the 13-foot-long behemoth.

Panorama is a must for a poster this epic. Kandis Elliot's "Fishes of Wisconsin" poster.
Panorama is a must for a poster this epic. Kandis Elliot’s “Fishes of Wisconsin” poster.

This week, a few interesting tidbits about the Mississippi silvery minnow (Hybognathus nuchalis). 
Photo: Marilyn Larsen
Photo: Marilyn Larsen

The Mississippi silvery minnow, like most (but not all) minnows is a small, silver-colored fish found in large schools. This particular minnow prefers the slack water habitat or pools and backwaters  along medium to large rivers and streams. It’s range stretches all along its namesake river from Wisconsin to the Mississippi delta, although it doesn’t stray too far east or west of the Mississippi (except for a population in Texas).
Hybognathus nuchalis doesn’t sit too far up the food chain – it’s a bottom feeder and, according to the “Fishes of Texas” website, mainly ingests mud or other “bottom ooze” from which it then digests and organic matter or algae present. This is made possible by its remarkably (for a minnow) long intestine, which is curled up inside of the fish but stretches to more than twice its body length.
Louis Agassiz
Louis Agassiz

One other cool fact about the Mississippi silvery minnow is that it has been an established species in the scientific literature for a long time and, in fact, was given its name by Louis Agassiz, in 1855.
Agassiz was an influential early scientist and made huge contributions to the fields of geology and zoology. (He was also a stout denier of Darwinian evolution and  held some views on humans that fall into the “scientific racism” category). However, Agassiz’s legacy and contributions to science are long – he has several species, mountains, capes, lakes and even a crater on Mars named after him.
He was also infamous for his unusual teaching style – putting a graduate student or post doc into a laboratory with only biological specimens and no instructions and demanding that the learn all there was to know about the subject at hand. Stories from Agassiz proteges led to the parable of “Agassiz and the sunfish,” which the famous poet, Ezra Pound, used to open his ABC of Reading. 

“No man is equipped for modern thinking until he has understood the anecdote of Agassiz and the fish:

A post-graduate student equipped with honors and diplomas went to Agassiz to receive the final and finishing touches. The great man offered him a small fish and told him to describe it.

Post-Graduate Student: ‘That’s only a sunfish.’

Agassiz: ‘I know that. Write a description of it.’

After a few minutes the student returned with the description of the Ichthus Heliodiplodokus, or whatever term is used to conceal the common sunfish from vulgar knowledge, family of Heliichtherinkus, etc., as found in textbooks of the subject.

Agassiz again told the student to describe the fish.

The student produced a four-page essay. Agassiz then told him to look at the fish. At the end of three weeks the fish was in an advanced state of decomposition, but the student knew something about it.”

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For more on the minnow, check out the Fishes of Texas website. 

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