7174 - Laserfiche WebLink

Home Browse Search

THE UNIVERSITY OF MICHIGAN J. %1. M~ 'JM OF ZOOLOGY 4 January 1977 Dr. Roy Johnson Grand Canyon.l`iational Park Box 129 Grand Canyon.,. Arizona $6023 Dear Roy: This letter is in response to a part of the letter written to you on December 2, 1976, by Royal D. Suttkus and Glenn H. Clemmer. In paragraph 3 of that letter,theywrite as follows: "Identi- fication of-young and small juvenile specimens of Gila has not been made up to this time." I am unable to understand this statement considering that Sut was at the session in which he and I and others talked about the fishes and aquatic resources of Grand Canyon National Park, and in_which I showed a photograph of juveniles of Gila cypha, G. elegans, and G, robusta. For as long as 50 years, we have been able to identify the bonytail and the rourdtail chubs dow.~ to about 20 mm standard length, and in the past six months we have been able to identify humpback chubs down to around 30 mm S.L. In my profes- sional opinion, all of the juveni es and all of the population of chubs from the mouth of the Little Colorado River are, in fact, Gila c ha. I am enclosing the working key that was submitted with our MS just recently, that resulted from the paper presented at the conference in New Orleans. I was very disappointed that you were not at that session, considering that both Suttkus and I were talking about the fishes of Grand Canyon National Park. The MS referred to is by Gerald R. Smith, myself, and W. Daniel Sable, and is entitled, "Species Relationships Among Fishes of the Genus Gila in the IIpper Colorado River Drainage." Please note that this is an unpublished MS key and is not to be released publicly at this time. I also send a photograph (not the one submitted for publication), shotoing juveniles of the three species of chubs in the main channel Colorado River. At the top is Gila elegans, in the middle is G. cypha, and at the bottom is G. robusta. idote the indication of length. There is no question in our minds that the juvenile;and~. even the young of G. cypha can be identified if the proper procedures are used. I am still awaiting your response to my proposal for a research project on the humpback chub. Sincerely, ~~ Robert R. Miller Curator of Fishes Enc.