9492 - Laserfiche WebLink

Home Browse Search

The source of specimens upon which selected character-range extensions are based are documented with those updates in the results section "Errata and Updated Descriptive Data for the Guide by Snyder and Muth (1990)." Culture and Developmental Study As indicated in the above list, many study specimens were part of a developmental series oflongnose sucker that had been reared in 1979 from Parvin Lake (Larimer County, Colorado) stock by E. Wick and other LFL staff. Unfortunately, that rearing effort was terminated before many specimens became metalarvae. To supplement the 1979 series and collected early juveniles used for this description, and to provide better representation of morphological diversity in the description, additional series of embryos, larvae, and early juveniles were reared from two artificially spawned broods in 2001. Like the earlier 1979 series, both broods were the progeny of captures from eastern-slope populations in north-central Colorado; attempts to secure ripe adults from western Colorado populations were unsuccessful. One brood was the progeny of a single pair of un-injected fish from among several adults captured and transported for this purpose by CD OW biologist K. Kehmeier and crew from Upper Big Creek Lake in Jackson County. The other brood consisted of the offspring from a much less successful fertilization using hormone-injected (human chorionic gonadotropin) fish-another female from among the Upper Big Creek Lake captures and a small male captured by S. Seal from the Spring Creek drainage in Fort Collins, Larimer County. The collection, holding, and use oflongnose suckers in or near spawning condition was permitted under Colorado State (scientific-collection) License 01-AQ902. Adult fish were held, hormone injected if necessary, stripped of gametes, and euthanized; and artificially fertilized eggs and subsequent progeny were reared, euthanized, and preserved in Colorado State University's indoor Aquatic Research Laboratory (Department of Fishery and Wildlife Biology) with the approval of the university's Animal Care and Use Committee (Animal Welfare Assurance Number A3572-01, Protocol Number 00-313A-Ol). The eggs for both broods were maintained in a flow-through Heath incubator, and upon hatching, the larvae were transferred for subsequent rearing to small net boxes suspended in partially shaded flow- through troughs and later directly into the troughs themselves. The incubator and troughs were served with filtered well water at about 180C. Eggs were treated once with malachite green for fungus and the larvae were fed live, and later frozen, brine shrimp as well as dry flake and semi- moist particulate food. Parallel developmental series of specimens from each brood were either fixed in 10% formalin and preserved in phosphate-buffered 3% formalin or preserved directly in 95% ethanol without prior formalin fixation. Additional details of collecting trips, adult longnose sucker captures, artificial fertilization of eggs, culture, and preservation are provided by Snyder (2001). Methods for developmental study of longnose sucker larvae and early juveniles, including analysis of morphometric, meristic, pigment, and developmental-state characters; clearing and alizarin-red staining of whole specimens for skeletal study; illustration; and data analysis and summarization generally followed Snyder and Muth (1990). However, most morphometric measurements were made using multiple digital images of the specimens and a computer image-analysis and measurement program (Optimas 5.1, Optimas Corp., Seattle). Also, digital images, rather than photographs, were enlarged and traced for major outlines and features in drawings and to illustrate selected skeletal characters. Images were captured by computer through a digital camera attached to a low-power stereo-zoom microscope or macro- 13