title: Embryonic development of lake whitefish Coregonus clupeaformis: a staging series, analysis of growth and effects of fixation.
abstract: A reference staging series of 18 morphological stages of laboratory reared lake whitefish Coregonus clupeaformis is provided. The developmental processes of blastulation, gastrulation, neurulation as well as development of the eye, circulatory system, chromatophores and mouth are included and accompanied by detailed descriptions and live imaging. Quantitative measurements of embryo size and mass were taken at each developmental stage. Eggs were 3·19 ± 0·16 mm (mean ± s.d.) in diameter at fertilization and embryos reached a total length (LT ) of 14·25 ± 0·41 mm at hatch. Separated yolk and embryo dry mass were 0·25 ± 0·08 mg and 1·39 ± 0·17 mg, respectively, at hatch. The effects of two common preservatives (formalin and ethanol) were examined throughout development and post hatch. Embryo LT significantly decreased following fixation at all points in development. A correction factor to estimate live LT from corresponding fixed LT was determined as live LT = (fixed LT )(1·025) . Eye diameter and yolk area measurements significantly increased in fixed compared with live embryos up to 85-90% development for both measurements. The described developmental stages can be generalized to teleost species, and is particularly relevant for the study of coregonid development due to additionally shared developmental characteristics. The results of this study and staging series are therefore applicable across various research streams encompassing numerous species that require accurate staging of embryos and descriptions of morphological development.
authors.affiliation: Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Sreetharan
authors.affiliation: Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L8, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Thome
authors.affiliation: Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L8, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Mitz
authors.affiliation: Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Eme
authors.affiliation: Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
authors.forename: C A
authors.initials: CA
authors.lastname: Mueller
authors.affiliation: Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L8, Canada.
authors.forename: E N
authors.initials: EN
authors.lastname: Hulley
authors.affiliation: Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, Saskatchewan, S4S 0A2, Canada.
authors.forename: R G
authors.initials: RG
authors.lastname: Manzon
authors.affiliation: Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, Saskatchewan, S4S 0A2, Canada.
authors.forename: C M
authors.initials: CM
authors.lastname: Somers
authors.affiliation: Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L8, Canada.|Northern Ontario School of Medicine, 935 Ramsey Lake Road, Sudbury, Ontario, P3E 2C6, Canada.
authors.forename: D R
authors.initials: DR
authors.lastname: Boreham
authors.affiliation: Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
authors.forename: J Y
authors.initials: JY
authors.lastname: Wilson
mesh_terms: D000818:Animals; D001756:Blastoderm / Q000254:growth & development; D004625:Embryo, Nonmammalian / Q000033:anatomy & histology; D047108:Embryonic Development; D005306:Fertilization; D010063:Ovum / Q000254:growth & development; D012487:Salmonidae / Q000196:embryology* / Q000254:growth & development
keywords: coregonid; embryo; fixative; morphology; teleost