Sturgeon Fishes

2.4.4 Cleavage Defects.- 2.4.5 Percentage of Fertilization.- 2.5 Gastrulation.- 2.5.1 Reorganization of the Embryo During Gastrulation.- 2.5.2 The Fate Map by the Beginning of Gastrulation and the Dynamics of Morphogenetic Movements.- 2.5.3 Inductive Interactions During Gastrulation.- 2.5.4 Gastrulation Defects.- 2.6 Development of the Embryo from the End of Gastrulation to the Onset of Heart Beating.- 2.6.1 Neurulation.- 2.6.2 Development of the Embryo from the Closure of the Neural Folds to the Onset of Heart Beating.- 2.6.3 Developmental Defects.- 2.7 Development of the Embryo from the Onset of Heart Beating to the Time of Hatching.- 2.7.1 Morphology of the Embryo.- 2.7.2 Structure of Atypical Embryos at the End of Incubation.- 2.7.3 Duration of the Hatching Period and the Means by Which the Embryos are Liberated from Their Membranes.- 2.8 Duration and Rate of Embryogenesis in Various Acipenserid Species and Their Dependence on Temperature. Chronology of Development.- 2.8.1 Duration of Embryogenesis as Expressed in Astronomical Time Units.- 2.8.2 Relative Duration of Embryonic Periods.- 2.8.3 Method of Characterizing the Duration of Various Developmental Periods in Dimensionless Values.- 2.8.4 The Age of Embryos and Chronology of the Embryogenesis.- 3 Development of Prelarvae.- 3.1 Characteristics of the Prelarval Period of Development.- 3.2 Stages of Prelarval Development.- 3.3 Timing of Prelarval Development.- 3.4 Prelarval Development During the Period Between Hatching and up to the Beginning of Rhythmic Respiratory Movements.- 3.5 Development of Prelarvae from the Beginning of Rhythmic Respiratory Movements and up to Transition to Active Feeding.- 3.6 Differences Between Prelarvae of Different Sturgeon Species A. gueldenstaedti H. huso, A. stellatus, A. ruthenus, P. kaufmanni.- 3.7 Defects of Prelarval Development.- 4 Environmental Conditions of Spawning and Development.- 4.1 General.- 4.1.1 The Concept of Thresholds.- 4.1.2 Spawning Conditions.- 4.1.3 Relationships of the Developing Embryo with the Environment at Various Developmental Stages.- 4.2 Temperature Range.- 4.3 Oxygen Content of Water and Gas Metabolism in Embryos.- 4.4 Light Conditions.- 4.5 Quality of Water.- 4.6 The Range of the Ecological Optimum.- 5 Control of Incubation Conditions.- 5.1 General.- 5.2 Duration of Development as a Criterion for the Evaluation of Incubation Conditions.- 5.3 Normal Embryonic and Prelarval Development.- 5.4 Losses During Incubation, Their Magnitude and Sources.- Appendix A Quick Method for the Determination of Gonad Maturity in the Sturgeon (Kazanskii et al. 1978).- Appendix B Duration of Oocyte Maturation Time in Vitro as a Criterion for Selecting Sturgeon Spawners for Breeding (B.E Goncharov).- Appendix C Comparative Quantitative Determination of the Gonadotropic Activity in Sturgeon Pituitaries (Goncharov 1972).- Appendix D Relative Characteristic of Developmental Duration.- Appendix E Determination of Time for Injection of Pituitary Suspension and Inspection of Females After Pituitary Injection for Obtaining Eggs at the Optimal Time at Different Temperatures.- E.2 Determination of Time for Inspection of Females and Collecting Eggs.- E.3 Example for Calculation of the Maturation Time and Time of Female Inspection.- Appendix F Artificial Insemination of Sturgeon Eggs (Ginsburg 1963).- Appendix G Sampling for Determination of Fertilization Percentage, Extent of Losses, and Percentage of Abnormal Embryos.- Plates I-XX.- Abbreviations for Figures and Plates.- References.