University of South Carolina Scholar Commons Theses and Dissertations Spring 2020 Morphological Changes in the Visual Sensory System of Congeneric Fishes Inhabiting Clear and Turbid Aquatic Environments Habeeb Mohsin Hammadi Alsudani Follow this and additional works at: https://scholarcommons.sc.edu/etd Part of the Biology Commons Recommended Citation Alsudani, H. M.(2020). Morphological Changes in the Visual Sensory System of Congeneric Fishes Inhabiting Clear and Turbid Aquatic Environments. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/5939 This Open Access Dissertation is brought to you by Scholar Commons. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. MORPHOLOGICAL CHANGES IN THE VISUAL SENSORY SYSTEM OF CONGENERIC FISHES INHABITING CLEAR AND TURBID AQUATIC ENVIRONMENTS by Habeeb Mohsin Hammadi Alsudani Bachelor of Fisheries & Marine Resources University of Basrah, 1998 Master of Fish Physiology & Histology University of Basrah, 2009 Submitted in Partial Fulfillment of the Requirements For the Degree of Doctor of Philosophy in Biological Sciences College of Arts and Sciences University of South Carolina 2020 Accepted by: Joseph M. Quattro, Major Professor Roger Sawyer, Major Professor Soumitra Ghoshroy, Committee Member Daniel Speiser, Committee Member Wayne Carver, Committee Member Cheryl L. Addy, Vice Provost and Dean of the Graduate School © Copyright by Habeeb Mohsin Hammadi Alsudani, 2020 All Rights Reserved. ii DEDICATION To the souls of my parents and brothers, my beloved wife, the flowers of my life (My sons Mohsin, Asif, and Elias), all my family and all my teachers and friends without whom it was almost impossible to finish this work. iii ACKNOWLEDGEMENTS I would like to express my sincere gratitude to my dissertation advisor Prof. Roger Sawyer and Prof. Joseph M. Quattro for their great support and encouragement throughout my doctoral study on the scientific and personal level. I am grateful especially for Dr. Soumitra Ghoshroy, who has taught me the initials in the field of Electron Microscopy. I would like to extend my gratitude to my dissertation committee members Dr. Daniel Speiser and Dr. Wayne Carver for their guidance and discussion. I gratefully acknowledge the financial support provided by the Iraqi Ministry of Higher Education and Scientific Research for covering all my study cost at the University of South Carolina. I owe my appreciation to my professors and colleagues at the University of Basrah and the Iraqi Cultural Office at Washington DC, for their continuous encouragement during my study. Special thanks to Dr. Basim Jasim, Dr. Fatima Sultan, Dr. Jassim Mohsen Abed and Dr. Amjed K. Resen for their support and encouragement. Many thanks to Fritz Rohde (NOAA Federal) without him would not have been possible getting the samples, and my former and current colleagues in Department of Biological Sciences for their friendship and sharing ideas especially Matthew Greenwold. No words can describe my deepest gratitude to my brothers with their families especially Ali Alsudany and Dr. Salah Alsudany for being always with me and for me. From deep in my heart, I would love to express my heartful thanks to my wife Hind and my sons Mohsin, Asif, and Elias for their patience, support, and encouragement. iv ABSTRACT This study examined the histological aspects of the visual system of six species of fish. Menidia extensa and Fundulus waccamensis are found in Lake Waccamaw, which is a unique aquatic environment of the Atlantic coastal plain characterized by low turbidity, higher pH and clarity. Menidia beryllina, Menidia menidia, Fundulus diaphanus and Fundulus heteroclitus are found in the Waccamaw River, which is characterized by high turbidity. These species have undergone morphological changes likely related to inhabiting two ecological systems that differ in their environmental characteristics. We tested the hypothesis that fish modify their visual system to adapt to various environments. The advantage of the present study was that all parts of the retina were examined using the modified method of Alsudani et al 2018. The number of rods and cones calculated in the whole retina. It was found that light availability has a significant influence on the quality of the visual system. The number of cones are higher in bright environment of both genera. It was observed that a higher number of rods across species in Waccamaw River found to have acclimatized to low light environments. Furthermore, these species are characterized by having a pattern of photoreceptors called double layers that are considered as a method of optimal exploitation of light available in improving vision. Also, the investigation was to evaluate the effects that the quantity of light available in a specific habitat has on the development of the optic nerve and optic tectum in six species of fish. The results suggest that light has a specific influence on the development of both optic nerve and tectum. The number of optic nerve fibers in clear water fish are higher than for v dark water fish. The size of the optic tectum is smaller in fish that inhabit dark water compared to that for clear water fish. vi TABLE OF CONTENTS DEDICATION…………………………………………………………………………... iii ACKNOWLEDGEMENTS……………………………………………………………... iv ABSTRACT……………………………………………………………………………… v LIST OF TABLES………………………………………………………………………. ix LIST OF FIGURES……………………………………………………………………… xi CHAPTER 1. INTRODUCTION…………………………………………………………1 INTRODUCTION……………………………………………….………...…...…. 2 CONVERGENCE AND PARALLELISM EVOLUTION…………..………….… 3 CONVERGENT EVOLUTION………………...……………………...…………. 6 CONVERGENT EVOLUTION OF FISH………………….……………………... 8 CONVERGENT EVOLUTION OF EYE………………..………………………. 11 RESEARCH OBJECTIVES……………………………….…………………….. 14 CHAPTER 2. IMPROVED BIOLOGICAL TISSUE PREPARATION PROCEDURE FOR SCANNING ELECTRON MICROSCOPIC IMAGING…………...…….…17 INTRODUCTION……………….………………………………………………. 18 RESULTS AND DISCUSSION…………………………………………….…… 18 vii CHAPTER 3. DIFFERENCES EXIST IN THE HISTOLOGICAL STRUCTURE OF THE EYE MANIFESTED IN THE MOSAIC STRUCTURE OF THE RODS AND CONE…………………………………………………………………………..... 24 INTRODUCTION………………….……………………………………………. 25 METHODS…………………..…………………………………………………... 29 RESULTS…………….……….…………………………………………………. 30 DISCUSSION …………………………………………………………………... 36 CHAPTER 4. DIFFERENCES EXIST IN THE HISTOLOGICAL STRUCTURE OF THE OPTIC NERVE, WHICH INCLUDES THE NUMBER AND SIZE OF THE NERVE FIBERS WITHIN THE OPTIC NERVE………………………………. 56 INTRODUCTION…………………………..…………………………………… 57 METHODS……………………..…………………………………………….….. 60 RESULTS…………………………………………..……………………………. 62 DISCUSSION ……………………………………………………………………64 CHAPTER 5. SUMMARY AND CONCLUSIONS ……...…………………………… 81 SUMMARY AND CONCLUSIONS …………………………………………... 82 REFERENCES………………………………...……………………………...…………83 viii LIST OF TABLES Table 3.1: Total Length of Fish (TL) mm, The Diameter of Eyeball (DE) µm, % Diameter of Eyeball to Total Length (D/L), Number of Rod (NR), Number of Cone (NC), Total Number of Photoreceptor (NP), % Rod to Photoreceptor (R\P), % Cone to Photoreceptor (C/P), and % Rod to Cone (C/R) with mean (M) ± standard deviation (SD) of different individuals of Menidia extensa. ........................................................................................ 42 Table 3.2: Total Length of Fish (TL) mm, The Diameter of Eyeball (DE) µm, % Diameter of Eyeball to Total Length (D/L), Number of Rod (NR), Number of Cone (NC), Total Number of Photoreceptor (NP), % Rod to Photoreceptor (R\P), % Cone to Photoreceptor (C/P), and % Rod to Cone (R/C) with average (A) ± standard deviation (SD) of different individuals of Menidia beryllina. ...................................................................................... 43 Table 3.3: Total Length of Fish (TL) mm, The Diameter of Eyeball (DE) µm, % Diameter of Eyeball to Total Length (D/L), Number of Rod (NR), Number of Cone (NC), Total Number of Photoreceptor (NP), % Rod to Photoreceptor (R\P), % Cone to Photoreceptor (C/P), and % Rod to Cone (R/C) with mean (M) ± standard deviation (SD) of different individuals of Menidia menidia. ....................................................................................... 44 Table 3.4: Total Length of Fish (TL) mm, The Diameter of Eyeball (DE) µm, % Diameter of Eyeball to Total Length (D/L), Number of Rod (NR), Number of Cone (NC), Total Number of Photoreceptor (NP), % Rod to Photoreceptor (R\P), % Cone to Photoreceptor (C/P), and % Rod to Cone (R/C) with mean (M) ± standard deviation (SD) of different individuals of Fundulus waccamensis. ............................................................................. 45 Table 3.5: Total Length of Fish (TL) mm, The Diameter of Eyeball (DE) µm, % Diameter of Eyeball to Total Length (D/L), Number of Rod (NR), Number of Cone (NC), Total Number of Photoreceptor (NP), % Rod to Photoreceptor (R\P), % Cone to Photoreceptor (C/P), and % Rod to Cone (R/C) with mean (M) ± standard deviation (SD) of different individuals of Fundulus diaphanus. .................................................................................. 46 Table 3.6: Total Length of Fish (TL) mm, The Diameter of Eyeball (DE) µm, % Diameter of Eyeball to Total Length (D/L), Number of Rod (NR), Number of Cone (NC), Total Number of Photoreceptor (NP), % Rod to Photoreceptor (R\P), % Cone to Photoreceptor (C/P), and % Rod to Cone (R/C) with mean (M) ± standard deviation (SD) of different individuals of Fundulus