University of New Hampshire University of New Hampshire Scholars' Repository Doctoral Dissertations Student Scholarship Spring 1978 SOME ASPECTS OF THE BIOLOGY OF THREE NORTHWESTERN ATLANTIC CHITONS: TONICELLA RUBRA, TONICELLA MARMOREA, AND ISCHNOCHITON ALBUS (MOLLUSCA: POLYPLACOPHORA) PAUL DAVID LANGER University of New Hampshire, Durham Follow this and additional works at: https://scholars.unh.edu/dissertation Recommended Citation LANGER, PAUL DAVID, "SOME ASPECTS OF THE BIOLOGY OF THREE NORTHWESTERN ATLANTIC CHITONS: TONICELLA RUBRA, TONICELLA MARMOREA, AND ISCHNOCHITON ALBUS (MOLLUSCA: POLYPLACOPHORA)" (1978). Doctoral Dissertations. 2329. https://scholars.unh.edu/dissertation/2329 This Dissertation is brought to you for free and open access by the Student Scholarship at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of University of New Hampshire Scholars' Repository. 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Silver prints of "photographs" may be ordered at additional charge by writing the Order Department, giving the catalog number, title, author and specific pages you wish reproduced. 5. PLEASE NOTE: Some pages may have indistinct print. Filmed as received. University Microfilms International 300 North Zeeb Road Ann Arbor, Michigan 48106 USA St. John's Road, Tyler's Green High Wycombe, Bucks, England HP10 8HR 7820461 U nger * paul oavid SOME ASPECTS OF THE BIOLOGY OF THREE NORTHWESTERN ATLANTIC1CHITONSf TONlCELLA RUBRA# TONICELLA MARHOREA* ANO ISCHNQfiHlTON ALBU8 (MOLLUSCAl POLYPIACOPHORA)\ UNIVERSITY OF NEW HAMPSHIRE# PH#D»# 1978 © 1978 PAUL DAVID LANGER ALL RIGHTS RESERVED SOME ASPECTS OF THE'BIOLOGY OF THREE NORTHWESTERN ATLANTIC CHITONS: TONlCELLA RUBRA. TONlCELLA MARMOREA. AND ISCHNOCHITON ALBUS (MOLLUSCA: POLYPLACOPHORA) by PAUL D. LANGER B. S., Fort Lewis College, 1967 M. S., University of New Hampshire, 1968 A THESIS Submitted to the University of New Hampshire In Partial Fulfillment of The Requirements for the Degree of Doctor of Philosophy Graduate School Department of Zoology May 1978 This thesis has been examined and approved. Thesis dir ,J. raw;wyer, Prof. of Zoology Edward N. Francq, AssX- Prof. of Zoology Larry G . '^girris, Assoc. Prof. of Zoology Robert L. Vadas, Assoc. Prof. of Botany, Oceano­ graphy, and Zoology/ University of Maine at Orono / (p 7 — 7 ACKNOWLEDGMENTS There are many people to whom I would like to extend recognition and thanks for helping to make this dissertation possible. In particular, I thank Larry G. Harris for his enduring patience and help. My apprecia­ tion to Philip J. Sawyer, Robert L. Vadas, James Erickson, Frank Bowman, Jr., the members of my committee, and the faculty and graduate students at the University of New Hampshire. I also extend my deepest appreciation to Helga, Ingeborg, Patrick, and the many others whose names I have failed to mention but whose friendship, contribu­ tions, and advice are recognized and truly appreciated. TABLE OF CONTENTS LIST OF TABLES............................................ vi LIST OF ILLUSTRATIONS.................................... ix ABSTRACT................................................... xi GENERAL INTRODUCTION..................................... 1 ECOLOGY AND HABITAT DESCRIPTION......................... 3 Introduction.......................................... 3 Materials and Methods................................ 3 Deep Cove........................................ 5 Cape Neddick..................................... 7 Results............... 9 Habitat Description and Natural History....... 9 Deep Cove.................................... 9 Physical Characteristics............... 9 Biological Characteristics............ 15 Cape Neddick................................. 24 Physical Characteristics............... 24 Biological Characteristics............ 25 Predation......................................... 26 Population Structure............................ 29 Population Distribution-Pattern of Species Occurrence..................... 29 Size Distribution........................... 32 Population Density.................. 35 Encrusting Organisms............................ 46 Morphological Variations........................ 53 Behavior.......................................... 58 Habitat Selection and Activity Patterns... 58 Homing Behavior............................. 61 Discussion ..................................... 63 Summary............................................... 80 FEEDING BIOLOGY........................................... 85 Introduction.......................................... 85 Materials and Methods................................ 86 Results............................................... 87 Intraspecific Diet Analysis.................... 87 Tonicella rubra, Deep Cove................. 93 Tonicella rubra, Cape Neddick.............. 104 TonicelTa marmorea, Deep Cove............. 104 Tonicella marmorea, Cape Neddick........... Ill Ischnochiton albus, Deep Cove ............. 115 Discussion............................................ 119 Interspecific Diet Analysis.................... 119 Summary................... 132 iv REPRODUCTIVE BIOLOGY 134 Introduction..................... 134 Materials and Methods........... 135 Results................... ....... 135 Gonad Size and Color........ 135 Breeding Season--Gonad Index 136 Tonicella rubra......... 136 Tonicella marmorea...... 140 Ischnochiton albus...... 141 Sex Ratios................... 142 Discussion....................... 144 Summary........................... 147 FINAL DISCUSSION..................... 148 LITERATURE CITED..................... 161 v LIST OF TABLES la. Physical and chemical data from Deep Cove, M a i n e................................................. 12 lb. Physical and chemical data from Cape Neddick, M a i n e ................................................. 12 2. The associated fauna from Deep Cove, Maine ........ 16 3. Chiton predators and their observed relative abundance............................................. 27 4. Percent composition of the total chiton popu­ lation by species.................................... 30 5. Mean length and weight of each species of chiton................................................ 37 6. Mean length and weight of each species of chiton by sex........................................ 38 7. Encrusting organisms found on each species of chiton................................................ 48 8. The frequency of occurrence of encrusting phyla on each species of chiton........................... 50 9. The percent of encrusted forms in the chiton population by depth interval for Deep Cove........ 51 10. Distribution of encrusting organisms on the dorsal surface of each species of chiton.......... 52 11. Percent of the total chiton population en­ crusted............................................... 54 12. Distribution of morphological variations among the three species of chitons........................ 56 13. Percent of the total chiton population with less than eight shell plates........................ 57 14. Percent of morphological variants by depth for Deep Cove........................................ 59 15. Chiton digestive tracts examined and their state................................................. 88 16. Occurrence of chiton prey ........................... 89 vi 17 • Frequency of occurrence of prey phyla in chiton digestive tracts from Deep Cove............ 94 18. Tonicella rubra: Frequency of occurrence of prey phyla by season (Deep Cove)................ 95 19. Tonicella rubra: Frequency of occurrence of prey phyla by depth interval (Deep Cove) ....... 98 20. Percent volumes of algal and/or animal mate­ rial in the chiton diets (Deep Cove)............... 99 21. Estimated percent volumes of algae in the chiton diets by season (Deep Cove)...............