Assessment of the potential for culture of the Chinese clam (Chione gnidia) in the estuary of La Cruz, Sonora, Mexico Item Type text; Thesis-Reproduction (electronic) Authors Aubert, Hernan, 1963- Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 03/10/2021 01:38:52 Link to Item http://hdl.handle.net/10150/278727 INFORMATION TO USERS The most advanced technology has been used to photograph and reproduce this manuscript from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. 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Ann Arbor, MI 48106 1 ASSESSMENT OF THE POTENTIAL FOR CULTURE OF THE CHINESE CLAM (CHIONE GNIDIA) IN THE ESTUARY OF LA CRUZ, SONORA, MEXICO. by Hernan Aubert A thesis submited to the faculty of the SCHOOL OF RENEWABLE NATURAL RESOURCES In partial fulfillment of the requirements For the Degree of MASTERS OF SCIENCE WITH A MAJOR IN WILDLIFE & FISHERIES SCIENCE In the Graduate College THE UNIVERSITY OF ARIZONA 19 9 0 2 STATEMENT BY AUTHOR This thesis has been submited in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the university library to be made available to borrowers under rules of the library. Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in partmay be granted by the head of the major department or the Dean of the Graduate College when in his or her judgement the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author SIGNED: APPROVAL BY THESIS COMMITTEE This thesis has been approved on the date shown below: /a/zpAo 4L0. Eugen<lugen^J Maughan, Thesis Director Date Unit Leader, Arizona Cooperative Fish and Wildlife Research Unit (jtywAiUo Q. Charles D. Ziebell, Assistant Unit Date Leader, Arizona Cooperative Fish and Wildlife Research Unit William Associate Date Professor of Fisheries Science 3 ACKNOWLEDGEMENTS I would like to thank Dr. Eugene Maughan, Dr. Charles Ziebell and Dr. William Matter for the invaluable assistance, cooperation and good will shown throughout this project. Also, I would like to thank the above mentioned persons whose editing skills made this thesis possible. In the preparation of the tables drawings and charts, Francisco Ornelas gave freely of his time for review and discussion, and to him I am truly indebted. Ernesto Meza Vega deserves a special mention; without his dedication cooperation and helpful suggestions the present study would not have been developed. Finally, and more specially, I would like to acknowledge the tremendous support I received from my wife, Marcela Vasquez, who was always at my side helping and encouraging me during moments of total desperation. 4 TABLE OF CONTENTS Page LIST OF FIGURES 5 LIST OF TABLES 8 ABSTRACT 9 INTRODUCTION 10 Status of aquaculture in Mexico 12 BACKGROUND INFORMATION 15 Estuary Huivuilai 15 Estuary La Cruz 20 DESCRIPTION OF STUDY AREA 24 MATERIALS AND METHODS 26 RESULTS 34 DISCUSSION 44 CONCLUSIONS 49 APPENDIX A Residual and Full Normal plots, statistical analysis 51 LIST OF REFERENCES 68 5 LIST OF FIGURES Figure Page 1. Map of Huivuilai coast 16 2. Map of Kino Bay 21 3. Diagram of experimental units 27 4. Mean temperature variation at Estuary La Cruz.. 29 5. Cummulative growth of clams in study sites in La Cruz and Huivuilai (experiment 1) 36 6. Cummulative mortality in the pool and the canal site in La Cruz (experiment 1) 38 7. Cummulative growth of clams on several types of sediment (experiment 2) 40 8. Cummulative growth of clams in pool and canal environments (experiment 4) 41 9. Cummulative mortality of clams in pool and canal environments (experiment 4) 43 6 la. Full normal plot for total mortality (experiment 1) . 52 2a. Residual plot for total mortality (experiment 1) 53 3a. Full normal plot for growth periods (experiment 1) 54 4a. Residual plot for growth periods (experiment 1) 55 5a. Full normal plot for growth over the total periods of experiment 1 56 6a. Residual plot for growth over the total periods of experiment 1 57 7a. Residual plot for total mortality (experiment 2) 58 8a. Full normal plot for total mortality (experiment 2) 59 7 9a. Full normal plot for growth periods (experiment 2) 60 10a. Residual plot for growth periods (experiment 2) 61 11a. Full normal plot for growth periods (experiment 3) 62 12a. Residual plot for growth periods (experiment 3) 63 13a. Full normal plot for total mortality (experiment 4) 64 14a. Residual plot for total mortality (experiment 4) 65 15a. Full normal plot for growth periods (experiment 4) 66 16a. Residual plot for growth periods (experiment 4) 67 8 LIST OF TABLES Table Page 1. Summary of environmental conditions for the pool and canal habitats in the Estuary La Cruz... 25 2. F values of the 2x2 factorial anova (growth)... 35 3. F values of the 2x2 factorial anova (mortality) 37 9 ABSTRACT Growth and mortality of the Chinese clam (chione gnidia) were examined in the Estuary of La Cruz, Sonora, Mexico from 1987 to 1989. Clams were reared in trays in two habitats of the Estuary of La Cruz, the pool and the canal, where four experiments were carried out. In experiment 1 growth and mortality under two densities and two environments was assessed. Experiment 2 yield information on growth and mortality of clams growing on four different substrates and at two densities. Experiment 3 assessed growth and mortality in high density conditions, and experiment 4 assessed growth after a period of growth stagnation. In all cases, highly significant differences in growth and mortality were observed between environments. The pool was found to be the place where higher total growth and least mortality occurred. However, the sizes achieved by clams in the pool suggest that the Estuary of La Cruz is not a suitable environment for the cultivation of this clam, and that the introduction of C. gnidia in this area is not feasible under present habitat conditions. 10 INTRODUCTION Clams are generally classified in the order Heterodonta. All clams are characterized by heterodont or schizodont hinge dentition, similarity of adductor muscles, equality of size of valves, and shells smooth or concentrically ribbed and with an elongate sub-rectangular, or ovoid shape (Newel 1969). Clams support commercial, sport and subsistence fisheries throughout the world and are in high demand, especially in the U.S. (Nanzi et al. 1980). Unfortunately, the harvest of most clams is declining. According to Manzy (1989), declining clam populations are caused by a number of factors, including pollution and overfishing. In response to declining natural populations, interest in aquaculture of commercial clam species has grown, especially in the last decade. Basic biological research has yielded knowledge of environmental requirements, ecological interactions, and, to some extent, diseases and disease treatment for some commercial species (Rhodes 1985, Winter et al. 1984). Culture techniques for hatchery, nursery, and field growout have also been developed for several commercial clam species. Furthermore, commercial facilities have been constructed to produce and supply seed and to grow out seeds to market size. Despite these 11 efforts, clam culture produced only 15% of the world's total landings in 1989 (Manzy et al. 1989). By the turn of the century, predictions are that clan culture will account for 25 % of the total production (Parker 1986). Even though clam aquaculture is not as widely practiced as oyster and mussel culture, it comprises a significant part of worldwide aquaculture production. In 1975, world clam culture produced 6 million metric tons, 9 million metric tons in 1979, and 10.5 million metric tons in 1985 (FAO 1987). Yield was estimated to be 13 million metric tons in 1986 (Parker 1986). This increase in cultured clams accounted for about 14 % of the total world commercial catch in 1985 and 15 % in 1986.