Effects of a Threadfin Shad Introduction Upon Black Crappie and Smallmouth Buffalo Pupulations in Roosevelt Lake
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Effects of a threadfin shad introduction upon black crappie and smallmouth buffalo pupulations in Roosevelt Lake Item Type text; Thesis-Reproduction (electronic) Authors Beers, Gary Delman, 1942- 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 25/09/2021 03:32:11 Link to Item http://hdl.handle.net/10150/551797 EFFECTS OF A THREADFIN SHAD INTRODUCTION UPON BLACK CRAPPIE AND SMALLMOUTH BUFFALO POPULATIONS IN ROOSEVELT LAKE by Gary Delman Beers A Thesis Submitted to the Faculty of FISHERIES MANAGEMENT In Partial Fulfillment of the Requirements For the Degree of MASTER OF SCIENCE In the Graduate College THE UNIVERSITY OF ARIZONA 1 9 6 5 STATEMENT BY AUTHOR This thesis has been submitted 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 part may be granted by the Dean of the Graduate College when in his judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author. APPROVAL BY THE THESIS DIRECTOR This thesis has been approved on the date shown below: ACKNOWLEDGMENTS Sincere gratitude is expressed to Dr. William J. McConnell, Head of the Arizona Cooperative Fisheries Research Unit, for his timely guidance throughout the study and for his suggestions in the preparations of the manuscript. Helpful advice on the manuscript was also received from Drs. Donald A. Thomson and William B. Heed, University of Arizona. Special thanks are due Calvin Doner, Marley Conrad, and Leonard Sexton for valuable help in the field. The cooperation of the Arizona Game and Fish Department and the Arizona Cooperative Wildlife Research Unit are gratefully acknowledged. iii TABLE OF CONTENTS Page LIST OF T A B L E S ..................................................... vi LIST OF FIGURES.................................................... vii ABSTRACT......................................................... viii INTRODUCTION ..................................................... 1 STUDY A R E A ....................................................... 3 THREADFIN S H A D ................................................... 6 VO VO vO 00 00 00 ^ 00 vO VO VO Methods. Data Collection ............ Food Habit Analysis ........ Results........................ Length-frequency Distributions Food Habits ................ BLACK CRAPPIE....................................................... 13 Methods.......................... 13 Lengths and W e i g h t s ....................................... 13 Food Habit Analysis....................................... 13 Results....................................................... 16 Food H a b i t s ............................................... 16 Condition Coefficients..................................... 16 Scale Analysis............................................. 19 SMALLMOUTH BU FFALO................................................. 21 Methods....................................................... 21 Data Collection........................................... 21 Scale Preparation and Analysis............................. 21 Body-scale Relationship ................................ 22 Validity of the Scale Method............................... 27 iv V Page SMAILMOUTH BUFFALO Results....................................................... 30 Length-frequency of Collections ..... ................ 30 Past Growth R a t e s ......................................... 30 Condition Coefficients..................................... 30 DISCUSSION Threadfin Shad— Black Grapple Relationship ................ 34 Availability of Small Threadfin Shad..... ........... 35 Black Grapple Food H a b i t s ................................. 35 Condition of Black Grapple................................. 36 Food Habits of Threadfin Shad................................. 41 Smallmouth Buffalo--Threadfin ShadRelationship................44 Growth Rates, 1952-64 .................................. 44 CONCLUSIONS......................................................... 49 APPENDIX A ......................................................... 50 APPENDIX B ......................................................... 51 LITERATURE CITED ................................................. 52 LIST OF TABLES Table Page 1. Relative abundance of organisms in the diet of sixty threadfin shad longer than 12 cm (TL) from Roosevelt Lake, Spring of 1965....................................... 12 2. Percentage frequency of occurrence of each organism in the diet of 47 black crappie from Roosevelt Lake, Spring of 1965............................................. 17 3. Relation of "K" to length among 1006 black crappie according to 10 mm standard length frequency intervals, 1959-65 captures........................................... 20 4. Average calculated standard lengths in mm attained at successive ages by the V, VI, VII, and VIII year old smallmouth buffalo from Roosevelt Lake, 1960-65 captures. 32 5. Relation of "K" to length among 955 smallmouth buffalo according to 20 mm standard length frequency intervals, 1960-65 captures........................................... 33 6. Average Kg%, values for various black crappie populations in other regions of the United Sta t e s.................... 37 7. Comparison of average weights for each 10 mm standard length interval of black crappie from Roosevelt Lake in Arizona and Lake George in Florida........................ 39 8. Comparison of the first two year's growth of the smallmouth buffalo spawn from 1952-53, 1957-58, and 1960 ............ 47 9. Average growth rates of V and VI year old smallmouth buffalo prior and subsequent to 1958...................... 48 vi LIST OF FIGURES Figure Page 1. Elevations of Roosevelt Lake, January, 1950 - December, 1964 .................... ........................ 5 2. Relative length frequencies of threadfin shad from Roosevelt Lake, 1964-65. Collected with gill nets ..... 10 3. Relative length frequencies of threadfin shad from Roosevelt Lake, October, 1961 and October, 1962. Collected by electric shocker................................. 11 4. Relationship of standard length to the combined length of five terminal vertebrae of ten threadfin s h a d .............. 15 5. Length frequency of 96 threadfin shad found in the stomachs of 47 black crappie during the Spring of 1965 . 18 6. Photographs of Smallmouth buffalo scales (x4.5)............ 23 7. Scale radius-body length relationship established from measurements of 590 smallmouth buffalo ..................... 28 8. Length frequencies of 955 smallmouth buffalo from Roosevelt Lake, 1960-65..................................... 31 vii ABSTRACT An investigation of some effects of a recently developed threadfin shad (Dorosoma petenense, Gunther) population upon the existing black crappie (Pomoxis nigromaculatus, LeSueur) and small- mouth buffalo (Ictiobus bubalus. Rafinesque) populations, in Roosevelt Lake, Arizona, was made in 1964 and 1965. Food habit analyses indicated that small threadfin shad are the most important items in the diet of the adult crappie. The black crappie was in excellent condition (KgL = 4.06, based on 1006 fish) apparently as a result of a plentiful supply of good forage size shad throughout the year. Scales of 480 smallmouth buffalo collected since 1959 reveal that the growth rate has diminished since the shad introduction in 1958, apparently as a result of food competition. viii INTRODUCTION During the past two decades, the threadfin shad (Dorosoma petenense Gunther) has attained widespread recognition as a valuable forage fish. Many food habit studies demonstrate that the shad is the principal food of predacious fish populations (spotted bass, Dendy, 1946; rainbow trout, Fetterolf, 1957; large-mouth bass, Melander, 1961a; striped bass, Stevens, 1957; and Goodson, 1964; carp, Melander, 1961b; white and black crappies, Finklestein, 1960; and catfish, Melander, 1961b). However, there is very little factual information about other direct or indirect effects a shad introduction may have on the pre existing fish populations. Fetterolf (1957) reported that the trout in two Tennessee reservoirs were heavier and grew more rapidly as a result of foraging upon shad. Recently, Melander (1961a) presents similar results for the largemouth bass in Lake Mead. More recently, McConnell and Gerdes (1963) described less favorable effects of a shad introduction in a small lake in Arizona. They found that, due to rapid growth of the shad progeny after one short spawning period in the late spring, yearling centrarchids had difficulty finding suitable fish forage during the succeeding fall, winter, and spring. Since 1955, threadfin shad have been introduced into several large; warm-water reservoirs on the drainages of the Colorado, Salt, and Gila Rivers in Arizona. The shad are presently thriving in these 2 waters. Some effects of this introduction on a game fish and a rough fish