Effects of Myxobolus Cerebralis on the Population Dynamics of Kokanee in Porcupine Reservoir, Utah
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Utah State University DigitalCommons@USU All Graduate Theses and Dissertations Graduate Studies 5-2002 Effects of Myxobolus cerebralis on the Population Dynamics of Kokanee in Porcupine Reservoir, Utah Arthur E. Butts Utah State University Follow this and additional works at: https://digitalcommons.usu.edu/etd Part of the Life Sciences Commons Recommended Citation Butts, Arthur E., "Effects of Myxobolus cerebralis on the Population Dynamics of Kokanee in Porcupine Reservoir, Utah" (2002). All Graduate Theses and Dissertations. 4436. https://digitalcommons.usu.edu/etd/4436 This Thesis is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. EFFECT OF MYXOBOLUS CEREBRALIS ON THE POPULATION DYNAMIC OF KO KANEE IN PORCUPINE RE ERVOLR, UTAH by Anhur E Butts A thesis submitted in panial fulfillment of the requirements for the degree of MASTER OF SCI NCE in Fisheries Biology Approved UTAH TATE IVERSITY Logan, Utah 2002 UMI Number: 1408258 UMI Microform 1408258 Copyright 2002 by ProQuest lnformalion and Learning Company. All rights reserved. This microform edition is protecled againsl unaulhorized copying under Title 17, United Stales Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml48106-1346 ABSTRACT Effects of Myxobolus cerebra/is on the Population Dynamics of KokJinee in Porcupine Reservoir, Utah by Arthur E. Butts, Master of Science Utah State University, 2002 Major Professor: Dr. David A. Beauchamp Depanment. Fisheries and Wildlife This study tracked the chronology and severity of Myrobo/us cerebra/is infection and related it to survival of age-0 kokanee to determine whether M cerebra/is represented a significant agent ofmonality in the population. Environmental conditions and losses to predation were identified and linked to age-0 kokanee survival to identifY other sources ofmonality in the population. We attempted to track survival of age-0 kokanee from the outmigrati on into the reservoir until the end of the first growing season in September of each year. The number of age-0 kokanee that entered the reservoir was calculated by obtaining estimates of total egg deposition and egg-to-fry survival for the 1999 brood year. Age-0 kokanee were primarily infected by the parasite after they had entered the reservoir in spring Prevalence and severity increased rapidly throughout the summer and nearly all age-0 kokanee were infected by August of both years. In total, 495 age-0 kokanee were examined for clinical lesions associated with M cerebra/is in 1999 and 2000, but only one fish displayed a cranial abnormality in 2000. Low survival rates of age-0 kokanee from July through September were observed and coincided with increased prevalence and severity. However. because of high reservoir temperatures, low food levels, predation, and entrainment, evidence forM cerebra/is acting as a direct source of monality on age-0 kokanee was elusive during our study. In age-l and older kokanee, we did not find any evidence that M cerebra/is had an effect on growth and overall condition of the fish. Infection severity and presence of clinical signs varied between years and were likely more related to limitations of the diagnostic techniques. Any effects that M cerebra/is may have had on kokanee are likely to occur during the first growing season iii and may impact the host 's abili ty to cope with the other environmental stressors identified at Porcupine Reservoir. Despite high mortality rates. the kokanee population at Porcupine Reservoir was considered to be overabundant based on estimated densities and length distributions of spawning fish. M. cerebra/is did not appear to have a significant effect on the abundance of the kokanee population but we were unable to detemline whet her or not the parasite was a source of direct mortality because of other potential sources of mortality. {Ill pages) iv ACKNOWLEDGMENTS I would like to thank the Utah Division of Wildlife Resources and United States Geological Service/Biological Research Division for funding and cooperative efforts. Craig Schaugaard, Kent Sorenson, Chris Wilson, and Eric Wagner provided valuable assistance and insight during the initital stages of this research. Matt Helm, Mike Golden, Jon Flinders, Mark Smith, and Brett Thompson provided invaluable support and friendship in the field and laboratory. Without my technicians, I would not have been able to accomplish this research. Special thanks to my advisor, Dave Beauchamp, for his invaluable assistance, patience, mentoring, and friendship. No class, book, or other individual could have taught me more about fisheries or being a professional than Dave. I will never be able to thank my parents, Charles and Alice, enough for the endless sacrifices that they have made so that I could receive an education. At times, I'm sure they didn't know if! would make it out of high school. so I hope that my compl etion of this degree is a reward for their perseverance. And finally to my beautiful wife and best friend, Kresta, and my "children," Niezhone and Scooter. Kresta provided friendship, support, and reason when I most needed it and was always willing to help in the field when nobody else could. Thanks for putting up with me. Niezhone and Scooter, my four legged techs, were always ready to give me a lift when so many things went wrong. Arthur E. Butts v CONTENTS Page ABSTRACT ................... ..... .. ii ACKNOWLEDGMENTS .iv LIST OF TABLES .... ....... ..... ... vi LIST OF FIGURES . ..... viii CHAPTER INTRODUCTION ....... .•........... ................................•.. .......................... ...... .. 1 References ................. ..... ............. .......... .. ....... .. ············ 5 2 AN ASSESSMENT OF THE I 998 AND I 999 SPA \Vli.'ING ESCAPEMENTS AND FRY RECRUITME TIN A POPULATION OF KOKANEE INFECTED BY MYXOBOLUS CEREBRA U S AT PORCUPINE RESERVOIR, UTAH ..... ...... ..... 9 Abstract ······· · 9 Introduction .... .............................................. ····················· ...... .. ........... 9 Study Site ..... ...... .. ... 12 Methods ........................ ............................ ......... 12 Results . .... ···························· ........... 21 Discussion ............................. ...................... ............................................. 37 References ............................................................................................................... 43 2 SURVIVAL OF AGE-0 KOKANEE IN A POPULATION INFECTED BY MYXOBOLUS CEREBRAU S IN PORCUPINE RESER VOIR, UTAH ..... ........ 46 Abstract ................................ ... ..... ......... .... 46 Introduction ............................... ....................................... 46 Methods ........................ ......................... ......................................................... 50 Results ................................................................... ................................................ 61 Discussion .................................... .... ..................... ................................ .. .................... 84 References ...................... ··· ··························· .................. 94 4 CONCLUSION .... ........................ ·················· ······ ····· ................. ...................... 100 vi LIST OF TABLES Table Page 2-1 Sum of observed ranked deformities, percent fish with deformities, deformity ranking, infection prevalence, and average spores per I 00 fields for spawning kokanee at Porcupine Reservoir for 1996-1999 spawning runs. Sample size fo r all years was 60 fish ........ .. ....... ......................... ......... 22 2-2 Live spawner counts from daily visual surveys and abundance estimates from area-under-the-curve (AUC) calculations for each survey interval during the 1998 and 1999 escapement period..................................... ....................................... ........ 25 2-3 Est imated kokanee egg deposition in the East Fork Little Bear River in 1998 and 1999. Estimates are based on a size-specific fecundity model, female size distribution, total abundance of females (26, 118 in 1998; 11 ,299 in 1999), and an average egg retention rate of3.59 eggs/female ................... ....... 28 2-4 Values for parameters used to estimate total fry outrnigration during spring 2000 at Porcupine Reservoir. Total number of fry captured and estimates for total fry abundance using both flow expansion and trap efficiency techniques are shown as well. The mean trap efficiency estimate of 4.6% for days when recaptures were greater than zero was assumed for all dates in which marked fry were not recapu ted in the trap .. .... 35 2-5 Comparison between reponed kokanee and sockeye egg-to-fry survival rates from various western populations. Estimates !Tom Bradford (1995) were estimated !Tom a summary graph of35 different populations of sockeye that were compiled from various sources ........................................................... .. 42 3-1 Parameters used during the collection and analysis ofhydroacoustic data ........... ...... 54 3-2 Diet composition of prey, as wet weight percentages of the stomach contents for two size classes ofbrown trout, cutt hroat trout, and rainbow trout during spring and summer 2000. Prey energy densities (Jig) that were used in the bioenergetic simulations