The Life History Characteristics, Growth, and Mortality of Juvenile Alewife, Alosa Pseudoharengus, in Coastal Massachusetts
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University of Massachusetts Amherst ScholarWorks@UMass Amherst Masters Theses Dissertations and Theses July 2016 The Life History Characteristics, Growth, and Mortality of Juvenile Alewife, Alosa pseudoharengus, in Coastal Massachusetts Julianne Rosset University of Massachusetts Amherst Follow this and additional works at: https://scholarworks.umass.edu/masters_theses_2 Recommended Citation Rosset, Julianne, "The Life History Characteristics, Growth, and Mortality of Juvenile Alewife, Alosa pseudoharengus, in Coastal Massachusetts" (2016). Masters Theses. 373. https://doi.org/10.7275/8425638 https://scholarworks.umass.edu/masters_theses_2/373 This Open Access Thesis is brought to you for free and open access by the Dissertations and Theses at ScholarWorks@UMass Amherst. It has been accepted for inclusion in Masters Theses by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. THE LIFE HISTORY CHARACTERISTICS, GROWTH, AND MORTALITY OF JUVENILE ALEWIFE, ALOSA PSUEDOHARENGUS, IN COASTAL MASSACHUSETTS A Thesis Presented by JULIANNE ROSSET Submitted to the Graduate School of the University of Massachusetts Amherst in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 2016 Environmental Conservation THE LIFE HISTORY CHARACTERISTICS, GROWTH, AND MORTALITY OF JUVENILE ALEWIFE, ALOSA PSUEDOHARENGUS, IN COASTAL MASSACHUSETTS A Thesis Presented by JULIANNE ROSSET Approved as to style and content by: _______________________________________ Adrian Jordaan, Chair _______________________________________ Allison H. Roy, Chair _______________________________________ Michael P. Armstrong, Member ____________________________________ Curtice R. Griffin, Department Head Department of Environmental Conservation DEDICATION To those closest to me. ACKNOWLEDGEMENTS First and foremost, I would like to thank my parents. They instilled in me a passion for the environment, woke me up early in the morning to watch NASA rockets launch from Cape Canaveral, never let me quit on chemistry, calculus, my dreams. Instilled in me a passion for science, travel, exploration. Thank you for never drawing lines around what I could be, thank you for your love and support. I owe both of my advisors, Dr. Adrian Jordaan and Dr. Allison Roy, so much gratitude for taking me on as a student, working with me on this thesis, helping me navigate through graduate school. Also, many thanks to my fellow graduate students who made daily life a little bit easier, who helped me laugh through these years. And to the undergraduate students who helped me extract nearly 3,000 otoliths from young-of-year fish, you’re awesome. A special thanks to folks at the Massachusetts Department of Marine Fisheries, without them this thesis would not be possible. In particular, thanks to Ben Gahagan who volunteered his advice and time when I needed it. Last but certainly not least I would like to thank Corey Eddy. I would not have made it through graduate school without you. You have been such a positive force in my life and have been so integral to my success and happiness. iv ABSTRACT THE LIFE HISTORY CHARACTERISTICS, GROWTH, AND MORTALITY OF JUVENILE ALEWIFE, ALOSA PSUEDOHARENGUS, IN COASTAL MASSACHUSETTS MAY 2016 JULIANNE ROSSET, B.S. UNIVERSITY OF WEST FLORIDA M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professors Adrian Jordaan and Allison H. Roy Over the past two centuries, anadromous alewife populations have drastically declined due to damming, inadequate fish passage, overfishing in the ocean and freshwater, climate change, and reduction in habitat quality. Alewife populations are currently assessed by counting adult fish as they migrate upstream, but little is known about resulting juvenile production within lakes. Lack of knowledge of freshwater life history characteristics of juvenile alewife limits our understanding of overall productivity. For this thesis, I fill existing information gaps by (1) characterizing the timing of adult alewife migrations and subsequent spawning (Chapter 2), and (2) assessing juvenile alewife density, size, growth, and mortality within lakes, and abiotic factors influencing these estimates across lakes (Chapter 3). Twenty lakes across coastal Massachusetts were sampled for juvenile alewife and water quality in summer 2014. Each lake was sampled three times: Round 1 (29 May to 15 June), Round 2 (26 June to 16 July), and Round 3 (27 July to 15 August). Analyses of instream adult counts and otolith-based estimates of spawning date from captured juveniles showed a v distinct delay (7-28 d) between the beginning of the adult migration run and spawning, and spawning continued 13-48 days after adults stopped migrating. These findings further corroborate recent discoveries that suggest alewife exhibit asynchronous spawning and has large implications for freshwater foodwebs. Lakes, overall, did not produce the same sized fish and there appears to be substantial variations of length-at-age with some lakes exhibiting large differences. No change in length-at-age occurred in August, thus differences were achieved earlier in the growing season. Additionally, all 20 lakes exhibited variable growth, density, and mortality rates that yielded generally weak relationships with abiotic and biotic factors. Juvenile alewife density was positively related to juvenile density in the previous sampling Round, suggesting that a single sampling date may be sufficient to estimate relative lake density across the landscape. Factors affecting growth were not consistent; overall growth was positively correlated with DOC, while the last 20 days of growth was negatively correlated with secchi depth. While different, these responses are likely the result of the same mechanisms, both intrinsically linked with zooplankton abundance, prey availability, and feeding behavior within lakes. No significant correlate was found for mortality. In the future, the data in this thesis can be incorporated into models to improve stock assessments and support timely adaptive management strategies. vi TABLE OF CONTENTS Page ACKNOWLEDGEMENTS ............................................................................................... iv ABSTRACT .........................................................................................................................v LIST OF TABLES ...............................................................................................................x LIST OF FIGURES ........................................................................................................... xi CHAPTER 1. INTRODUCTION ...................................................................................................1 2. TEMPORAL PATTERNS OF ALEWIFE MIGRATION AND SPAWNING IN COASTAL MASSACHUSETTS .................................................6 2.1 Introduction ........................................................................................................6 2.2 Methods..............................................................................................................8 2.2.1 Study sites ...........................................................................................8 2.2.2 Adult fish counts .................................................................................9 2.2.3 Young-of-year fish sampling ............................................................10 2.2.4 Otolith processing and age estimation ..............................................10 2.2.5 Data analysis .....................................................................................12 2.3 Results ..............................................................................................................13 2.4 Discussion ........................................................................................................14 3. DENSITY, GROWTH, AND MORTALLITY OF JUVENILE ALEWIFE IN COASTAL MASSACHUSETTS .....................................................................27 vii 3.1 Introduction ......................................................................................................27 3.2 Methods............................................................................................................31 3.2.1 Study Sites ........................................................................................31 3.2.2 Rainfall ..............................................................................................32 3.2.3 Water quality .....................................................................................32 3.2.4 Alewife sampling ..............................................................................33 3.2.5 Otolith processing and spawn date estimation ..................................34 3.2.6 Data analysis .....................................................................................35 3.3 Results ..............................................................................................................38 3.3.1 Density ..............................................................................................39 3.3.2 Size and Growth ................................................................................39 3.3.3 Mortality ...........................................................................................40 3.4 Discussion ........................................................................................................40 3.4.1 Density ..............................................................................................40