PACIFIC HERRING (Clupea Pallasii) EGG ACCUMULATION on EELGRASS
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PACIFIC HERRING (Clupea pallasii) EGG ACCUMULATION ON EELGRASS (Zostera marina) AND OTHER SUBSTRATES IN TOMALES BAY, CALIFORNIA A Thesis Presented to the faculty of the Department of Biological Sciences California State University, Sacramento Submitted in partial satisfaction of the requirements for the degree of MASTER OF SCIENCE in Biological Science (Ecology, Evolution, and Conservation) by Hali Rederer SPRING 2020 © 2020 Hali Rederer ALL RIGHTS RESERVED ii PACIFIC HERRING (Clupea pallasii) EGG ACCUMULATION ON EELGRASS (Zostera marina) AND OTHER SUBSTRATES IN TOMALES BAY, CALIFORNIA A Thesis by Hali Rederer Approved by: __________________________________, Committee Chair Ronald M. Coleman, Ph.D. __________________________________, Second Reader Timothy Davidson, Ph.D. __________________________________, Third Reader Benjamin Becker, Ph.D. ____________________________ Date iii Student: Hali Rederer I certify that this student has met the requirements for format contained in the University format manual, and that this thesis is suitable for electronic submission to the Library and credit is to be awarded for the thesis. __________________________, Graduate Coordinator ___________________ James Baxter, Ph.D. Date Department of Biological Sciences iv Abstract of PACIFIC HERRING (Clupea pallasii) EGG ACCUMULATION ON EELGRASS (Zostera marina) AND OTHER SUBSTRATES IN TOMALES BAY, CALIFORNIA by Hali Rederer Pacific Herring (Clupea pallasii) as a species is a microcosm of the biodiversity conservation and restoration challenges facing our time. Overfishing is a global concern to the point of being considered an extinction crisis for particular fisheries. Understanding how, where, and when a particular species reproduces may be critical to understanding how a species responds to fishing pressure. The Pacific Herring is a small pelagic fish of the family Clupeidae. It is found throughout the Northern Pacific Ocean and has a North America range from Alaska to Baja Mexico. The Pacific Herring fishery in Tomales Bay has been closed to commercial fishing since 2007 because of overfishing, market price decline, and low fishing effort. This closure provided an opportunity to gain insight into the spawning habits and ecological context of spawning Tomales Bay Pacific Herring living under low fishing pressure. It has been long noted that herring tend to spawn in eelgrass (Zostera marina) meadows, but the extent of this dependency has not been thoroughly examined. So, it becomes essential to clarify and quantify the role of eelgrass as a spawning substrate for herring. Reported here are the results of a two-year field study of Pacific Herring spawning activity (2016 -2018) in Tomales Bay investigating the following question: Do Pacific Herring prefer v natural eelgrass for spawning compared to other natural or artificial substrates? Eelgrass is the dominant vegetation in Tomales Bay. It is a submerged seagrass found nearshore, ranging from Alaska through Baja California and is found around the globe. Two nearshore westerly sites in Tomales Bay were selected for this project: Sacramento Landing and Chicken Ranch Beach. Experimental intertidal and subtidal spawning sites were built using three different types of artificial substrate and installed at each site. The experimental substrates were Artificial Eelgrass, Concrete, and the existing Bottom (bare, sand, silt, or rock). The spawning data from the experimental substrate meadows were compared to natural eelgrass meadows near the study sites. Herring roe abundance and density (layering of roe) were measured on each substrate. Potential predators on or near the sites were counted during herring roe data collection and environmental conditions were recorded (tide, turbidity, and temperature). Results from data analysis with Repeated Measures One-Way ANOVA and with multiple comparisons using Sidak’s multiple comparisons test strongly support the hypothesis that spawning Pacific Herring roe is mostly found on natural eelgrass compared to alternative substrate measured by the accumulation of eggs after spawning events. This finding indicates that herring will spawn in natural eelgrass beds even in the presence of predators. Findings from this study support local eelgrass conservation and restoration efforts as an important component of Pacific Herring fisheries preservation and sustainability . ______________________________________, Committee Chair Ronald M. Coleman, Ph.D. _____________________________________ Date vi ACKNOWLEDGEMENTS I began this science adventure as a citizen scientist volunteer at Point Reyes National Seashore in 2008 over ten years ago. I was a furloughed State of California field surveyor for Caltrans. Like most state employees during the recession, I had extra time on my hands. I take great pride in completing this research project. Many people have generously contributed their time and energy to this thesis and my success. Heartfelt thanks to National Park Service Scientist Dr. Sarah Allen. She Was the first person to talk to me about carrying out a research project on Pacific Herring in Tomales Bay. She also allowed me access to her residence to conduct eelgrass herring spaWning surveys from her dock. Dr. Allen connected me to the Inverness Yacht Club who also allowed herring surveys from their facilities. Dr. Benjamin Becker gave his time and advice generously on design, methods, and statistical analysis. As a Point Reyes National Seashore Scientist and Science Coordinator, Dr. Becker was instrumental in providing support for the duration of my Tomales Bay field research, including the use of the Sacramento Landing Marine Research Station. Dr. Timothy Davidson was neW to Sacramento State when I approached him to be on my committee. He accepted and I couldn’t be more grateful. Dr. Davidson has provided advice on the design and the scope of this research. I am grateful for the assistance of Ryan Bartling, Environmental Scientist and Pacific Herring biologist for the California Department of Fish and Wildlife. David Bui and Laura A. Givens assisted me in the field as undergraduate students, even in cold rainy weather. David is an aWesome field technician and scuba diving buddy and Laura is an excellent researcher. My advisor and the chair of my committee Dr. Ronald Coleman is an extraordinary vii teacher, fisheries biologist, and mentor. At every step of this thesis project he has provided insight, expertise, and encouragement. Heartfelt thanks to my Caltrans supervisors and coworkers. They allowed me to take time off from work for graduate school. Thanks to the remarkable Biological Sciences faculty at CSUS whose classes I took and learned so much from. Most of all I thank DaWn Whitney Whose encouragement and support continues to make this endeavor possible. Grants funded this research. Thank you: Point Reyes National Seashore Association Fund for Marine Science Research Professional Engineers in California Government CSU Council on Ocean Affairs, Science and Technology Travel Grant Sigma XI This thesis is dedicated to scientists Who study common “unremarkable” species, leaving the charismatic animals and plants to others. It takes willing researchers digging deep to explain to people why they need to care about species that are considered an unlimited resource, so abundant they need little attention or concern (e.g., the Passenger Pigeon, Pacific Herring,...). Carry-on. viii TABLE OF CONTENTS Page Acknowledgements ................................................................................................................ vii List of Tables ............................................................................................................................ x List of Figures .......................................................................................................................... xi Chapter 1. INTRODUCTION ............................................................................................................. 1 The Pacific Herring Fishery .............................................................................................. 3 Tomales Bay Spawning Pacific Herring Biomass Fluctuations ........................................ 7 Reproductive Biology of Pacific Herring ........................................................................ 12 Key Importance of Eelgrass for Spawning Herring ........................................................ 14 Spawning Site Selection: Where Do Pacific Herring Lay Their Eggs? .......................... 15 Hypothesis and Objectives .............................................................................................. 18 2. MATERIALS AND METHODS ....................................................................................... 19 Tomales Bay .................................................................................................................... 19 Sites ................................................................................................................................ 21 Approach to Field Work ................................................................................................ 22 Data Analysis .................................................................................................................. 36 3. RESULTS .......................................................................................................................... 38 4. DISCUSSION ...................................................................................................................