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FISH in a TIDALLY DYNAMIC REGION in MAINE: HYDROACOUSTIC ASSESSMENTS in RELATION to TIDAL POWER DEVELOPMENT by Haley A. Viehman

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FISH in a TIDALLY DYNAMIC REGION in MAINE: HYDROACOUSTIC ASSESSMENTS in RELATION to TIDAL POWER DEVELOPMENT by Haley A. Viehman FISH IN A TIDALLY DYNAMIC REGION IN MAINE: HYDROACOUSTIC ASSESSMENTS IN RELATION TO TIDAL POWER DEVELOPMENT By Haley A. Viehman B.S. Cornell University, 2009 A THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science (in Marine Bioresources) The University of Maine May, 2012 Advisory Committee: Gayle Zydlewski, Assistant Professor of Marine Science, Advisor Michael Peterson, Professor of Mechanical Engineering James McCleave, Professor Emeritus of Marine Science LIBRARY RIGHTS STATEMENT In presenting this thesis in partial fulfillment of the requirements for an advanced degree at the University of Maine, I agree that the Library shall make it freely available for inspection. I further agree that permission for “fair use” copying of this thesis for scholarly purposes may be granted by the Librarian. It is understood that any copying or publication of this thesis for financial gain shall not be allowed without my written permission. Signature: Date: FISH IN A TIDALLY DYNAMIC REGION IN MAINE: HYDROACOUSTIC ASSESSMENTS IN RELATION TO TIDAL POWER DEVELOPMENT By Haley A. Viehman Thesis Advisor: Dr. Gayle Zydlewski An Abstract of the Thesis Presented in Partial Fulfillment of the Requirements for the Degree of Master of Science (in Marine Bioresources) May, 2012 Fish ecology in regions of extreme tidal flows is poorly understood, but as these areas link on- and off-shore habitats, they are important to many marine and diadromous fish species. Strong tidal currents are also being targeted for energy extraction, but the effects of tidal energy devices on fish are unknown. The probability of fish encountering a tidal energy turbine is highly dependent on the vertical distribution of fish at the project site. In extremely tidal coastal areas, fish presence and distribution is heavily influenced by tidal, diel, and seasonal cycles. Understanding the vertical distribution of fish therefore requires sampling on a fine temporal and spatial scale. Stationary hydroacoustic surveys may be used to gather these data, as part of a BACI (Before, After, Control, Impact) type study design, to predict then monitor the effects of tidal energy devices on fishes. Starting in May 2010, a down-looking, single-beam SIMRAD echosounder and a DIDSON (Dual-frequency IDentification SONar) unit were used to document the relative density of fish throughout the water column at a targeted pilot project site and a control site in Cobscook Bay, Maine. Stationary 24-hour surveys were carried out each season to examine variation in fish density and vertical distribution. Relative fish density was highest in spring and fall, and almost always increased near the bottom, regardless of tide or time of day. Tide and day/night had some effect on the vertical distribution of fish, but the effect was not the same each month. Results from these analyses will be used to predict the likelihood of fish encountering the turbine and to create a basis for comparison of data collected after device installation. Direct observation of fish reactions to a full-scale test device was carried out in September of 2010. A test turbine suspended below a floating research platform was monitored for 24 hours using two DIDSON units. A higher proportion of fish interacted with the device when it was still than when it was rotating. A greater portion interacted at night, and the type of interaction shifted from avoidance during the day to passing into the turbine at night. This behavioral shift was most obvious in small fish (<10 cm), nearly all of which passed through the device at night; most large fish (>20 cm) still avoided the turbine. Most fish were present at night during the slack tide. Combining the baseline knowledge of where fish are in the water column with knowledge of how they behave in close proximity to an operating tidal device will provide a more complete picture of the potential effects these devices could have once installed. THESIS/DISSERTATION/PROJECT ACCEPTANCE STATEMENT On behalf of the Graduate Committee for Haley A. Viehman I affirm that this manuscript is the final and accepted thesis. Signatures of all committee members are on file with the Graduate School at the University of Maine, 42 Stodder Hall, Orono, ME. Dr. Gayle Zydlewski, Assistant Professor of Marine Science Date ii ACKNOWLEDGEMENTS I would like to thank my advisory committee, Drs. Gayle Zydlewski, Michael Peterson, and James McCleave, for the opportunity to participate in this research, and for their continuous enthusiasm and dedication to the project. This work would not have been possible without the unlimited guidance and patience of Dr. Zydlewski. I would also like to thank the other members of the Maine Tidal Power Initiative for their insights and support. Thanks go out to Garrett Staines and Alexander Jensen, who provided invaluable support in the lab and the field, and to Amy Wyman for her close attention to hours of DIDSON footage. Thanks as well to the other members of the Zydlewski lab who aided in field work preparation or took shifts on the acoustics boat. The employees of Ocean Renewable Power Company were essential to this project, generously contributing time and resources to the work in Cobscook Bay. The input of Donald Degan and Anna-Maria Mueller was invaluable in shaping acoustic analyses. None of this work could have taken place without the knowledge and skill of Captain Butch Harris and his crew, and I thank them for their boundless iii generosity and support through many long hours of acoustic surveys, and for the countless times they have gone out of their way to assist us during this process. Funding was provided by the United States Department of Energy project #DE-EE0000298. Finally, I wish to thank my family for their unlimited love and support. iv TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................. iii LIST OF TABLES .............................................................................................................. x LIST OF FIGURES ........................................................................................................... xi Chapter 1. AN APPROACH FOR ASSESSING FISH PRESENCE IN RELATION TO TIDAL POWER DEVELOPMENT .....................................................................1 1.1 Abstract............................................................................................................1 1.2. Introduction ...................................................................................................2 1.3. General Methodology ...................................................................................6 1.4. Sampling Gears .............................................................................................7 1.4.1. Benthic and Pelagic Trawling .......................................................8 1.4.2. Seines, Fyke nets, Weirs ................................................................9 1.4.3. Acoustic Telemetry ........................................................................9 1.4.4. Hydroacoustics .............................................................................10 1.4.5. Acoustic Imaging: the Dual-frequency IDentification SONar (DIDSON) ........................................................................13 v 1.5. Case study: Cobscook Bay ........................................................................14 1.5.1 Site Considerations ........................................................................15 1.5.2 Sampling Gear ...............................................................................16 1.5.3 Data Analysis .................................................................................17 1.6. Discussion ....................................................................................................18 1.6.1. Sampling Schedule .......................................................................18 1.6.2. BACI Approach ............................................................................19 1.6.3. Sampling Gear ..............................................................................20 1.7. Recommendations .......................................................................................22 2. VERTICAL DISTRIBUTION OF FISH AT A TIDALLY DYNAMIC REGION TARGETED FOR ENERGY EXTRACTION .........................................23 2.1. Abstract.........................................................................................................23 2.2. Introduction .................................................................................................24 2.3. Methods ........................................................................................................28 2.3.1. Site ..................................................................................................28 2.3.2. Equipment .....................................................................................29 2.3.3. Field Sampling ..............................................................................32 2.3.4. Data Analysis ................................................................................33 vi 2.3.4.1. Acoustic Data Processing .............................................35 2.3.4.2. Analysis of variance in total area backscatter of the entire water column ..........................................39 2.3.4.3. Analysis of the distribution of area backscatter within the water column ........................40 2.4. Results ...........................................................................................................41
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