University of Rhode Island DigitalCommons@URI Open Access Master's Theses 2013 A Difference in Perspective: A Comparison of Ecosystem and Single-Species Focused Fisheries Management Catherine M. Foley University of Rhode Island, [email protected] Follow this and additional works at: https://digitalcommons.uri.edu/theses Recommended Citation Foley, Catherine M., "A Difference in Perspective: A Comparison of Ecosystem and Single-Species Focused Fisheries Management" (2013). Open Access Master's Theses. Paper 45. https://digitalcommons.uri.edu/theses/45 This Thesis is brought to you for free and open access by DigitalCommons@URI. It has been accepted for inclusion in Open Access Master's Theses by an authorized administrator of DigitalCommons@URI. For more information, please contact [email protected]. A DIFFERENCE IN PERSPECTIVE: A COMPARISON OF ECOSYSTEM AND SINGLE-SPECIES FOCUSED FISHERIES MANAGEMNET BY CATHERINE M. FOLEY A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS IN MARINE AFFAIRS UNIVERSITY OF RHODE ISLAND 2013 MASTER OF ARTS IN MARINE AFFAIRS THESIS OF CATHERINE M. FOLEY APPROVED: Thesis Committee: Major Professor: Richard Burroughs Seth Macinko Jeremy Collie Nasser H. Zawia DEAN OF THE GRADUATE SCHOOL UNIVERSITY OF RHODE ISLAND 2013 ABSTRACT Currently, most fisheries management bodies utilize a narrow, single-species focus in decision-making processes. These methodologies, however, fail to recognize the interrelated nature of ecosystems, and as such are unable to produce realistic and valid estimates of sustainable yield. One proposed method of integrating ecosystem data into the decision-making process of fisheries management involves quantifying ecosystem diversity. This study evaluates historical fisheries management success in terms of changes in biological diversity and evaluates the potential use of length and species diversity measurements to aid managers in understanding fishery-induced community changes. To evaluate these relationships, a comparison of ecological and management outcomes of the Georges Bank and Eastern Bering Sea groundfish fisheries was performed. These ecosystems were selected due to the strong importance groundfish fisheries play in both regions. Fisheries on Georges Bank are generally considered to be among the world’s most poorly managed and are considered to be in a state of severe decline. In contrast, Alaskan fisheries are generally considered to be among the most successfully managed in the world. Fishery independent survey data from Georges Bank and the Eastern Bering Sea were evaluated for at least an eighteen year period. Changes in the proportion of length distributions, mean length, and maximum length of annual trawl catches were evaluated for the entire catch and particular species of interest. Annual measurements of species diversity were quantified through the use of species richness, evenness, and trophic diversity calculations and overall trends were evaluated between the ecosystems. Results indicate that fishing pressure is correlated to fish size distributions in both ecosystems, however the relationship between fishing pressure and species diversity is slight in both ecosystems. Additionally, a surprising trend of increasing species diversity is apparent in both ecosystems, despite the simultaneous decline of several stocks on Georges Bank. Lastly, an evaluation of management approaches revealed that management of the Georges Bank region has been largely reactive, responding to immediate ecological needs of the fishery. In the Eastern Bering Sea, groundfish management has been comparatively proactive, seeking to address needs of the fishery prior to reaching critical management points. These differing management styles are apparent in the ecological assessments of both ecosystems. Frequently, the reactive management actions on Georges Bank resulted in more immediate responses in single species abundance and ecosystem diversity, while the more proactive management actions in the Eastern Bering Sea resulted in little ecological change in the system. These results highlight the importance of utilizing a proactive approach to fisheries management and suggest that changes in ecosystem and community composition should be strongly considered in all management actions to gain a more holistic perspective. Furthermore, they suggest that management goals related to the maintenance of biological diversity may not be suitable because of inadequate understanding of community dynamics. ACKNOWLEDGEMENTS There are a number of people who made this research possible. I wish to thank my major professor, Dr. Richard Burroughs for his continued support. Additionally, I would like to acknowledge my thesis committee members, Dr. Seth Macinko and Dr. Jeremy Collie, for helping to shape this project. I especially want to thank my family, for their constant love and encouragement. I would not have made it this far without their sound advice and encouraging words at exactly the right moments. Financial support for this research was provided by the Coastal Institute Graduate Fellowship Program and a teaching assistantship through the Department of Biological Sciences. iv TABLE OF CONTENTS Abstract .......................................................................................................................... ii Acknowledgements ....................................................................................................... iv Table of Contents ........................................................................................................... v List of Tables................................................................................................................. ix List of Figures ............................................................................................................... xi 1 Introduction ............................................................................................................. 1 2 Background ............................................................................................................. 7 2.1 History of Fisheries Management ................................................................... 7 2.2 Management Landscape and the Role of Science ......................................... 12 2.3 The State of Science in Fisheries Management ............................................. 17 2.4 Diversity as an Ecosystem Assessment Tool ................................................ 21 2.5 Georges Bank Groundfish Fishery ................................................................ 27 2.6 Eastern Bering Sea Groundfish Fishery ........................................................ 32 3 Methods ................................................................................................................ 40 3.1 Data ............................................................................................................... 40 3.1.1 Georges Bank ......................................................................................... 40 3.1.1.1 Demersal Communities................................................................... 40 3.1.1.2 Fishing Effort .................................................................................. 41 3.1.1.3 Commercial Landings ..................................................................... 42 3.1.1.4 Climate ............................................................................................ 42 3.1.2 Eastern Bering Sea ................................................................................. 43 3.1.2.1 Demersal Community ..................................................................... 43 v 3.1.2.2 Fishing Effort .................................................................................. 44 3.1.2.3 Commercial Landings ..................................................................... 44 3.1.2.4 Climate ............................................................................................ 45 3.2 Length Diversity ............................................................................................ 45 3.3 Species Diversity ........................................................................................... 48 3.3.1 Species Richness .................................................................................... 49 3.3.2 Species Evenness ................................................................................... 50 3.3.3 Trophic Diversity ................................................................................... 50 3.4 Evaluation of Changes in Community Structure ........................................... 51 4 Results ................................................................................................................... 53 4.1 Fishing Effort & Commercial Landings ........................................................ 53 4.1.1 Georges Bank ......................................................................................... 53 4.1.2 Eastern Bering Sea ................................................................................. 54 4.2 Single Species Abundance ............................................................................ 55 4.2.1 Georges Bank ......................................................................................... 55 4.2.2 Eastern Bering Sea ................................................................................. 56 4.3 Climate & Environmental Indices ................................................................