Fishing Impacts on Marine Ecosystems Off

FISHING IMPACTS ON MARINE ECOSYSTEMS OFF BRAZIL, WITH EMPHASIS ON THE NORTHEASTERN REGION by KATIA DE MEIRELLES FELIZOLA FREIRE B. Sc., University of Rio Grande, 1990 M. Sc., University of Rio Grande, 1995 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES (Resource Management and Environmental Studies) THE UNIVERSITY OF BRITISH COLUMBIA September 2005 © Katia de Meirelles Felizola Freire, 2005 Abstract This study is the first contribution towards the development of ecosystem-based fisheries management in northeastern Brazil, through the exploration of fishing policies based on a trophic model. The following objectives were addressed: 1) analysis of the richness of common names of Brazilian fishes; 2) reconstruction of time series of marine catches; 3) modelling of trophic interactions off northeastern Brazil; and 4) assessment of fishing policies. The analysis of common names indicated a high richness of names per species (average = 6) and the use of the same common name for different species, with a negative impact on the accuracy of catch statistics. The reconstruction of catch time series was based on landings from national yearbooks, and from ICCAT and FAO's databases (1978-2000), allowing for the detection of 'fishing down the food web' in northeastern Brazil. The trophic model estimated a total biomass for this ecosystem of 222 tonnes-km"2 (excluding detritus), and indicated a low degree of omnivory and the high importance of detritus. Simulations for 2001-2028 indicated that current fishing effort is unsustainable for lobsters and swordfish; however, the model inadequately described the dynamics of swordfish, tunas, and other large pelagics, which have large distribution areas. The simulation of optimum fishing policies led to a diverse fleet when ecosystem health was emphasized. If the main objective was economic or social (or a combination of both and ecosystem health), manual collection of coastal resources, and demersal industrial fisheries could be boosted, while the lobster and longline fisheries should be phased out. A 50% reduction in effort for lobster fisheries would not produce significant changes in lobster biomass; a reduction in effort to the 1978 level (JMSY) would lead to biomass recovery. The instability of institutions responsible for fisheries management in Brazil has had a deleterious impact on the resources. This negative impact is expected to increase due to the current split of responsibility between two institutions with diverse agendas. An improvement in the collection system of catch statistics is recommended, which would consider a standardized set of common names, as well as gathering information on biological, economic, and social components of this ecosystem and its fisheries. Table of Contents Abstract ii Table of Contents iv List of tables vii List of figures viii List of appendices x Acknowledgements xi CHAPTER 1. General introduction 1 1.1. Historical perspective of the world fisheries 2 1.2. A framework for fisheries management 5 1.3. History of fisheries management in Brazil 11 1.4. Issues on fisheries management in Brazil 16 1.5. Objectives 18 1.6. Description of the study area 19 1.7. Overview of the main marine resources exploited off northeastern Brazil 21 a) Lobsters 23 b) Shrimps 24 c) Tuna and tuna-like fishes 26 d) Southern red snapper 28 e) Crabs 29 f) Turtles 30 g) Whales 31 Summary of the exploitation status of the main resources 31 1.8. Thesis outline 32 1.9. Bibliography 32 CHAPTER 2. Richness of common names of Brazilian marine fishes and its effect on catch statistics 41 2.1. Introduction. 41 2.2. Material and methods 42 2.3. Results 44 a) Richness of common names 44 b) Effect of common names' richness on catch statistics 48 c) The case for standardization of common names 54 iv 2.4. Discussion 58 2.5. Bibliography 62 CHAPTER 3. Analysis of catch data from marine fisheries off Brazil 67 3.1. Introduction 67 3.2. Material and methods 71 3.3. Results and discussion 74 a) Commercial fisheries 74 b) Recreational fisheries 90 c) Subsistence fisheries 91 d) Research fisheries 92 e) Ornamental fisheries 93 f) Discards 94 g) Distant water fleets 96 3.4. Conclusions 98 3.5. Bibliography 99 CHAPTER 4. Description of the marine ecosystem off northeastern Brazil using a trophic model 109 4.1. Introduction 109 4.2. Methods HI 4.2.1. ECOPATH model 111 4.2.2. Habitat area 112 4.2.3. Functional groups 113 4.2.4. Basic input 114 4.2.5. Diet composition 119 4.2.6. Landing data 119 4.2.7. Balancing the model 121 4.2.8. Time-dynamic simulation using Ecosim 123 4.3. Results : 127 4.4. Discussion 140 4.5. Bibliography 148 CHAPTER 5. Assessing fishing policies for northeastern Brazil 175 5.1. Introduction 175 5.2. Material and Methods 179 5.2.1. Fleet definition and landing data 181 5.2.2. Ex-vessel prices of 'fish' products 181 5.2.3. Fishing costs and profits 181 5.2.4. Optimum fishing policy search 184 5.2.5. Lobster fishery and future fishing policies 187 5.3. Results J 88 5.4. Discussion 195 5.5. References 204 CHAPTER 6. Concluding remarks 211 List of tables Table 1.1: Some international or regional fisheries-related agreements 17 Table 1.2: Status of the main fisheries off northeastern Brazil 25 Table 2.1: Common names related to the highest number of species 45 Table 2.2: Common names associated with the ten highest mean annual catches 50 Table 2.3: List of species presenting one unique common name 56 Table 3.1: Structure of the ACCESS database of landing statistics 71 Table 3.2: Sources used to compile landing statistics 71 Table 4.1: Basic input for the 1970s Ecopath with Ecosim model 130 Table 4.2: Diet matrix for the 1970s Ecopath with Ecosim model 131 Table 4.3: System statistics obtained from Ecopath with Ecosim 138 Table 4.4: Relative flows by discrete trophic level 139 Table 5.1: Groups used in the simulations of fishing policies 180 Table 5.2: Price per kilogram of each group 182 Table 5.3: Cost of each fishing fleet 184 Table 5.4: Estimated number of jobs provided by each fishery type 186 Table 5.5: Changes in biomass and catch for spiny lobsters 195 List of figures Figure 1.1: Framework for fisheries management 7 Figure 1.2: Location of the East Brazil Large Marine Ecosystem 19 Figure 1.3: Framework to the development of the analysis of the impact of fisheries 20 Figure 1.4: Five political regions of Brazil and nine States of the northeastern region 22 Figure 2.1: Flowchart used to split catch amongst all commercial species 46 Figure 2.2: Richness of names of Brazilian marine fishes 47 Figure 2.3: Relationship between no. of names, commercial importance, and habitat 48 Figure 2.4: Mean annual catch of 'bagre' split amongst all species 51 Figure 2.5: Annual catch of 'sardinha verdadeira' split amongst all species 52 Figure 2.6: Link between common and scientific names for 'linguado' 53 Figure 2.7: Catch data split amongst species for 'linguado' 55 Figure 3.1: Decision diagram on the correspondence of common and scientific names 73 Figure 3.2: Landing data for Brazilian marine fisheries 75 Figure 3.3: Comparison amongst landings recorded in ICC AT databases 78 Figure 3.4: Landings of tunas, bonitos and mackerels, swordfish, billfishes, and sharks 79 Figure 3.5: Main species caught by Brazilian marine commercial fisheries 80 Figure 3.6: Groups represented in landings from Brazilian marine commercial fisheries 81 Figure 3.7: States with the highest landings in Brazil 81 Figure 3.8: Landings of the industrial and artisanal marine fisheries 82 Figure 3.9: Landings of the main groups from fisheries in northeastern Brazil 83 Figure 3.10: Mean trophic level of landings for Brazil and northeastern Brazil 85 Figure 3.11: Schematic drawing indicating the overlapping of resources 85 Figure 3.12: Changes in mean trophic level for landings from northeastern Brazil 86 Figure 3.13: Fishing-in-balance index for northeastern Brazil 87 Figure 3.14: Landings originating with fisheries off Ceara and Rio Grande do Norte 89 Figure 3.15: Proportion of other fishes in relation to total landings 90 Figure 4.1: Mixed trophic impact in northeastern Brazil marine ecosystem 133 Figure 4.2: Verification of the model: spiny lobsters and southern red snapper 134 Figure 4.3: Verification of the model: tuna and tuna-like fishes 135 Figure 4.4: Changes in biomass in relation to the Ecopath level 136 Figure 4.5: Variation of the system statistics for East Brazil 136 Figure 5.1: Biomass changes in relation to the original biomass under status quo 188 Figure 5.2: Relative changes in fishing effort for each fleet in four scenarios 190 Figure 5.3: Mean relative change in biomass in four scenarios 191 Figure 5.4: Relative changes in fishing effort under the mandated rebuilding scenario 192 Figure 5.5: Mean relative change in biomass under the mandated rebuilding scenario 193 Figure 5.6: Changes is biomass of spiny lobsters in relation to the 1978 baseline 194 List of appendices Appendix 1: Glossary of terms used throughout this thesis 221 Appendix 2: List of species included in each functional group 222 Appendix 3: Input parameters for functional groups included in the Ecopath model 232 Appendix 4: Sources used to estimate the diet composition for all species 245 Acknowledgements I would like to say thank you to all of those who contributed in some way to this final product: General: - My supervisor Daniel Pauly for his supervision during all my years at UBC and for showing me what being a real scientist means; My supervisory

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