Australian Government Assistance to the Seychelles Tsunami Relief Effort: Assessing Impacts to Near-Shore Fisheries
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Australian Government Assistance to the Seychelles Tsunami Relief Effort: Assessing impacts to near-shore fisheries Timothy Skewes, Yimin Ye, Charis Burridge October 2005 AusAID Seychelles Enquiries should be addressed to: Timothy Skewes CSIRO Marine and Atmospheric Research PO Box 120 Cleveland QLD 4163 Australia 233 Middle Street Cleveland Queensland Australia Telephone (07) 3826 7200 Int +61 7 3826 7200 Facsimile (07) 3826 7222 Int +61 7 3826 7222 Web site: http://www.marine.csiro.au Important Notice © Copyright Commonwealth Scientific and Industrial Research Organisation (‘CSIRO’) Australia 2005 All rights are reserved and no part of this publication covered by copyright may be reproduced or copied in any form or by any means except with the written permission of CSIRO. The results and analyses contained in this Report are based on a number of technical, circumstantial or otherwise specified assumptions and parameters. The user must make its own assessment of the suitability for its use of the information or material contained in or generated from the Report. To the extent permitted by law, CSIRO excludes all liability to any party for expenses, losses, damages and costs arising directly or indirectly from using this Report. Use of this Report The use of this Report is subject to the terms on which it was prepared by CSIRO. In particular, the Report may only be used for the following purposes. • this Report may be copied for distribution within the Client’s organisation; • the information in this Report may be used by the entity for which it was prepared (“the Client”), or by the Client’s contractors and agents, for the Client’s internal business operations (but not licensing to third parties); • extracts of the Report distributed for these purposes must clearly note that the extract is part of a larger Report prepared by CSIRO for the Client. The Report must not be used as a means of endorsement without the prior written consent of CSIRO. The name, trade mark or logo of CSIRO must not be used without the prior written consent of CSIRO. Acknowledgements Jan Robinson and Riaz Aumeeruddy of the Seychelles Fishing Authority were instrumental in defining the project objectives, making the data available, participating in fieldwork and in the interpretation of the results. Thanks to Maria Cedras (SFA) and Stephane Morgan (RV L`Amitie) for their assistance in the field. This study was funded by AusAID through its Tsunami Relief Fund. Thanks to Jill Bell of AusAID for facilitating this project. National Library of Australia Cataloguing-in-Publication entry: Skewes, Timothy. Australian government assistance to the Seychelles Tsunami Relief Effort : assisting impacts to near-shore fisheries. Bibliography. Includes index. ISBN 1 921061 29 4. ISBN 1 921061 30 8 (pdf). 1. Fisheries - Seychelles. 2. Indian Ocean Tsunami, 2004. I. Ye, Yimin. II. Burridge, Charis. III. CSIRO. Marine and Atmospheric Research. IV. Australian Agency for International Development. V. Title. 338.372709696 Table of Contents Executive Summary...............................................................................................................6 Introduction............................................................................................................................ 7 Inshore finfish fishery ........................................................................................................... 7 Small boat survey database................................................................................................................ 8 Sites sampled.................................................................................................................................. 9 Effort data recorded....................................................................................................................... 10 Boat type and fishing gear............................................................................................................. 11 Catch ............................................................................................................................................. 14 Assessing the impact of tsunami on fish stocks................................................................................ 17 Changes in catch per unit effort .................................................................................................... 18 Changes in monthly fishing effort.................................................................................................. 26 Statistical analysis ......................................................................................................................... 30 Discussion ......................................................................................................................................... 34 Shallow reef benthic fisheries............................................................................................ 35 Methods............................................................................................................................................. 35 Analysis ......................................................................................................................................... 35 Results............................................................................................................................................... 37 Discussion ......................................................................................................................................... 44 References ........................................................................................................................... 45 Appendices .......................................................................................................................... 46 Seychelles tsunami fisheries impacts 3 Figures Figure 1. Seychelles CAS database; number of sample days per month for all sites. .......................... 8 Figure 2. Plot of average sample days per month (for months with samples) for each year 1985 to 2005................................................................................................................................................. 9 Figure 3. Total number of sample days for each site for the period 1985 to 2005. ............................... 9 Figure 4. Proportion of total yearly sampling effort (days) for each landing site for 1985 to 2005. ..... 10 Figure 5. Number of records for EXISTING, LANDED and SAMPLED at all sites sampled for each year 1985 to 2005. ........................................................................................................................ 11 Figure 6. Plot of the proportion of EXISTING boats that were recorded as LANDED (Proportion LANDED) and the proportion of LANDED boats that were sampled (Proportion SAMPLED) for each year for all sites. ................................................................................................................... 11 Figure 7. Number of records for EXISTING, LANDED and SAMPLED for each vessel-gear combination (that had more than zero records) at all sites sampled between 1985 and 2005. ... 12 Figure 8. Plot of the proportion of EXISTING boats that were recorded as LANDED (Proportion LANDED) and the proportion of LANDED boats that were sampled (Proportion SAMPLED for each boat/gear combination for all sites and years....................................................................... 13 Figure 9. Plot of the proportion of overall LANDED records for each vessel-gear combination at all sites sampled for each year. ......................................................................................................... 13 Figure 10. Total yearly catch in samples for each boat type (All data except 1996). .......................... 15 Figure 11. Total yearly catch in samples for Foot and Pir only (same as Figure 10) (All data except 1996). ............................................................................................................................................ 15 Figure 12. Total yearly catch in samples for each gear type (All data except 1996). .......................... 16 Figure 13. Total catches in sampled vessels of the 18 fish species/species groups recorded in the CAS monitoring program for 1985 to 2005. .................................................................................. 16 Figure 14. Annual catches of the 18 fish species/species groups recorded in the CAS monitoring program. ........................................................................................................................................ 17 Figure 15. Raw CPUEs in each month from 1985 to 2005 for the seven selected species (S1=,S2=…)................................................................................................................................... 19 Figure 16. Monthly mean CPUEs from April 1985 to March 2005 for the 7 selected fish species (S1=, S2=…). Red marks post-tsunami. ................................................................................................. 23 Figure 17. Monthly total fishing effort in sampled vessels from April 1985 to March 2005 targeting the seven selected fish species (For Species S1, S2, S3, S5 and S15, efforts was measured by man*hours of fishing, and for Species S8 and S9, in traps*hours). Red marks post-tsunami...... 27 Figure 18. Map of Mahe Island, a central granitic island of the Mahe Plateau with the location of 12 sites resampled after