Stock assessment approach for the Napoleon fish, Cheilinus undulatus, in Indonesia

FAO Fisheries and Aquaculture Circular No. 1023

STOCK ASSESSMENT APPROACH FOR THE NAPOLEON FISH,
CHEILINUS UNDULATUS, IN INDONESIA

A tool for quota-setting for data-poor fisheries under CITES Appendix II
Non-Detriment Finding requirements


by

Yvonne Sadovy
Department of Ecology and Biodiversity
University of Hong Kong
China, Hong Kong Special Administrative Region

André E. Punt
School of Aquatic and Fishery Sciences
University of Washington
Seattle, WA, United States of America

William Cheung
Fisheries Centre
University of British Columbia
Vancouver, Canada

Marcelo Vasconcellos
Fisheries Management and Conservation Service
Fisheries and Aquaculture Department
Food and Agriculture Organization of the United Nations
Rome, Italy

Sasanti Suharti
Research Center for Oceanography
Indonesian Institute of Sciences
Jakarta, Indonesia

Bruce D. Mapstone
Antarctic Climate and Ecosystems Cooperative Research Centre
Hobart, Tasmania, Australia

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
Rome, 2007

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ISBN 978-92-5-1055775-9

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© FAO 2007

Sadovy, Y; Punt, A.E.; Cheung, W.; Vasconcellos, M.; Suharti, S.; Mapstone, B.D. 2007.
Stock assessment approach for the Napoleon fish, Cheilinus undulatus, in Indonesia. A tool for quotasetting for data-poor fisheries under CITES Appendix II Non-Detriment Finding requirements. FAO Fisheries Circular. No. 1023. Rome, FAO. 2007. 71pp. Contains a CD-ROM.

This CD-ROM includes a Microsoft® EXCEL® file with a Visual Basic macro that runs the model

Abstract

A stock assessment approach for the Napoleon fish (humphead wrasse), Cheilinus undulatus, is presented as a tool for determining sustainable catch levels of the species. The model was developed primarily for application in Indonesia and in collaboration with the Research Center for Oceanography, Indonesian Institute of Sciences (LIPI). The model can be adapted for estimating sustainable catch levels in other countries, if suitable estimates of reef area and fish densities are available. The approach is composed of a population model and a method for estimating stock density based on underwater visual surveys, allows for the representation of "grow out" of net-caged animals, a significant part of the trade, includes the ability to account for uncertainty in most of the parameters of the model, and can compute a sustainable catch (and its associated uncertainty) corresponding to a user-specified level of fishing mortality. The resultant model is implemented using Microsoft EXCEL and Visual Basic, with a graphical user interface for easy use (the EXCEL spreadsheet is included in the CD-Rom provided with this Fisheries Circular). Sustainable fishing mortality rates for the species in Indonesia can be estimated based on commonly used biological reference points (e.g. FMSY; F20%). Results of sensitivity tests indicated that the relationship between stock and recruitment remains the major uncertainty affecting the estimation of sustainable fishing rates. Preliminary estimates of export quotas for Indonesia are provided taking into account the official statistics on the volume of domestic catches and estimated illegal and unreported exports. Estimated export quotas were highly sensitive to the estimated habitat area suitable for the species, which highlights the need for more accurate estimates of reef habitat areas in Indonesia. Quotas depend heavily on successful implementation and are one of several possible approaches to achieving sustainable exports of a CITES Appendix II listed species.


Contents



Preparation of this document  (Download pdf 453 kb)
Abstract
Glossary of acronyms

1  INTRODUCTION  (Download pdf 130 kb)

2  METHODS  (Download pdf 794 kb)
2.1  Conceptual framework
2.2  Calculating biological reference points using a yield model
2.3  Model parameterization and quantification of uncertainty
2.4  Abundance estimation
2.5  Calculation of catches using actual estimates of abundance
3  RESULTS  (Download pdf 907 kb)
3.1  Parameterization of the yield model
3.2  Model validation
3.3  Abundance estimation
3.4  Sensitivity analyses
3.5  Preliminary estimates of sustainable export quota
4  DISCUSSION  (Download pdf 78 kb)
4.1  Limitations and recommendations for improving the approach
4.2  Use of the model as part of a management system
4.3  Current and recommended conservation measures for the Napoleon fish in Indonesia
5  REFERENCES  (Download pdf 67 kb)

APPENDIXES  (Download pdf 586 kb)

Appendix A.  Meta-analysis of steepness of the stock-recruitment relationship for coral reef fishes

Appendix B.  Default values for the amount of illegal, unreported and unregulated fishing exports
                      and domestic consumption of Napoleon fish

Appendix C.  Performance of status and characteristics of Napoleon fish in grow-out phase
                      within the Indonesian waters

Appendix D.  A user-interface for a stock assessment model of the humphead (=Napoleon) wrasse