Reef Fish Resources Survey in the Maldives - Phase II-BOBP/WP/80

WORKING PAPERS - BOBP/WP/80

Reef Fish Resources Survey in the Maldives - Phase II


by
R. C. Anderson, Z. Waheed, M. Rasheed and A. Arif


Executing Agency: FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS

Bay of Bengal Programme Madras, India, 1992

Table of Contents


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© FAO 2004

PREFACE

This paper describes the second phase of a reef fish resources survey carried out in the Maldives and presents preliminary estimates of reef fish densities and maximum potential yields. This follows an earlier phase carried out during 1987-88 in North Male Atoll from the research vessel Faruinas (Van der Knaap et al 1991) of the Ministry of Fisheries and Agriculture. That first survey phase established that handlines and longlines are the best gear for catching Maldivian reef fish, it collected a considerable quantity of information of value for long-term stock assessment and for potential developers, and it made a first estimate of potential yields from N. Male Atoll. The second phase was conducted in Shaviyani, Alifu and laaniu Atolls during 1989-91.

Species compositions and catch rates for the major gear and fishing areas were established, regional and seasonal differences were noted and a considerable quantity of information on the biological characteristics of commercial species was collected.

Preliminary estimates indicate a maximum potential yield of commercial reef fish (i.e. medium to large snapper, grouper, emperor and reef associated jack)of the order of 30,000 ± 13,000 t/year. The atoll basins (which constitute by far the largest part of the Maldivian atolls) are identified as having relatively large reef fish resources. The deep reef slopes outside the atolls support some high value species, hut their total potential yield is relatively small. It must, however, be noted that the stock assessment presented here is only of a preliminary nature and if the reef fishery is to be expanded, possibilities for which appear to be good, detailed monitoring will be required to make a more precise stock assessment.

The effort of several persons who worked on this survey need to be acknowledged. The staff of the Marine Research Section, particularly Hussein Shareef, Au Waheed, Ahmed Shareef, Ibrahim Naeem, Hussein Zahir, gave assistance with fieldwork and data compilation. Ali Naeem of MOFA assisted with the installation and the maintenance of electronic equipment on Farumas. The skippers (Yoosuf Idrees, Ibrahim Naseem, Adam Fulhu, Abdul Ghanee) and crew of Farumas cheerfully carried out the fieldwork, often in conditions that were far from ideal. Maizan Hassan Maniku, Lars Engvall, K. Sivasubramaniam, Martin Van der Knaap, Janne Fogeigren and Michel Kulbicki contributed by making useful comments on an early draft of this report. Constructive comments were also received from Drs. Daniel Pauly and Jeffrey Polovina.


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TABLE OF CONTENTS


WORKING PAPERS - BOBP/WP/80pdf

1. INTRODUCTION

1.1 Project background
1.2 Existing reef fisheries

2. MATERIALS AND METHODS

2.1 Fishing vessel
2.2 Fishing gear
2.3 Fishing survey
2.4 Catch sampling
2.5 Analytical methods

3. FISHING SURVEY RESULTS

3.1 Longline fishing inside the atolls
3.2 Comparison of normal v. circle hooks
3.3 Longline fishing outside the atolls
3.4 Handlining
3.4.1 Day handlining
3.4.2 Night handlining
3.4.3 Commercial handlining catch rates
3.5 Trolling
3.6 Other fishing methods

4. STOCK ASSESSMENTS

4.1 Models available
4.2 Atoll basins
4.3 Shallow reef areas
4.4 Deep reef slopes
4.5 Total stock assessment

5. BIOLOGICAL FINDINGS

5.1 Species composition
5.2 Regional variation
5.3 Seasonal variation
5.4 Size composition

TABLES

1. Summary of fishing effort during the reef fish survey
2. Summary of catch and effort by major fishing gear in Shaviyani Atoll
3. Summary of catch and effort by major fishing gear in Alifu Atoll
4. Summary of catch and effort by major fishing gear in Laamu Atoll
5. Approximate sizes of Maldivian atolls
6. Number of standard I 50-hook longlines deployed in the atoll basins of the three target atolls during different periods
7. Catch rates by longline of reef fish species and species groups inside the three target atolls
8. Composition of longline catches (percentage by weight) in the atoll basins of four Maldivian atolls
9. Comparison of catches by normal hooks and circle hooks
10. Summary of longline fishing effort at different depths on outer atoll reefs from both Phase I and Phase II of the Reef Fish Survey
11. Catch rates by longline on the outer reef at different depths (Data both Phase I & II)
12. Catch rates of major species and species groups by day handlining
13. Catch rates of major species and species groups by night handlining
14. Summary of trolling catch rates
15. Contributions of major reef fish species to the catches of four major fishing gear (¾)

MAPS, CHARTS AND FIGURES

1. Map of the Maldives
2. General arrangement of exploratory research vessel, R.V. Faruo’nas
3. Multifilament bottom set longline
4. Vertical stick longline/trolling
5. Traditional handline
6-12 Length Frequency Data
6. Aprlon Virescens
7. .Aprlon Virescens (Shaviyani Atoll)
8. Lwjanus DeMur
9. Snapper
10. Loxodon Macrorhinus
11. Emperor
12. Grouper

REFERENCES

APPENDICES

I. Total numbers and weight (kg) of fish (by species) caught by longline inside the three target atolls
II. Total numbers and weight (kg) of fish (by species and depth) caught by longline on outer atoll reef slopes during Phase II of the Reef Fish Survey
III. Total numbers and weight (kg) of fish (by species and atoll) caught by day handlining
IV. Numbers of fish and weight (kg) of fish (by species and atoll) caught by night handlining

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