Sample-Based Fishery Surveys - A Technical Handbook













Table of Contents


Prepared by
Constantine Stamatopoulos
Senior Fishery Data Officer
Fishery Information, Data and Statistics Unit
FAO Fisheries Department

ISSN 0429-9345
FAO
FISHERIES
TECHNICAL
PAPER
425

Food and Agriculture Organization of the United Nations

Rome, 2002

The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

ISBN 92-5-104699-9

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© FAO 2002


Table of Contents


PREFACE

1. INTRODUCTION

1.1 UTILITY OF BASIC FISHERY DATA
1.2 COST-EFFECTIVE FISHERY SURVEYS
1.3 SUSTAINABLE FISHERY SURVEYS
1.4 ROLE OF FIELD STAFF
1.5 ROLE OF OFFICE STAFF

2. CONCEPTS IN ESTIMATING CATCH

2.1 A GENERIC FORMULA FOR ESTIMATING CATCH
2.2 SECONDARY ESTIMATES

3. CONCEPTS IN ESTIMATING EFFORT

3.1 COMPLETE ENUMERATION (CENSUS)
3.2 CENSUS IN SPACE, SAMPLING IN TIME
3.3 CENSUS IN TIME, SAMPLING IN SPACE
3.4 SAMPLING IN SPACE AND IN TIME

4. GENERAL SAMPLING CONSIDERATIONS

4.1 CENSUS COSTS AND OBJECTIVES OF SAMPLING
4.2 ACCURACY AND PRECISION IN SAMPLING
4.3 ACCURACY AS A FUNCTION OF SAMPLE SIZE
4.4 A PRIORI ACCURACY INDICATORS
4.5 SAFE SAMPLE SIZE FOR LANDINGS AND EFFORT
4.6 VARIABILITY INDICATORS
4.7 STRATIFICATION AND ITS IMPACT ON SURVEY COST
4.8 THE PROBLEM OF BIASED ESTIMATES
4.9 NEED FOR REPRESENTATIVE SAMPLES
4.10 THE “BOAT” AND “GEAR” APPROACHES

5. SURVEY STANDARDS

5.1 STRATIFICATION
5.2 CLASSIFICATIONS
5.3 VALIDITY OF SURVEY STANDARDS OVER TIME

6. SURVEYS FOR BASIC FISHERY DATA

6.1 SAMPLING IN SPACE AND IN TIME
6.2 CENSUS IN TIME AND SAMPLING IN SPACE
6.3 CENSUS IN SPACE AND SAMPLING IN TIME
6.4 CENSUS FOR EFFORT AND SAMPLING FOR LANDINGS
6.5 BRIEF DISCUSSION ON THE FOUR GENERIC SURVEYS

7. ACTIVE DAYS SURVEYS

7.1 OBJECTIVE
7.2 DATA RECORDING

8. FRAME SURVEYS

8.1 OBJECTIVES
8.2 SITES AND BOAT/GEAR CLASSIFICATIONS
8.3 SEASONAL/SEQUENTIAL VARIATION OF FISHING GEAR
8.4 CONCURRENT USE OF FISHING GEAR
8.5 FORMS FOR DATA COLLECTION
8.6 BRIEFING OF DATA COLLECTORS
8.7 SURVEY TESTING AND IMPLEMENTATION
8.8 FRAME SURVEY DATA SUMMARIES
8.9 SUMMARIES WITH GROUPED HOMEPORTS
8.10 ABSOLUTE AND RELATIVE ACCURACY

9. BOAT ACTIVITY SURVEYS

9.1 OBJECTIVES OF BOAT ACTIVITY SURVEYS
9.2 TARGET DATA POPULATION AND ACTIVITY STATUS
9.3 SAMPLING REQUIREMENTS
9.4 BACS RELYING ON FRAME SURVEYS
9.5 SAMPLING FOR BOAT ACTIVITIES
9.6 COMBINATION WITH LANDING SURVEYS
9.7 BRIEFING OF DATA COLLECTORS
9.8 IMPLEMENTATION ASPECTS
9.9 FREQUENT PROBLEMS

10. LANDING SURVEYS

10.1 OBJECTIVES OF LANDING SURVEYS
10.2 SAMPLING REQUIREMENTS
10.3 A GENERAL-PURPOSE FORM
10.4 CASE STUDIES
10.5 TRAINING OF DATA COLLECTORS
10.6 BRIEFING OF DATA COLLECTORS
10.7 IMPLEMENTATION ASPECTS
10.8 FREQUENT PROBLEMS

11. DATA PROCESSING

11.1 NEED FOR AUTOMATED PROCEDURES
11.2 DATA FLOWS
11.3 SURVEY STANDARDS
11.4 PROCESSING OF PRIMARY DATA
11.5 DATA CHECKING AND MONITORING
11.6 ESTIMATION PROCESSES
11.7 BASIC REPORTING
11.8 TRAINING AND OPERATIONAL GUIDELINES

12. DATA STORAGE AND DISSEMINATION

12.1 GENERAL-PURPOSE DATABASES
12.2 FUNCTIONAL CHARACTERISTICS
12.3 REGIONAL DATABASES

13. FURTHER READING

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