GENERAL FISHERIES COMMISSION FOR THE MEDITERRANEAN - No. 73 GENERAL FISHERIES COMMISSION FOR THE MEDITERRANEAN - No. 73

Studies and Reviews

Manual of Fisheries Sampling Surveys: Methodologies for Estimations of Socio-Economic Indicators in the Mediterranean Sea

by

Evelina Sabatella
Istituto Ricerche Economiche per la Pesca e l’Acquacoltura
Salerno,
ITALY

Ramón Franquesa
Gabinete de Economía del Mar
Universitat de Barcelona
Spain

   

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
Rome, 2004

Table of Contents

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ISBN 92-5-105093-7
ISSN 1020-7236

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© FAO 2004


Sabatella, E.; Franquesa, R.

Manual of fisheries sampling surveys: methodologies for estimations of socio-economic indicators in the Mediterranean Sea.

Studies and Reviews. General Fisheries Commission for the Mediterranean. No. 73. Rome, FAO. 2003. 37p.

ABSTRACT

This manual on sampling methodologies for the development of socio-economic indicators was initiated by the Sub-Committee on Economic and Social Sciences (SCESS) of the General Fisheries Commission for the Mediterranean Scientific Advisory Committee. It was prepared jointly by the Istituto Ricerche Economiche per la Pesca e l’Acquacoltura (IREPA) and the Gabinete de Economía del Mar (GEM) within the framework of the ad hoc Working Group on Socio-Economic Indicators of SCESS.

The manual is aimed at all decision-makers who may need to collect data to build socio-economic indicators. At an international level, it can be used to facilitate and simplify reporting under international conventions and agreements on matters relating to the sustainable development of the world’s fisheries. Regional fisheries bodies and stakeholders involved in fisheries decision-making, such as the fishing industry, other user groups, certification bodies, local communities and non-governmental organizations, may also draw upon this manual to assist in meeting societal goals for fisheries.

The methodologies can be applied to fisheries at many different levels, from individual fisheries and coastal management units to a global level. The manual aims to encourage consistent use of statistical methods in data collection. Governments may also wish to adapt the manual to the specific requirements of their national fisheries.



Table of Contents


PREPARATION OF THIS DOCUMENT

ACKNOWLEDGEMENTS

1. INTRODUCTION

1.1 Socio-economic indicators
1.2 Study of the existing situation
1.3 Geographical and technical fleet segmentation
1.4 The scope of this manual

2. POPULATION AND SAMPLING

2.1 Potential methods for data collection
2.2 Advantages of sampling methods
2.3 Some statistical terms

2.3.1 Mean
2.3.2 Variance and standard deviation
2.3.3 Normal distribution and confidence limits

2.4 The role of sampling theory
2.5 Probability sampling
2.6 Alternatives to probability sampling
2.7 Bias and its effects

3. THE PRINCIPAL STEPS IN A SAMPLE SURVEY

3.1 Objectives of the survey
3.2 Population to be sampled
3.3 Data to be collected
3.4 Degree of precision desired
3.5 The questionnaire and the choice of the data collectors
3.6 Selection of the sample design
3.7 Sampling units
3.8 The pre-test
3.9 Organization of the field work
3.10 Summary and analysis of the data
3.11 Information gained for future surveys

4. SURVEY METHODS AND QUESTIONNAIRE DESIGN

4.1 Simple random sampling
4.2 Stratified random sampling
4.3 The estimation of sample size and allocation across strata

4.3.1 Sample size with more than one item

4.4 Estimation of parameters
4.5 Sources of error in surveys

4.5.1 Sampling errors
4.5.2 Effects of non-response

5.REFERENCES CONSULTED

APPENDIXES

A - List of socio-economic indicators
B - Fleet segmentation and parameters of the socio-economic structure for the operative units
C - Questionnaires for the collection of socio-economic data
D - Implementation of the bethel method (SAS ® HML)
E - Optimal sample size and the differences Between neyman and Bethel methods - an example

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