This manual contains guidance on data collection methods for developing socio-economic indicators, and it can be used to facilitate and simplify reporting under international conventions and agreements on matters relating to the sustainable fisheries development. The methodologies can be applied to fisheries at many different levels, from individual fisheries and coastal management units to a global level, and it aims to encourage consistent use of statistical methods in data collection.

This document provides tested and standardized tools to collect the data needed for a socio-economic assessment of a fishery, including sampling design, quality checks and how to transform inputs into statistics.

The main objective of this manual is to present the basic and standard concepts of sampling methods applied to fisheries science. In order to ensure sound fisheries research, it is essential to have reliable data from landing ports, fishery stocks and research surveys. A rational management of fishing resources can then be established to ensure a sustainable exploitation rate and responsible fisheries management, providing long-term benefits for all. This document provides an introduction to sampling theory and introduces the theory of the three worlds (population, sample and sampling), as well as a short revision of probability concepts. It also provides an overview of the simple random, random stratified, cluster and two-stage sampling methods. The expressions for estimating the mean and total of the populations, their sampling distributions, the expected values, the sampling variances and their estimates are included and justified for each of the sampling designs. The document also contains a case study of biological sampling from landing ports and exercises that should be used to further understanding of the objectives of sampling and its advantages for fishery resource studies.