Sampling Methods Applied To Fisheries Science

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.

This was the first effort to standardize methods for inland fish sampling across North America and, as such, was a joint effort contributed to by a large group of talented and dedicated individuals, in addition to the authors and coeditors. While these sampling methods were primarily developed for North America, most could be used with little or no modification in other areas of the world. Those involved with standard sampling efforts in North America would welcome the opportunity to collaborate with scientists from other regions to develop methods to share data worldwide.