The objective is for the fellows to get an in-depth understanding of common stock assessment methods and their application. The course takes 5 weeks with lectures and practical sessions daily. The emphasis within the course depends on the background of the students which may vary from one year to the next.
In the first part sampling procedures and presentation and interpretation of biological characteristics of stocks are covered. This is followed by gear selectivity, survey design and data management.
The population dynamics of a fish stock are described by viewing the stock as a collection of cohorts. This leads to methods for calculating yield per recruit and estimating
stock-recruitment curves and yield potential using various assumptions, leading to methods for
long- and short-term catch forecasts. The formulation of harvest control rules and their relationship to the precautionary approach is described, and the risk involved due to assessment errors and
environmental fluctuations. The methodology is developed
simultaneously for different data scenarios, ranging from data-poor situations with e.g. survey length distributions and landings data through data-rich situations where the age composition of
catches may be known. This is possible by separating carefully the model
description of population dynamics from the description of how the data relate to model outputs.
The entire content of the population dynamics part of the course are available as web pages on http://tutor-web.net.
