This manual is a selection, from the entire field of fish population dynamics, of methods that are applicable totropical fish and fisheries and can be implemented with the help of programmable calculators. The methods selected cover the following areas: length-weight relationships, mesh selection, growth, mortality, population size estimation by various methods (e.g., tagging, virtual population analysis), yield-per-recruit assessments, stock-recruitment relationships, surplus-yield models, the rate of increase of populations and aspects of multispecies stocks and fisheries.