The estimation of recruitment from stage frequency data.

A general relationship is derived for the area of the sample curve for a given stage in the life-cycle, in terms of the mean survival rate and duration and the number entering the stage. The influence of recruitment, development and mortality patterns on the area of the sample curve is investigated. The results indicate a simple method of analysing stage frequency data to produce a best estimate of the number entering each stage. A test example, using simulated data, is provided with a discussion of the method in relation to other techniques based on the area of the sample curve.