This manual describes computer programs written in Microsoft BASIC (version 2.20B) for use on an Apple Ile micro-computer (with CP/M operating system) and EPSON RX-80 F/T printer.

These programs include a modification of Bhattacharya’s method for identifying and separating normal distributions, in a mixture of distributions in length frequency data, and computation of Chi square statistics for testing goodness of fit, as described by Pauly and Caddy (1985). This package includes a program that plots the frequency distributions for several samples of data. It is useful for estimating growth parameters and calculates the catch at length for each of the mean length groups separated, and gives 95% and 99% confidence limits for each mean.

Growth parameters can also be estimated using length-at-age data by the Ford- Walford Plot and von Bertalanffy Plot programs. In cases where the ages of fish are not known and a series of sizes at relative ages is not available, growth parameters can still be estimated using data on length increase in time (such as also obtained from tagging-recapture data) by the Gulland and Holt Plot program. This package also includes Sparre’s, Jones’ and Van Zalinge’s method for estimating total mortality coefficients from length frequency data. A new method for estimating the asymptotic length and mortality coefficient as proposed by J.A. Wetherall is also presented. This manual and the programs have been prepared by the BOBP project “Marine Fishery Resources Management in the Bay of Bengal” (RAS/81/051). The project commenced January 1983 and terminated December 1986. It was funded by the UNDP.

This document and the programs have not been officially cleared by the governments concerned or by the FAO.