Elementary Statistics (1+1)

1.6.1 Computer and fisheries statistics

The wide spread use of computers has had a tremendous impact on statistical analysis of fisheries data. Computers can perform calculations much faster and accurately. The use of computers makes it possible to devote more time for improvement of quality of data collected and interpretation of results. Many number of computer software packages are available for carrying out most of the descriptive and inferential statistical analysis. Some of the statistical packages that are widely used include Statistical Packages for the Social Sciences (SPSS), SAS and SYSTAT. These packages differ with respect to their input requirements, their output formats and the specific calculations they perform. Therefore, before using a particular package or a program, input requirements should be studied carefully and program’s output format to be studied for proper interpretation of results. Spread sheet software Microsoft Excel is also used for conducting statistical analysis using Data analysis / Analysis Tool pak and Tool bar function fx.

Length based Fish Stock Assessment (LFSA) and Electronic Length Frequency Analysis (ELEFAN) packages developed during eighties by Food and Agricultural Organisation (FAO) and International Centre for Living Aquatic Resources Management (ICLARM) respectively have been very popular in fish stock assessment studies. In nineties FAO and ICLARM joined together and developed a new program package for length based fish stock assessment called FISAT (FAO – ICLARM Stock Assessment Tools) incorporating the positive aspects of the parent packages LFSA and ELEFAN. Other important fish stock assessment programmes produced by FAO include BEAM1, 2, 3 and 4 for bio-economic modeling and CLIMPROD dealing with surplus production models incorporating environmental variables. The computer software packages mentioned here are only indicative and not exhaustive.