Measuring Fish Lengths from Instant Photographs Using a Digitizing Tablet and Minicomputer

Abstract

A modification of photographic techniques for measurement of fish lengths has been developed, which uses instant photography and a digitizing tablet with a minicomputer. Instant photography allows print inspection while live fish are retained and “retakes” of poor quality photographs can be made. A photographic record of test animals is obtained, and fish may then be measured from the photographs at any convenient time. The digitizing tablet decreases time for fish measurement from photographs and maintains or improves accuracy over manual techniques. Raw data are entered directly into the minicomputer, which is programmed to perform summary statistics after all groups are measured. Summary statistics and raw data are printed to a prescribed format by the computer. The elimination of manual data entry and subsequent data validation will result in a substantial savings in time.