Tropical Stock Assessment Packagesfor Programmable

Fishery biology, particularly the applied aspect of stock assessment, became a truly quantitative science in the mid-1950s, when the Beverton & Holt and Schaefer"workhorse" models for stock assessment were produced. Unfortunately, the computations involved in using either of these models and their variants and successors were generallyquite tedious. In the 1960s and early 1970s, various authors, tempted by the availability of large computers, began to expand on the availablem04els,adding a variable here, a species there. However, the use of large computers as a research tool in fisheries remained, as a whole, limited to a few centers of excellence, and many of the earlier leads were not pursued. In the mid-1970s, a new type of hardware became available which changed all that: microcomputers and programmablecalculators. Microcomputers In spite of a wide range of available brands and models, the present lines of microcomputers are essentially similar, with most capacities ranging from 2 to about 60 kilobytes,and prices ranging from about US$500 to 5,000 (including bottom-line peripheralssuch as cassette drive).The relativeuniformity of performance of the majormodels in the market is based on the fact that they tend to be built around the same microprocessors; more importantly (for the users), the overwhelming majority of microcomputers are programmable in the easy-to-leamBASIC. Manufacturer-suppliedsoftware for microcomputers is generallylimited to business applications and bloodthirsty "games," while scientific programsare generally limited to standard statistical methods such as can be performed, and with almost equal ease, with programmablecalculators. ProgrammableCalculators As opposed to the situation prevailing with microcomputers, the bulk of sales of programmable calculators is essentially attributable to two firms (Texas Instruments and Hewlett-Packard). This situation has led to a wide range of software being available to