Simulation of angler-exploitation of salmon in the Rakaia River

[First paragraph(s)...]
The aim of simulation methods is to test hypotheses about the behaviour of complex natural systems by using a computer to perform a sequence of instructions which imitate the way in which we suspect that the system operates. The set of instructions represents a model of the system, translated into a computer language, and results are obtained by running the computer programme and using different starting conditions. Because digital computers operate at very high speed they can calculate very complicated interactions within a system in a very short time. This paper gives a preliminary account of some work in progress which is exploring the factors influencing the catch taken by anglers fishing for quinnat salmon in the Rakaia River. The central parts of the study concern the behaviour of the fishermen, the upstream movement of the fish and the physical characteristics of the river in so far as they affect fishing success.