New Zealand Journal of Marine and Freshwater Research abstracts

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Estimating population parameters in an 'open' fish population

R. F. COOMBS

Fisheries Research Division, Ministry of Agriculture & Fisheries,
P.O. Box 19-062, Wellington, New Zealand

Abstract A model for an 'open' fish population is described. Basically an expansion of the classical catch equation, it includes a 'population change' coefficient to allow for changes in population size induced by causes other than fishing. The model relates this coefficient to catch, fishing effort, initial population size, and catchability coefficient. With observed catch and fishing effort data incorporated, the remaining parameters are estimated by minimising sums of squares. This estimation process is applied to data from both real and simulated fisheries, and is shown to be effective if the basic assumptions of the model are met. If this is not so considerable errors occur, and these are investigated with respect to the examples.

Fisheries Research Division Publication 356
Received 12 July 1976; revision received 14 December 1978 Fisheries Research Division Publication 356

PDF file of entire paper: medium quality (515K); (scanned from paper original: notes about this process)

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