Mortality estimation

Mortality is an essential parameter in understanding the dynamics of any population and sharks are no exception. Without knowledge of how fast individuals are removed from a population it is impossible to model the population dynamics or estimate sustainable rates of exploitation or other useful management parameters. Two separate types of mortality occur in shark (or fish for that matter) populations. First, natural mortality (commonly referred to by the letter M), which is the loss to the population from natural sources such as predation, disease and old age, and second fishing morality (referred to by the letter F) which, as the name suggests, is the loss to the population from fishing. Fishing and natural mortality combine to give total mortality (referred to by the letter Z), such that Z = M + F (8.1).

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Management Techniques for Elasmobranch Fisheries

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978-92-5-105403-1

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