Breadcrumbs Section. Click here to navigate to respective pages.

Chapter

Chapter

# Mathematical Models of a Fishery.

DOI link for Mathematical Models of a Fishery.

Mathematical Models of a Fishery. book

# Mathematical Models of a Fishery.

DOI link for Mathematical Models of a Fishery.

Mathematical Models of a Fishery. book

Click here to navigate to parent product.

## ABSTRACT

The basic relationship in this approach 1 to the behavior of an unexploited fish population is the following one:

Equation 1 states that the dependence of the natural growth rate, ~ , on the population, N, is such that it is zero when N=O and when N=N., positive when O<N <N. and negative when N>N •. When N=%N., the natural rate of increase attains a maximum. Further, over the range of positive growth rates, the relation is symmetrical about N = 112 N.. As Beverton and Holt pointed out (P. 330), the few experimental studies supporting equation 1 refer to increase in numbers, not in weight. To assume that growth in popUlation weight is also a sym-

p

(;f'[-

lmd 1"

which the assumption that "the increase of the population depends solely on its total weight and is independent of the age-and size-composition of the individuals comprising them" appears to be the most serious. They remark, however, that this approach "seems to describe well enough the essential features of the growth towards stationary states of the very few natural populations for which suitable data are available." For this reason 'it will be adopted in what follows.