Question

Roselin had an aquarium at her home with 10 fish in it. In a year, a fish gave birth to 7 fish. During this period, 3 adult fish had died. Roselin’s father purchased 2 more pairs of fish from market for the aquarium. Later, Roselin gifted 4 fish from the aquarium to her friend.

Find out the growth rate of fish in Roselin’s aquarium.

Answer 1

Growth rate (r) = `"Net increase in population" /"Initial population"`

Initial population (N) = 10

Births = 7. Deaths = 3

Immigration (purchased) = 2 pairs = 4 fish

Emigration (gifted) = 4 fish

Net Change (∆N) = (7 + 4) − (3 + 4)

= 11 − 7 = 4

Growth Rate = `4/10` = 0.4 per fish per year.