Question

I'm having trouble on how to find the population change and pop. growth of the Zebra Mussels in this question.

Three years ago, a 5 km³ section of the Great Lakes was studied and approximately 89 000 zebra mussel colonies were found. Each colony produced 120 colonies over a three-year period.

However, only 2% of the new colonies survived past the first year. Over the three years, there were 97 000 dead colonies that were washed ashore in the Great Lakes. Many of the zebra mussels attach themselves to hard surfaces, such as boats and trailers.

It was estimated that approximately 85 000 colonies attached themselves to boats and left the area. Many of these zebra mussels died, but some managed to hitchhike on boat equipment and enter other waterbodies. Negligible numbers of zebra mussels migrated from other lakes.

Calculate the change in population size and growth rate. (ΔN = (Natality + Immigration) - (Mortality + Emigration))?

Answer 1

According to question,

Initial number of colonies= 89000

First we have to calculate growth rate (r)

Therefore,