Chapter 56, Problem 1TY

Summary Introduction

Introduction: Mark-recapture technique is used to estimate the population size. This method was used by the researchers involved in population biology. These researchers used to capture animals, tag these animals, and release them afterward. Tagged animals can mix easily with unmarked individuals and form the part of the population.

Answer to Problem 1TY

Correct answer: The estimated population size as per the data given will be 348.75 (that is 349). The formula for calculating marked recapture technique was used to calculate the estimated population size. Hence, the correct answer is option b.

Explanation of Solution

Reason for correct answer:

$\text{Total}\text{population}\text{size(N)=}\frac{\text{Number}\text{of}\text{marked}\text{individuals}\text{in}\text{first}\text{catch×Total}\text{number}\text{of}\text{second}\text{catch}}{\text{Number}\text{of}\text{marked}\text{recaptures}\text{in}\text{second}\text{catch}}$

According to this formula, estimated population size can be calculated with marked recapture technique. The student in the first catch was able to mark 45 individuals. In his second capture after 2 week, he was able to capture 62 individuals. Out of 62 individuals, 8 were marked. By substituting the data in the formula, the estimated population size can be obtained:

$\begin{array}{c}N=\frac{45\times 62}{8}\\ =\frac{2790}{8}\\ =349\end{array}$

Option b is given as “349”.

According to the data provided, the estimated population size of mosquito fish would be 349. Hence, the correct answer is option b.

Reasons for the incorrect answer:

Option a. is given as, “134”.

According to the data provided and the formula for calculating the estimated population size, the average population size of mosquito fish cannot be 134. The correct population size is 349. Hence option a. is incorrect.

Option c. is given as “558”.

According to the formula for calculating the estimated population size of mosquito fish and the data provided, the estimated population size cannot be 558. Hence, option c. is incorrect.

Option d. is given as, “1016”.

The estimated population size of the mosquito fish cannot be 1016 according to the data provided and calculations done. Hence, option d. is incorrect.

Option e. is given as; “22320”.

According to the formula for calculating the estimated population size of mosquito fish and the data provided, the estimated population size cannot be 22,320. Hence, option e. is incorrect.

Hence, the options a., c., d., and e. are incorrect.

Conclusion

The average estimated size of mosquito fish population based on the data provided is 349.