Calculating Mortality Rates and Survival Rate of Walleye Population
How can we calculate the actual survival rate, actual total mortality rate, and total instantaneous mortality rate for a population of Walleye?
A. What is the survival rate, actual total mortality rate, and total instantaneous mortality rate for a population of Walleye based on the provided data?
B. If the mortality rate remains constant, how many Walleye will be alive after 3 years if we start with 10,000 Age-0 Walleye?
C. Assuming the mortality rate stays constant, how many Walleye will be alive after 4.5 years when starting with 10,000 Age-0 Walleye?
Answer:
To calculate the survival rate, total mortality rate, and total instantaneous mortality rate for a population of Walleye, we need to analyze the data provided.
To find the survival rate, we can subtract the number of Age-3 Walleye caught the following year from the number of Age-3 Walleye caught in the initial year and then divide by the initial number of Age-3 Walleye.
The survival rate is calculated as follows:
(36 - 42) / 36 = -6/36 = -1/6
The actual total mortality rate is the negative of the survival rate, which equals 1/6.
To determine the total instantaneous mortality rate, we divide the total mortality rate by the number of trap nets and the duration they were set for:
Total Instantaneous Mortality Rate = 1/6 / (6 nets * 24 hours) = 1/144
Calculation for B:
If the mortality rate remains constant and we start with 10,000 Age-0 Walleye, the number of Walleye alive after 3 years can be determined by:
10,000 * (1 - 1/6)^3
Calculation for C:
Similarly, if we want to calculate the number of Walleye alive after 4.5 years, we use the same formula but with 4.5 years instead of 3:
10,000 * (1 - 1/6)^4.5